JP7540179B2 - Sewing equipment - Google Patents

Description

The present invention relates to a sewing device.

A conventional sewing device has a presser foot that presses down on the fabric near the stitch formation position. The presser foot is attached to the lower end of a presser bar, which can move between a raised position where the presser foot releases the fabric and a presser position where the fabric is pressed down. When the presser foot moves, the distance between a part of the presser bar and a reference changes steadily. A position sensor detects the position of the presser foot at the presser position. The sewing device sets the sewing conditions of the sewing device according to the fabric thickness based on the output value of the position sensor.

JP 2007-007391 A

The sewing device automatically calculates the sewing conditions for the sewing device depending on the thickness of the fabric and performs sewing. Even when sewing a material with a fabric thickness that the operator did not intend, the sewing device automatically sets the sewing conditions depending on the fabric thickness, so the operator does not realize that he or she is sewing a material with a fabric thickness that he or she did not intend.

The present invention aims to provide a sewing device that improves the convenience of the operator when sewing according to the thickness of the material to be sewn.

The sewing device of claim 1 of the present invention includes a needle plate on which a sewing object is placed, a needle bar that extends vertically and has a sewing needle attached to its lower end, a needle bar mechanism that moves the needle bar up and down, a main shaft motor that drives the needle bar mechanism, a presser bar that can have a presser foot attached to its lower end and presses the sewing object placed on the needle plate from above with the presser foot, and a detection unit that detects the detected thickness, which is the thickness of the sewing object pressed by the presser foot, and includes an acquisition unit that acquires a reference thickness, which is the thickness of one or more sewing objects that serve as a reference, a comparison unit that compares the detected thickness with the reference thickness, and a notification control unit that notifies the comparison result of the comparison unit. The sewing device notifies the comparison result between the detected thickness and the reference thickness. The operator can refer to the comparison result notified by the sewing device and can check whether the sewing object placed on the needle plate and pressed by the presser foot is the sewing object intended by the operator based on the comparison result. This allows the sewing device to be more convenient for the operator than ever before when sewing according to the thickness of the material being sewn.

The sewing device of claim 2 of the present invention further includes a warning threshold acquisition unit that acquires a warning threshold used to compare the difference between the detected thickness and the reference thickness, and the notification control unit issues a warning when the difference between the reference thickness and the detected thickness is equal to or greater than the warning threshold. By appropriately setting the warning threshold, the sewing device can notify the operator that a sewing material of an unintended thickness has been placed on the needle plate. By referring to the warning, the operator can avoid, for example, sewing on an unintended sewing material.

The sewing device of claim 3 of the present invention further comprises a change threshold acquisition unit that acquires a change threshold smaller than the warning threshold, and a condition change unit that changes the sewing conditions according to the detected thickness when the difference between the reference thickness and the detected thickness is smaller than the warning threshold and equal to or greater than the change threshold. By appropriately setting the warning threshold and change threshold, the sewing device can automatically change the sewing conditions according to the detected thickness when the difference between the reference thickness and the detected thickness is not large enough for an operator to issue a warning, but is not suitable for sewing under the sewing conditions set according to the reference thickness. The sewing device can save the operator the trouble of changing the sewing conditions while sewing.

The sewing device of claim 4 of the present invention further includes an effective threshold acquisition unit that acquires an effective threshold smaller than the warning threshold, and an effective setting unit that activates a penetration force improvement function that improves the penetration force of the sewing needle through the sewn material by driving the main shaft motor with a current pattern different from that when sewing the sewn material of the reference thickness when the difference between the reference thickness and the detected thickness is smaller than the warning threshold and the value obtained by subtracting the reference thickness from the detected thickness is equal to or greater than the effective threshold. By appropriately setting the warning threshold and effective threshold, the sewing device can automatically activate the penetration force improvement function when the difference between the reference thickness and the detected thickness is not so large that the operator stops sewing, but the sewing needle has difficulty penetrating the sewn material when sewing under sewing conditions set according to the reference thickness. The sewing device can save the operator the trouble of activating the penetration force improvement function while sewing.

The sewing device of claim 5 of the present invention further includes a sewing stop unit that stops the drive of the main shaft motor when the difference between the reference thickness and the detected thickness acquired while the main shaft motor is driven is equal to or greater than the warning threshold. By appropriately setting the warning threshold, the sewing device can prevent the operator from continuing to sew a material of an unintended thickness.

The detection unit of the sewing device of the sixth aspect of the present invention detects the detected thickness before the main shaft motor starts to drive, and the notification control unit notifies the comparison result between the reference thickness and the detected thickness detected before the main shaft motor starts to drive. The operator can refer to the comparison result notified by the sewing device , and based on the comparison result, can check before sewing whether the workpiece placed on the needle plate and held down by the presser foot is the workpiece intended by the operator. Therefore, the sewing device can further improve the convenience for the operator when sewing according to the thickness of the workpiece compared to the conventional method.

The detection unit of the sewing device of claim 7 of the present invention detects the detected thickness while the main shaft motor is driven, and the notification control unit issues a warning when the detected thickness changes while the main shaft motor is driven. When the detected thickness changes while the main shaft motor is driven, the sewing device can notify the operator by issuing a notification. The operator can refer to the notification from the sewing device and take appropriate action depending on whether the change in detected thickness is intended by the operator or not.

The detection unit of the sewing device of claim 8 of the present invention further includes a condition change unit that detects the detected thickness while the main shaft motor is driven, and changes the sewing conditions in response to the detected thickness when the detected thickness changes while the main shaft motor is driven. When the detected thickness changes while the main shaft motor is driven, the sewing device can automatically change the sewing conditions in response to the detected thickness. The sewing device can save the operator the trouble of changing the sewing conditions during sewing.

The detection unit of the sewing device of claim 9 of the present invention detects the detected thickness while the main shaft motor is driven, and the notification control unit notifies the sewing workpiece that is not between the needle plate and the presser foot when the detected thickness detected while the main shaft motor is driven is smaller than a predetermined value, and further includes a sewing stop unit that stops the drive of the main shaft motor when the detected thickness detected while the main shaft motor is driven is smaller than the predetermined value. The sewing device can notify the sewing workpiece that is not between the needle plate and the presser foot and stop the drive of the main shaft motor. The sewing device can avoid the continued drive of the main shaft motor after sewing to the edge of the sewing workpiece.

The sewing device of claim 10 of the present invention further includes a warning threshold acquisition unit that acquires a warning threshold used to compare the difference between the detected thickness and the reference thickness, the acquisition unit acquires the reference thickness in a set order while the main shaft motor is driven, the comparison unit compares the detected thickness with the next reference thickness in the set order when the detected thickness detected while the main shaft motor is driven changes, and the notification control unit issues a warning when the difference between the detected thickness and the next reference thickness in the set order is equal to or greater than the warning threshold. When sewing a sewing material whose thickness changes during sewing, the sewing device can avoid detecting a portion where the thickness changes as an abnormality. When detecting a change in the detected thickness, the sewing device compares the detected thickness with the next reference thickness in the set order, so that the standard thickness and the detected thickness can be appropriately compared even when sewing a sewing material whose thickness changes during sewing.

The sewing device of claim 11 of the present invention further includes a memory unit that stores a plurality of combinations of the reference thickness and the set order while the main shaft motor is driven, and the acquisition unit acquires the plurality of combinations stored in the memory unit in the set order. When sewing a sewing material whose thickness changes during sewing, the sewing device can avoid detecting a portion where the thickness changes as an abnormality. When the sewing device detects a change in the detected thickness, it compares the detected thickness with the next reference thickness in the set order, so that the reference thickness can be appropriately compared with the detected thickness even when sewing a sewing material whose thickness changes during sewing.

The sewing device of claim 12 of the present invention further includes a memory control unit that sets the detected thickness detected by the detection unit as the reference thickness and stores multiple combinations of the reference thickness and the set order in the memory unit. The sewing device can store multiple combinations of the reference thickness and the set order in the memory unit, with the detected thickness detected by the detection unit as the reference thickness. The sewing device can reduce the influence of the mounting tolerance of the detection unit on the sewing device compared to a device that obtains combinations of the reference thickness and the set order from another device.

FIG. FIG. 2 is a perspective view of a portion of the internal structure of the sewing device 1. FIG. 1A is a left side view of a portion of the internal structure of the sewing device 1 when the presser mechanism 44 is in the needle down position, and FIG. 1B is a left side view of a portion of the internal structure of the sewing device 1 when the presser mechanism 44 is in the needle up position. FIG. 2 is a block diagram of an electrical configuration of the sewing device 1. Flow diagram of sewing process. 1 is a flow diagram of a setting process. 11 is a flowchart of a pre-sewing detection process. 11 is a flowchart of a process for detecting during sewing. 1A is an explanatory diagram of the thickness of a workpiece W1 in a first specific example, and FIG. 1B is an explanatory diagram of a workpiece W2 in a second specific example.

