JPH0735966B2 - Method and device for measuring bottom thickness of score part of can lid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is for measuring the bottom thickness of a score portion formed on an easily opened can lid used for canning of beer cans, carbonated beverage cans, coffee beverage cans and the like. Method and apparatus.

(Prior Art) As a method of measuring the bottom thickness of a score portion formed on a can lid that is easily opened, Japanese Patent Laid-Open No. 63-263403 discloses that a first slit light is projected so as to be orthogonal to the score portion. The second slit light is projected onto a portion corresponding to the reflection portion of the first slit light on the surface opposite to the score portion, and the first reflected light by the first slit light and the second reflected light by the second slit light are emitted. There has been proposed a method of synthesizing reflected light of the above and measuring the bottom thickness based on the synthesized light.

Since this method uses two optical systems to combine them, the device is complicated, and if the vertical position of the can lid is slightly misaligned, the reflected image will be out of the microscope's field of view. It is easy to occur.

Further, the portion of the surface opposite to the score portion where the second slit light is projected is not a smooth surface due to the influence of plastic deformation during formation of the score portion, and has some unevenness (FIG. 3; (See FIG. 7 of JP-A 2-179329), the second reflected light is likely to be scattered, and the reflection direction is slightly different for each can lid. Therefore, it is troublesome to adjust the composition for each can lid. Therefore, the problem that the measurement speed is slowed down and the measurement accuracy is lowered tends to occur.

(Problems to be Solved by the Invention) An object of the present invention is to provide a bottom thickness measuring method for a score portion and a device therefor which can be measured quickly and with high accuracy by a relatively simple device.

(Means for Solving the Problems) The method for measuring the bottom thickness of the score portion of the can lid of the present invention is as follows: The slit light is projected obliquely downward to the top end of the measurement terminal whose top portion is a curved surface with a small radius of curvature, and the reflected light Is imaged to store the imaging position of the apex, and in a state where the measuring terminal and the slit light are fixed, the score portion of the can lid corresponding to the substantially central portion in the width direction of the bottom surface of the score portion. The can lid is placed horizontally on the measuring terminal so that the portion of the surface on the opposite side to the apex is in contact with the top end, and the slit light is orthogonal to the score portion in the contacted portion. , The reflected light of the slit light from the bottom surface of the score portion is imaged, and the bottom thickness of the score portion is measured based on the distance between the stored imaging position of the top end and the image formation of the bottom surface of the score portion. It is characterized by

The measuring device for the bottom thickness of the score portion of the can lid of the present invention is a support device for a can lid that horizontally supports the can lid in cooperation with a fixed measuring terminal whose top portion is a curved surface having a small radius of curvature; An optical microscope having a light projector capable of projecting slit light obliquely downward and a light receiver for forming an image of reflected light from the apex; a device for storing the image formation position of the apex; approximately the center in the width direction of the bottom surface of the score part. The can lid so that the portion of the surface of the can lid opposite to the score portion, which corresponds to the portion, contacts the apex, and the slit light is orthogonal to the score portion in the contacted portion. A positioning device for mounting on the measuring terminal and the support; and, in a state where the can lid is mounted as described above, an image of reflected light from the bottom surface of the score portion of the slit light and the storage device. A device for measuring the distance between the stored image points of the apex. Characterized in that it comprises a.

(Operation) In the method of the present invention, first, the slit light is projected obliquely downward on the top end of the measurement terminal to form an image of the reflected light, and the image forming position of the top end is stored. The can lid is placed on the measuring terminal so that the top end is in contact with the portion 8 of the surface opposite to the score portion corresponding to the substantially central portion in the width direction of the bottom portion of the score portion. Will be remembered.

Therefore, the distance between the image formation of the reflected light from the bottom surface of the score portion of the slit light and the stored image formation position of the apex is proportional to the bottom thickness of the score portion. Therefore, the bottom thickness of the score portion can be measured based on the distance between the image formation position stored at the top end and the image formation on the bottom surface of the score portion.

