JPS61149818A - Inspecting instrument for defect of vessel - Google Patents

Abstract

PURPOSE:To inspect a defect accurately in short inspection time by providing two holes for decompression suction and pressure detection on an inspecting plate and detecting the inside pressure after performing the decompression suction for a vessel to be inspected on the inspecting plate. CONSTITUTION:The hole 11 for the decompression suction and the hole 12 for the pressure detection are provided on the inspecting plate 3 having the flat surface supporting opening ends 1a, 1a' of the vessels 1, 1' to be inspected. A constant pressure decompressing pump 15 and a pressure sensor 18 are connected with these holes 11, 12 respectively. Then, when the vessel 1' to be inspected is conveyed on this inspecting plate 3, first, the inside of the vessel 1a' is decompressed with the constant pressure decompressing pump 15 through the suction hole 11 and the vessel 1' is adhered closely to the inspecting plate 3 and then, the inside pressure within the vessel 1a' is detected with the pressure sensor 18 through the detection hole 12 to detect the defect such as flash, hole and resin replenishment deficiency, etc. of the vessel 1a'.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is for inspecting defects such as holes, holes, and insufficient filling of resin at the open end of a hollow container whose one end is formed as an open end. The invention relates to a device.

[Conventional technology]

The internal space of a cup-shaped container, for example, which has an open end, is depressurized or pressurized relative to the outside air, and the pressure change is monitored to inspect defects such as pinhole defects and irregularities in the open end of the container. Devices for this purpose are disclosed, for example, in JP-A-53-55187 and JP-A-56-22905.
It is known from the publication no. The device disclosed in the former item reduces the pressure inside the container to a predetermined pressure, then disconnects the depressurization source and determines the quality of the container by measuring the degree of pressure change after a certain period of time. is long, making it unsuitable for use as an online inspection device. - On the other hand, in the latter device, the inside of the container is connected to a constant pressure source and the quality of the container is determined by measuring the degree to which the inside of the container is pressurized. During the measurement period, it is necessary to press the container against a constant pressure source in order to seal the open end of the container. Therefore, for example, if the container is made as a plastic molded product, flexible defects such as flakes attached to the open end will be crushed by the pressure and cannot be detected.

Furthermore, each of the conventional devices mentioned above requires an accurate positioning mechanism because the measurement results will vary greatly if the container to be inspected is not accurately positioned with respect to the measurement jig. , the complexity of the structure is unavoidable. In addition, the pressure detectors in these devices are connected midway through the pressure reduction or pressurization piping and obtain pressure changes as mechanical displacement, so they are susceptible to pressure loss and cannot accurately measure pressure. It also has the disadvantage of being difficult.

[Problem that the invention seeks to solve]

The present invention eliminates the drawbacks of the conventional techniques described above, enables accurate inspection while shortening inspection time, and also enables accurate positioning of the container at the inspection position and pressing of the container. The purpose of the present invention is to provide an inspection device that does not require a complicated mechanism.

[Means to solve the problem]

In order to solve the above problems, the inspection device of the present invention uses an inspection plate in which at least two holes, a suction hole for pressure reduction and a detection hole for pressure detection, are formed, and the inspection plate is connected to the suction hole. The open end of the container, which has been sucked by a constant pressure vacuum source, is received by a flat surface formed on the inspection plate. Then, a pressure detector is connected to the detection hole which is provided separately from the piping leading from the suction hole to the constant pressure reduction source, and the open end of the container is suctioned to the flat surface of the inspection plate by the constant pressure reduction source. The pressure inside the container is then measured using a pressure detector.