The physical configuration of the sewing device 1 of the present invention will be described. In the following description, the left and right, front and back, and up and down are indicated by arrows in the figure. As shown in Figures 1 and 2, the sewing device 1 is an integrated feed sewing machine, and includes a bed section 2, a leg column section 3, an arm section 4, and a head section 5. The bed section 2 has a needle plate 14 on its upper surface, and houses a shuttle mechanism, a feed mechanism 36, and a feed amount adjustment mechanism 37. The shuttle mechanism is driven by the rotation of the lower shaft 40, and entangles the upper thread and the lower thread below the needle plate 14. The lower shaft 40 rotates in synchronization with the main shaft 31 by a belt 35 stretched between the main shaft 31 and the lower shaft 40. The feed mechanism 36 includes an upper and lower feed shaft 38, an eccentric link 69 (see Figure 4), an eccentric rod (not shown), a converter 66, a horizontal feed shaft 39, a link mechanism 53, and a feed dog 17, and drives the feed dog 17 in synchronization with the rotation of the lower shaft 40 to move the sewn material in the conveying direction at a predetermined feed amount. The conveying direction is backward or forward. The lower shaft 40, the vertical feed shaft 38, and the horizontal feed shaft 39 extend in the left-right direction. The vertical feed shaft 38 is in front of the horizontal feed shaft 39. The vertical feed shaft 38 is connected to the lower shaft 40 via an eccentric link 69 that is eccentric with respect to the axis of the lower shaft 40. The eccentric rod is eccentrically provided on the lower shaft 40 to the right of the eccentric link 69. The converter 66 is connected to the rear end of the eccentric rod eccentrically provided on the lower shaft 40, and transmits the rotation of the lower shaft 40 due to the rotation of the main shaft 31 to the horizontal feed shaft 39. The left end of the vertical feed shaft 38 and the left end of the horizontal feed shaft 39 are connected to the feed dog 17 via a link mechanism 53. The feed amount adjustment mechanism 37 includes a feed amount adjustment motor 24, an intermediate shaft 28, a converter 66, a cam lever 67, a cam disc 65, and the horizontal feed shaft 39. The intermediate shaft 28 extends in the left-right direction and is connected to the horizontal feed shaft 39 via a converter 66. The right end of the intermediate shaft 28 has a cam lever 67, which contacts a cam disk 65 provided on the output shaft of the feed adjustment motor 24. The feed adjustment motor 24 is a pulse motor. The feed adjustment motor 24 rotates the output shaft to change the rotation amount of the horizontal feed shaft 39 via the cam disk 65, cam lever 67, intermediate shaft 28, and converter 66, thereby adjusting the feed amount in the front-rear direction of the sewing workpiece by the feed mechanism 36. When the lower shaft 40 rotates in synchronization with the rotation of the main shaft 31, the vertical feed shaft 38 and the horizontal feed shaft 39 swing, and the feed dog 17 rotates in an elliptical trajectory counterclockwise or clockwise when viewed from the left side.

The leg column 3 extends upward from the right end of the bed 2 and houses the main shaft motor 21, presser motor 22, belt 35, and drive link 41. The main shaft motor 21 rotates the main shaft 31. The presser motor 22 is a pulse motor located to the left and rear of the main shaft motor 21, and adjusts the downward pressure applied to the workpiece by the presser foot 11 attached to the lower end of the presser bar 10. The presser motor 22 can also move the presser foot 11 up and down. The drive link 41 is connected to the horizontal feed shaft 39 and the needle bar swing shaft 42.

The arm 4 extends leftward from the upper end of the column 3. The arm 4 has a display 15, input units 16 and 19, and a thread tension controller 13 on its front side. The display 15 is a liquid crystal display that displays images, and the input unit 16 is a touch panel provided on the front side of the display 15, and can input various instructions to the control unit 90. The input unit 19 is provided to the right of the display 15 and is a switch that inputs various instructions to the control unit 90. The thread tension controller 13 has a thread tension solenoid 25 (see Figure 5), and applies a predetermined tension to the upper thread by driving the thread tension solenoid 25. The arm 4 houses the thread tension solenoid 25, the alternating lift amount adjustment motor 23, the main shaft 31, the presser shaft 26, the needle bar swing shaft 42, the intermediate shaft 27, the swing shaft 45, and the alternating lift amount adjustment mechanism 50. The tension solenoid 25 is a proportional solenoid, and the sewing device 1 can adjust the tension applied to the needle thread by adjusting the drive voltage supplied to the tension solenoid 25. The alternating lift amount adjustment motor 23 is a pulse motor provided to the left of the main shaft motor 21 and the presser motor 22. The main shaft 31, the presser shaft 26, the needle bar swing shaft 42, the intermediate shaft 27, and the swing shaft 45 extend in the left-right direction. The right end of the main shaft 31 is connected to the main shaft motor 21, and the left end is connected to the needle bar mechanism 32. The presser shaft 26 is located behind the main shaft 31, and has a sector gear 64 at its right end. The sector gear 64 meshes with a pinion 61 provided on the output shaft of the presser motor 22, and rotates when the presser motor 22 is driven. Therefore, the presser shaft 26 rotates when the presser motor 22 is driven. The left end of the presser shaft 26 is connected to the presser mechanism 44. The right end of the needle bar swing shaft 42 is connected to the drive link 41, and the left end is connected to the swing mechanism 34. The alternating lift amount adjustment mechanism 50 includes an alternating lift amount adjustment motor 23, a cam mechanism 62, an intermediate shaft 27, a converter 63, and a swing shaft 45. The output shaft of the alternating lift amount adjustment motor 23 is connected to the intermediate shaft 27 via the cam mechanism 62. The intermediate shaft 27 is connected to the swing shaft 45 via the converter 63. The alternating lift amount adjustment motor 23 rotates the output shaft to change the swing amount of the swing shaft 45 via the cam mechanism 62, the intermediate shaft 27, and the converter 63, thereby adjusting the alternating lift amount. The alternating lift amount is the amount of lift from the needle plate 14 when the middle presser bar 8 and the outer presser bar 10 move up and down alternately in synchronization with the rotation of the main shaft 31.

The head 5 is mounted on the left end of the arm 4, and has a thread take-up lever 12 mounted in front of it. The thread take-up lever 12 pulls up the upper thread and knots it with the lower thread. The head 5 houses a needle bar mechanism 32, a thread take-up lever mechanism 33, a presser foot mechanism 44, a swing mechanism 34, and a detector 49. The needle bar mechanism 32 is connected to the main shaft 31, and moves the needle bar 6 up and down. The thread take-up lever mechanism 33 moves the thread take-up lever 12 up and down in sync with the rotation of the main shaft 31.

The presser mechanism 44 is connected to the left end of the presser shaft 26, and includes an outer presser bar 10, a middle presser bar 8, a swing shaft 45, links 46, 47, 70, a triangular lever 48, a biasing member 51, an adjustment member 52, a converter 63, and an eccentric rod 68. The outer presser bar 10 extends vertically, and the outer presser foot 11 can be attached and detached to its lower end. The middle presser bar 8 extends vertically in front of the outer presser bar 10. The middle presser foot 9 can be attached and detached to its lower end. The left end of the swing shaft 45 is connected to a link 46 extending vertically. The lower end of the link 46 is connected to the rear end of a link 47 extending in the front-rear direction. The triangular lever 48 is triangular plate-shaped when viewed from the left side, and one of the three corners is connected to the front end of the link 47. Of the three corners of the triangular lever 48, the remaining two are connected to the outer presser bar 10 and the link 70. One end of the link 70 is connected to the triangular lever 48, and the other end is connected to the middle presser bar 8. The biasing member 51 is a coil-shaped compression spring that is inserted around the outer presser bar 10 and presses the outer presser bar 10 downward. The adjustment member 52 is cylindrical, and the biasing member 51 is inserted inside it, allowing it to move up and down. The adjustment member 52 moves up and down by the drive of the presser motor 22, and adjusts the downward pressure applied by the biasing member 51 to the outer presser bar 10. The converter 63 is connected to the rear end of an eccentric rod 68 provided eccentrically on the main shaft 31, and transmits the rotation of the main shaft 31 by the drive of the main shaft motor 21 to the swing shaft 45, swinging the swing shaft 45. When the swing shaft 45 swings due to the rotation of the main shaft 31, the link 46 swings around the swing shaft 45. The link 47 moves forward and backward in response to the swing of the link 46, and moves the outer presser bar 10 and the middle presser bar 8 up and down via the triangular lever 48. As shown in FIG. 4(A), when the link 47 moves forward, the outer presser bar 10 rises and the middle presser bar 8 falls. As shown in FIG. 4(B), when the link 47 moves backward, the outer presser bar 10 falls and the middle presser bar 8 rises. The presser mechanism 44 moves the outer presser bar 10 and the middle presser bar 8 up and down in opposite phases, that is, alternately, in synchronization with the rotation of the main shaft 31, and the outer presser foot 11 and the middle presser foot 9 alternately press the sewing material from above toward the needle plate 14.

