JP2009121946A - Device for inspecting preform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for inspecting preform, capable of high-speed transferring of preform by vacuum-sucking the preform, without pressing a suction head against it, when it is subjected to vacuum suction. <P>SOLUTION: The device for inspecting preform which inspects a preform 1 photographing the preform 1 that revolves about its own axis includes a plurality of suction heads 25 for vacuum-sucking the opening 1a of the preform 1; a main rotor 20 for making the plurality of suction heads that are rotating about own axes, respectively; and a rotary valve for making intermittently each of the suction heads 25 and a vacuum source communicate, in which there is a gap between the suction heads 25 and the opening 1a of the preform 1, when the opening 1a of the preform 1 is vacuum-sucked by the suction head 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a preform inspection apparatus that inspects the appearance of a preform, which is a preformed product of a PET bottle, with a camera, and in particular, when vacuum-adsorbing the preform, the suction head is not pressed against the preform. The present invention relates to a preform inspection apparatus that enables high-speed conveyance of a preform by vacuum-adsorbing the preform.

The PET bottle is preformed into what is called a preform, and the preform is heated and molded into a bottle. The preform has a test tube shape, that is, a flat mouth portion and a spherical bottom portion, and a ring-shaped neck ring at the neck portion.
A conventional preform inspection apparatus includes a star wheel for transferring a preform, and a main rotor for rotating the suction head by rotating the suction head by rotating the suction head by vacuum suction of the mouth of the transferred preform. The reform is photographed with a camera and the appearance of the preform is inspected.

Conventionally, when a preform is transferred from an inlet star wheel or the like to a main rotor, a neck ring at a neck portion of the preform is transferred onto a guide rail (crossover plate). Then, after the suction head is lowered and pressed against the mouth of the preform, evacuation is started. While evacuating, the preform is conveyed to a predetermined position while the neck ring slides on the guide rail. Thus, in order to ensure reliable vacuum suction, it is necessary to press the suction head against the mouth of the preform, and as a result, the neck ring of the preform is pressed against the guide rail.
Japanese Patent No. 3422967 Japanese Patent No. 3859323

  As described above, when vacuum-adsorbing the preform, the preform is moved while the vacuum is pulled while the neck ring of the preform is pressed against a flat guide rail such as SUS by the suction head. Friction occurs in the neck ring of the reform. If the conveyance speed of the main rotor is about 400 BPM, the temperature rise of the guide rail due to friction does not pose a problem, but if it exceeds 800 BPM, which is high-speed conveyance, there arises a problem that the guide rail is heated to a high temperature.

Further, a collision sound is generated when the suction head is pressed against the mouth of the preform, and the mouth is sometimes damaged. The guide rail is easily deformed by the impact when the suction head is pressed against the mouth of the preform, and if the preform is conveyed at high speed while evacuating, a larger amount of frictional heat is generated in the guide rail, resulting in high speed conveyance. You are in a situation where you cannot.
Furthermore, since the friction force is generated between the neck ring of the preform and the guide rail due to the pressing force of the suction head, a bending moment acts on the shaft portion of the suction head, and the shaft portion of the suction head may be deformed. .

  Furthermore, even when the preform is transported at a high speed, the minimum necessary suction time is required in order to vacuum-suck the preform, as in the case of low-speed transport. When the conveyance speed is doubled from 400 BPM to 800 BPM, the distance for pressing the preform against the guide rail also needs to be twice as long. In this case, the shape of the cam (cam contour) for raising and lowering the suction head needs to be steeper than in the prior art, and high speed response may not be possible due to the problem of the maximum acceleration of the cam.

  The present invention has been made in view of the above-described circumstances, and enables high-speed conveyance of a preform by vacuum-adsorbing the preform without pressing the suction head against the preform when vacuum-adsorbing the preform. An object is to provide a preform inspection apparatus.

In order to achieve the above-described object, the present invention includes a plurality of suction heads that vacuum-suck the mouth portion of a preform, a main rotor that revolves while rotating the plurality of suction heads, the suction heads, and a vacuum source. And a rotary valve that intermittently communicates with the preform, and in a preform inspection apparatus that photographs and inspects a preform that rotates with a camera, when the suction head vacuum-sucks the mouth of the preform, A gap is provided between the mouth of the preform.
According to the present invention, when the suction head vacuum-sucks the mouth portion of the preform, there is a gap between the preform and the mouth portion of the preform, so that the neck ring of the preform is pressed against the guide rail. The friction between the guide rail and the neck ring of the preform can be drastically reduced.

