JP2014144508A - Desktop cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desktop cutter which can be driven by both a commercial power supply and a battery, thereby, even during the operating time of a commercial power cord, the good workability is maintained without removal.SOLUTION: A desktop cutter has a base portion 1 and an electric motor 21 which drives rotationally a cutting tool and also includes a cutting part 10 is supported movably for the base portion, a charging circuit 42 and a control circuit 43 which are established in the base portion 1, a commercial power cord 45 which is connected to the charging circuit 42 and the control circuit 43 so as to be pulled out from the base portion 1, and a main battery 40 which is formed in the cut section 10 to supply electric power to the electric motor 21, wherein the charging circuit 42 charges the main battery 40 while the control circuit 43 is a composition of performing the electric motor control and the battery charge control.

Description

  The present invention relates to a tabletop cutting machine that cuts a material to be cut on a base portion with a rotating cutting tool.

  This type of tabletop cutting machine includes a base section, a cutting section having an electric motor that rotationally drives a cutting tool such as a circular saw, and a cutting section support mechanism that supports the cutting section in a swingable manner. An operator manually lowers a cutting part that rotates a tool to cut a material to be cut placed on the base part, and a configuration that uses a commercial power supply (AC100V) as a power source is common. It is.

  On the other hand, the following Patent Document 1 and Patent Document 2 disclose battery-powered tabletop cutting machines that can be used in the absence of a commercial power source, and Patent Document 3 drives either a commercial power source or a DC power source (battery power source). A possible tabletop cutting machine is disclosed.

Japanese Patent No. 4164417 Japanese Patent No. 4021029 JP 2011-167830 A

  Since Patent Document 1 and Patent Document 2 are only driven by a battery, there is a tendency that the amount of work is limited, and when the capacity of the battery is exhausted, a charger for charging the battery is required. . Patent Document 3 can be driven by a commercial power source and driven by a battery. However, since the commercial power cord is connected to a cutting unit having an electric motor and a cutting tool, the cutting unit is used when cutting the workpiece with the cutting tool. When the is swung, the commercial power cord moves. For this reason, it is necessary to consider the routing of the commercial power cord.

  The present invention has been made in view of such a situation, and an object of the present invention is to be able to be driven by a commercial power source and a battery, or to be driven by a battery having a charging function and when the commercial power cord is used. The object is to provide a tabletop cutting machine that does not move and has good workability.

  The first aspect of the present invention is a tabletop cutting machine. This tabletop cutting machine has a base part, an electric motor that rotationally drives a cutting tool, a cutting part that is supported movably with respect to the base part, a control circuit provided in the base part, A commercial power cord connected to a control circuit and drawn from the base portion, and a main battery provided at the cutting portion and supplying power to the electric motor, wherein the control circuit controls the electric motor. And

  The second aspect of the present invention is a tabletop cutting machine. This tabletop cutting machine has a base part, an electric motor that rotationally drives a cutting tool, a cutting part that is supported movably with respect to the base part, and a control circuit and a charging circuit provided in the base part And a commercial power cord connected to the control circuit and drawn from the base portion, and a main battery provided at the cutting portion and supplying power to the electric motor, the charging circuit charging the main battery The control circuit controls the electric motor and the main battery.

  In the second aspect, the charging circuit may charge the main battery only when the motor is not energized. In this case, the charging circuit may be configured not to charge the main battery for a predetermined time from when the energization of the electric motor is turned off.

  In the second aspect, the charging circuit may be configured to charge the main battery when a battery voltage of the main battery becomes a predetermined voltage or less.

  In the second aspect, it is preferable that a sub-battery is provided in the base portion and can be charged by the charging circuit.

  In the first or second aspect, the apparatus includes a battery voltage detecting means for detecting a battery voltage of the main battery and a display unit, and the display unit displays a display prompting charging when the battery voltage becomes a predetermined voltage or less. It is good to have a configuration to perform.

  2nd aspect WHEREIN: The battery voltage detection means and display part which detect the battery voltage of the said main battery and the said sub battery are provided, and the said display part is a display which prompts charge when the said battery voltage becomes below a predetermined voltage. It is good to be the composition which performs.

  In the first or second aspect, when the battery voltage detection unit and the display unit are provided, the battery voltage detection unit and the display unit may be provided in the cutting unit, or the display unit may The base portion may be provided.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the tabletop cutting machine according to the present invention, driving by a commercial power source and driving by a battery are possible, and the commercial power cord does not move at the time of cutting work, so that workability can be improved.