The swing mechanism 34 is connected to the needle bar swing shaft 42, and swings the needle bar 6 and the intermediate presser bar 8 in the transport direction of the workpiece in synchronization with the rotation of the main shaft 31 by an amount corresponding to the swing amount of the needle bar swing shaft 42. As shown in FIG. 4(A), the presser mechanism 44 is said to be in the needle down position when the lower end of the sewing needle 7 is below the needle plate 14, the presser foot 11 is in a position above the needle plate 14, and the intermediate presser foot 9 is in a position close to the feed dog 17. While the presser mechanism 44 is in the needle down position, the sewing device 1 swings the needle bar 6, the intermediate presser bar 8, and the feed dog 17 backwards with the sewing needle 7 stuck in the workpiece. As shown in FIG. 4(B), when the lower end of the sewing needle 7 is above the needle plate 14, the outer presser foot 11 is in a position close to the needle plate 14, and the middle presser foot 9 is in a position above the needle plate 14, the presser mechanism 44 is said to be in the needle up position. While the presser mechanism 44 is in the needle up position, the sewing device 1 swings the needle bar 6, the middle presser bar 8, and the feed dog 17 forward with the sewing needle 7 not pierced into the material being sewn.

The detector 49 outputs the detection result according to the thickness of the material to be sewn to the control unit 90. The detector 49 is, for example, a magnetic sensor provided in the head 5, and detects the vertical position of a magnetic body 71 provided in a presser bar holder 60 that supports the outer presser bar 10 so that it can move up and down. The sewing device 1 is equipped with a needle bar 6, an outer presser bar 10, and an inner presser bar 8, which move up and down when driven by the main shaft motor 21, at the bottom of the head 5. The needle bar 6 extends up and down in front of the inner presser bar 8, and a sewing needle 7 can be attached and detached to its lower end. The thread spool supplies the upper thread to the eye of the sewing needle 7.

The electrical configuration of the sewing device 1 will be described with reference to FIG. 5. The control unit 90 of the sewing device 1 has a CPU 91, a ROM 92, a RAM 93, a storage device 94, an input/output interface (I/O) 95, and drive circuits 81 to 86. The CPU 91 controls the overall operation of the sewing device 1. The ROM 92 stores programs and the like for executing various processes in advance. The RAM 93 temporarily stores various information generated during the execution of various processes. The storage device 94 is non-volatile and stores various set values. The storage device 94 stores a number table 96, a setting table 97, and a threshold table 98. The number table 96 stores the correspondence between the reference thickness, the number of sheets, the feed amount, the thread tension, the presser foot pressure, the alternating rise amount, and the number of rotations. The reference thickness is the reference thickness of the sewn material that is stacked by the number of sheets indicated by the number of sheets. The feed amount is the amount that the feed mechanism 36 transports the sewn material during one rotation of the main shaft 31, and is adjusted by driving the feed amount adjustment motor 24. The thread tension is an amount indicating the tension applied to the upper thread, and is adjusted by driving the thread tension solenoid 25. The presser foot pressure is an amount corresponding to the downward pressure applied to the sewing workpiece by the outer presser foot 11 attached to the lower end of the outer presser bar 10, and is adjusted by driving the presser motor 22. The alternating lift amount is an amount corresponding to the height from the needle plate 14 when the presser mechanism 44 alternately moves the outer presser bar 10 and the inner presser bar 8 up and down, and is adjusted by driving the alternating lift amount adjustment motor 23. The rotation speed is the rotation speed of the output shaft of the main shaft motor 21. The setting table 97 stores the correspondence between the setting order and the reference thickness. The setting order corresponds to the order in which the sewing workpiece of the reference thickness is sewn. The threshold table 98 stores various threshold values. The tables 96 to 98 may be stored in a peripheral device connected to the sewing device 1, another sewing device 1, or in the cloud. The tables 96 to 98 may be viewed, changed, and set using the sewing device 1, a PC connected to the sewing device 1, a smartphone, or other device.

Each drive circuit 81 to 86 is connected to the I/O 95. Drive circuit 81 is connected to the spindle motor 21 and drives the spindle motor 21 according to control commands from the CPU 91. Drive circuit 82 is connected to the feed amount adjustment motor 24 and drives the feed amount adjustment motor 24 according to control commands from the CPU 91. Drive circuit 83 is connected to the alternating lift amount adjustment motor 23 and drives the alternating lift amount adjustment motor 23 according to control commands from the CPU 91. Drive circuit 84 is connected to the presser motor 22 and drives the presser motor 22 according to control commands from the CPU 91. Drive circuit 85 is connected to the thread tension solenoid 25 and drives the thread tension solenoid 25 according to control commands from the CPU 91. Drive circuit 86 is connected to the display unit 15 and drives the display unit 15 according to control commands from the CPU 91.

Encoders 56-59, input units 16 and 19, pedal 18, and detector 49 are connected to I/O 95. Encoder 56 detects the rotational position and rotational speed of main shaft 31 connected to the output shaft of main shaft motor 21, and inputs the detection result to I/O 95. Encoder 57 detects the rotational position and rotational speed of the output shaft of feed amount adjustment motor 24, and inputs the detection result to I/O 95. Encoder 58 detects the rotational position and rotational speed of the output shaft of alternating lift amount adjustment motor 23, and inputs the detection result to I/O 95. Encoder 59 detects the rotational position and rotational speed of the output shaft of presser motor 22, and inputs the detection result to I/O 95. Input units 16 and 19 detect various instructions, and input the detection result to I/O 95. Pedal 18 detects the operation direction and operation amount of pedal 18, and inputs the detection result to I/O 95. Detector 49 inputs the detection result according to the thickness of the sewing workpiece to I/O 95.

With reference to Figs. 6 to 10, the sewing process will be described using two specific examples shown in Figs. 10(A) and 10(B). The CPU 91 compares the detection result of the detector 49 with the reference thickness stored in the memory device 94 during the sewing process, and performs processing according to the comparison result. The first specific example in Fig. 10(A) is an example in which the number of the sewn workpieces W1 changes from two to three to four in sequence during sewing. When the CPU 91 detects a change in the detected thickness during sewing in the sewing process of the first specific example, it reads out the next reference thickness in the setting order among the reference thicknesses stored in the setting table 97, and performs processing to compare the detected thickness with the reference thickness. The detected thickness is the thickness of the sewn workpiece held down by the presser foot 11, detected by the detector 49. The second specific example in Fig. 10(B) is an example in which the number of the sewn workpieces W2 does not change during sewing, but the thickness of the sewn workpieces W2 changes. In the sewing process of the second specific example, the CPU 91 executes processing to compare the detected thickness with the reference thickness using the detected thickness or a reference thickness according to the sewing conditions being set. The sewing process starts when the sewing device 1 is powered on. The CPU 91 reads the sewing process program from the ROM 92 into the RAM 93 and executes the sewing process. The sewing processes of the two specific examples are performed at different times, but to simplify the explanation, the sewing processes of the two specific examples will be explained in parallel.

As shown in FIG. 6, the CPU 91 performs an initialization process (S1). The CPU 91 determines whether a sewing instruction has been detected based on the detection result of the input unit 16 (S2). When sewing with the sewing device 1, the operator operates the input unit 16 to input a sewing instruction. When a sewing instruction has not been detected (S2: NO), the CPU 91 determines whether a setting instruction has been detected based on the detection result of the input unit 16 (S5). When the operator sets at least one of the number table 96, the setting table 97, and the threshold table 98, the operator operates the input unit 16 to input a setting instruction. When a setting instruction has not been detected (S5: NO), the CPU 91 performs S14. When a setting instruction has been detected (S5: YES), the CPU 91 performs a setting process (S6). In the setting process, the CPU 91 sets the number table 96, the setting table 97, and the threshold table 98 in accordance with the operator's instructions. The worker operates the input unit 16 to input instructions to set either the number table 96, the setting table 97, or the threshold table 98.