According to one aspect of the present invention, the suction head is configured to be raised and lowered by a cam, and when the suction head is lowered to the lowest position, the suction head and the mouth of the preform The cam contour of the cam is set so as to have the gap between them.
According to the present invention, by securing a slight clearance between the preform and the preform, the position of the suction head can be kept high, and the cam shape (cam contour) at the time of suction can be made gentle. is there.

Pressing the conventional suction head against the mouth of the preform means that if there is no preform, the suction head will be lowered further, and conversely if there is a preform, the suction head will be slightly Located above.
That is, conventionally, in order to ensure that the suction head is in contact with the mouth of the preform, the cam shape (cam contour) is set so that the suction head can be lowered further below the mouth of the preform. Yes. This is because if the lowermost position of the suction head is set to the same height as the mouth of the preform, the suction head may not contact the mouth of the preform. Therefore, conventionally, the suction head is raised and lowered in accordance with the cam shape by its own weight.

As mentioned above, since the lowest point of the cam is the state where there is no preform in the past, the cam follower is lifted from the cam accordingly, and the preform is removed in the next step. The cam follower collided with the cam when ascending, and as a result, there were problems of impact and sound during high-speed operation.
According to the present invention, since the clearance is provided between the suction head and the mouth of the preform and this is the lowest point of the cam, the cam follower is not lifted from the cam regardless of the presence or absence of the preform. . That is, since the cam follower keeps rolling without always leaving the cam, the cam follower does not collide with the cam when the suction head is lifted from the lowermost position, and there is no problem of impact or sound. .

According to one aspect of the present invention, when the suction head vacuum-sucks the mouth portion of the preform, the guide head includes a guide rail that supports a neck ring of the preform, and a temperature sensor is installed on the guide rail. And
According to the present invention, the temperature of the guide rail can be monitored by the temperature sensor.
According to one aspect of the present invention, when the temperature sensor exceeds a set temperature range, the drive of the preform inspection apparatus is stopped or decelerated.

The present invention has the following effects.
1) When the suction head vacuum-sucks the mouth of the preform, there is a gap between the preform and the mouth of the preform, so the neck ring of the preform is not pressed against the guide rail, and the guide Friction between the rail and the neck ring of the preform can be greatly reduced. Therefore, the preform can be conveyed at high speed.
2) Since the suction head has a gap between the preform and the mouth of the preform when the mouth of the preform is vacuum-sucked, the preform is not damaged at the time of suction. The shaft does not deform.
3) In the case of the conventional system in which the suction head is pressed against the mouth of the preform and vacuum suction is performed, the position of the suction head is further lowered at the start of suction compared to the end of the inspection. By securing a slight clearance with the reform, the position of the suction head can be kept high, and the cam shape (cam contour) at the time of suction can be made gentle.
4) The frictional heat generated from the guide rail is not the case where the preform is transported at high speed, but the positional relationship between the suction head and the guide rail is poorly adjusted or the dimensions of the preform to be supplied are different. However, before damaging the inspection device or preform, the temperature of the guide rail is monitored using a temperature sensor installed on the back side of the guide rail. It is possible to operate at low speed.

Hereinafter, an embodiment of a preform inspection apparatus according to the present invention will be described with reference to FIGS.
FIG. 1 is a plan view showing the overall configuration of the preform inspection apparatus. As shown in FIG. 1, the preform inspection apparatus includes an entrance star wheel 3 that carries a preform 1 to be inspected into a main rotor 20, and a main rotor 20 that inspects the preform 1 while conveying the preform 1. And an exit star wheel 4 for carrying out the preform 1 after inspection from the main rotor 20.

  2 is a sectional view taken along line II-II in FIG. FIG. 2 is a diagram showing the main rotor 20 that handles the preform. As shown in FIG. 2, the preform has a substantially test tube shape, the mouth 1a is flat, the body 1b is cylindrical, the bottom 1c is spherical, and has a neck ring 1d at the neck. As shown in FIG. 1, guide rails 6 and 6 that support the neck ring 1 d of the preform 1 are installed along the pitch circle of the inlet star wheel 3.

