JPS6353401A - Circumferential ruggedness detector for metal body - Google Patents

Abstract

PURPOSE:To achieve accurate detection of the entire circumferential surface, by transferring a metal body with a circular diametrical section being turned to discriminate the presence of ruggedness by a signal with a lengthy overcurrent type displacement sensor arranged in the direction of the transfer. CONSTITUTION:As a can 1 rotatively transferred by a transfer means 10 reaches one end of overcurrent type displacement sensors 20a and 20c, gate circuits 31a and 31c open in response to a detection signal of a timing sensor 23 to send outputs of the sensors 20a and 20c to comparators 32a and 32c, which 32a and 31c compare the outputs of the sensors with a signal of a setter 33 to detect ruggedness on the entire upper and lower circumferential surfaces of the can 1. When the output of the sensor 20c exceeds a set range, the comparator 32 outputs a detection signal to a decision unit 34 and a deficiency decision signal is outputted. When the can 1 makes a turn to reach the other end of the sensors 20a and 20c, it is detected with a timing sensor 24 and the circuit 31a and 31c are closed to complete the detection of the upper and lower circumferential surfaces of the can 1. Then, the can 1 is detected with a timing sensor 25 as it reaches one end of a displacement sensor 24 and with a gate circuit 31b opened, the results are sent to a comparator 32b to execute the detection of ruggedness over the entire circumference in the central portion of the can 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting irregularities on the outer peripheral surface of a metal body having a circular cross section in the radial direction.

[Prior Art] Conventionally, it has sometimes been necessary to inspect whether or not irregularities exist on the outer peripheral surface of metal objects such as metal containers and various types of shafts that have a circular cross section in the radial direction. . That is, for example, in the case of cans, etc., during the molding process of the can, the can body may buckle or have irregularities due to poor contact τ of the seam portion. As described above, cans with unevenness on the can body have poor aesthetic appearance and significantly reduce commercial value, and are a major cause of poor sealing of cans due to poor sealing. In addition, due to the phenomenon in which a portion of the can body protrudes due to the unevenness, there is a drawback that one can may become clogged in the conveyor belt during the can manufacturing process. Therefore, it is necessary to detect cans with irregularities on the can body as defective cans and to separate them from good cans.

[Problems to be solved] One possible method for detecting this type of defective can, especially defective metal cans, is to use an eddy current displacement sensor, but conventional eddy current displacement sensors have a Since the measurement range for upper displacement is narrow, in order to inspect the entire circumference of the can body,
A large number of eddy current displacement sensors had to be placed closely together. For this reason, there are problems in that interference occurs between the displacement sensors, making it impossible to perform accurate inspection, and that the signal processing device becomes extremely complex due to the need to process signals from a large number of displacement sensors.

In order to eliminate these problems, a method of inspecting cans by rotating the can at a fixed location and using a small number of eddy current displacement sensors to detect irregularities on the can body as changes in the distance between the sensor and the can circumferential surface is considered. However, with this method, changes in the distance between the sensor and the can periphery due to uneven rotation of the can or irregularities in roundness may be mistaken for irregularities on the can body, resulting in a lack of accuracy and poor inspection. There was a problem that it caused a decrease in speed.

The above-mentioned problems always occur when using a PI+current type displacement sensor to detect irregularities on the outer peripheral surface of not only cans but also metal bodies having a circular radial cross section.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a device for detecting irregularities on the outer peripheral surface of a metal body that can accurately detect irregularities on the outer peripheral surface of a metal body using a small number of displacement sensors. do.

[Means for Solving Problems] In order to achieve the above object, the device for detecting irregularities on the outer circumferential surface of a metal body of the present invention includes a transfer means for rotating and transferring the metal body, which has a circular cross section in the radial direction; It is composed of an elongated eddy current type displacement sensor arranged along the transport direction of the means, and a circuit for determining the presence or absence of unevenness based on the signal from the eddy current type displacement sensor.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic perspective view of an embodiment in which the present invention is used as a device for detecting irregularities on the outer peripheral surface of a metal can for canned goods.

FIG. 2 similarly shows a plan view, and FIG. 3 similarly shows a side view.

In these drawings, 10 is a transport means for transporting the can 1. This transfer means 10 includes a transfer member 11 such as a belt conveyor that moves the can 1 in a straight line, and a rotation member 12 such as a belt that rotates the can 1. The zero rotation member 12 is arranged on one side of the transfer member 11. Displacement sensor 2 (described later)
I faced 0. In the height direction of the other side (in the axial direction of the can), two pieces of wood are arranged at appropriate intervals, and the shoulder and bottom portions of the can 1 are pressed against each other to give rotation to the can 1. . At this time, the rotating member 12 is constantly pressed toward the displacement sensor 20 side by the outer member 13, and the can 1 is pushed toward the displacement sensor 20 side.
If the can 1 is pressed against the side, even if the can 1 is deformed in the radial direction due to eccentricity, etc., the circumferential surface of each can 1 will always be detected by the displacement sensor 2.
0 and eliminates measurement error. Also, at this time, as shown in FIGS. 2 and 3, the can 1 and the displacement sensor 20
By interposing a fixed-sized spacer 14 made of a non-magnetic and insulating material such as Bakelite between them, the distance between the circumferential surface of the can 1 and the displacement sensor 20 can always be kept constant, and measurement accuracy can be improved. I can figure it out.