[First embodiment]

In FIG. 1 showing an example of an inspection device using the present invention,
A cylindrical container 1 constructed as an injection molded product of plastic material is conveyed in the direction of arrow X by a conveyor belt 2 with its open end 1a facing down. An inspection plate 3 is arranged substantially vertically below the terminal end of the conveyor belt 2, and a chute 4 is provided opposite the inspection plate 3. The distance between the inspection plate 3 and the chute 4 is set to be slightly wider than the height of the container l, so that the container 1 dropped from the end of the conveyor belt 2 has its open end 1a facing left. In this state, it falls between the inspection plate 3 and the chute 4.

In addition, an appropriate side plate (not shown) is also used to prevent the container 1 from escaping to the side during the falling process of the container 1. Further, the inspection plate 3 and the chute 4 may be arranged diagonally as long as the containers 1 sent from the conveyor belt 2 fall by themselves.

A solenoid 5 having a stopper 7 fixed to its tip is attached to the chute 4. Then, by driving the solenoid 5, the stopper 7 is projected toward the inspection plate 3 side through the opening 4a formed in the chute 4, and falls between the inspection plate 3 and the chute 4. Hold the container 1' in the position shown.

The inspection plate 3 has suction holes 11. An inspection hole 12 is formed. A solenoid valve 14 is connected to the suction hole 11 via a suction pipe 13. A constant pressure vacuum pump 15 is connected, and a pressure gauge 18 is connected to the inspection hole 12 via a pipe 17. The suction hole 11 and the inspection hole 12 face into the open end l'a of the container l° whose fall is stopped by the stopper 7, and when the constant pressure reducing pump 15 is operated with the solenoid valve 14 open. The pressure inside the container 1' is reduced through the suction hole 11, and the container 1° is attracted to the inspection plate 3 whose open end 1'a side is configured as a flat surface. In addition, as the electromagnetic valve 14, for example, a three-way valve is used, and when this is opened, the suction hole 1
1 and the constant pressure reducing pump 15 are directly connected, and when the suction hole 11 is closed, the suction hole 11 and the constant pressure reducing pump 15 are separated, and the suction hole 11 is opened to the outside air.

Furthermore, if a plurality of suction holes 11 are provided and suction is performed using a common constant pressure reducing pump 15, time for suctioning the container 1'' onto the inspection plate 3 can be saved.

The pressure inside the container 1' is measured by a pressure sensor 18 through an inspection hole 12. The pressure sensor 18 is configured to output an electrical signal corresponding to the measured pressure, and the electrical signal detected here is compared in a comparison circuit 21 via a processing circuit 20, and the electrical signal is set to a predetermined value. The internal pressure of the container l'' is determined depending on whether the pressure is greater than or not, and the quality of the container l'' is determined.

When it is detected that the container 1 is defective, the solenoid 23 is pulled in and activated via the solenoid drive circuit 22, and the distribution plate 24 is moved to the position shown by the two-dot chain line, as indicated by the arrow Y. The container 1'' is separated from the good product path to the defective product path indicated by arrow Z.

The operation of the inspection apparatus having the above configuration will be explained with reference to the block diagram of the electrical system shown in FIG. The conveyor belt 2 is intermittently turned ON-OFF as shown in FIG. 3 via a motor drive circuit 26 operated by a processing circuit 20.
The conveyance motor 27 is used to drive the conveyor. Since the containers l are placed on the conveyor belt 2 at predetermined intervals, near the end of the ON state of the conveyor motor 27, the O
Before entering the FF state, only one container 1'' to be inspected is dropped between the inspection plate 3 and the chute 4.

At this point, a signal from the processing circuit 20 causes the solenoid drive circuit 29. Since solenoid 5 is activated,
The stopper 7 is in the protruding position, the solenoid valve 14 is open, and air is being sucked from the suction hole 11. Therefore, the falling container 1° (see Figure 1) is
At the same time as the puff stops the drop, its open end 1+a is brought into close contact with the flat surface of the inspection plate 3.

