JP4771066B2 - Reverse lid detection system with photoelectric switch using band-like light beam - Google Patents

Description

  The present invention relates to a reverse lid detection technique for automatically discriminating one that has been conveyed in the reverse direction from the lid members supplied in a laminated form in a can winding process.

  A substantially disk-shaped can lid wound around a can body opening such as a two-piece can is packed in a laminated form and carried in. This is unpacked and supplied to the conveying device in the can tightening process to perform the tightening process. In this case, the laminated lid members have the opposite sides (hereinafter referred to as the reverse cover). If it is called), tightening becomes a problem. In order to prevent this, Patent Documents 1 and 2 are known as devices for detecting when a reverse lid is mixed in a can lid material in a laminated form. For example, the can lid inversion inspection apparatus disclosed in Patent Document 1 is abutted against the bottom of a bag 20 in which can lids 1 formed in a substantially disk shape are stacked and stored as shown in FIG. 5A. The tester 25 and the detection mechanism 30 that detects the position of the tester 25 in a state where the tester 25 is abutted against the bottom of the bag 20 are provided. According to this inspection apparatus, when the can lid 1 on the bottom side is inverted, the inspector 25 applied to the can lid 1 is displaced as compared with the case where the can lid 1 is normal. Position. Therefore, it is possible to detect whether or not the can lid 1 is inverted by detecting the position of the inspector 25 by the detection mechanism 30. Further, in Patent Document 2, as shown in FIG. 5B, two detection sensors 40 and 41 are provided in a state where the can lid laminated body 1 is clamped from both sides by the mounting table 14 and the pressing member 15 constituting the clamping mechanism. By detecting the state (posture) of the can lid positioned at the end of the can lid laminated body 1 by compressing a large number of laminated can lids from both sides, there is no gap between the can lids. A technique for detecting the posture of the camera is disclosed. These technologies are intended for inspection of can lids in the form of being stored inside the bag as a lid material, and are performed on the line as a pre-process for winding the can body in the winding process. is not.

  The present applicant performs this reverse lid inspection on the line as a pre-process for winding around the can body in the winding process. This inspection method is a system that irradiates the peripheral edge of the lid from a direction orthogonal to the moving direction with respect to the substantially circular lid conveyed in a laminated form, and arranges a light receiver on the opposite side. As shown in the upper part of FIG. 4, when the can lid is normally laminated in the forward direction and conveyed, the light beam is transmitted from the periphery of the can lid because the can lid is nested and densely laminated. The light is not received by the light receiver, but when the reverse lid is inserted as shown in the lower part of FIG. The light passes through the gap and is received by the light receiver. In principle, this inspection method detects the reverse lid based on whether or not spot beam light is received. In the drawings, (a) and (c) are cross-sectional views showing the laminated form of can lids, and (b) and (d) are side view outlines thereof.

The irradiation light used in this conventional reverse lid detection photoelectric switch is a spot beam that is obtained by narrowing the light from the white light source. Therefore, depending on the type of lid, even if it is a normal lid, the tab and embossing overlap. There has been a problem that even a slight gap generated between the lids and a minute gap caused by the accordion phenomenon (curved laminated form) of the lid is erroneously recognized as a reverse lid. Not only the light receiver directly receives the light from the light source, but also the can lid surface is a metal surface close to a mirror surface, so it may receive light reflecting off the gap, and this also superimposes scattered light and diffracted light etc. Cause malfunction. Even if a configuration capable of adjusting the sensitivity of the light amount detected by the light receiver is adopted, it is not easy to determine light leakage due to the reverse lid and other factors by itself.
Japanese Patent Laid-Open No. 6-122432 “Reversal Inspection Apparatus for Can Lids” Published on May 6, 1994 Japanese Patent Laid-Open No. 2000-177719 “Reversal Inspection Apparatus for Can Lids” Published on June 27, 2000

  An object of the present invention is to provide a system capable of accurately detecting a reverse lid by discriminating a gap caused by a reverse lid and a narrow gap based on other factors from a row of can lids conveyed in a stacked form. There is to do.