As shown in FIGS. 4 and 5, the eddy current type displacement sensor 20 has an elongated cross section of E cedar.

For example, it is composed of a main body 21 made of ferrite and a coil 22 wound around a core portion 21a of the main body 21. The operating principle of this eddy current type displacement sensor 20 is the same as that of a normal eddy current type displacement sensor, but it has width direction characteristics and height direction characteristics as shown in FIGS. 6 and 7UA. .

That is, the displacement sensor 20 is capable of accurate measurement over a wide range except for a portion of each of its four circumferences. Therefore, by making the effective measurement range of the displacement sensor 20 in the width direction longer than the circumferential length of the can 1, it is possible to reliably measure irregularities around the entire circumference of the can.

In this embodiment, three displacement sensors 20 are arranged in a staggered manner to detect irregularities on the outer periphery of the can.

That is, the first displacement sensor 20a and the third displacement sensor 20c are arranged at different heights at the same position along the transfer member 11 so as to detect irregularities on the upper and lower parts of the can 1. . Further, the second displacement sensor 20b
and the first and third displacement sensors 20a at positions adjacent to the second displacement sensors 20a, 20c.

20c, and is designed to detect irregularities in the center of the can 1. At this time, the first and second displacement sensors 20a and the second and third displacement sensors 20a.

When 20b, 20b, and 20c are arranged so as to overlap slightly in the height direction, each displacement sensor 20a, 2
The effective detection range (height direction) of 0b and 20c is 1g closely adjacent to each other, making it possible to inspect the can 1 in the axial direction (crystalline direction) without fail.

In this case, the length of one rotating member 12 is equal to the length of the displacement sensor 2.
The length corresponds to 0a (20c) and 20b, that is, the length of two displacement sensors.

23.24, 25.26 are timing sensors,
The timing sensors 23 and 24 are arranged so that the can 1 is the displacement sensor 20.
The timing sensors 25 and 26 detect when the can l enters and leaves the effective detection range in the width direction of the displacement sensor 20b. Detect. In addition, in the case of this embodiment, the can 1 rotates twice.

30 is a circuit (8th
This discrimination circuit 30 shown in FIG.
, 20b, 20c are sent to the timing sensor 23,
Comparator 32a based on the signals from 24, 25 and 26
, 32b, 32c.
, 31c, a setter 33 that sends a setting signal to each comparator 32a, 32b, 32c, and each comparator 32a, 32b.

32c, and a determiner 34 that determines whether or not there are irregularities on the outer periphery of the can based on the signal from 32c.

Next, the operation of the embodiment device will be explained f5I. The can 1 is transferred while being rotated by the transfer means 10, and when it reaches the boundary of the effective detection range at one end of the eddy current type displacement sensors 20a, 20c, the timing sensor 23 detects this. The gate circuits 31a and 31c are opened by the signal from the timing sensor 23, and the displacement sensor 20a
.

The output from 20c is sent to comparators 32a, 32c. The comparator 32a compares the signal from the sensor 20a with the setting signal from the setting device 33 based on the displacement detected and sent by the rotational movement of the can 1, and detects irregularities on the entire circumference of the can 1. Similarly, the comparator 32C is connected to the can 1.
Detects unevenness around the entire circumference of the curved portion.

Now, if there is an unevenness in the lower part of the can 1 due to buckling or the like, and the output of the displacement sensor 20c changes beyond the allowable range of the set signal, the comparator 32c outputs an unevenness detection signal to the determination W34. When the can 1 has rotated almost once and reaches the boundary of the effective detection range at the other end of the displacement sensors 30a, 30c, the timing sensor 24 detects this, and the gate circuits 31a, 3
Close 1c. This completes the detection of irregularities on the upper and lower parts of the can 1.

Next, when the displacement sensor 20b reaches the boundary of the effective detection range on one end side, the timing sensor 25 detects this, opens the gate circuit 31b, and switches the displacement sensor 20b.
The output of the spider is sent to the comparator 32. Thereby, in the same way as in the case described above, irregularities around the entire circumference of the central portion of the can 1 are detected. Then, when the can 1 rotates approximately once and reaches the boundary of the effective detection range at the other end of the displacement sensor 30b, the timing sensor 26 detects this and closes the gate circuit 31b.

The determiner 34 is one of the comparators 32a.

When the unevenness detection signals are input from 32b and 32c, the inspected can 1 is determined to be a defective can! 1-1 and output. The output from the determiner 34 is used as an activation signal for a defective can discharging device (not shown), or as an alarm signal to notify an inspector of the presence of defective cans.