The side view which shows 1st Embodiment of the tabletop cutting machine which concerns on this invention. The front view. The front view of FIG. 1 which shows the state which removed the sub battery from the base part. The side view at the time of cutting | disconnection operation | movement in 1st Embodiment. The side view of the state which pulled out the cutting part to the front in 1st Embodiment. The circuit diagram of a 1st embodiment. The circuit diagram which shows 2nd Embodiment of the tabletop cutting machine which concerns on this invention. The flowchart of charge of the main battery and sub battery in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  A first embodiment of a tabletop circular saw as a tabletop cutting machine according to the present invention will be described below with reference to FIGS. In addition, the up-down direction and the front-back direction in the following description are defined as shown in FIG.

  In these figures, the tabletop circular saw includes a base portion 1 on which a workpiece 50 can be placed, a cutting portion 10 having an electric motor 21 that rotationally drives a circular saw blade 20 as a cutting tool, and a cutting portion 10 as a base. Cutting that swings in the vertical direction of the part 1 and supports the slidable parallel to the base part 1 and also supports the rotating surface (side surface) of the circular saw blade 20 so as to be tiltable with respect to the upper surface of the base part 1. Part support mechanism 30.

  The base portion 1 has a structure that can be placed on a floor surface, a table surface, or the like. A turntable 2 having an upper surface that is substantially flush with the upper surface of the base portion 1 is embedded in the base portion 1. It is connected to the base portion 1 so as to be rotatable via a rotation shaft orthogonal to the upper surface. During work, the material to be cut 50 can be placed on the base portion 1 and the turntable 2.

  Although the structure of the cutting part support mechanism 30 will be described later, the cutting part support mechanism 30 is attached to the turntable 2. When the turntable 2 is rotated, the cutting part support mechanism 30 and the cutting part are integrated therewith. 10 also rotates (that is, the direction relative to the base portion 1 changes).

  The base portion 1 is provided with a fence 3, and when the workpiece 50 is cut, the cutting operation is performed with the fence 3 in contact with one surface of the workpiece 50, thereby stable cutting. So that you can do the work. When the turntable 2 is rotated with respect to the base portion 1, the position of the cutting portion 10 that rotates together with the turntable 2 is changed with respect to the fence 3, thereby rotating the fence 3 and the circular saw blade 20. The angle with the surface (side surface) changes, and the workpiece 50 abutted against the fence 3 can be cut at various angles.

  The cutting portion support mechanism 30 is attached to the turntable 2 via the tilting shaft 4 and the tilting shaft 4 supported substantially parallel to the upper surface of the turntable 2 in the vicinity of the rear side (left side shown in FIG. 1) end portion of the turntable 2. A holder 5 that can be freely tilted (the posture can be adjusted from a standing state perpendicular to the upper surface of the turntable to a left-right direction so as to form a predetermined angle with respect to the upper surface), and the holder 5 At least two guide bars 7 fixedly supported in parallel to the upper surface of the table, a slider 8 provided slidably with respect to the guide bar 7, and a hinge 9 for slidably connecting the cutting portion 10 to the slider 8 It has.

  In order to fix the holder 5 at a predetermined inclination angle, a bracket 51 in which an arc-shaped long hole 51 a centering on the tilting shaft 4 is formed from the rear end of the turntable 2 at the rear of the holder 5. The shaft portion 52a of the clamp lever 52 penetrates the elongated hole 51a and is screwed into the holder 5. By tightening the clamp lever 52, the holder 5 can be fixed at an arbitrary inclination angle with respect to the upper surface of the turntable. By fixing the inclination angle of the holder 5, the circular saw blade 20 is also fixed at the same inclination angle, and so-called inclination cutting can be performed.

  The cutting unit 10 transmits the rotation of the electric motor 21 to the rotary shaft 22 to which the circular saw blade 20 is fixed via the rotation transmission mechanism, and includes a cutting unit case 11 that houses the electric motor 21 and the rotation transmission mechanism. A main cover 12 that covers the upper part of the circular saw blade 20 is formed integrally with the cutting part case 11.