The reverse lid detection system of the present invention has a pressing bar that holds and holds the top of a generally circular can lid that is conveyed in a stacked form, and moves relative to the can lid that is pressed by the pressing bar. Means for irradiating the peripheral edge of the can lid from a direction orthogonal to the direction to the wide band-shaped light beam in the stacking direction; and a light receiver for receiving the light beam on the opposite side of the irradiation means across the can lid row Comprises means for outputting an ON / OFF binary signal according to the amount of received light.
A laser beam was used as the band-shaped light beam, and the width of the band-shaped light beam was set to 3 mm or more.
The reverse lid detection system of the present invention employs a configuration in which the ON / OFF threshold value of the amount of received light can be set according to the type of can lid.

The reverse lid detection system of the present invention is provided with a pressing rod that holds and holds the top of the can lid, and this pressing rod has a function of holding and holding the can lid to be inspected from the top. The presence of the reverse lid is detected by the light from the irradiation means being received by the light receiver via the gap at the peripheral edge that occurs when the reverse lid is present. The circular can lid is irradiated with a wide band-shaped light beam in the laminating direction from the direction orthogonal to the moving direction to the peripheral edge of the can lid, so if there is a reverse lid, it corresponds to the gap width The amount of received light is received, and there is a large difference in the amount of light received from a case where light is received through a narrow gap caused by the overlapping state of tabs and embosses. There is nothing.
In addition, when laser light is used as the band-like light beam, it is possible to provide a light beam having high directivity compared with general light, and having good detection accuracy of transmitted light without any phenomenon such as scattering.
The width of the band-shaped light beam is set to 3 mm or more, so that the difference in the amount of light received between the narrow gap caused by the overlap of tabs and embosses that can be considered up to about 2 mm and the wide gap caused by the reverse lid. Can be reliably distinguished.
In addition, the reverse lid detection system of the present invention employs a configuration in which the ON / OFF threshold value of the amount of received light can be set according to the type of can lid, so that the amount of received light varies depending on the type of can lid. An appropriate threshold value can be adjusted in accordance with the fluctuation, and detection without malfunction can be further ensured.

  The present invention replaces the conventional spot beam light in order to reliably discriminate between the gap caused by the reverse lid and the narrow gap based on other factors from the can lid row conveyed in a stacked form. The idea is to use a strip-shaped light beam. And as a more preferable form, the directivity of irradiation light is improved by using laser light instead of general light, and light reception noise due to light scattering is reduced. An embodiment of the present invention will be described with reference to FIG. Reference numeral 1 denotes a can lid to be inspected, which is conveyed from the front side to the back side of the drawing by the conveyor 6 in a stacked state as shown in FIG. A laser beam irradiator 2 that irradiates a laser beam from a direction perpendicular to the conveying direction on the peripheral portion of the can lid 1 and a light receiver 3 that faces the conveyor 6 are disposed. An output unit 5 having a threshold setting function is connected to the terminal. The most characteristic configuration of the present invention is that the laser beam emitted from the laser beam irradiator 2 is band-shaped, that is, the shape when the plane is irradiated is a line shape as shown in FIG. It is in the point which adopted. Incidentally, FIG. 2A shows a shape when a conventional spot beam is irradiated onto a flat surface, which is a minute circle. 2 (c) and 2 (d) show the state when the light beam of the present invention and the conventional apparatus is irradiated on a normal laminated can lid without a reverse lid, and FIGS. 2 (e) and 2 (f). ) Schematically shows a state in which the light beam of the present invention and the conventional apparatus is irradiated to the gap portion of the abnormal laminated form including the reverse lid.