The constant pressure vacuum pump 15 is -110011IIIH20 (
The inside of the container 1゛ is suctioned at a constant pressure of (mm) water column,
After that, the pressure sensor 18 is activated for a predetermined time, and the inspection hole 1
2, the pressure inside the container 1' is measured. Therefore, if the container 1' has no defects such as pinholes or cracks at the open end, the pressure sensor 18 will detect a pressure of -1100 mmH2O. At times, if a burr or the like is formed on the open end 1''a of the container 1', the degree of depressurization inside the container 1'' will differ depending on the height of the burr.
Pressures higher than 100 mmH2O will be detected. In addition, -1100mmH20 is inside the container 1'.
Since only a relatively weak pressure is applied, the Paris 1
There is no way that 9 can be bent.

As described above, the pressure sensor 18 outputs an electrical signal corresponding to the measured pressure. The electric signal obtained in this way is determined by using, for example, a peak value hold circuit, and the highest pressure measured until the pressure sensor 18 ends its operation (as it is a negative pressure with respect to the external pressure, the absolute value The value corresponding to the lowest value) is inputted to the comparison circuit 2 as a detection signal via the processing circuit 20.

Note that in this case, an electric signal corresponding to the measured pressure at the end of the operation of the pressure sensor 18 may be used instead of the detection signal.

The comparison circuit 18 is composed of a well-known comparator using an operational amplifier or the like, and the detection signal from the processing circuit 20 is
When the value is larger than a predetermined value, a defect signal is fed back to the processing circuit 20. and,
When the defect signal is fed back to the processing circuit 20, the solenoid drive circuit 22. The distribution plate 24 is actuated via the solenoid 23, and is moved to the position indicated by the two-dot chain line in FIG. When the solenoid valve 14 is closed after the pressure inside the container 1'' is measured in this way, the inside of the container 1'' becomes the external pressure, so the stopper 7 is pulled in.
The container 1' falls due to its own weight, and when the plate 24 is at the two-dot chain line position, the container 1' is discharged into the defective product path in the direction of the arrow Z.

When the above-mentioned process is completed, the processing circuit 20 outputs an activation signal to the motor drive circuit 26 to feed and drive the conveyor belt 2, so that the same action is repeated for the next container to be sent. become.

In this way, in this inspection device, the container 1 at the inspection position
It is only necessary to suction the opening end 1°a of the
1 and the inspection hole 2 need only be roughly positioned within 1° a of the open end of the container 1', which simplifies the construction and saves time.

[Second embodiment]

In a second embodiment of the invention, schematically illustrated in FIG. They are placed with their open ends facing down and are fed sequentially onto the inspection plate 35. Inspection plate 3
5 is provided with a suction hole 11 connected to a constant pressure reducing pump 15 via a solenoid valve 14 and an inspection hole 12 connected to a pressure sensor 18, and performs the same function as the first embodiment.

The suction hole 11. When the container 31 is moved to the inspection position where the inspection hole 12 is provided, a photosensor 36 that detects reflected light from the side surface of the container 31 is activated, for example. When the detection signal from the photosensor 36 is input to the processing circuit 20, the solenoid valve 14 is opened and the inside of the container 31 is depressurized by the constant pressure reducing pump 15, and the container 31 is transferred to the inspection plate 3.
At the same time, the identification device 38 for identifying the type of container is activated. As a result, the type of container 31 at the inspection position is read, and its identification signal is input to the processing circuit 20. As the identification device 38,
When determining the planar size of the containers 31, 32, and 33, for example, the determination can be made from the outline of the container using a TV camera or the like.

A light receiver may be arranged to make the determination based on the total amount of reflected light from the top surface of the container. Furthermore, when the reflectances of the upper surfaces of the containers 31 to 32 are different from each other, the type of container can also be determined from the intensity of reflected light.

When the type of the container is determined by the identification device 38, the processing device 20 activates the comparison circuit 40. , selects a predetermined value, and compares its value with the electrical signal from the pressure sensor 18.