7, in the setting process, the CPU 91 judges whether or not an instruction to set the number table 96 has been detected based on the detection result of the input unit 16 (S21). The thickness of the sewing material detected by the detector 49 increases as the number of overlapping sewing materials increases. For example, when the operator wants to store the correspondence between the thickness of the sewing material detected by the detector 49 and the number of overlapping sewing materials in the number table 96, the operator inputs an instruction to set the number table 96. When an instruction to set the number table 96 is detected (S21: YES), the CPU 91 judges whether or not the presser mechanism 44 is in the needle up position based on the detection result of the input unit 16 (S22). When the presser mechanism 44 is in the needle up position, the presser bar 10 to which the presser foot 11 is attached is in a lowered position close to the needle plate 14. The operator places one or a predetermined number of reference sewing objects on the needle plate 14, places the presser mechanism 44 in the needle up position, and operates the input unit 16 to input a signal indicating that the presser mechanism 44 has been placed in the needle up position. The CPU 91 continues the determination in S22 until it detects that the presser mechanism 44 is in the needle up position (S22: NO). When it detects that the presser mechanism 44 is in the needle up position (S22: YES), the CPU 91 sets the detected thickness, which is the detection result of the detector 49, as the reference thickness (S23). The CPU 91 acquires the number of sewing objects designated by the operator based on the detection result of the input unit 16 (S24). The CPU 91 stores the reference thickness set in S23 and the number acquired in S24 in the number table 96 in association with each other (S25). The detected thickness detected in S23 changes depending on the setting of the sewing device 1 at the time of detection, so the CPU 91 may store the setting of the sewing device 1 at the time of detection in association with the reference thickness and the number of pieces. The CPU 91 determines whether an instruction to end the setting of the number table 96 has been detected based on the detection result of the input unit 16 (S26). If an instruction to end the setting of the number table 96 has not been detected (S26: NO), the CPU 91 returns the process to S22. If an instruction to end the setting of the number table 96 has been detected (S26: YES), the CPU 91 performs the process of S48.

When an instruction to set the number table 96 is not detected (S21: NO), the CPU 91 judges whether an instruction to set the setting table 97 is detected based on the detection result of the input unit 16 (S31). For example, when the operator is about to sew a sewing material in which the number of sewing materials changes during sewing or the thickness of the sewing material changes, the operator operates the input unit 16 to input an instruction to set the setting table 97. When an instruction to set the setting table 97 is detected (S31: YES), the CPU 91 sets the variable N indicating the setting order to 0 (S32). The CPU 91 adds one to the variable N to update it (S33). The CPU 91 judges whether the presser mechanism 44 is in the needle up position as in S22 (S34), and continues the judgment of S34 until it detects that the presser mechanism 44 is in the needle up position (S34: NO). When it is detected that the presser mechanism 44 is in the needle up position (S34: YES), the CPU 91 sets the detected thickness, which is the detection result of the detector 49, to the reference thickness (S35). The CPU 91 sets the variable N to the setting order, and stores the correspondence between the setting order and the reference thickness set in S35 in the setting table 97 (S36). The CPU 91 determines whether or not an instruction to end the setting of the setting table 97 has been detected based on the detection result of the input unit 16 (S37). If an instruction to end the setting of the setting table 97 has not been detected (S37: NO), the CPU 91 returns the process to S33. If an instruction to end the setting of the setting table 97 has been detected (S37: YES), the CPU 91 performs the process of S48.

When an instruction to set the setting table 97 is not detected (S31: NO), the CPU 91 determines whether an instruction to set the threshold table 98 is detected based on the detection result of the input unit 16 (S41). When an instruction to set the threshold table 98 is not detected (S41: NO), the CPU 91 performs S48. When an instruction to set the threshold table 98 is detected (S41: YES), the CPU 91 determines whether an instruction to set the warning threshold is detected based on the detection result of the input unit 16 (S42). The warning threshold is used in a process to determine whether to issue a warning depending on the comparison result between the thickness of the sewing material detected by the detector 49 before or during sewing and the reference thickness. When an instruction to set the warning threshold is detected (S42: YES), the CPU 91 sets the warning threshold based on the detection result of the input unit 16 and stores the warning threshold in the threshold table 98 (S43). When an instruction to set a warning threshold is not detected (S42: NO), or after S43, the CPU 91 determines whether an instruction to set a change threshold has been detected based on the detection result of the input unit 16 (S44). The change threshold is used in the process of determining whether to change the sewing conditions depending on the result of comparing the thickness of the sewing work detected by the detector 49 before or during sewing with the reference thickness. When an instruction to set a change threshold is detected (S44: YES), the CPU 91 sets the change threshold based on the detection result of the input unit 16, and stores the change threshold in the threshold table 98 (S45).

When an instruction to set the change threshold is not detected (S44: NO) or after S45, the CPU 91 judges whether an instruction to set the effective threshold is detected based on the detection result of the input unit 16 (S46). The effective threshold is used in the process of judging whether the penetration force improvement function is set to be effective depending on the result of comparing the thickness of the sewn material detected by the detector 49 with the reference thickness before or during sewing. The CPU 91 in this example improves the penetration force of the sewing needle 7 through the sewn material by driving the main shaft motor 21 with a specific current pattern different from that when sewing a sewn material of the reference thickness. The specific current pattern may appropriately adopt a known current pattern, and may include, for example, current supply that supplies a current larger than the current supplied to the main shaft motor 21 when the rotation speed of the main shaft motor 21 is higher than a predetermined rotation speed for a period longer than the period from when the sewing needle 7 stops to when the main shaft motor 21 starts to move forward due to the start of current supply to the main shaft motor 21, and current cut-off that cuts off the supply of current for a predetermined time after current supply. The specific current pattern may be one in which the rotation direction of the spindle motor 21 is reversed at a predetermined interval, for example, within a range in which the sewing needle 7 does not reach the top dead center or bottom dead center at which the sewing needle 7 reverses its direction of movement.

When an instruction to set the effective threshold is detected (S46: YES), the CPU 91 sets the effective threshold based on the detection result of the input unit 16 and stores it in the threshold table 98 (S47). When an instruction to set the effective threshold is not detected (S46: NO), or after S47, the CPU 91 determines whether an instruction to end the setting process is detected based on the detection result of the input unit 16 (S48). When an instruction to end the setting process is not detected (S48: NO), the CPU 91 returns the process to S21. When an instruction to end the setting process is detected (S48: YES), the CPU 91 ends the setting process and returns the process to the sewing process in FIG. 6.

When a setting instruction is not detected (S5: NO) or after S6, the CPU 91 performs the process of S14. When a sewing instruction is detected (S2: YES), the CPU 91 judges whether the presser mechanism 44 is in the needle up position (S3) as in S22, and continues the judgment of S3 until it detects that the presser mechanism 44 is in the needle up position (S3: NO). When it detects that the presser mechanism 44 is in the needle up position (S3: YES), the CPU 91 performs a pre-sewing detection process (S4). In the pre-sewing detection process, the CPU 91 performs a process according to the result of comparing the detected thickness of the sewn material based on the detection result of the detector 49 before sewing starts with the reference thickness stored in the memory device 94.

8, the CPU 91 detects the detection result of the detector 49 as the detected thickness and stores it in the RAM 93 (S51). The CPU 91 detects the detected thickness T11 for the sewing workpiece W1 in the first specific example and stores it in the RAM 93. The CPU 91 detects the detected thickness T21 for the sewing workpiece W2 in the second specific example and stores it in the RAM 93. The CPU 91 acquires the reference thickness (S62). In the first specific example, the CPU 91 acquires the reference thickness T2 for the setting order of 1. In the second specific example, the CPU 91 acquires the reference thickness T2 when the number of sheets closest to the detected thickness T21 detected in S51 is two sheets among the reference thicknesses stored in the sheet number table 96. The CPU 91 compares the detected thickness acquired in S51 with the reference thickness acquired in S62 (S63). The method of comparing the detected thickness with the reference thickness may be set appropriately. In this example, the CPU 91 calculates the difference obtained by subtracting the reference thickness acquired in S62 from the detected thickness acquired in S51. For example, the CPU 91 may compare the detected thickness with a reference thickness and calculate the number of the sewing objects placed on the needle plate 14. For example, the CPU 91 may calculate the thickness of the sewing object by subtracting the detected thickness when the needle plate 14 contacts the presser foot 11 from the detected thickness when the sewing object placed on the needle plate 14 is pressed by the presser foot 11. The CPU 91 refers to the threshold table 98 and acquires the warning threshold H1 (S64). The CPU 91 may acquire the warning threshold H1 stored in the threshold table 98 of the storage device 94, may acquire the warning threshold H1 input by the operator based on the detection result of the input unit 16, or may acquire the warning threshold H1 from another device (for example, another sewing device). The CPU 91 judges whether the absolute value of the difference calculated in S63 is equal to or greater than the warning threshold H1 acquired in S64 (S65). When the absolute value of the difference is equal to or greater than the warning threshold H1 (S65: YES), the CPU 91 issues a warning (S66). The CPU 91 displays, for example, an error message "abnormal fabric thickness warning" on the display unit 15. The CPU 91 stores a sewing disable setting in the RAM 93 that does not allow sewing to start (S67).