  The rear end portion of the cutting portion case 11 is rotatably connected to the slider 8 via a hinge 9 and is attached to the base portion 1 so as to be swingable in a direction approaching and moving away from the base portion 1. The cutting part case 11 is urged by a spring (not shown) provided around the hinge 9 so as to lift upward. Therefore, unless a downward operating force is applied to the operation handle 14 provided on the upper portion of the cutting portion case 11, the cutting portion 10 is dead by a stopper (specific description is omitted) provided around the hinge 9. The position is restricted to a point (state in FIG. 1). The operation handle 14 is provided with a trigger switch SW1 for controlling the rotation and stop of the electric motor 21.

  The cutting part 10 has a protective cover 16 that covers a portion of the circular saw blade 20 that is not covered by the main cover 12. The protective cover 16 is supported so as to rotate and move along the inside of the main cover 12. When the operating shaft 14 is pushed down toward the bottom dead center when the rotary shaft 22 of the cutting part 10 is at the top dead center, the protective cover 16 is rotated counterclockwise as shown by an arrow L in FIG. Then, the circular saw blade 20 is exposed so that the workpiece 50 can be cut as shown in FIG.

  In addition to the operation handle 14, the cutting part case 11 is provided with a transport handle 15 for transporting the entire tabletop circular saw. The carrying handle 15 is substantially parallel to the upper surfaces of the base portion 1 and the turntable 2 in a state where the cutting portion 10 is swung downward as shown in FIG.

  As shown in FIG. 6, both the AC commercial power source and the battery power source can be used as the power source of the electric motor 21, the main battery 40 is provided in the cutting unit 10 incorporating the electric motor 21, and the base unit 1 includes a sub-battery 41 and a charging circuit 42 and a control circuit 43 that can charge both the main battery 40 and the sub-battery 41. The DC power of the main battery 40 is supplied to the electric motor 21 via the trigger switch SW1. A commercial power cord 45 electrically connected to the charging circuit 42 and the control circuit 43 is drawn from the base unit 1 and connected to a commercial power source (AC 100 V). The base portion 1 and the cutting portion 10 are electrically connected by a cable 48. Further, the main battery 40 is detachable from the cutting part 10, and the sub battery 41 is also detachable from the base part 1. A rail structure (not shown) is used for the main battery 40 and the cutting part 10 that receives the main battery 40, and the main battery 40 can be attached and detached by sliding from the front side to the rear side shown in FIG. .

  AC 100 V is applied to the control circuit 43 via the commercial power cord 45 and the battery voltages of the main battery 40 and the sub battery 41 are applied. The power supply of the control circuit 43 itself is performed from either the main battery 40 or the sub battery 41 (for example, from a battery having a battery voltage higher than a predetermined voltage among the batteries attached to the base unit 1 and the cutting unit 10). Receive power). The control circuit 43 has a built-in battery voltage detection means, and can detect the battery voltage of each of the batteries 40 and 41. The control circuit 43 displays a display unit when the battery voltage becomes equal to or lower than the predetermined voltage. 44 is driven to cause the display unit 44 to perform a display for prompting charging. At the same time, the battery voltage detection result (that is, information on which battery needs to be charged) is output to the charging circuit 42. The display unit 44 controlled by the control circuit 43 is provided in the cutting unit 10, for example.

  The charging circuit 42 outputs DC power for charging the main battery 40 and the sub battery 41 to each of the batteries 40 and 41 in a state where the supply of AC 100 V is received via the commercial power cord 45, and is controlled. In response to the battery voltage detection result of the circuit 43, the battery whose battery voltage is equal to or lower than the predetermined voltage is charged. Further, since the DC power of the charging circuit 42 can be supplied to the electric motor 21 via the trigger switch SW1, the electric motor 21 can be directly driven in a state where the main battery 40 and the sub battery 41 are not attached. It is.

  In the first embodiment described above, when the main battery 40 and the sub battery 41 are not attached and the commercial power cord 45 is plugged into the commercial power outlet, the trigger switch SW1 is turned on. The DC power of the charging circuit 42 is directly supplied to the electric motor 21, and the electric motor 1 rotationally drives the circular saw blade 20. As a result, the workpiece 50 can be cut by pushing down the operation handle 14 toward the bottom dead center as shown in FIG. At this time, as shown in FIG. 5, a wide workpiece 50 can be cut by sliding the slider 8 to which the cutting portion 10 is swingably attached along the guide bar 7.

