JPH0552817A - Defect inspecting apparatus of seamless metal can - Google Patents

Abstract

PURPOSE:To obtain a defect inspecting apparatus of an inner organic coating layer of a seamless metal can, which can perform 100% inspection. CONSTITUTION:An inspecting apparatus comprises a metallic sleeve 6 to which a seamless metal can 7 can be out-fitted, a metallic spindle 5 to which the sleeve 6 is fixed, a device for rotating the spindle 5, and a freely rotatable elastic roll which can apply pressure to an entire length of a body of the seamless metal can 7 which has been out-fitted to the sleeve 6. The apparatus further comprises an electrode terminal 10 which is supported by the spindle 5 via an electrically insulated cylinder 9 and can be in contact with an end face 7c of the seamless metal can out-fitted to the sleeve 6, a dc. power source for applying high voltage current voltage between the sleeve 6 and the electrode terminal 10 and an electric circuit for determining a defect of an inner organic coating layer based on the current flowing between the sleeve 6 and the electrode terminal 10.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an inner surface organic material of a seamless metal can having an organic coating layer such as a plastic film film or a coating film on the inner surface, which is used for canning beer cans, carbonated beverage cans, coffee beverage cans and the like. The present invention relates to a defect inspection device for a coating layer.

[0002]

2. Description of the Related Art Japanese Utility Model Laid-Open No. 2-59109 (Actual application No. 1)
No. 55451) describes that an organic coating layer is formed on both surfaces, for example, a thickness of 30 μm on the surface to be the inner surface of the can.
m polyethylene terephthalate film, a metal plate having a 20 μm-thick polyethylene terephthalate film adhered to the outer surface of the can, for example, a blank of tin-free steel (thickness is 0.13 mm). A seamless metal can having an organic coating layer on both sides formed by drawing is described.

The inner surface organic coating layer of this type of seamless metal can sometimes causes defects such as scratches and local peeling portions during drawing and redrawing. Defects are particularly likely to occur on the inner wall organic coating layer of the body wall and the outer wall of the annular protrusion at the bottom. These defects are not preferable because they corrode the metal due to the contents, leading to elution of metal ions into the contents and perforation of the metal layer.

As a defect inspection method for the inner surface organic coating layer,
Conventionally, the enamel rater method has been mainly used (for example, “Handbook of Packaging Technology”, No. 1845).
Page, July 20, 1983, Nikkan Kogyo Shimbun). This is so that the metal plate side having the organic coating layer becomes the positive electrode,
This is a method of applying a constant voltage (usually 6 V) between the electrode (negative electrode) immersed in an electrolytic solution (eg, 1% NaCl aqueous solution) and measuring the flowing electrolytic current. It is said to be almost proportional to the area.

In this enamellator method, the object to be inspected is contaminated by the electrolytic solution, so that even if the inspection value is normal, it is difficult to pass it to the subsequent production process, and the inspection of the object to be inspected is performed. There is also a problem in that it takes time and labor to attach to the device in order to prevent electrolyte leakage. Therefore, the enamellator method has been conventionally used only for sampling inspection. Therefore, a defective product may be mixed in the product.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a defect inspection apparatus for an inner surface organic coating layer of a seamless metal can, which can be applied to 100% inspection. Further, the present invention is capable of performing 100% inspection automatically.
An object of the present invention is to provide a defect inspection device for an inner organic coating layer of a seamless metal can.

[0007]

A defect inspection apparatus for an inner surface organic coating layer of a seamless metal can of the present invention is a defect inspection apparatus for an inner surface organic coating layer of a seamless metal can. Externally attachable metal sleeve,
Through a metal spindle to which the sleeve is fixed, a device that rotates the spindle, a freely rotatable elastic roll that can press the barrel wall of a seamless metal can that is inserted into the sleeve over substantially the entire length, and an electrically insulating cylinder. Based on the current flowing between the sleeve and the electrode terminal, the electrode terminal that is supported by the spindle and can contact the end surface of the seamless metal can that is externally inserted into the sleeve, the DC power supply that applies a high DC voltage between the sleeve and the electrode terminal, And an electric circuit for determining a defect in the inner surface organic coating layer. In the present specification, a seamless metal can has at least an inner surface or an organic coating layer on both surfaces, and after being formed by redrawing or the like, the opening end is trimmed, and the body wall has a cylindrical shape over the entire length. Refers to things.

