JP2622257B2 - Empty can size inspection equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for inspecting main dimensions of an empty can manufactured in a can manufacturing line.

[Background Art] A can used for canned beer or the like is formed by first punching, drawing, or the like a cylindrical empty can with a bottom. The empty can thus formed is filled with contents after being subjected to a process of expanding its opening into a flange shape, and the empty can and the empty lid are caulked and fixed at the flange-shaped portion. Products.

By the way, variations occur in the main forming dimensions of the empty can, that is, the height from the bottom to the upper edge of the side plate (hereinafter referred to as trim height), the thickness of the side plate and the depth of the recess formed in the bottom of the empty can. In such a case, the sealing property between the can lid and the main body is deteriorated, or the can is deformed by the pressure of the contents, resulting in a defective product. For this reason, conventionally, an operator measures the above dimensions at a plurality of locations of the empty can using a dial gauge or the like, and performs quality control so that defective products do not occur in a subsequent process.

[Problems to be Solved by the Invention] However, when the above inspection is performed manually, measurement requires a long time due to the large number of measurement points per unit. Not only is required, but also there are problems such as variations in the measurement position and errors in reading the dial gauge depending on the operator, and the reliability of the inspection is low.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is possible to perform a dimension inspection of an empty can in a very short time, and it is possible to automate an inspection operation, as well as to perform an inspection. It is an object of the present invention to provide an empty can size inspection device capable of greatly improving the reliability of the can.

[Means for Solving the Problems] The dimensional inspection apparatus for empty cans according to claim 1 of the present invention has a cylindrical shape with a bottom and a concave portion which is depressed toward the opening at the center of the bottom. A height measuring mechanism for measuring the height from the bottom of the empty can formed with the upper edge of the side plate portion to the upper edge of the side plate portion while rotating the empty can, and the empty can. A thickness measuring mechanism for measuring the thickness of the side canal by sandwiching the side plate portion with a measuring element while rotating, a depth measuring mechanism for inserting the measuring element into the concave portion and measuring the depth, and an empty can for each type. A storage mechanism for storing the empty cans from the storage mechanism, a transport mechanism for sequentially transferring the empty cans from the storage mechanism to the respective measurement mechanisms, and removing the measured empty cans from the measurement mechanism, and the empty cans based on the measurement results by the respective measurement mechanisms. And a control mechanism to judge the quality of The storage mechanism and each of the measurement mechanisms are arranged in an annular shape around the transport mechanism in plan view.

The apparatus for inspecting dimensions of empty cans according to claim 2 is:
2. The dimensional inspection apparatus for empty cans according to claim 1, wherein the transport mechanism removes the empty cans taken out of the storage mechanism into the height measurement mechanism prior to the thickness measurement mechanism and the depth measurement mechanism. And is controlled to be transferred to the measuring mechanism.

An apparatus for inspecting dimensions of an empty can according to claim 3 is the apparatus for inspecting dimensions of an empty can according to claims 1 or 2, wherein the height measuring mechanism or the depth measuring apparatus is used. At least one of the mechanisms is provided with a master gauge for performing the zero setting of each of the above-mentioned measuring elements.

The dimensional inspection device for empty cans according to claim 4 is the dimensional inspection device according to any one of claims 1 to 3, wherein the height measuring device is the empty can. The guide ring is inserted from above to correct the deformation at the upper end of the empty can to form a perfect circle, and a sensor for detecting the lowered position of the guide ring.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 is a plan view showing the entirety of an empty can size inspection apparatus (hereinafter referred to as an inspection apparatus) according to an embodiment. The inspection device shown in this figure includes a robot hand (transportation mechanism) A, a can stocker (storage mechanism) B,.
The height measuring mechanisms C and C, the thickness measuring mechanisms D and D, and the depth measuring mechanisms E and E are sequentially connected in a clockwise direction, and each of the mechanisms is controlled by a microcomputer (control mechanism, not shown). Operation control and reading and counting of measurement results are performed.

Here, the can stocker B is configured such that both end portions of the empty can are hung on the guide plates 1.1 spaced apart from each other in the horizontal direction, and a plurality of cans are stored.
The distance between the guide plates 1.1 is set in accordance with the size of a can or a 350 ml can. Guide plate 1
Are arranged inclined downward toward the robot hand A, and are provided in a plurality of stages up and down, so that empty cans are sorted for each production lot of the can making line.

Next, the height measuring device will be described with reference to FIG. 2. In the figure, reference numeral 2 denotes a frame. On the upper surface of the frame 2, a support base 3 having an upper half formed in a ring shape
Is attached. A shaft body 4 whose axis is oriented in the vertical direction is rotatably supported inside the support base 3 via bearings 5. A through hole 4a is formed inside the shaft body 4, and a vacuum exhaust device (not shown) is connected to an opening at the lower end of the through hole 4a. The shaft body 4 is provided with a gear 6,
7 and a stepping motor 8 so as to be rotatable. Further, a disk 9 is attached to the lower end of the shaft body 4. A plate (not shown) is attached to the disk 9. On the other hand, a sensor 10
Is attached. The sensor 10 senses when the plate passes in front of it, and detects a reference position of the shaft body 4 in the circumferential direction.

Further, a turntable 11 whose axis is aligned with the axis of the shaft body 4 is attached to the upper end surface of the shaft body 4. A through hole 11a is formed in the center of the turntable 11, and the empty can P placed on the upper surface can be sucked by vacuum suction from the through hole 11a. Also, on the upper surface of the turntable 11,
A V-shaped block 12 for positioning the empty can P is attached.