  On the other hand, although the commercial power source cannot be used, when one or both of the main battery 40 and the sub battery 41 are mounted, the control circuit 43 is higher than the predetermined voltage when the trigger switch SW1 is turned on. A voltage battery is selected and power is supplied to the motor 21. When both the main battery 40 and the sub battery 41 exhibit a battery voltage higher than the predetermined voltage, the use of the main battery 40 is prioritized. The power supply from the sub battery 41 is performed by connecting the sub battery 41 to the electric motor 21 via the switch circuit in the charging circuit 42 (however, when the main battery 40 is also mounted, the sub battery 41 is connected to the main battery 40). Power is supplied with the batteries 41 connected in parallel). In addition, the display unit 44 performs a display prompting charging (that is, displaying a battery that needs to be charged) when the battery voltage of the mounted battery becomes equal to or lower than a predetermined voltage.

  When one or both of the main battery 40 and the sub battery 41 are attached and the commercial power cord 45 is plugged into a commercial power outlet, charging is performed until the attached battery is fully charged. At this time, priority is given to the charging of the battery which shows the battery voltage below the predetermined voltage. The operation when the trigger switch SW1 is turned on is the same as in the case of battery driving.

  According to the present embodiment, the following effects can be achieved.

(1) The main battery 40 is provided in the cutting part 10, and the charging circuit 42 and the control circuit 43 are provided in the base part 1, so that the commercial power cord 45 is pulled out from the base part 1. Since the base part 1 is fixed at the time of use, the commercial power cord 45 does not move at the time of cutting work, so that workability can be improved. That is, there is no inconvenience such that the commercial power cord 45 is pulled and disconnected from the commercial power outlet as the cutting portion 10 swings or slides. In addition, the commercial power cord 45 becomes a resistance, and the swinging and sliding operation of the cutting part 10 is not made difficult.

(2) By providing the charging circuit 42, the main battery 40 and the sub battery 41 can be charged. At this time, since the control circuit 43 has the battery voltage detecting means, it is possible to preferentially charge from the battery whose battery voltage is equal to or lower than a predetermined value (that is, the remaining amount is equal to or lower than the predetermined value). When only the battery whose battery voltage is equal to or lower than the predetermined value (that is, the remaining amount is equal to or lower than the predetermined value) is charged, the battery life can be extended by suppressing the charge / discharge cycle of the battery.

(3) The control circuit 43 can output the detection result by the battery voltage detection means to the display unit 44 and display it on the display unit 44. For example, by detecting the battery voltage of the main battery 40 and the sub battery 41 by the battery voltage detection means, the display unit 44 performs a display prompting charging of a battery whose battery voltage is equal to or lower than the predetermined voltage.
In addition, the power supply to the display unit 44 and the control circuit 43 is performed from a battery having a battery voltage higher than a predetermined voltage among the mounted main battery 40 and sub battery 41, for example, the main battery 40 When the voltage is lowered, the power supply to the display unit 44 and the control circuit 43 is performed by the sub battery 41, and the main battery 40 can be prevented from being overdischarged.

  A second embodiment of the present invention will be described with reference to FIGS. In this case, the mechanical structure is the same as that of the first embodiment, but the electrical configuration is different. In FIG. 7, a main battery 40 is provided in the cutting part 10 incorporating the electric motor 21, and a sub battery 41 is disposed on the base 1, and both the main battery 40 and the sub battery 41 can be charged. An AC / DC converter 43A including a charging circuit 42 and a control circuit is provided. The display unit 44 controlled by the AC / DC converter 43A including the control circuit is provided in the cutting unit 10. The DC power of the main battery 40 is supplied to the electric motor 21 via a switch circuit 47 including a trigger switch SW1 (shown in FIG. 1 and the like). On / off information (information on whether or not the motor 21 is energized) of the switch circuit 47 is output to an AC / DC converter 43A including a charging circuit 42 and a control circuit.

  In this case, the charging circuit 42 charges the main battery 40 only when the electric motor 21 is not rotating (only in a non-energized state). Control for charging only when the electric motor 21 is not rotating may be performed on the side of the AC / DC converter 43A including the control circuit, or the charging circuit 42 itself may have such a control mechanism. The reason for charging the main battery 40 only when the motor 21 is not rotating is that the battery voltage fluctuates greatly while the motor 21 is energized, and it is not possible to judge whether the battery is fully charged or less than the predetermined voltage. Because it becomes accurate.