When the absolute value of the difference is not equal to or greater than the warning threshold H1 (S65: NO), the CPU 91 refers to the threshold table 98 and acquires the change threshold H2 (S71). As in S64, the method of acquiring the change threshold H2 may be changed as appropriate. The change threshold H2 in this example is a value smaller than the warning threshold H1. The CPU 91 determines whether the absolute value of the difference calculated in S63 is equal to or greater than the change threshold H2 acquired in S71 (S72). When the absolute value of the difference is equal to or greater than the change threshold H2 (S72: YES), the CPU 91 refers to the number of sheets table 96 and sets sewing conditions according to the detected thickness detected in S51 (S73). The CPU 91 in this example sets the sewing conditions to the feed amount, thread tension, presser foot pressure, alternating lift amount, and number of revolutions according to the detected thickness. When the absolute value of the difference is not equal to or greater than the change threshold (S72: NO), or following S73, the CPU 91 refers to the threshold table 98 and acquires the effective threshold H3 (S74). As in S64, the method of obtaining the valid threshold H3 may be changed as appropriate. In this example, the valid threshold H3 is a value smaller than the warning threshold H1. The valid threshold H3 may be the same as the change threshold H2, or they may be different from each other.

The CPU 91 judges whether the difference calculated in S63 is equal to or greater than the effective threshold value H3 acquired in S74 (S75). When the difference is equal to or greater than the effective threshold value H3 (S75: YES), the CPU 91 sets the penetration force improvement function to be active (S76). When the difference is not equal to or greater than the effective threshold value H3 (S75: NO), or after S76, the CPU 91 notifies the result of the comparison between the detected thickness in S63 and the reference thickness (S77). For example, the CPU 91 may display on the display unit 15 the number of the sewing objects placed on the needle plate 14, may display on the display unit 15 the difference calculated in S63, or may display on the display unit 15 the thickness of the sewing object. When the sewing conditions are changed in S73, the CPU 91 may notify the changed sewing conditions. The CPU 91 may notify the setting status of the penetration force improvement function. Since the detected thickness detected in S51 varies depending on the settings of the sewing device 1 at the time of detection, such as the presser foot pressure, the feed dog 17, and the position of the presser foot 11, the comparison contents may be displayed together with the settings at the time of detection. The CPU 91 may indicate the difference between the detected thickness and the reference thickness as a numerical value, a percentage, or the like, or may display the detected thickness and the reference thickness side by side. The CPU 91 may display the comparison result in text or as a diagram. The CPU 91 stores in the RAM 93 a sewing permission setting that permits the start of sewing. Following S67 or S78, the CPU 91 ends the pre-sewing detection process, and returns the process to the sewing process of FIG. 6.

After S4, the CPU 91 refers to the RAM 93 and determines whether or not a sewing permission setting is stored in the RAM 93 (S7). When the RAM 93 stores a sewing permission setting (S7: NO), the CPU 91 performs the process of S14. When the RAM 93 stores a sewing permission setting (S7: YES), the CPU 91 determines whether or not a sewing start instruction has been detected (S8). When starting sewing, the operator depresses the pedal 18, which inputs a sewing start instruction to the control unit 90. When the sewing start instruction is not detected (S8: NO), the CPU 91 determines whether or not an interrupt instruction to interrupt the sewing process has been detected based on the detection result of the input unit 16 (S15). For example, the operator takes into consideration the notification result in S77, and operates the input unit 16 to input an interrupt instruction when repositioning the sewing object. When an interrupt instruction is not detected (S15: NO), the CPU 91 returns the process to S8. When a stop command is detected (S15: YES), the CPU 91 performs processing in S14.

When the CPU 91 detects a sewing start command (S8: YES), it starts sewing under sewing conditions corresponding to the detected thickness (S9). In the first and second specific examples, the CPU 91 refers to the number of sheets table 96 and acquires the sewing conditions corresponding to the reference thickness T2. When the sewing conditions are changed in S4, the CPU 91 acquires the changed sewing conditions. The CPU 91 drives the thread tension solenoid 25 in accordance with the sewing conditions to adjust the thread tension. The CPU 91 drives the feed amount adjustment motor 24 in accordance with the sewing conditions to adjust the feed amount. The CPU 91 drives the alternating lift amount adjustment motor 23 in accordance with the sewing conditions to adjust the alternating lift amount. The CPU 91 drives the presser motor 22 in accordance with the sewing conditions to adjust the presser foot pressure. The CPU 91 drives the main shaft motor 21 in accordance with the sewing conditions to adjust the rotation speed, and when the penetration force improvement function is enabled, controls the current supply pattern of the main shaft motor 21.

The CPU 91 judges whether or not a sewing stop command has been detected (S10). When the operator stops sewing, the pedal 18 is released, and the pedal 18 inputs a sewing stop command to the control unit 90. The CPU 91 also detects a sewing stop command when the RAM 93 stores a sewing stop setting. When the CPU 91 detects a sewing stop command (S10: YES), it stops driving the thread tension solenoid 25 and the main shaft motor 21, and stops sewing under the sewing conditions according to the detected thickness (S11). When the sewing stop command is not detected (S10: NO), the CPU 91 judges whether or not it is time to detect based on the detection result of the encoder 56 (S12). In this example, the CPU 91 executes a sewing detection process when the rotation angle of the main shaft 31 is a predetermined angle as the detection time. The predetermined angle is, for example, the angle when the presser mechanism 44 is in the needle up position. When it is not time to detect (S12: NO), the CPU 91 returns the process to S10. When it is time to detect (S12: YES), the CPU 91 performs a sewing detection process (S13). In the sewing detection process, the CPU 91 performs a process according to the result of comparing the detected thickness of the sewing material based on the detection result of the detector 49 during sewing with the reference thickness stored in the memory device 94.

9, the same step numbers are assigned to the processes similar to those in the pre-sewing detection process in FIG. 8, and the description is omitted or simplified. The CPU 91 detects the detection result of the detector 49 as the detected thickness (S51). The CPU 91 refers to the threshold table 98 in the storage device 94 and acquires the thickness threshold (S52). The thickness threshold is a threshold for detecting that the sewing material is not present between the needle plate 14 and the presser foot 11, and is set in consideration of the detection accuracy of the detector 49, etc. The CPU 91 judges whether the detected thickness detected in S51 is equal to or greater than the thickness threshold (S53). When the detected thickness is not equal to or greater than the thickness threshold (S53: NO), the CPU 91 notifies that the thickness of the sewing material is 0 (S54). The CPU 91 displays, for example, an error message "There is no sewing material between the needle plate and the presser foot" on the display unit 15. The CPU 91 stores the sewing stop setting in the RAM 93 (S55), ends the sewing detection process, and returns the process to the sewing process in FIG. 6.

When the detected thickness is equal to or greater than the thickness threshold (S53: YES), the CPU 91 determines whether the detected thickness has changed (S56). The CPU 91 determines that the detected thickness has changed when, for example, the absolute value of the difference between the detected thickness detected in the previous sewing detection process or pre-sewing detection process and stored in RAM 93 and the detected thickness detected in the current sewing detection process and stored in RAM 93 is equal to or greater than the change threshold stored in the threshold table 98. The change threshold may be set appropriately taking into account the detection accuracy of the detector 49, and is, for example, a value smaller than the warning threshold H1, the change threshold H2, and the effective threshold H3.

When the CPU 91 acquires the detected thickness T12 in the first specific example (S51, S53: YES), it determines that the detected thickness has changed (S56: YES) and issues a warning (S57). The CPU 91 displays, for example, a message "Cloth thickness change detected" on the display unit 15. The CPU 91 refers to the setting table 97 and determines whether the next setting order is stored in the setting table 97 (S58). The CPU 91 determines that the next setting order is stored in the first specific example (S58: YES), sets the sewing conditions whose setting order corresponds to the next sewing condition 2 (S59), and acquires the reference thickness T3 corresponding to the setting order of 2 (S60). The CPU 91 compares the detected thickness T12 detected in S51 with the reference thickness T3 acquired in S60, and calculates the difference between the detected thickness T12 and the reference thickness T3 (S63). The CPU 91 refers to the threshold table 98 and obtains the warning threshold H1 (S64), and determines that the absolute value of the difference calculated in S63 is not equal to or greater than the warning threshold H1 (S65: NO). The CPU 91 refers to the threshold table 98 and obtains the change threshold H2 (S71), and determines that the absolute value of the difference calculated in S63 is not equal to or greater than the change threshold H2 (S72: NO). The CPU 91 refers to the threshold table 98 and obtains the effective threshold H3 (S74), and determines that the difference calculated in S63 is not equal to or greater than the effective threshold H3 (S75: NO). The CPU 91 reports the comparison result of S63 (S77), ends the sewing detection process, and returns the process to the sewing process of FIG. 6.