Since the portion 8 of the surface opposite to the bottom surface of the score portion is stored in this manner, it is not necessary to measure the position of this portion 8 for each can lid. Can be done quickly.

Further, since the position of the portion 8 on the opposite side of the bottom surface of the score portion is not affected by the unevenness of the portion, the bottom thickness of the score portion can be measured with high accuracy.

The device of the present invention has a simple structure because the projector and the optical system including the projector need only be one above the can lid.

(Example) In FIG. 1, 1 is a measuring terminal and 2 is a top portion 1a of the measuring terminal.
Slit light projected obliquely downward to the apex 1a1 of the
Is reflected light reflected from the apex 1a1. The top portion 1a of the measuring terminal 1 is formed of a glossy, light-reflecting hemispherical curved surface.

Reference numeral 4 denotes the field of view of the eyepiece of the optical microscope into which the reflected light 3 enters, 3'is the image formation of the reflected light 3, and 3'a is the image formation of the reflected light from the apex 1a1. 5a and 5b are cursor lines orthogonal to each other, and the cursor lines 5a and 5b are respectively points 3 '.
By aligning the intersections of the cursor lines on 3'a so that they are the normals and cutting lines of the imaged 3'in a,
The imaging position 3'a of the top end 1a1 is stored in advance. The cursor line 5a is provided with a scale (not shown) for distance measurement.

Next, while maintaining the above state, as shown in FIG. 2, the side opposite to the score portion 7 corresponding to the substantially central portion 7a1 in the width direction of the bottom surface 7a of the score portion 7 having the inverted trapezoidal cross section of the can lid 6. The can lid 6 is horizontally placed so that the portion 8 of the surface of the can contacts the top end 1a1 (Fig. 3) and the slit light 2 is orthogonal to the portion of the score portion 7 directly above the portion 8. Place on top of 1.

4'shows the field of view of the microscope in this case, 1
3'a is the reflected light 13a from the bottom surface 7a of the score portion of the slit light 2
, 13'b is an image of the reflected light 13b from the shoulder 7b of the score part.

The distance d (d = mxD, m is the microscope magnification; FIG. 2) between the stored image forming position 3'a of the top 1a1 and the image forming 13'a of the bottom 7a is proportional to the bottom thickness t of the score part 7. To do. That is, when the incident angle is θ, t = d / 2m · sin θ (1)

The width of the bottom surface of the score portion 7 is usually about 10 to 30 μm. In order to ensure sufficient contact between the contact portion 8 having a slight unevenness in its vicinity and the top end 1a1 and to facilitate positioning when placing the can lid 6, the curvature radius r of the top portion 1a is About 0.05
It is preferably about 1.0 mm.

Further, it is preferable that the width of the slit (not shown) for forming the slit light 2 is larger than the width of the upper end of the score portion 7 (for example, 2 to 3 mm), and the thickness is as thin as possible (for example, 10 μm). .

A CCD camera or an image pickup tube may be applied to the eyepiece lens of the microscope to take out the image formations 3 ′ and 13′a as image signals, and the image formation position 3′a of the top end 1a1 may be stored to obtain the bottom thickness. The method of processing the video signal in this case will be described later.

Next, an embodiment of the device of the present invention will be described.

In FIG. 4, FIG. 5, FIG. 6, FIG. 7, and FIG. 8, 20 is the measuring station for the bottom thickness of the score portion, and 21 is the can lid 6.
Is a chute for feeding into the measuring station 22. A teardrop-shaped score portion 7 defining an opening is formed on the upper surface of the can lid 6, and 9 is a ring tab.

In the measuring station 20, a can lid receiver 22 composed of two parallel rods, which can be moved up and down via a pin 22a by a drive structure (not shown), and a chuck wall portion 6a of the can lid 6 (fifth portion).
(Fig.) To rotate the can lid 6 on its own axis and to vertically position the can lid 6 by three vertical positioning rollers 23 which can move up and down by a small amount, the measuring terminal 1, and the measuring terminal 1. Measuring terminal 1 for supporting the can lid 1 horizontally at three points in cooperation with
Two supports 24 having the same structure as the above are provided.