On the inspection plate 35, since the container 31 is constantly being moved, even if the constant pressure reducing pump 15 depressurizes the inside of the container 31 by 1100 mn+H20 during that time, this is -11 mn+H20.
When the pressure reaches 00111RH20, the pressure corresponding to the internal volume of the container is measured by the pressure sensor 18. Therefore, as mentioned above, by comparing the predetermined value set for each type of container with the pressure measurement value just before the container finishes passing through the inspection position, the quality of the container can be automatically determined depending on the type of container. This will enable inspection.

As a modification of the second embodiment, a variable pressure reducing device may be used instead of the constant pressure reducing pump 15, and the reduced pressure may be changed as appropriate depending on the type of container.

〔Example〕

Example data when the first embodiment is used is as shown in FIG. The horizontal axis in FIG. 5 indicates the height of the open end l'a of the container 1'', and the vertical axis indicates the internal pressure of the container 1° detected by the pressure sensor 18.As is clear from this data, , the greater the height of Paris, -1100
Voltage reduction of mmH20.

The ultimate pressure by the pressure pump 15 increases (decreases in absolute value), and in correspondence with the pressure measured by the pressure sensor 18, it becomes possible to inspect for defects due to paris. Therefore, as a comparison standard in the comparison circuit 21, for example, −200111111H
If 20 is set, containers with a height of 19 of 0.25 mm or more can be sorted out as defective products. Of course, it is also possible to determine when it is time to replace the mold used to manufacture the container based on the frequency of occurrence of defective products and the deterioration of the ultimate pressure.

〔Effect of the invention〕

As mentioned above, according to the inspection device of the present invention, there is no need to precisely position the container to be inspected at the inspection position, and there is no need to use any additional mechanism to press the container for this positioning. In addition, there is no need to place the container in perfect contact with the inspection position, and there is no need for an excessive pressure source like in the past, making it possible to inspect weak defects such as burrs in a short time. Become. Moreover, the device of the present invention does not require any special measuring jig to support the container at the inspection position, and does not require any special conveyance means to transport the container to the inspection position. It is very effective as an online inspection device used in container manufacturing lines. In terms of inspection accuracy, the pressure inside the container is measured through an inspection hole that is separate from the suction hole that suctions the inside of the container, making it possible to perform highly accurate inspections without the influence of pressure loss.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a first embodiment of the invention. FIG. 2 is a block diagram showing an example of a circuit configuration used in the first embodiment. FIG. 3 is a chart diagram explaining the operation timing of each part in the first embodiment. FIG. 4 is a schematic diagram showing a second embodiment of the invention. FIG. 5 is a graph showing example data when the first embodiment is implemented. 1.1゛...Container 1a, l'a...Open end 2...Transport belt 3...Inspection plate 4...
・Chute 7...Stopper 11...Suction hole
12..Inspection hole 14..Solenoid valve 15..Constant pressure reduction pump 18..Pressure sensor 19..Paris 20..Processing circuit 21..Comparison circuit 24..Distribution is plate 36..Photo sensor 38..Identification Device
40... Comparison circuit 42... Data memory.

Claims (4)

[Claims] (1) An inspection plate including a flat surface for receiving the open end of the container to be adsorbed, and in which a suction hole for depressurization and a detection hole for pressure detection are formed, and a constant pressure decompression source connected to the suction hole. , a pressure detector connected to the detection hole, and the pressure inside the container is reduced by the constant pressure reduction source, and the pressure inside the container is measured by the pressure sensor while the open end side of the container is pressed against a flat surface. A container defect inspection device characterized by measuring defects. (2) The container defect inspection device according to claim 1, wherein the pressure detector is a pressure sensor that outputs an electrical signal corresponding to the measured pressure. (3) The container defect inspection device according to claim 2, further comprising a comparison circuit that compares whether or not the electric signal reaches a predetermined value. (4) The container defect inspection device according to claim 3, further comprising a solenoid valve provided between the suction hole and the constant pressure reduction source.