As shown in the upper part of FIG. 4, when a normal laminated can lid without a reverse lid is being conveyed by the conveyor 6, there is no gap between the laminated can lids. Therefore, the band-shaped laser beam is shielded on the peripheral portions of all the stacked can lids light receiver 3 of a length l ₀ which is projected from the laser irradiator 2 as shown in FIGS. 2 (d) Not reach. However, when a band-shaped laser beam is irradiated to an abnormal layered portion including the reverse lid, the peripheral edge of the normal lid and the peripheral edge of the reverse lid as shown in FIG. A gap of length l ₁ is formed between In this case, among the band-shaped laser beam length l ₀ which is projected from the laser irradiator 2, the amount corresponding to the length l ₁ reaches the light receiver 3 via the gap. This is the amount of light received in an ideal state where the beam irradiation direction and the surface of the can lid are completely parallel. The amount of received light is al _1, and this is the maximum amount of light received by the light receiver 3. Here, a is a constant corresponding to the brightness of the beam light projected from the light irradiator 2. Actually, a slight inclination occurs, but the ring-shaped convex portions overlap with each other, so that a large inclination is unlikely to occur and there is no great difference in the amount of received light. Basically, it is the same as the conventional apparatus in that the presence or absence of the reverse lid can be determined by the presence or absence of the amount of received light. Next, the phenomenon in the slight gap generated between the can lids caused by the tabs and the embossed overlap and the accordion phenomenon that caused the malfunction in the conventional apparatus will be considered. Since the gap of this kind is to at most about 2mm as described above, the amount of light received by the light receiver 3 as was the gap minimum width d when band-shaped laser beam length l ₀ of the present invention is irradiated on the portion Becomes ad. Now, even if the gap length l ₁ between the peripheral portion and the peripheral portion of Gyakufuta normal direction of the can lid if a can lid comprising a 8 mm, larger gap width d made between the can lid is not reversed lid Since it is 2 mm, the ratio of the amount of received light is 2a / 8a = 1/4. That is, the amount of transmitted light from the gap based on other causes with respect to the amount of light received by the reverse lid is ¼ or less. In the case of a conventional spot beam having a diameter of about 1 mmφ, the beam passes through the gap and is directly received by the light receiver as shown in FIG. Also, if the gap width d formed between the can lids that are not the reverse lid is 2 mm, the beam light passes through the gap and is directly received by the light receiver in this case as well. It becomes a malfunction. Also, even in a narrow gap of 1 mm or less, the beam light partially penetrates, and since general light that is not a laser is used, reflected light and diffracted light scattered light are superimposed on it. This causes a malfunction. In this respect, according to the method of the present invention, since the irradiation beam light is in a band shape, the difference in the gap width can be detected as the difference in the amount of received light, so that the reverse lid can be determined effectively.

  Actually, a laser beam irradiator with a beam width of 10 mm was adopted, and reverse lid detection was performed on three types of can lids. When the sample 1 can lid is stacked, the gap between the reverse lids is 6 mm. When the sample 2 can lid is stacked, the gap between the reverse lids is 8 mm. When the sample 1 can lids are stacked, the reverse lid The gap formed between them is 10 mm. First, the amount of light received when directly projecting from the laser beam irradiator 2 without a can lid and received by the light receiver 3 is 3.386, and when the sample 1 is inspected, the amount of light received by the reverse lid is 1. .300, that is, 38% of the total amount of received light, when the sample 2 is inspected, the amount of light received by the reverse lid is 2.300, that is, 68% of the total amount of received light, and when the sample 3 is inspected, the amount of light received by the reverse lid is 2. .700, or 80% of the total light received. In the case of sample 3, the gap width is 10 mm, and the width of the laser beam used is also 10 mm. Therefore, the amount of light received should ideally be 100%, but in reality it was 80%. It is understood that this is due to factors such as the fact that the plane of the beam does not completely match the beam direction.

  A narrow gap caused by the overlapping of tabs and embosses, and a gap due to the accordion phenomenon can be considered to be about 2 mm at most, so if the width of the belt-like light beam is 3 mm or more, the beam having a width exceeding the gap width of the reverse lid Even if not, it is possible to identify the difference in the amount of received light caused by factors other than the reverse lid and the wide gap caused by the reverse lid. Of course, in principle, it is advantageous to adopt a beam having a width larger than the gap width of the reverse lid.