When the CPU 91 acquires the detected thickness T13 in the first specific example (S51, S53: YES), it determines that the detected thickness has changed (S56: YES) and issues a warning (S57). The CPU 91 refers to the setting table 97 and determines that the next setting order is stored in the setting table 97 (S58: YES), sets the sewing conditions corresponding to the next setting order of 3 (S59), and acquires the reference thickness T1 corresponding to the setting order of 3 (S60). The CPU 91 compares the detected thickness T13 detected in S51 with the reference thickness T1 acquired in S60, and calculates the difference between the detected thickness T13 and the reference thickness T1 (S63). The CPU 91 refers to the threshold table 98 and acquires the warning threshold H1 (S64), and determines that the absolute value of the difference calculated in S63 is equal to or greater than the warning threshold H1 (S65: YES). The CPU 91 issues a warning (S66) and stores the sewing stop setting in the RAM 93 (S68). The CPU 91 ends the sewing detection process and returns the process to the sewing process in FIG. 6.

When the CPU 91 acquires the detected thickness T22 in the second specific example (S51, S53: YES), it determines that the detected thickness has not changed (S56: NO), and ends the detection process during sewing and returns the process to the sewing process in FIG. 6. When the CPU 91 acquires the detected thickness T23 in the second specific example (S51, S53: YES), it determines that the detected thickness has changed (S56: YES), and the CPU 91 issues a warning (S57). The CPU 91 refers to the setting table 97 and determines that the next setting order is not stored in the setting table 97 (S58: NO). The CPU 91 acquires the reference thickness T2 corresponding to the current sewing conditions (S62). The CPU 91 compares the detected thickness T23 detected in S51 with the reference thickness T2, and calculates the difference between the detected thickness T23 and the reference thickness T2 (S63). The CPU 91 refers to the threshold table 98, acquires the warning threshold H1 (S64), and determines that the absolute value of the difference calculated in S63 is not equal to or greater than the warning threshold H1 (S65: NO). The CPU 91 refers to the threshold table 98, acquires the change threshold H2 (S71), and determines that the absolute value of the difference calculated in S63 is equal to or greater than the change threshold H2 (S72: YES). The CPU 91 changes the sewing conditions corresponding to the detected thickness T23 detected in S51 to the sewing conditions associated with the reference thickness T3 that is closest to the detected thickness T23 in the number of sheets table 96 (S73). The CPU 91 refers to the threshold table 98, acquires the effective threshold H3 (S74), and determines that the difference calculated in S63 is equal to or greater than the effective threshold H3 (S75: YES). The CPU 91 sets the penetration force improvement function to be effective (S76). When the difference calculated in S63 is not equal to or greater than the effective threshold H3 (S75: NO), the CPU 91 may set the penetration force improvement function to be ineffective. The CPU 91 notifies the result of the comparison in S63 (S77), ends the sewing detection process, and returns the process to the sewing process in FIG. 6.

After S13, the CPU 91 returns the process to S10. The CPU 91 determines whether or not an operation to turn off the power of the sewing device 1 has been detected (S14). If an operation to turn off the power has not been detected (S14: NO), the CPU 91 returns the process to S2. If an operation to turn off the power is detected (S14: YES), the CPU 91 ends the sewing process.

In the sewing device 1 of the above embodiment, the sewing device 1, the needle bar 6, the sewing needle 7, the presser bar 10, the presser foot 11, the needle plate 14, the main shaft motor 21, the needle bar mechanism 32, the detector 49, and the memory device 94 are examples of the sewing device, the needle bar, the sewing needle, the presser bar, the presser foot, the needle plate, the main shaft motor, the needle bar mechanism, the detection unit, and the memory unit of the present invention. The CPU 91 that performs S62 is an example of an acquisition unit of the present invention. The CPU 91 that performs S63 is an example of a comparison unit of the present invention. The CPU 91 that performs S57, S66, and S77 is an example of an alarm control unit of the present invention. The CPU 91 that performs S64 is an example of a warning threshold acquisition unit of the present invention. The CPU 91 that performs S71 is an example of a change threshold acquisition unit of the present invention. The CPU 91 that performs S59 and S73 is an example of a condition change unit of the present invention. The CPU 91 that performs S74 is an example of an effective threshold acquisition unit. The CPU 91 that performs S76 is an example of an effective setting unit. The CPU 91 which performs S68, S10 and S11 is an example of the sewing stop section of the present invention. The CPU 91 which performs S55 is an example of the sewing stop section of the present invention. The CPU 91 which performs S36 is an example of the memory control section of the present invention.

The sewing device 1 includes a needle plate 14, a needle bar 6, a needle bar mechanism 32, a main shaft motor 21, a presser bar 10, a detector 49, and a CPU 91. The needle plate 14 is used to place the sewing material. The needle bar 6 extends vertically, and a sewing needle 7 can be attached to the lower end. The needle bar mechanism 32 moves the needle bar 6 up and down. The main shaft motor 21 drives the needle bar mechanism 32. The presser bar 10 is used to place a presser foot 11 at the lower end, and the presser foot 11 presses the sewing material placed on the needle plate 14 from above. The detector 49 detects the detected thickness, which is the thickness of the sewing material pressed by the presser foot 11 (S51). The CPU 91 acquires the reference thickness, which is the thickness of one or more sheets of sewing material that serve as a reference (S62, S60). The CP 91 compares the detected thickness with the reference thickness (S63). The CPU 91 reports the comparison result (S77). The sewing device 1 notifies the operator of the result of the comparison between the detected thickness and the reference thickness, so the operator can refer to the result of the comparison notified by the sewing device 1 and can check whether the workpiece placed on the needle plate 14 and held down by the presser foot 11 is the workpiece intended by the operator based on the result of the comparison. Therefore, the sewing device 1 can improve the operator's convenience when sewing according to the thickness of the workpiece compared to the conventional method.

The CPU 91 acquires a warning threshold H1 used to compare the difference between the detected thickness and the reference thickness ( S64 ). When the difference between the reference thickness and the detected thickness is equal to or greater than the warning threshold H1 (S65: YES), the CPU 91 issues a warning (S66). By appropriately setting the warning threshold H1, the sewing device 1 can notify the operator that a sewing workpiece of an unintended thickness has been placed on the needle plate 14. By referring to the warning, the operator can avoid sewing on an unintended sewing workpiece.

The CPU 91 acquires a change threshold H2 that is smaller than the warning threshold H1 (S71). When the difference between the reference thickness and the detected thickness is smaller than the warning threshold H1 (S65: NO) and is equal to or greater than the change threshold H2 (S72: YES), the sewing conditions are changed according to the detected thickness (S73). By appropriately setting the warning threshold H1 and the change threshold H2, the sewing device 1 can automatically change the sewing conditions according to the detected thickness when the difference between the reference thickness and the detected thickness is not large enough for the operator to issue a warning, but is not suitable for sewing under the sewing conditions set according to the reference thickness. The sewing device 1 can save the operator the trouble of changing the sewing conditions during sewing. Since the sewing device 1 sets the thread tension according to the detected thickness, sewing can be performed taking into account the friction between the sewing material and the upper thread according to the thickness of the sewing material. Since the sewing device 1 sets the presser foot pressure according to the detected thickness, the sewing material can be appropriately pressed down and sewn. The sewing device 1 sets the amount of alternating lift according to the detected thickness, which reduces the possibility of not being able to overcome the stepped portion and suppresses noise caused by the stepped portion colliding with the presser foot 11. The sewing device 1 adjusts the rotation speed of the main shaft motor 21 according to the detected thickness, which increases the possibility of completing sewing within the expected work time.