Further, the defect inspection apparatus for the inner surface organic coating layer of the seamless metal can of the present invention is a defect inspection apparatus for the inner surface organic coating layer of a seamless metal can, which is made of metal to which the seamless metal can can be inserted. Turret board with multiple spindles made of metal to which sleeves are fixedly attached along the peripheral edge; fixed to the frame that supports the turret board, and the gears attached to the spindle rotate as the turret board rotates. Sun gear; means for vacuum suction of a seamless metal can at a charging station and external insertion to a sleeve; supported by a spindle through an electrically insulating cylinder so that it can contact the end surface of a seamless metal can externally inserted into the sleeve Electrode terminal; DC power supply that applies high voltage DC voltage between sleeve and electrode terminal; Substantially the barrel wall of seamless metal can that is externally inserted into the sleeve A free-rotating elastic roll that can be pressed over its entire length; the elastic roll is separated from the sleeve at least while the seamless metal can is inserted and discharged from the sleeve, and at least a high-voltage DC voltage is applied between the sleeve and the electrode terminal. A cam device for rocking the elastic roll so that it presses the seamless metal can for a period of time; a means for ejecting the seamless metal can from the sleeve with pressurized air at the delivery station; and pressing by the elastic roll of the rotating seamless metal can. When there is a defect in the inner surface organic coating layer of the exposed portion, an electric circuit for detecting a pulse wave generated by the discharge based on the applied high-voltage DC voltage is provided.

[0009]

According to the invention of claim 1, a seamless metal can is supported by the spindle through a metal spindle to which a metal sleeve capable of external insertion is fixed, and an electrically insulating cylinder.
Since the electrode terminal that can contact the end surface of the seamless metal can externally attached to the sleeve and the DC power supply that applies a high-voltage DC voltage between the sleeve and the electrode terminal are provided, the seamless metal can is externally inserted into the sleeve, and When a signal that applies a high voltage DC voltage is applied to the DC power supply with the end faces in contact with the electrode terminals, a high voltage DC voltage is applied between the sleeve and the metal layer of the seamless metal can via the inner organic coating layer. ..

While the sleeve is being rotated by a device for rotating the spindle, a freely rotating elastic roll is attached to the barrel wall of a seamless metal can that is externally inserted (usually slightly loosely for easy external insertion) into the sleeve. Is pressed against the body wall portion, the pressed portion of the body wall portion forms an axial strip-shaped contact portion with the sleeve. Even when the above high-voltage DC voltage is applied, discharge is unlikely to occur in the non-contact portion, and in the contact portion where there is no defect in the inner surface organic coating layer, but when there is a defect portion in the inner surface organic coating layer in the contact portion, a defect occurs. Discharge occurs in some parts. An electric circuit that determines a defect in the inner organic coating layer based on a current flowing between the sleeve and the electrode terminal can detect a defect in the inner organic coating layer by detecting the discharge current.

Since the body wall portion rotates together with the sleeve,
The strip-shaped close contact portion moves sequentially in the circumferential direction, and the elastic roll can press the trunk wall substantially over the entire length, so that the close contact portion extends substantially the entire length of the trunk wall portion. Therefore, it is possible to inspect substantially the entire surface of the inner surface organic coating layer of the body wall portion. Further, by making the inner surface of the outer wall portion of the annular protruding portion at the bottom of the externally inserted seamless metal can closely contact the corresponding portion of the sleeve, it is possible to inspect for defects in the inner surface organic coating layer on the inner surface of the outer wall portion. The seamless metal can whose defect is not detected by the above inspection is sent to the next step and processed by flange processing etc. to become a product, and the seamless metal can with the defect detected is rejected by the inspection device. Therefore, it is possible to perform 100% inspection.

According to the invention of claim 2, in addition to the invention of claim 2, a plurality of spindles are fixed to a turret board axially mounted along a peripheral edge thereof and a frame for axially supporting the turret board. As it has a sun gear that rotates the gear attached to the spindle as it rotates,
With the revolution of the spindle, the spindle can be automatically rotated (rotated). Further, since a means for vacuum-sucking the seamless metal can at the charging station to insert the seamless metal can onto the sleeve is provided, the seamless metal can can be automatically inserted to the sleeve fixed to the spindle. Further, since the delivery station is provided with means for ejecting the seamless metal can from the sleeve by pressurized air, the seamless metal can that has been inspected can be automatically ejected from the sleeve.