Reference numeral 25 is a rotary belt for rotationally driving the drive positioning roller 23a, 26 is a stopper for stopping and positioning the rotating can lid 1 at a fixed position, and 27 is the can lid 1 fed from the chute 21. Is a stopper for stopping just above the position to be engaged with the positioning roller 23.

The positioning stopper 26 is located above the can lid receiver 22 on one side,
It is pivotally attached through a pin 40 so as to be orthogonal to the can lid receiver 22 (FIGS. 4 and 7), and its inner end surface 26a has a shape corresponding to the outer edge of the corner portion 9a of the ring tab 9. A through hole 26b is formed near the outer end. The fixed rod 42 is inserted through the through hole 26b, and the vicinity of the outer end is biased by the spring 41. The stopper 26 is normally kept horizontal, and is arranged so that the inner end surface 26a is located at the same level as the ring tab 9 when the can lid 6 is engaged with the positioning roller 23.

The circumferential position of the can lid 6 is determined by the outermost portion of the score portion 7.
It is carried out so that the substantially central portion of the bottom surface 7a in 7x in the width direction is located right above the top end 1a1 of the measuring terminal 1 (see FIGS. 4 and 8).
The positioning device is configured as shown in FIG.

An optical microscope 30 provided above the measurement station 20 with a projector 28 that projects the slit light 2 onto the top end 1a1 of the measurement terminal and a light receiver 29 that receives the reflected light 3 from the top end 1a1.
However, the plane formed by the optical axes of the projector 28 and the projector 29 is the can lid receiver.
It is arranged so as to be orthogonal to 22 (Fig. 7).

The bottom thickness of the score portion of the can lid 6 is measured by the above apparatus as follows.

As shown in FIG. 4, the can lid is conveyed in the direction of the arrow A along the guide surface 21a of the chute 21 and is in the raised position of the measuring station 20 (the guide surfaces 21a and 22b are at the same level in this state). The can lid 6 on the guide surface 22b of the receiver 22 is
It is stopped by the stopper 27.

Immediately, the can lid receiver 22 descends to engage the chuck wall portion 6a of the can lid 6 with the positioning roller 23 in the raised position, as shown in FIG. In this state, the bottom surface of the can lid 6 does not contact the top end 1a1 of the measuring terminal 1 and the top end 24a of the support 24.

At the same time, the rotating belt 25 starts and the driving positioning roller 23
When a is rotated to rotate the can lid 6 in the direction of arrow B, the ring tab 9 engages with the inner end surface 26a of the stopper 26 and the can lid 6 stops.

When the inner end of the stopper 26 happens to ride on the tab 9 when the can lid 6 engages with the positioning roller 23, the stopper 26 swings and slightly lowers to the outer end, and the can lid 6 is rotated by the rotation of the can lid 6. When the inner end is disengaged from the tab 9, the spring 26 is pushed up and the stopper 26 becomes horizontal.

At the same time as the can lid 6 stops, the positioning roller 23 also stops and moves down slightly. Then, as shown in FIG. 8, a portion 8 of the outermost portion 7x of the score portion 7 on the side opposite to the substantially central portion 7a1 in the width direction of the bottom surface 7a comes into contact with the top end 1a1 of the measuring terminal 1 to form a can lid. 6 is horizontally supported by the measuring terminal 1 and the support 24 at three points.

In this state, the reflected light 13a of the slit light 2 from the bottom surface 7a of the score portion is, as shown in FIG.
Image as.

The linear sensor CCD camera 3 is attached to the eyepiece 31 of the light receiver 29.
2 is attached, and the image formation 13'a is C as shown in FIG.
Input to CD camera 32. The output of the CCD camera 32 is processed by the signal processing circuit 33 and then input to the differential amplifier 35.

On the other hand, before the work is started, the image forming position 3'a of the reflected light 3 from the top end 1a1 of the measuring terminal is stored in the memory 34 in the same manner in advance in a state where the can lid 6 is not in the measuring station 20. The slit light 2 is always projected during the work.