  In addition, the charging circuit 42 does not charge the main battery 40 for a predetermined time (for example, a time of 5 minutes or more) from the time point when the energization of the motor 21 is turned off. This control can be performed by controlling the charging circuit 42 using a timer function of the AC / DC converter 43A including the control circuit. The reason why the motor 21 is not charged for a predetermined time after the energization of the electric motor 21 is turned off is that the electric motor 21 is frequently turned on and off in a short time during the cutting operation. This is to avoid the occurrence of the problem. Thereby, the charging / discharging cycle of a battery can be suppressed and the lifetime of a battery can be extended.

  FIG. 8 is a flowchart showing an example of the charging operation of the main battery 40 and the sub battery 41 in the second embodiment. When the AC power is turned on, it is determined whether or not the sub battery is attached to the base unit 1 in step S1, and if the sub battery is already attached (YES), it is determined whether or not the sub battery is fully charged in step S2. When the battery is not fully charged (NO), the sub-battery 41 is charged by the charging circuit 42 in step S3.

  If NO in step S1 or YES in step S2, the operation proceeds to the charging operation of the main battery 40 after step S4. In step S4, it is determined whether or not the main battery is attached to the cutting unit 10. If the main battery is not attached (NO), the process returns to step S1. If the determination in step S4 is YES, it is determined in step S5 whether the motor (electric motor 21) is being driven. If it is determined in step S5 that the motor is being driven (YES), the process returns to step S1. If the energization of the electric motor 21 is off, the determination in step S5 is NO, and the process proceeds to step S6 to determine whether or not a predetermined time has elapsed since the motor drive was stopped. If the determination in step S6 has not elapsed (NO), the process returns to step S1. If the determination in step S6 is YES, it is determined in step S7 whether the main battery is fully charged. If the main battery is fully charged (YES), the process returns to step S1. If the main battery 40 is not fully charged, the determination in step S7 is NO, and it is determined in step S8 whether the main battery 40 is below a predetermined remaining amount (in other words, below a predetermined voltage). If it is not less than the predetermined remaining amount (in the case of NO), the process returns to step S1. If YES in step S8, the main battery 40 is charged in step S9. In step S10, it is determined whether the main battery is fully charged. If the main battery is fully charged (YES), the process returns to step S1. If the main battery 40 is not fully charged, the determination in step S10 is NO, and the presence or absence of a motor drive operation is determined in step S11. If there is a motor drive operation (in the case of YES), the process returns to step S1 after the main battery charging is stopped in step S12. If there is no motor drive operation, the process returns to step S9 and charging is continued.

  In the case of the second embodiment, the AC / DC converter 43 </ b> A including the charging circuit 42 and the control circuit uses the energization information of the electric motor 21 output from the switch circuit 47 to more appropriately charge the main battery 40. Can be done. That is, by charging the main battery 40 only when the motor 21 is not driven (not rotating), the battery voltage fluctuates due to energization of the motor, so that the battery is fully charged or less than the predetermined voltage. It can be avoided that the determination of whether there is any is inaccurate. Further, by not charging the motor 21 for a predetermined time after the drive is stopped (energization is turned off), it is possible to prevent the main battery 40 from being charged little by little due to repeated turning on and off of the motor 21 during the cutting operation.

  Further, by providing the AC / DC converter 43A including the control circuit, sufficient DC power is supplied to the motor 21 from the AC / DC converter 43A including the control circuit even when both the main battery 40 and the sub battery 41 are not mounted. Supply is possible and speed control of the electric motor 21 is also possible.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  In each embodiment, although the case where the display part 44 was provided in the cutting | disconnection part 10 was illustrated, you may provide the display part 44 in the base part 1. FIG. In this case, there is no need to provide the control circuit 43 or the AC / DC converter 43A including the control circuit and the cord 44 for electrically connecting the display unit 44 from the base unit 1 to the cutting unit 10, and more Sliding motion is easier to perform. A battery protection circuit may be provided for each of the batteries 40 and 41.

  In each embodiment, when the commercial power source is connected, power is supplied from the commercial power source to the electric motor 21 and the electric motor 21 can be driven. However, only the electric power supply from the battery to the electric motor 21 is possible. In such a configuration, the commercial power supply may be configured to supply power only for charging the main battery 40 and the sub battery 41. In such a configuration, it is necessary to provide an AC / DC converter in order to be able to drive the electric motor 21 with the power of the commercial power source, or the electric motor 21 itself can be driven by both AC and DC power sources. There is no need to do this, and an inexpensive configuration can be obtained.