Further, at least during the period when the seamless metal can is externally inserted and during the period when it is discharged from the sleeve, the elastic roll is separated from the sleeve, and at least during the period when a high voltage DC voltage is applied between the sleeve and the electrode terminal, the elastic roll is seamless. Since the cam device for swinging the elastic roll to press the metal can is provided, it is possible to easily and automatically prevent the elastic roll from being inserted into the sleeve and discharged from the sleeve. Further, the elastic roll can automatically press the seamless metal can while the high voltage DC voltage is applied between the sleeve and the electrode terminal. Furthermore, when there is a defect in the inner surface organic coating layer of the portion pressed by the elastic roll of the rotating seamless metal can, an electric circuit for detecting the pulse wave generated by the discharge based on the applied high voltage DC voltage is provided. By this electric circuit, it is possible to automatically detect a defect in the inner surface organic coating layer.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is a turret disk which is fixed to a central shaft 2 which is axially mounted on a frame 3 via roller bearings 4. The central shaft 2 rotates at a constant speed (for example, at about 80 rpm) by a driving device (not shown) provided on the left side of the drawing. Along the periphery of the turret board 1, a plurality of pieces (for example, 18
A spindle 5 made of carbon steel is mounted on the shaft.
The sun gear 1 fixed to the frame 3 is attached to the spindle 5.
A gear 14 that engages with the spindle 3 is installed.
Is designed to rotate with the revolution of the turret board 1.

As shown in detail in FIG. 2, the spindle 5 includes a body 5a and a tip member 5b screwed to the tip thereof.
Is equipped with. A sleeve 6 made of cemented carbide (herein, referred to as metal including cemented carbide) is fixed to the front portion of the spindle 5. Within the range where the seamless metal can 7 is easily inserted into the sleeve 6, the difference between the outer diameter of the sleeve 6 and the inner diameter of the seamless metal can 7 is made as small as possible, that is, the seamless metal can 7 is attached to the sleeve 6.
The outer diameter of the sleeve 6 is set to be slightly smaller than the inner diameter of the seamless metal can 7 (for example, smaller by about 0.25 mm) so as to be gently extrapolated.

The shape of the outer surface 6a at the tip of the sleeve 6 is such that the outer wall portion 7 of the annular protruding portion at the bottom of the seamless metal can 7 is formed.
When the seamless metal can 7 is completely inserted into the sleeve 6, the outer surface 6a has an outer wall portion 7a.
It is defined to be in close contact with the inner surface of a. Sleeve 6
A recess 8 into which a dome-shaped central panel 7b at the bottom of the externally inserted seamless metal can 7 can be inserted is formed by the vicinity of the tip of the spindle and the tip member 5b of the spindle.

A cylindrical body 9 made of synthetic resin (for example, MC nylon) having a flange portion 9a that abuts on the end surface 6b of the sleeve 6 is fixed to a portion of the spindle 5 between the sleeve 6 and the turret board 1. The cylindrical body 9 is provided with an electrode terminal 10 (for example, made of stainless steel or cemented carbide) that can contact the end surface 7c of the externally inserted seamless metal can 7, and is pressed toward the sleeve 6 by the compression spring 12. The electrode holding ring 11 is mounted slidably along the tubular body 9. One end of the compression spring 12 is held by the protruding ring 9b of the tubular body 9, and when the seamless metal can 7 is not externally inserted, the electrode holding ring 11 engages with the flange portion 9a of the tubular body. There is.

The electrode terminal 10 includes a pin 15 and a spindle 5.
Lead wire 16, slip ring 18, which is inserted through the hole portion 17 of
The brush 19, the conducting wire 20 that passes through the central hole 21 (FIG. 1) of the central shaft 2, and the rear end of the central shaft 2 (the left end of FIG. 1;
High-voltage DC power supply 61 via a slip ring and a brush (not shown) attached to (not shown)
Connect to grounded positive electrode (see Figure 4). On the other hand, the spindle 5 includes a terminal 22, a slip ring 23, and a brush 2.
4, a lead wire 25 inserted through the central hole 21 of the central shaft 2, and a slip ring and a brush (not shown) attached to the rear end of the central shaft 2 to connect to the negative electrode of the high-voltage DC power supply 61. The spindle 5 is a turret board 1.
A cylindrical synthetic resin layer 26 (FIG. 2; eg MC
It is electrically insulated from the main body of the frame 1 and the brushes 19 and 24 by (made of nylon), and the sun gear 13 by the tooth portion 14a of the gear 14 made of synthetic resin.