Note that the signal from the timing sensor 26 is transmitted to each comparator 3.
It is also used as a reset signal for 2a, 32b, 32c and the determiner 34.

The above-mentioned irregularities on the outer periphery of the can include not only buckling but also various aspects such as steps at the seam in seamed cans. It is a broad concept that also includes containers with a circular radial cross section, such as elastic and flexible containers made of composite materials made of laminated paper, plastic, and metal foil such as aluminum.

The present invention is not limited to the embodiments described above,
For example, it also includes modifications such as linear.

■ A device that uses only one long eddy current displacement sensor.

■ Long eddy current displacement sensor 2 A device with multiple pieces arranged in the height direction (in the axial direction of the metal body).

This is effective for detecting irregularities on the outer peripheral surface of a metal body that is long in the axial direction.

■ A device with a plurality of elongated eddy current displacement sensors arranged in the direction of travel, which is effective for detecting irregularities on the outer peripheral surface of large-diameter metal objects.

■ A device that uses a type of transport means that can transport and rotate a metal object at the same time.

■ This device was used to inspect the neck-in portion of metal cans for damage.

■ As shown in FIG. 10, a device in which a long vortex 71 type displacement sensor 20 is tilted upward, in this case,
A guide member disposed along the displacement sensor 20 performs the rotational transfer of the metal body, so this guide member becomes the transfer means 10.

As shown in FIG. 11, the transfer means 10 is composed of a turret 11 that transfers the metal object while revolving it, and a rotary table 12 in a turret pocket that rotates the metal object, and a long vortex 1rLjt type. If the displacement sensor 20 is formed in an arc shape along the direction of transport of the metal body, it becomes possible to attach the detection device to, for example, the process of tightening the lids of cans.

■ A device used as a device for detecting irregularities on the outer peripheral surface of a metal body formed into a cone or a truncated cone, in this case, a long eddy current type displacement sensor 20 is used as shown in FIG. Place it at the same slope angle as the outside slope.

■ A device used as a device for detecting unevenness on the outer peripheral surface of a metal body that has portions with different diameters in the axial direction, in this case, a long eddy current type displacement sensor 20 is used as a device with different diameters as shown in FIG. The arrangement shall be made according to the different parts of the

[Phase] A device in which the length of the elongated eddy current displacement sensor (effective detection range) in the width direction is shorter than the circumferential length of the metal body. This is effective when the rotation speed is high.

■ The circuit for determining irregularities on the outer circumferential surface has a circuit configuration other than the above.

['9: Effect of light] As described above, according to the device of the present invention, by using a long eddy current type displacement sensor, it is possible to accurately detect irregularities on the entire circumference of the outer peripheral surface of a metal body with a small number of displacement sensors. can be detected.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of an embodiment of the present invention, Fig. 2 is a plan view, Fig. 3 is a side view, Fig. 4 is a perspective view of an eddy current displacement sensor, and Fig. 5 is a longitudinal section. 6 is a characteristic diagram in the width direction of the same sensor as above, FIG. 7 is a characteristic diagram in the height direction of the same sensor as above, FIG. 8 is a block diagram of the discrimination circuit, and FIG. 9 is a discrimination circuit showing the operating state of the device. Time charts for each part,
10 to 13 show explanatory diagrams of other embodiments. 1: Can (metal body) 10: Transfer means 11: Transfer member 12: Rotating member 20, eddy current displacement sensor 30

Claims (6)

[Claims] (1) A transfer means that rotates and transfers a metal body having a circular radial cross section, a long eddy current type displacement sensor arranged along the transfer direction of this transfer means, and this eddy current type displacement sensor. An apparatus for detecting irregularities on the outer peripheral surface of a metal body, comprising a circuit for determining the presence or absence of irregularities based on a signal from a displacement sensor. (2) The apparatus for detecting irregularities on the outer peripheral surface of a metal body according to claim 1, characterized in that a plurality of eddy current type displacement sensors are arranged in the axial direction of the metal body. (3) The apparatus for detecting irregularities on the outer circumferential surface of a metal body according to claim 1, characterized in that a plurality of eddy current type displacement sensors are arranged in the direction of movement of the metal body. (4) The apparatus for detecting irregularities on the outer peripheral surface of a metal body according to claim 1, characterized in that a plurality of eddy current type displacement sensors are arranged in a staggered manner in the axial direction or the traveling direction of the metal body. (5) The metal according to claim 1, 2, 3, or 4, characterized in that the transfer means comprises a transfer member that transfers the metal object in the advancing direction and a rotating member that rotates the metal object. Device for detecting irregularities on the outer circumferential surface of the body. (6) The apparatus for detecting irregularities on the outer peripheral surface of a metal body according to claim 1, 2, 3, 4, or 5, wherein the metal body is a metal can.