The sewing device 1 acquires an effective threshold H3 that is smaller than the warning threshold H1 (S74). When the difference between the reference thickness and the detected thickness is smaller than the warning threshold H1 (S65: NO) and the difference obtained by subtracting the reference thickness from the detected thickness is equal to or greater than the effective threshold H3 (S75: YES), the penetration force improvement function is enabled to improve the penetration force of the sewing needle 7 through the sewn material by driving the main shaft motor 21 with a current pattern different from that used when sewing a sewn material of the reference thickness (S76). In general, when the penetration force of the needle bar 6 through the sewn material is insufficient, the sewing needle 7 cannot penetrate the sewn material, resulting in poor sewing. When the penetration force of the needle bar 6 through the sewn material is excessive, noise increases, making the worker uncomfortable. By appropriately setting the warning threshold H1 and the effective threshold H3, the sewing device 1 can automatically enable the penetration force improvement function when the difference between the reference thickness and the detected thickness is not large enough for the operator to issue a warning, but the sewing needle 7 has difficulty penetrating the sewn material when sewing under the sewing conditions set according to the reference thickness. The sewing device 1 can save the operator the trouble of enabling the penetration force improvement function while sewing. The sewing device 1 can prevent a decrease in sewing quality caused by insufficient penetration force of the needle bar 6.

When the difference between the reference thickness and the detected thickness obtained while the main shaft motor 21 is driven is equal to or greater than the warning threshold H1, the sewing device 1 stops driving the main shaft motor 21 (S68, S10: YES, S11). By appropriately setting the warning threshold H1, the sewing device 1 can prevent the operator from continuing to sew a material with an unintended thickness.

The CPU 91 of the sewing device 1 detects the detected thickness based on the detection result of the detector 49 before the main shaft motor 21 starts to drive (S51 in FIG. 8), and notifies the result of comparing the reference thickness with the detected thickness detected before the main shaft motor 21 starts to drive (S77 in FIG. 8). The operator can refer to the comparison result notified by the sewing device 1 , and can check, based on the comparison result, before sewing, whether the workpiece placed on the needle plate 14 and held down by the presser foot 11 is the workpiece intended by the operator. Therefore, the sewing device 1 can further improve the convenience for the operator when sewing according to the thickness of the workpiece compared to the conventional method.

The CPU 91 of the sewing device 1 detects the detected thickness while the main shaft motor 21 is driven based on the detection result of the detector 49 (S51 in FIG. 9), and issues a warning if the detected thickness changes while the main shaft motor 21 is driven (S56: YES, S57). The sewing device 1 can notify the operator by issuing a warning when the detected thickness changes while the main shaft motor 21 is driven. The operator can refer to the warning issued by the sewing device 1 and take appropriate action depending on whether the change in detected thickness was intended by the operator or not. For example, the operator can know from the warning issued by the sewing device 1 that the sewing material has unintentionally fallen out from between the needle plate 14 and the presser foot 11. For example, the operator can notice from the warning issued by the sewing device 1 that the sewing material has unintentionally been folded and sewn.

The CPU 91 of the sewing device 1 detects the detected thickness while the main shaft motor 21 is driven based on the detection result of the detector 49 (S51 in FIG. 9), and if the detected thickness changes while the main shaft motor 21 is driven (S56: YES), changes the sewing conditions according to the detected thickness (S59, S73). When the detected thickness changes while the main shaft motor 21 is driven, the sewing device 1 can automatically change the sewing conditions according to the detected thickness. The sewing device 1 can save the operator the trouble of changing the sewing conditions while sewing.

The CPU 91 of the sewing device 1 detects the thickness while the main shaft motor 21 is driven based on the detection result of the detector 49 (S51 in FIG. 9), and when the detected thickness while the main shaft motor 21 is driven is smaller than a predetermined value (S53: NO), it notifies the user that the sewing material is not between the needle plate 14 and the presser foot 11 (S54), and when the detected thickness while the main shaft motor 21 is driven is smaller than a predetermined value, it stops driving the main shaft motor 21 (S55). The sewing device 1 notifies the user that the sewing material is not between the needle plate 14 and the presser foot 11, and can stop driving the main shaft motor 21. The sewing device 1 can avoid continuing to drive the main shaft motor 21 after sewing to the edge of the sewing material.

The CPU 91 of the sewing device 1 acquires multiple reference thicknesses in the set order while the main shaft motor 21 is driven (S60), and when the detected thickness detected while the main shaft motor 21 is driven changes, it compares the detected thickness with the next reference thickness in the set order (S63). When the difference between the detected thickness and the next reference thickness in the set order is equal to or greater than the warning threshold H1 (S65: YES), the CPU 91 issues a warning (S66). When sewing a sewing material whose thickness changes during sewing, the sewing device 1 can avoid detecting a part where the thickness changes as an abnormality. When the sewing device 1 detects a change in the detected thickness, it compares the detected thickness with the next reference thickness in the set order, so that the detected thickness can be appropriately compared with the reference thickness even when sewing a sewing material whose thickness changes during sewing. By referring to the notification results of the sewing device 1, the operator can notice, for example, when sewing the same sewing pattern repeatedly several times, that the workpiece has slipped out from between the needle plate 14 and the presser foot 11, that the workpiece has been sewn in an unintentionally folded state, that the wrong number of workpieces has been sewn, or that the wrong type of workpiece has been sewn.

The sewing device 1 is equipped with a storage device 94 that stores multiple combinations of reference thicknesses and setting orders while the main shaft motor 21 is driven. The CPU 91 acquires the multiple combinations stored in the setting table 97 of the storage device 94 in the setting order (S60). When sewing a sewing material whose thickness changes during sewing as in the first specific example of FIG. 10(A), the sewing device 1 can avoid detecting a location where the thickness changes as an abnormality. When the sewing device 1 detects a change in the detected thickness, it compares the detected thickness with the next reference thickness in the setting order, so that it can appropriately compare the reference thickness with the detected thickness even when sewing a sewing material whose thickness changes during sewing.

The CPU 91 of the sewing device 1 sets the detected thickness detected by the detector 49 as the reference thickness (S23) and stores the combination of the reference thickness and the set order in the multiple storage devices 94 (S25). The sewing device 1 can store the combination of the reference thickness and the set order in the multiple storage devices 94, using the detected thickness detected by the detector 49 as the reference thickness. The sewing device 1 can reduce the influence of the mounting tolerance of the detector 49 on the sewing device 1, compared to a device that obtains the combination of the reference thickness and the set order from another device.

The present invention is not limited to the above embodiment. The type of sewing device 1 may be changed as appropriate, such as a lock stitch sewing machine or a top and bottom feed sewing machine. The sewing device 1 does not need to be equipped with a presser bar or presser foot. The method by which the detector 49 detects the thickness of the sewing material may be changed as appropriate, and may be, for example, any of the optical, eddy current, ultrasonic, and contact type proximity displacement sensors. The arrangement of the detector 49 and the detection timing may be changed as appropriate.

The program including the commands for the sewing device 1 to execute the sewing process may be stored in the storage device 94 of the sewing device 1 before the CPU 91 executes the program. Therefore, the program acquisition method, acquisition path, and device that stores the program may each be changed as appropriate. The program executed by the CPU 91 may be received from another device via a cable or wireless communication and stored in a storage device such as a flash memory. The other device may include, for example, a PC or a server connected to the sewing device 1 via a network.

A part or all of the processes performed by the sewing device 1 may be executed by an electronic device (e.g., an ASIC) other than the CPU 91. The processes performed by the sewing device 1 may be distributed among multiple electronic devices (e.g., multiple CPUs). The order of each step of the processes performed by the sewing device 1 may be changed, steps may be omitted, or additional steps may be added, as necessary. The scope of the present invention also includes a mode in which an operating system (OS) running on the sewing device 1 executes a part or all of each process in response to a command from the CPU 91. For example, the sewing device 1 may be modified as appropriate from the above embodiment as follows.

The sewing device 1 may change the sewing conditions according to the detected thickness of the sewn material, or may not change them. The sewing device 1 may enable or disable the setting of the penetration force improvement function according to the detected thickness of the sewn material, or may not change the setting. When the sewing device 1 changes the sewing conditions according to the detected thickness of the sewn material, the sewing conditions to be changed may be changed appropriately according to the configuration of the sewing device 1. The sewing device 1 may notify the comparison result and warning by any method such as voice output or warning light illumination. The setting method of at least one of the number table 96, the setting table 97, and the threshold table 98 may be changed appropriately. The sewing device 1 may change or omit the process using at least one of the warning threshold value H1, the change threshold value H2, the effective threshold value H3, the thickness threshold value, and the change threshold value. For example, the sewing device 1 may omit S68 in FIG. 9, and when the absolute value of the difference between the detected thickness and the reference thickness is equal to or greater than the warning threshold value H1 (S65: YES), it is not necessary to stop sewing by only notifying a warning (S66). The method of setting at least one of the warning threshold H1, the change threshold H2, the valid threshold H3, the thickness threshold, and the change threshold may be changed as appropriate. At least one of the warning threshold H1, the change threshold H2, the valid threshold H3, and the change threshold may be a value that changes depending on at least one of the detected thickness and the reference thickness, may be a value expressed by a mathematical formula, may be a value stored in a table in advance, or may be a value entered by the operator.