In FIG. 1, reference numeral 28 denotes an elastic roll rotatably attached to a shaft 29 for pressing the body wall portion 7d of the seamless metal can 7 externally inserted in the sleeve 6 over substantially the entire length. There is elastic rubber (for example, hardness 7
The sleeve 28a is made of an elastomer such as 0 urethane rubber). The shaft 29 of the elastic roll is fixed to an end 31a of the L-shaped arm 31 which is pivotally supported by a pin 30 fixed to the frame 1 on the spindle 5 side, and the other end 31b of the arm 31 is fixed to the end 31b. Cam roll 3
2 is pivoted.

The cam roll 32 is engaged with the cam surface 33a of the peripheral cam 33 fixed to the frame 3 while being pressed by a spring (not shown). The cam surface 33a is
As each sleeve 6 revolves, the elastic roll 28 separates from the sleeve 6 while moving from the A station to the B station shown in FIG. 3, and the elastic cam roll 28 presses the sleeve 6 while moving from the B station to the D station. However, it is formed so as to be separated again while returning from the D station to the A station.

As shown in FIGS. 1 and 2, each spindle 5
Further, the same number of guide holes 35 as the spindles 5 are formed through the inside of the turret board 1. The parallel portion 35a of the guide hole 35 with the central axis 2 is an opening 36a formed in the ring 36.
Connected to. The ring 3 is attached to a holding portion 37 that rotatably supports the tip portion 2a of the central shaft 2 and is fixed to the frame 3 in a non-rotatable manner.
A disk 38 is fixedly attached so as to be in contact with the disk 6. Ring 3
When the 6 rotates with the turret board 1, the ring 36 slides along the sliding surface 38 a of the disk 38. Disk 3
8 is a sliding surface 3 connected to a vacuum source (not shown)
A circular arc-shaped hole 39 as viewed from 8a is formed at a predetermined position in the circumferential direction so that the operations described in the paragraphs 0025 and 0026 are performed. Reference numeral 34 is an air cylinder for pressing the disk 38 against the ring 36.

In addition, the disk 38 also has similarly arcuate holes (not shown) which connect to a source of pressurized air (not shown) so that the operation described in paragraph 0029 is performed. It is formed at a predetermined position in the circumferential direction.
The opening 36a is provided with a hole 39 at a predetermined timing so that the operations described in the paragraphs 0025, 0026 and 0029 are performed as the turret board 1 rotates.
And a hole connected to the pressurized air source.

Reference numeral 40 denotes a can pusher having the same number as the spindle 5 provided in front of the sleeve 6, and the can pusher 4
The pin 42 fixed to the arm portion 41 supporting 0 is slidable along the hole portion 43a of the cylindrical body 43 attached to the turret board 1. Can pusher 4 on arm 41
A cam roll 44 is attached to the end opposite to 0.
The cam roll 44 is a cylindrical cam 45 fixed to the holding portion 37.
The cam surface 45a of the cam roll reciprocates in the axial direction of the spindle 5 at a predetermined timing so that the can pusher 40 performs the operation described in the paragraphs 0026 and 0029. Is configured.

A guide hole 40a is opened in the can pusher 40, and the guide hole 40a is connected to the ring 36 through a conduit 46.
Connected to the opening 36b of. The opening 36 is electrically connected to the hole 39 (connected to the vacuum source) at a predetermined timing so that the operations described in the paragraphs 0026 and 0029 are performed as the turret board 1 rotates. A canister 47 is attached to each cylindrical body 43 so as to be located between the sleeve 6 and the can pusher 40.

As shown in FIG. 3, the seamless metal can 7 drops along the chute 49, and the foot turret 5
0 pocket 50a (not shown in the figure, but there are more pockets than shown), is guided along the guide rod 48 in the direction of the arrow, and reaches the station A where the turret board 1 is contacted. Supported by. At station A, as shown in FIG.
The distance between the push surface 40b of the can pusher 40 and the front surface 6c of the sleeve 6 is slightly larger than the height of the seamless metal can 7. At this time, the opening 36a is just before being electrically connected to the hole 39, and the guide hole 35 is not connected to the vacuum source. The opening 36b is also blocked from the hole 39, and the guide hole 40a is not connected to the vacuum source. The elastic roll 28 is separated from the sleeve 6.