  Guide rails 7 and 7 that support the neck ring 1 d of the preform 1 are installed along the pitch circle of the outlet star wheel 4. The inlet side guide rails 8 and 8 are connected to the guide rails 6 and 6, and the outlet side guide rails 9 and 9 are installed adjacent to the outlet star wheel 4. The inlet side guide rails 8 and 8 and the outlet side guide rails 9 and 9 are downwardly inclined in the traveling direction.

  One illumination 10 is installed on the inner side of the pitch circle of the main rotor 20, and two photographing camera units 11 and 12 are installed on the outer side. The illumination 10 has an arc-shaped front surface along the pitch circle of the main rotor 20. The photographing camera units 11 and 12 are each composed of a mirror 13 and a CCD camera 14 and can cope with a high-speed line.

  A rotation timing belt 15 for rotating the preform 1 is disposed outside the pitch circle of the main rotor 20. A brake belt 16 for stopping the rotation of the preform 1 is disposed downstream of the rotation timing belt 15.

  As shown in FIG. 2, the main rotor 20 is supported by a rotary shaft 21, a support plate 23 fixed to the rotary shaft 21, and supported by the support plate 23 so as to be movable in the vertical direction, and the mouth 1 a of the preform 1. And a suction head 25 for vacuum suction. The rotary shaft 21 is rotatably supported by a bearing housing 24 having upper and lower bearings 22 and 22.

The rotating shaft 21 is connected to a motor (not shown), and a plurality of guide bars 37 are supported on a support plate 23 fixed to the rotating shaft 21. A support member 38 is supported on the guide bar 37 so as to be movable up and down. A fixed shaft 39 that is fixed to the frame F and extends downward is provided above the rotating shaft 21. A cam 40 is fixed to the fixed shaft 39.
On the other hand, the shaft portion 27 of the suction head 25 is supported by a support member 38, and a cam follower 42 fixed to the support member 38 engages with a cam 40 fixed to a fixed shaft 39, so that the support member 38 is vertically moved. It comes to move. The cam 40 is disposed over the entire circumference of the main rotor 20 and controls the vertical position of the suction head 25 by moving the suction head 25 up and down.

  FIG. 3 is a sectional view showing the detailed structure of the suction head 25. As shown in FIG. 3, the suction head 25 includes a suction head body 26 that vacuum-sucks the mouth portion 1 a of the preform 1, an elongated shaft portion 27 that holds the suction head body 26, a suction head body 26, and a shaft. And a connecting portion 28 for connecting the portion 27. The suction head body 26 has a tapered convex portion 26a inserted into the mouth portion 1a of the preform 1, and has a communication hole 26b inside. The shaft portion 27 has a communication hole 27a inside.

  As shown in FIGS. 2 and 3, the suction head 25 is rotatably supported by upper and lower bearings 44, 44. The bearing housing 45 that houses the upper and lower bearings 44 is supported by the support member 38. The suction head 25 has communication holes 26 b and 27 a inside, and the communication hole 27 a is communicated with a vacuum source (not shown) via a tube 47 and a rotary valve 50. The rotary valve 50 includes a rotating side member 51 that rotates in synchronization with the main rotor 20 and a fixed side member 52 that is fixedly provided, and a vacuum groove or an air release groove is provided on one side of the rotary valve 50. Is provided, and vacuuming, blocking of the vacuum path, or opening to the atmosphere is performed. A pulley 48 that engages with the rotation timing belt 15 is fixed to the suction head 25. The belt hooking portion that rotates the suction head 25 is positioned above the two bearings 44 and 44 that support the suction head 25.

  FIG. 4 is a schematic cross-sectional view showing the rotary valve 50. As shown in FIG. 4, the rotary side member 51 that rotates in synchronization with the main rotor 20 and a fixed side member 52 that is fixedly provided are provided. The rotary side member 51 and the fixed side member 52 are both cylindrical members. Thus, the inner peripheral surface of the rotation-side member 51 and the outer peripheral surface of the fixed-side member 52 are in sliding contact. On the outer peripheral surface of the stationary member 52, an arcuate groove 52a for evacuation and a rectangular groove 52b for opening to the atmosphere are formed. The arc-shaped groove 52a of the stationary member 52 is communicated with a vacuum source (vacuum pump) through a tube. The rotation-side member 51 is formed with a plurality of communication holes 51h communicating with the arc-shaped groove 52a and the rectangular groove 52b, and each communication hole 51h is connected to each suction head 25 via a tube 47 ( (See FIG. 2). In FIG. 4, only four communication holes 51 h formed in the rotation-side member 51 are shown, but in actuality, there are a large number of communication holes 51 h and the same number as the number of suction heads 25.