The direct input signal from the signal processing device 33 and the input signal from the memory 34 are subjected to subtraction processing in the differential amplifier 35, and
The distance d between the image forming position 3'a of 1a1 and the image forming 13'a of the bottom surface 7a (second
Is input to the arithmetic circuit 36, the arithmetic processing of Expression (1) is performed, and the bottom thickness t is output from the arithmetic circuit 36. This output is recorded in the recorder 37. When the bottom thickness t is out of the reference range value, an alarm is issued by the alarm device 38 and a reject signal is issued by the rejector 39.

As described above, the bottom thickness of the score portion of the can lid 6 successively fed to the measuring station 20 is measured almost at the same time as the feeding.

The present invention is not limited to the above embodiments,
For example, the curved surface on the top of the measuring terminal may have an appropriate shape such as a spheroid.

(Effect of the Invention) According to the present invention, there is an effect that the bottom thickness of the score portion can be measured quickly and with high accuracy by a relatively simple device.

[Brief description of drawings]

1 and 2 are drawings for explaining the method of the present invention,
Fig. 1 is a drawing showing a state in which slit light is projected on the top end of the measuring terminal, Fig. 2 is a drawing showing a state in which slit light is projected on the bottom surface of the score part, and Fig. 3 is a can lid on the measuring terminal. FIG. 4 is a vertical sectional view of an essential part showing a mounted state, FIG. 4 is a plan view of an apparatus which is an embodiment of the present invention, FIG. 5 is a vertical sectional view taken along the line VV of FIG. 4, and FIG. 4 is a vertical sectional view taken along the line VI-VI in FIG. 4, FIG. 7 is a side view seen from the VII-VII line side in FIG. 4, and FIG. 8 is a view showing a state in which the can lid is in contact with the measuring terminal. VI in the figure
FIG. 9 is a block diagram of a circuit for converting the image formation into a video signal and automatically calculating the bottom thickness of the score portion, taken along the line II-VIII. 1 ... Measurement terminal, 1a ... top, 1a1 ... top end, 2 ... slit light, 3 ... reflected light, 3'a ... imaging position, 5a, 5b ...
... cursor line, 6 ... can lid, 7 ... score part, 7a ... bottom surface, 8 ... contact part, 13'a ... imaging, 23 ... positioning roller, 24 ... supporting device, 26 ... Positioning stopper, 28 ...
… Emitter, 29 …… Receiver, 30 …… Optical microscope, 32 …… Linear CCD camera, 35 …… Differential amplifier.

Claims (2)

[Claims] 1. A slit terminal is projected obliquely downward to form an image of reflected light at the apex of a measuring terminal whose apex is a curved surface having a small radius of curvature, and the image forming position of the apex is stored, and the measuring terminal is stored. And, in a state where the slit light is fixed, the portion of the surface of the can lid opposite to the score portion, which corresponds to the substantially central portion in the width direction of the bottom surface, contacts the top end, and the slit. The can lid is placed horizontally on the measurement terminal so that the light is orthogonal to the score portion in the contacted portion, and the reflected light from the bottom surface of the score portion of the slit light is imaged, A bottom thickness measuring method for a score portion of a can lid, characterized in that the bottom thickness of the score portion is measured based on a distance between the stored image forming position of the top end and the image forming of the bottom surface of the score portion. 2. A support device for a can lid which supports the can lid horizontally in cooperation with a fixed measuring terminal whose top portion is a curved surface having a small radius of curvature;
An optical microscope having a projector capable of projecting slit light obliquely downward at the apex of the measurement terminal and a light receiver for imaging reflected light from the apex; a device for storing the imaging position of the apex; So that the portion of the surface of the can lid opposite to the score portion, which corresponds to the substantially central portion in the width direction, contacts the apex, and the slit light is orthogonal to the score portion at the contact portion. A positioning device for placing the can lid on the measuring terminal and the support; and, in a state where the can lid is placed as described above, binding of reflected light from the bottom surface of the score portion of the slit light. An apparatus for measuring a distance between an image and an imaging position of the top end stored in the storage device, the bottom thickness measuring device for a score portion of a can lid.