When the sleeve 6 slightly moves in the arrow X direction as the turret board 1 rotates in the arrow X direction,
Immediately due to the cam action, the can pusher 40 moves the sleeve 6
Then, the open end of the seamless metal can 7 is extrapolated to the front part of the sleeve 6 by moving about 2 cm toward. At this point, the opening 36a is electrically connected to the hole 39, and the seamless metal can 7 is pulled in by the vacuum suction force by the time it almost reaches the station B, as shown in FIG. The end surface 7c contacts the electrode terminal 10, and the inner surface of the bottom outer wall portion 7a is the outer surface 6 of the tip portion of the sleeve 6, except when
close to a. Immediately after the close contact with the elastic roll 2 by the cam action
8 swings and presses the seamless metal can 7 which rotates together with the sleeve 6. By the pressing, the strip-shaped close contact portion formed between the body wall portion 7d of the seamless metal can 7 and the sleeve 6 over substantially the entire length of the body wall portion 7d sequentially moves in the circumferential direction.

When almost reaching the station C, as will be described later, based on the signal 62 output from the proximity switch 56 (FIG. 4) in accordance with the rotation of the timing cam 55 attached to the central shaft 2 for each spindle 5. Then, the voltage application command signal 64 is input to the high voltage DC power supply 61, and the seamless metal can 7
Electricity is supplied between the sleeve and the sleeve 6. At the same time, the defect inspection of the inner surface organic coating layer is started, and the voltage application command signal 64 is turned off until almost reaching the station D, and the inspection is completed.

When the metal layer of the body wall portion 7d of the seamless metal can 7 is thin and easily deformed, it may come into contact with another object while being conveyed to the inspection device, and the body wall portion 7d may have a dent or the like. A metal can having a deformed portion and having no commercial value is likely to occur. In such a case, the seamless metal can 7 is pulled in by the vacuum suction force, and the deforming portion prevents the end surface 7c from coming into contact with the electrode terminal 10. By utilizing this phenomenon, as will be described later, it is possible to detect and reject the seamless metal can 7 having the body wall deforming portion having no commercial value.

Immediately after passing through the station D, the opening 36a is electrically connected to the hole connected to the pressurized air source, and at the same time, the opening 36b is electrically connected to the hole 39. Further, the can pusher 40 returns to the original position (position at the station A) by the cam action. Therefore, the seamless metal can 7 is pushed out of the sleeve 6 by the pressurized air, the bottom is vacuum-adsorbed by the can pusher 40, and the barrel wall 7d is held by the can holder 47.
Supported by.

In this state, the seamless metal can 7 moves to the sending station E and moves to the sending turret 51 at the sending station E. In Station F of the turret 51, the defective seamless metal can 7 which is judged by the electric circuit 60 to be "film defect" or "contact failure due to deformed portion" is rejected as described in paragraphs 0034 and 0037. It The seamless metal can 7 determined to be normal is sent from the station G to the next neck-in device.

Reference numeral 60 in FIG. 4 shows an electric circuit for defect inspection. The proximity switch 56 outputs a rectangular wave pulse signal 62 to the latch circuit 63 while the detection unit 55a of the timing cam 55 attached to the central shaft 2 passes the front surface of the proximity switch 56. When the latch circuit 63 outputs the voltage application command signal 64 to the high voltage DC power supply 61 based on the rise of the pulse signal 62, the DC power supply 61 causes the high voltage DC voltage between the sleeve 6 and the seamless metal can 7 (the voltage is usually 200 to 1000 V) is applied, the current flowing through the resistor 65 is converted into a voltage by the current-voltage conversion circuit 66, and this voltage is amplified by the isolation amplifier 67 to become the voltage V.

FIG. 5 shows an example of a time-voltage curve in the case of a normal seamless metal can 7 (the inner surface organic coating layer is made of a polyethylene terephthalate film having a thickness of 25 μm). The voltage V reaches the peak value Vs due to charging at the initial stage of voltage application, but thereafter gradually decreases. Figure 5
Shows an example of a time-voltage curve when the seamless metal can 7 having a defect in the inner organic coating layer is completely extrapolated to the sleeve 6, and the initial voltage peak value is Vs in the case of FIG. Is almost the same as. However, at the time point t3 when the defective portion is pressed against the sleeve 6 by the elastic roll 28, the discharge current flows, so that the voltage V increases and the voltage peak value becomes V3.
A pulse wave 57 of p is generated. FIG. 5 shows an example of a time-voltage curve when there is a defect such as a dent in the body wall portion 7d of the seamless metal can 7 and the end surface 7c does not come into contact with the electrode terminal 10. Peak value Vr
Is lower than the voltage peak value Vs, and the voltage V drops rapidly.