In the rotary valve 50 configured as described above, when the rotation-side member 51 rotates while being in sliding contact with the fixed-side member 52, a communication hole 51 h formed in the rotation-side member 51 is formed in an arc shape formed in the fixed-side member 52. While in a position facing the groove 52a, negative pressure from a vacuum pump communicated with the arc-shaped groove 52a is supplied to the suction head 25 connected to the communication hole 51h, and the preform 1 is sucked and held by the suction head 25. Is done. Further, when the communication hole 51h is displaced from the arc-shaped groove 52a, the negative pressure from the vacuum pump is cut off and the suction holding of the preform 1 by the suction head 25 is released. Thereafter, when the communication hole 51h communicates with the rectangular groove 52b for opening to the atmosphere, the suction head 25 is released to the atmosphere. Next, when the communication hole 51 h communicates with the arc-shaped groove 52 a again, negative pressure from the vacuum pump is supplied to the suction head 25.
As described above, the rotary valve 50 is in the process of 1) vacuuming ⇒ 2) shut-off (neutral) ⇒ 3) air release ⇒ 4) shut-off (neutral) ⇒ 5) re-evacuation ⇒ 6) shut-off (neutral) Rotation.

Next, the relationship between each process of the rotary valve 50 and the preform 1 will be described.
The preform 1 is vacuum-sucked by the suction head 25 by evacuation by the rotary valve 50, and then 2) Even at the neutral position, the pressure difference between the inside of the preform 1 and the suction head 25 is due to the vacuum pressure. Even if the vacuum system is shut off, it remains in the adsorbed state. 3) When the atmosphere is open, the vacuum pressure in the preform 1 is reduced to atmospheric pressure, and the preform 1 is separated from the suction head 25 by its own weight, and supports the neck ring 1d of the preform 1 from below. Supported by the guide rail 7, the preform 1 is conveyed to the next process on the downstream side. The suction head 25 repeats a series of operations of 5) vacuum suction by re-evacuation to the preform 1 newly conveyed to the main rotor 20.

Next, the overall operation of the preform inspection apparatus configured as shown in FIGS. 1 to 4 will be described.
The preform 1 is supplied to the inlet star wheel 3 from the inlet side guide rails 8 and 8. The preform 1 is transferred by the inlet star wheel 3 in a state where the neck ring 1 d is supported by the guide rails 6 and 6. Then, the preform 1 is delivered from the inlet star wheel 3 to the main rotor 20.

  When the preform 1 is transferred to the main rotor 20, the suction head 25 is lowered by the action of the cam 40, the suction head 25 is brought close to the mouth 1 a of the preform 1, and the tube 47 and the rotary valve 50 are interposed. The suction head 25 is communicated with a vacuum source, and vacuum suction of the preform 1 is started. At this time, as shown in FIG. 5, a slight gap C is formed between the bottom surface 25 a of the suction head 25 and the mouth portion 1 a of the preform 1. In other words, even if the suction head 25 is lowered by the action of the cam 40, the cam contour (cam) of the cam 40 so that a gap C is secured between the bottom surface 25a of the suction head 25 and the mouth 1a of the preform 1. Since the shape) is set, no pressing force is applied from the suction head 25 to the preform 1. In this case, the tapered convex portion 26 a of the suction head 25 is inserted into the mouth portion 1 a of the preform 1. As shown in FIG. 5, the preform 1 is conveyed at high speed while being supported by the guide rails 6 and 6, and the inside of the preform 1 is evacuated by the suction head 25, and the preform 1 is vacuumed by the suction head 25. Adsorbed.

Conventionally, the pressing amount of the suction head to the mouth of the preform is set to 3 mm. However, in the present invention, the pressing amount of the suction head 25 is eliminated and a clearance (gap) is conversely provided, and the guide The friction of the rail 6 is drastically prevented.
As a result of the experiment, it is possible to provide vacuum suction with a slight clearance of about 0.3 mm between the preform and the suction head, minimizing the vacuum leakage flow rate and solving the problem of frictional heat. did it. The vacuum pressure at this time was 2 kPa, and the air flow rate was 20 l / min.