9, and when the detected thickness is not equal to or greater than the thickness threshold (S53: NO), the sewing device 1 may simply issue a warning (S54) and not stop sewing. The sewing device 1 may obtain the detected thickness only before sewing starts or during sewing, and compare the detected thickness with the reference thickness. The sewing device 1 may omit S56 and not detect whether the detected thickness has changed during sewing. The sewing device 1 may omit S53 to S55, and may not detect or notify that there is no sewing material between the needle plate 14 and the presser foot 11. The sewing device 1 may not store the setting table 97, and may omit S58 to S60. The sewing device 1 may not perform part or all of the setting process in FIG. 7, and may set the reference thickness to the detection result of the input unit 16, for example. The sewing device 1 may detect the detected thickness during sewing of the sewing material at a predetermined time in at least one of S23 and S35. At this time, since the detected thickness changes depending on the sewing conditions of the sewing device 1, the CPU 91 may store the sewing conditions along with the detected thickness in S25 and S36. The sewing conditions may be appropriately selected from, for example, the number of stitches, whether or not there is a temporary stop, whether or not there is a thread break, a change in the feed amount, whether or not the rotation direction of the main shaft 31 is reversed, a change in thread tension, a change in the presser foot pressure, a change in the amount of alternating lift, and a change in the number of rotations.

1: Sewing device 6: Needle bar 7: Sewing needle 10: Presser bar 11: Presser foot 13: Thread tension controller 14: Needle plate 21: Main shaft motor 22: Presser motor 23: Alternating lift amount adjustment motor 24: Feed amount adjustment motor 25: Thread tension solenoid 27: Main shaft motor 32: Needle bar mechanism 34: Presser mechanism 36: Feed mechanism 37: Feed amount adjustment mechanism 49: Detectors 56 to 59: Encoder 90: Control unit 91: CPU
94: Storage device 96: Number table 97: Setting table

Claims (16)

a needle plate on which an object to be sewn is placed;
A needle bar extending in the vertical direction and capable of mounting a sewing needle at its lower end;
a needle bar mechanism for moving the needle bar up and down;
a main shaft motor that drives the needle bar mechanism;
a presser bar to which a presser foot can be attached at a lower end, and which presses down the workpiece placed on the needle plate from above with the presser foot;
A sewing device including a detection unit for detecting a thickness of the sewing material pressed by the presser foot,
an acquisition unit that acquires a reference thickness that is set in advance as a thickness of one or more pieces of the sewing material to be sewn;
A comparison unit that compares the detected thickness with the reference thickness;
a notification control unit that notifies a comparison result of the comparison unit;
a warning threshold acquisition unit that acquires a warning threshold used for comparing a difference between the detected thickness and the reference thickness;
The notification control unit issues a warning when the difference between the reference thickness and the detected thickness is equal to or greater than the warning threshold value, and further
a change threshold acquisition unit that acquires a change threshold that is smaller than the warning threshold;
a condition change unit that changes sewing conditions in accordance with the detected thickness when the difference between the reference thickness and the detected thickness is smaller than the warning threshold value and is equal to or larger than the change threshold value;
A sewing device comprising : an effective threshold acquisition unit that acquires an effective threshold that is smaller than the warning threshold;
and an enable setting unit that enables a penetration force increasing function that increases a penetration force of the sewing needle through the sewing workpiece by driving the main shaft motor with a current that is greater than a current that is passed through the main shaft motor when sewing the sewing workpiece of the reference thickness, when the difference between the reference thickness and the detected thickness is smaller than the warning threshold value and the value obtained by subtracting the reference thickness from the detected thickness is equal to or greater than the enable threshold value. 3. The sewing device according to claim 1, further comprising a sewing stop unit that stops driving the main shaft motor when a difference between the reference thickness and the detected thickness acquired while the main shaft motor is being driven is equal to or greater than the warning threshold value. The detection unit detects the thickness before the spindle motor starts to be driven,
2. The sewing device according to claim 1, wherein the notification control unit notifies the result of the comparison between the reference thickness and the detected thickness detected before the main shaft motor starts to be driven. The detection unit detects the thickness while the spindle motor is being driven,
5. The sewing device according to claim 4 , wherein the notification control unit issues a warning when the detected thickness detected while the main shaft motor is being driven changes. The detection unit detects the thickness while the spindle motor is being driven,
6. The sewing device according to claim 4 , further comprising a condition change unit which changes sewing conditions in response to a change in the detected thickness when the detected thickness changes while the main shaft motor is being driven. The detection unit detects the thickness while the spindle motor is being driven,
the notification control unit notifies the user that the sewing material is not between the needle plate and the presser foot when the detected thickness detected during driving of the main shaft motor is smaller than a predetermined value,
The sewing device according to any one of claims 4 to 6, further comprising a sewing stop unit that stops driving the main shaft motor when the detected thickness detected while the main shaft motor is being driven is smaller than the predetermined value. The sewing device according to any one of claims 1, 4 and 5, characterized in that the notification control unit displays the number of the workpieces placed on the needle plate as the result of the comparison between the detected thickness and the reference thickness. a needle plate on which an object to be sewn is placed;
A needle bar extending in the vertical direction and capable of mounting a sewing needle at its lower end;
a needle bar mechanism for moving the needle bar up and down;
a main shaft motor that drives the needle bar mechanism;
a presser bar to which a presser foot can be attached at a lower end, and which presses down the workpiece placed on the needle plate from above with the presser foot;
A sewing device including a detection unit for detecting a thickness of the sewing material pressed by the presser foot,
an acquisition unit that acquires a reference thickness that is set in advance as a thickness of one or more pieces of the sewing material to be sewn;
A comparison unit that compares the detected thickness with the reference thickness;
a notification control unit that notifies a comparison result of the comparison unit;
a warning threshold acquisition unit that acquires a warning threshold used for comparing a difference between the detected thickness and the reference thickness;
the acquiring unit, when sewing the sewing object whose reference thickness changes during sewing, acquires a plurality of the reference thicknesses in a set order, which is an order in which the sewing object having the reference thickness is sewn, while the main shaft motor is driven;
the comparison unit, when the detected thickness detected while the spindle motor is being driven changes, compares the detected thickness with the next reference thickness in the setting order;
The notification control unit issues a warning when a difference between the detected thickness and the next reference thickness in the set order is equal to or greater than the warning threshold value , and further
a change threshold acquisition unit that acquires a change threshold that is smaller than the warning threshold;
a condition change unit that changes sewing conditions in accordance with the detected thickness when the difference between the reference thickness and the detected thickness is smaller than the warning threshold value and is equal to or larger than the change threshold value;
A sewing device comprising : a memory unit that stores a plurality of combinations of the reference thickness during the drive of the main shaft motor and the setting order when sewing the sewing object in which the reference thickness changes during the sewing process;
The sewing device according to claim 9 , wherein the acquisition unit acquires the plurality of combinations stored in the storage unit in the set order. The sewing device according to claim 10, further comprising a memory control unit which, when an instruction to set the combination of the reference thickness and the setting order is detected, sets the detected thickness detected by the detection unit as the reference thickness and stores multiple combinations of the reference thickness and the setting order in the memory unit . The detection unit detects the thickness before the spindle motor starts to be driven,
10. The sewing device according to claim 9 , wherein the notification control unit notifies the result of the comparison between the reference thickness and the detected thickness detected before the main shaft motor starts to be driven. The detection unit detects the thickness while the spindle motor is being driven,
The sewing device according to claim 12 , wherein the notification control unit issues a warning when the detected thickness detected while the main shaft motor is being driven changes. The detection unit detects the thickness while the spindle motor is being driven,
The sewing device according to claim 1 2 or 1 3 , further comprising a condition change unit which changes sewing conditions in response to a change in the detected thickness detected while the main shaft motor is being driven. The detection unit detects the thickness while the spindle motor is being driven,
the notification control unit notifies the user that the sewing material is not between the needle plate and the presser foot when the detected thickness detected during driving of the main shaft motor is smaller than a predetermined value,
A sewing device as described in any one of claims 12 to 14, further comprising a sewing stop unit that stops driving the main shaft motor when the detected thickness detected while the main shaft motor is driven is smaller than the predetermined value. A sewing device as described in any one of claims 9 , 12 and 13, characterized in that the notification control unit displays the number of the workpieces placed on the needle plate as the comparison result between the detected thickness and the reference thickness .

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