Returning to FIG. 4, the voltage V is the film defect detection comparator 68 and the contact failure detection (the end face 7c is the electrode terminal 10).
It is input to the comparator 69 for detecting that it does not come in contact with.
The voltage V1 (see FIG. 5) set by the film defect detection voltage setting unit 70 is also input to the film defect detecting comparator 68. The voltage V1 is set to a value slightly larger than the voltage Vb (see FIG. 5) at the time t2 required for the voltage V when the seamless metal can 7 is normal to be substantially stable. If the voltage V is higher than the voltage V1, AND from the comparator 68
The ON signal is output to the circuit 71.

A film defect detection start timer 72 is also connected to the input terminal of the AND circuit 71. The coating film defect detection start timer 72 starts the time t2 (for example, 20 mse) from the rising time (time 0 in FIG. 5) of the rectangular wave pulse signal 62.
After c) has passed, an ON signal is output to the AND circuit 71. Therefore, when a pulse wave 57 (FIG. 5) having a peak value Vp higher than the set voltage V1 is generated at time t3 after time t2, the ON signal is input from the comparator 68 to the AND circuit 71, and the AND circuit 71 is latched by the latch circuit 73. Is set, and the latch circuit 73 outputs a signal 75 that "the seamless metal can 7 has an inner surface coating defect". The signal 75 is input to a computer (not shown), and when the seamless metal can 7 reaches the station F (FIG. 3), the computer outputs a reject signal.

On the other hand, the signal 75 is input to the one-shot circuit 77 via the OR circuit 76. The pulse wave output from the one-shot circuit 77 passes through the OR circuit 78 and then the latch circuit 6
3 is input to the R terminal to reset the latch circuit 63,
The voltage application command signal 64 is released. Therefore, the DC power supply 61
The voltage application to the seamless metal can 7 and the sleeve 6 by the is released, and the sleeve 6 by the discharge after the time t3 is released.
Damage is prevented. Further, the signal from the one-shot circuit 77 is input to the R terminal of the latch circuit 73, and the latch circuit 73 is also reset.

The contact failure detection comparator 69 detects the voltage V
Voltage V2 set by the contact failure detection voltage setting device 79
(See FIG. 5) are compared, and when V <V2, an OFF signal is output to the inverter 74, and the ON signal is output to the AND circuit 80. The voltage V2 is the voltage Va at the time t1 (t1≤t2) when the seamless metal can 7 is normal (see FIG. 5).
(Refer) It is set to a smaller value.

Reference numeral 83 is a contact failure detection time setting timer for setting time t1. When the time t1 is reached, a pulse wave is output from the one-shot circuit 81 to the AND circuit 80 and the latch circuit 82 is set.
From No. 2, a signal 84 is output that "defect in the body wall due to poor contact". The signal 85 is input to a computer (not shown), and when the seamless metal can 7 reaches the station F, the computer outputs a reject signal.

The ON signal from the latch circuit 82 is input to the one-shot circuit 77 via the OR circuit 76 to generate a pulse wave. This pulse wave is input to the R terminal of the latch circuit 82 to reset the latch circuit 82, and at the same time O
The voltage is applied to the R terminal of the latch circuit 63 via the R circuit 78 to reset the latch circuit 63 and release the voltage application command signal 64. Therefore, the voltage application from the DC power supply 61 to the seamless metal can 7 and the sleeve 6 is released, and the sleeve 6 is prevented from being damaged by the discharge after the time t1. In the case of FIG. 5 in which the end surface 7c of the seamless metal can 7 contacts the electrode terminal 10, V> V2, so the latch circuit 82 is not set and the "contact failure signal" 84 is not output.