In the case of the conventional method in which the suction head is pressed, the suction head has a lower position at the start of suction compared to the position at the end of the inspection, but in the present invention, between the suction head 25 and the preform 1. Furthermore, by securing a slight clearance (about 0.3 mm), the position of the suction head 25 can be kept high, and the cam shape (cam contour) at the time of suction can be made gentle.
As a result, adsorption is possible even at 800 BPM, which greatly exceeds the conventional conveyance speed of 400 BPM, eliminating problems such as guide rail frictional heat, preform scratches, maximum cam acceleration, and damage to the suction head shaft. We were able to.

  In addition to the case where the preform 1 is conveyed at high speed, the frictional heat generated from the guide rail 6 can be caused by poor adjustment of the positional relationship between the suction head 25 and the guide rail 6 or the dimensions of the preform 1 supplied. Although it may also occur in the case where they are different, a temperature sensor S is installed on the back side of the guide rail 6 as shown in FIG. By monitoring, when the abnormality exceeds the set range of the temperature sensor S, the inspection device is urgently stopped or operated at a low speed.

  When the suction of the preform 1 by the suction head 25 is completed, the suction head 25 is raised by the action of the cam 40, and the preform 1 is moved by the action of the rotation timing belt 15 in a state where the preform 1 is sucked by the suction head 25. The preform 1 is rotated together with the suction head 25, and the preform 1 is revolved by the main rotor 20. During this time, the body 1 b and the neck ring 1 d of the preform 1 are photographed by the photographing camera unit 11 or 12.

After the photographing is completed, the preform 1 stops rotating by the action of the brake belt 16. Thereafter, the preform 1 is delivered from the main rotor 20 to the exit star wheel 4.
At this time, in the preform 1, the neck ring 1d is supported by the guide rails 7 and 7. The normal preform 1 is transferred by the outlet star wheel 4 and transferred to the next process through the outlet side guide rails 9 and 9. On the other hand, the defective preform 1 is released from the suction support by the outlet star wheel 4 at the position of the defective product discharge chute 60 and discharged to the defective product discharge chute 60.

FIG. 1 is a plan view showing the overall configuration of the preform inspection apparatus. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view showing the detailed structure of the suction head. FIG. 4 is a schematic cross-sectional view showing a rotary valve. FIG. 5 is a diagram showing the relationship between the suction head and the preform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Preform 1a Mouth part 1b Body part 1c Bottom part 1d Neck ring 3 Inlet star wheel 4 Outlet star wheel 6,7 Guide rail 10 Illumination 11,12 Shooting camera unit 13 Mirror 14 CCD camera 15 Rotating timing belt 16 Brake belt 20 Main rotor 21 Rotating shaft 22 Bearing 23 Support plate 24 Bearing housing 25 Suction head 26 Suction head main body 26a Convex portion 27 Shaft portion 26b, 27a, 51h Communication hole 28 Connection portion 37 Guide bar 38 Support member 39 Fixed shaft 40 Cam 42 Cam follower 44 Bearing 45 Bearing housing 47 Tube 48 Pulley 50 Rotary valve 51 Rotating member 52 Fixed member 52a Circular groove 52b Rectangular groove 60 Defective product discharge chute

Claims (4)

A plurality of suction heads that vacuum-suck the mouth of the preform, a main rotor that revolves while rotating the plurality of suction heads, and a rotary valve that intermittently communicates each suction head with a vacuum source, In the preform inspection device that inspects the preform that rotates with the camera,
A preform inspection apparatus having a gap between the suction head and the preform mouth when the suction head vacuum-sucks the mouth of the preform. The suction head is configured to be raised and lowered by a cam;
The cam contour of the cam is set so that the gap is provided between the suction head and a mouth of the preform when the suction head is lowered to the lowest position. The preform inspection apparatus described. When the suction head vacuum-sucks the mouth portion of the preform, the guide head includes a guide rail that supports the neck ring of the preform.
The preform inspection apparatus according to claim 1, wherein a temperature sensor is installed on the guide rail. 4. The preform inspection apparatus according to claim 3, wherein when the temperature sensor exceeds a set temperature range, the drive of the preform inspection apparatus is stopped or decelerated.

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