  An embodiment of the present invention will be described with reference to FIG. In order to fasten the can lid around the can body, the present embodiment is installed on a line in which the can lid is supplied in a laminated form by a conveyor. The upper half of the can lid is indicated by the reference numeral 1 in FIG. 3B, and the lower half placed on the conveyor is omitted from the drawing. The can lid 1 is laminated in the depth direction of the drawing and is conveyed from the front side to the back side. In this embodiment, each component is fixed to a support bridge 10 installed in the line. A holding rod 7 that holds and holds the top of the can lid 1 and a guide rod 8 are disposed so as to sandwich the holding rod 7 from both sides, and the central portion of the support bridge 10 with its longitudinal direction directed in the direction of conveyance of the can lid. It is fixed to the holder via a holder 9. When the can lid 1 is in the center position, the guide rod 8 is installed at a position away from the peripheral edge so as not to contact the guide lid 8 so as to guide the can lid 1 loosely. A light irradiator 2 that irradiates a peripheral belt portion of the can lid 1 with a wide band-shaped light beam in a stacking direction from a direction orthogonal to the moving direction with respect to the generally circular can lid 1 conveyed in this stacked form; On the opposite side of the light irradiator 2, a light receiver 3 that receives the light beam is fixed opposite to both ends of the support bridge 10. The support bridge 10 is provided with a height adjustment function in response to the change in the peripheral position depending on the diameter of the can lid 1. The light irradiator 2 employs a 10 mm wide belt laser beam projecting device, and the light receiver 3 employs a 10 mm wide belt laser beam receiver (Keyence Corporation product name: LV-H100). . The light irradiator 2 and the light receiver 3 fixed opposite to both ends of the support bridge 10 are important in alignment, but the light irradiator 2 is provided with a function of adjusting the vertical and horizontal directions, Since a light diffusing sheet for beam confirmation is attached to the end of the light receiving portion of the light receiver 3, the light receiving position can be visually confirmed, and alignment is easy. The light amount signal received by the light receiver 3 is appropriately amplified by an amplifier 4 and includes means 5 for outputting an ON / OFF binary signal corresponding to the amount of received light. This output means includes an ON / OFF threshold value. A function that can be set as appropriate is provided. For example, a threshold value can be digitally set based on a ratio (% display) based on the amount of light received when direct irradiation is performed without the can lid 1. did. As for the reference value, the group of can lids 1 including a plurality of reverse lids may be moved, and the maximum value at that time may be adopted as a value corresponding to a state in which the reverse lid is parallel to the beam.

  When the reverse lid detection threshold is 600, which is 1.300 or less of the light reception amount of the narrowest reverse lid gap width sample 1, that is, 17.7% of the total light reception amount, samples 4 and 5 other than the above are included. In the test conducted using this embodiment on 400 lid bodies, no malfunction occurred.

It is a figure explaining the basic composition of the present invention. It is a figure which compares and demonstrates the condition when the light beam of this invention is irradiated from the side surface of the can lid of a laminated form. It is a figure which shows one Example of this invention. It is a figure explaining the form of the can lid row | line | column laminated | stacked including the form of the normally laminated can lid row | line | column and the reverse lid. It is a figure explaining the conventional apparatus which detects whether there exists a reverse lid in the can lid of a laminated form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Can lid 2 Light irradiator 3 Light receiver 4 Amplifier 5 Output device 6 Conveyor 7 Holding rod 8 Guide rod 9 Holder 10 Support bridge

Claims (4)

A pressing bar that holds and holds the top of a generally circular can lid that is conveyed in a stacked form is disposed, and the can lid is pressed from the direction perpendicular to the moving direction with respect to the can lid that is pressed by the pressing bar. A device for irradiating a peripheral light beam with a wide belt-like light beam in the stacking direction and a light receiver for receiving the light beam on the opposite side of the irradiation device across the can lid row are turned on / off depending on the amount of light received. A reverse lid detection system comprising means for outputting a value signal. The reverse lid detection system according to claim 1, wherein the belt-like light beam uses laser light .   The reverse lid detection system according to claim 1 or 2, wherein the width of the band-shaped light beam is 3 mm or more.   The reverse lid detection system according to any one of claims 1 to 3, wherein an ON / OFF threshold value of the amount of received light can be set according to a situation.

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