  In each of the embodiments, the sub battery 41 is detachable in addition to the main battery 40. However, the structure having only the main battery 41 or the sub battery 41 mounted on the base portion 1 can only be charged, and the motor. The power supply to 21 may be impossible. In the case where a charging function for charging the sub-battery 41 is provided in the base unit 1 and a cord is connected between the commercial power source and the base unit 1 to supply power for this charging, the cutting unit Since it is only necessary to electrically connect the main battery 40 attached to and detached from the motor 10 and the electric motor 21, it becomes easier to swing and slide the cutting part 10. In this case, when the main battery 40 is discharged, the charged sub battery 41 is attached to the cutting unit 40 instead of the main battery 40.

  In the embodiment shown in FIGS. 1 to 5, the main battery 40 is attached and detached by sliding from the front side to the rear side. However, the sliding direction of the main battery 40 may be any direction. . However, as in the embodiment shown in FIGS. 1 to 5, when the cutting portion 21 is swung and slid, it is better to provide it near the operation handle 14 held by the operator. 2 and 3, the main battery 40 is disposed at a position close to the circular saw blade 20, so that the cutting portion 10 is inclined obliquely by the weight of the main battery 40 which is a relatively heavy object. The configuration is such that the moment is hardly applied and the vertical movement is easy. For this reason, the operation handle 14 and the main battery 40 are overlapped when viewed from the front side, and such a configuration is desirable.

  In each embodiment, the circular saw blade is exemplified as the cutting tool, but the present invention can also be applied to a tabletop cutting machine using a rotating grindstone as the cutting tool.

DESCRIPTION OF SYMBOLS 1 Base part 2 Turntable 4 Tilt axis 5 Holder 7 Guide bar 8 Slider 9 Hinge 10 Cutting part 11 Cutting part case 12 Main cover 14 Operation handle 16 Protective cover 20 Circular saw blade 21 Electric motor 22 Rotating shaft 30 Cutting part support mechanism 40 Main Battery 41 Sub battery 42 Charging circuit 43 Control circuit 43A AC / DC converter including control circuit 44 Display unit 45 Commercial power cord 47 Switch circuit 50 Material to be cut SW1 Trigger switch

Claims (10)

A base part;
A cutting unit having an electric motor for rotationally driving the cutting tool and supported movably with respect to the base unit;
A control circuit provided in the base part;
A commercial power cord connected to the control circuit and drawn from the base portion;
A main battery that is provided in the cutting portion and supplies power to the electric motor;
The table cutting machine characterized in that the control circuit controls the electric motor. A base part;
A cutting unit having an electric motor for rotationally driving the cutting tool and supported movably with respect to the base unit;
A control circuit and a charging circuit provided in the base part;
A commercial power cord connected to the control circuit and drawn from the base portion;
A main battery that is provided in the cutting portion and supplies power to the electric motor;
The charging circuit is for charging the main battery,
The table cutting machine, wherein the control circuit controls the electric motor and the main battery.   The desktop cutting machine according to claim 2, wherein the charging circuit can charge the main battery only when the electric motor is not energized.   4. The tabletop cutting machine according to claim 3, wherein the charging circuit does not charge the main battery for a predetermined time from when the electric current of the electric motor is turned off.   The desktop cutting machine according to claim 2, wherein the charging circuit charges the main battery when a battery voltage of the main battery becomes a predetermined voltage or less.   The tabletop cutting machine according to any one of claims 2 to 5, wherein a sub-battery is provided in the base portion and can be charged by the charging circuit.   The battery voltage detecting means for detecting the battery voltage of the main battery and a display unit are provided, and the display unit displays a display prompting charging when the battery voltage becomes a predetermined voltage or less. The tabletop cutting machine according to any one of 5.   Battery voltage detection means for detecting the battery voltage of the main battery and the sub battery and a display unit are provided, and the display unit displays a display prompting charging when the battery voltage becomes a predetermined voltage or less. The tabletop cutting machine according to claim 6.   The tabletop cutting machine according to claim 7 or 8, wherein the battery voltage detection means and the display unit are provided in the cutting unit.   The tabletop cutting machine according to claim 7 or 8, wherein the display section is provided on the base section.