When the seamless metal can 7 is normal, the falling edge detection circuit 85 for the rectangular wave pulse signal 62 causes the pulse signal 6 to be detected.
2 fall time t4 (t4>t2; t4 is t2 + 10, for example)
0 msec) is detected and an ON signal is output to the OR circuit 78. The output signal from the OR circuit 78 is input to the R terminal of the latch circuit 63 to reset the latch circuit 63 and release the voltage application command signal 64.

[0040]

The apparatus of the invention according to claim 1 has an effect that defects of the inner surface organic coating layer of the seamless metal can can be detected by 100% inspection. The apparatus of the invention according to claim 2 has an effect that defects in the inner surface organic coating layer of the seamless metal can can be automatically detected by 100% inspection. Further, any of the inventions has an advantage that deformation defects such as dents on the body wall can be detected by 100% inspection or automatically by 100% inspection.

[Brief description of drawings]

FIG. 1 is a vertical sectional view taken along the line I-I of FIG.

FIG. 2 is a detailed enlarged vertical sectional view of a portion near the spindle in FIG.

FIG. 3 is a schematic front view of a mechanical portion of an apparatus according to an embodiment of the present invention and its accessory device.

FIG. 4 is a circuit diagram of an embodiment of an electric circuit in the device of the present invention.

5 is a diagram showing the relationship between the energization time and the output voltage of the isolation amplifier in the electric circuit shown in FIG.
In the case of a normal seamless metal can having no defect in the inner surface organic coating layer, FIG. 5 shows a case where the inner surface organic coating layer has a defect, but in the case of a seamless metal can having no deformation defect such as a dent on the body wall, FIG. FIG. 4 is a diagram showing a case of a seamless metal can that cannot be completely energized due to a deformation defect such as a dent on the body wall.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Turret board 3 Frame 5 Spindle 6 Sleeve 7 Seamless metal can 7c End surface 7d Body wall 9 Electrically insulating cylinder 10 Electrode terminal 13 Sun gear 14 Gear 28 Elastic roll 32 Cam roll (cam device) 33 Circumferential cam (cam device) 35 Guide hole (a part of vacuum suction means and pressurized air discharge means) 57 pulse wave 60 electric circuit 61 high voltage DC power supply

Claims (2)

[Claims] 1. A defect inspection apparatus for an inner organic coating layer of a seamless metal can, the apparatus rotating a metal sleeve into which the seamless metal can is externally inserted, a metal spindle to which the sleeve is fixed, and a spindle. Device, seamless metal externally inserted in sleeve A free-rotating elastic roll capable of pressing the barrel wall of the can over substantially the entire length, a seamless metal supported by a spindle via an electrically insulating cylinder, and externally inserted in the sleeve Equipped with an electrode terminal that can contact the end surface of the can, a DC power source that applies a high-voltage DC voltage between the sleeve and the electrode terminal, and an electric circuit that determines a defect in the inner organic coating layer based on the current that flows between the sleeve and the electrode terminal. A defect inspection apparatus for an inner surface organic coating layer of a seamless metal can, which is characterized in that 2. A defect in the organic coating layer on the inner surface of a seamless metal can.
In the inspection device, the device uses a seamless metal can
Metal sleeves to which the possible metal sleeves are attached.
Turret board with pindles attached along the periphery;
The turret board is fixed to the frame that supports the turret board.
Rotates the gear attached to the spindle with the rotation of
Sun gear; seamless metal can at charging station
For vacuum suctioning and externally inserting into the sleeve; Electrically insulating cylinder
It is supported by the spindle through the body and extrapolated to the sleeve.
Electrode terminals that can contact the end surface of a seamless metal can; pickpocket
DC power supply that applies a high voltage DC voltage between the probe and the electrode terminals;
The wall of the seamless metal can, which is externally attached to the sleeve, is
Free-rotating elastic roll that can be pressed over its entire length;
Period and three when at least seamless metal can is extrapolated
The elastic roll is separated from the sleeve while it is discharged from the sleeve.
However, at least the high voltage DC voltage is applied between the sleeve and the electrode terminals.
The elastic roll holds the seamless metal can for as long as it is applied.
A cam device that swings the elastic roll to press it;
Seamless metal cans with pressurized air
Means for discharging from leaves; and seamless gold during rotation
Internal organic coating on the part of the metal can pressed by the elastic roll
Based on the high voltage DC voltage applied when the layer is defective
Equipped with an electric circuit that detects the pulse wave generated by discharge
Inner surface organic coating of seamless metal can, characterized by
Layer defect inspection equipment.