On the other hand, a stand 13 is attached to the frame 2. The stand 13 is provided with a push piece 14 which can be moved toward and away from the V-shaped block 12 by an air cylinder (not shown). The push piece 14 comes into contact with the side surface of the empty can P by extending the air cylinder, thereby aligning the axis of the empty can P with the center of rotation of the turntable 11. In the stand 13, a shaft 15 whose longitudinal direction is directed vertically is slidably disposed in the vertical direction. An arm 16 is attached to the upper end of the shaft 15. A rack 17 is attached to the left end of the arm 16 with its longitudinal direction facing up and down. The rack 17 can be moved up and down by a reversible motor 18.

The other end of the arm 16 has a turntable
A guide ring 19 matching the rotation center of 11 is attached. The guide ring 19 has a larger diameter at the center in the axial direction of the outer periphery than at the upper end, and a tapered shape from the largest diameter portion to the lower side, and the outermost diameter is slightly smaller than the inner diameter of the empty can P. Has been made smaller. This guide ring
19 is inserted into the empty can P by lowering the shaft 15, whereby the deformation at the upper end of the empty can P is corrected to make it a perfect circle. Also, stand 13
Are mounted with a plurality of sensors 20 which are vertically separated from each other. These sensors 20... Detect the position of the arm 16, and the position of the lower end of the guide ring 19 is selected according to the type of the empty can P.

Next, a shaft 21 whose longitudinal direction is directed up and down is arranged on the frame 2, and a gauge arm 22 is attached to the upper end of the shaft 21. A digital gauge 23 with the tracing stylus 23a facing downward is attached to the tip of the gauge arm 22. The probe 23a of the digital gauge 23 is
It has a roller 24 whose axis is rotatable in the radial direction of the empty can P, and is slidable in the vertical direction and urged downward. Also, the probe 23a
Is mounted with a lever 25 projecting in the horizontal direction.

On the other hand, an air cylinder 26 having a piston rod 26a directed downward is attached to a middle portion of the gauge arm 22 in the longitudinal direction, and a disk 27 is attached to the piston rod 26a. The lever 25 is placed on the upper surface of the disc 27, whereby the tracing stylus 23a is lowered together with the disc 27 by extending the air cylinder 26, and the side plate portion of the empty can P It is designed to be placed on the upper edge.

Reference numeral 28 in the figure is a master gauge. The master gauge 28 is for performing zero setting of the digital gauge 23. That is, the height of the master gauge 28 is measured prior to the measurement of the trim height, and the actual value of the trim height is measured by adding the measured value of the trim height to the measured value. The master gauge 28 can be moved up and down by an air cylinder 29 and left and right by a linear motor 30.

Next, the thickness measuring device D will be described. In FIG. 3, reference numeral 31 denotes a frame. On the left side of the frame 31, a slide 34 slidable in the left-right direction in the figure by a feed screw 32 and a stepping motor 33 for rotating the feed screw 32 is arranged. On slide 34,
A support base 36 slidable by an air cylinder 35 in a direction perpendicular to the plane of the drawing is attached, and a chuck 37 having a center line directed in the left-right direction is attached to the support base 36. The chuck 37 is rotatable by a stepping motor 38.

On the right side of the frame 31, a mandrel shaft 39
Is attached with its axis facing left and right. The mandrel shaft 39 has a cylindrical shape, and is positioned so that the height of its axis is the same as the center line of the chuck 37. An empty can P is put on the mandrel shaft 39. Further, a contact 40 whose axial line is directed in the vertical direction and whose upper end surface slightly protrudes from the outer periphery of the mandrel shaft 39 is attached to the outer peripheral portion of the left end of the mandrel shaft 39. On the other hand, on the frame 31, a pusher 42 which is movable in the vertical direction by an air cylinder 41 is arranged. The lower surface of the push piece 42 is formed as an arc-shaped concave curved surface (fourth).
See figure). Then, the empty can P covered by the mandrel shaft 39 is pressed by the pusher 42, and the inner surface thereof is brought into contact with the contact 40.

Further, a digital gauge 43 in which a tracing stylus 43a is positioned above the contact 40 is attached to the frame 31.
The tracing stylus 43a is slidable up and down and urged downward. Also, the stylus 43a
A lever 44 projecting in the horizontal direction is attached to the upper side of the. On the right side of the digital gauge 43, an air cylinder 45 is attached with its piston rod 45a directed downward. A disk 46 is attached to the piston rod 45a.
The lever 44 is mounted on the upper surface of the disk 46. Under this configuration, the tracing stylus 43a is
It moves up and down along with 6.

Next, the depth measuring mechanism E will be described. In FIGS. 5 and 6, reference numeral 50 denotes a frame. flame
A support table 53 slidable in the left-right direction in FIG. 5 by a feed screw 51 and a stepping motor 52 for rotating the feed screw 51 is disposed on the upper surface of the 50. A shaft 54 whose axis is directed in the up-down direction is arranged on the support table 53, and the shaft 54 is slidable in the same direction by a linear motor 55. An arm 56 is fixed to the upper end of the shaft 54, and a digital gauge 57 is attached to the left end of the arm 56 with its tracing stylus 57a facing downward. The tracing stylus 57a is slidable up and down and urged downward. A stopper 58 wider than the outer diameter of the concave portion Pa of the empty can P is attached to the digital gauge 57.

A master gauge 59 similar to the above and a can guide 60 are attached to the upper surface of the frame 50. Can guide
Numeral 60 is for positioning the empty can P. In addition,
In the figure, reference numeral 61 denotes a sensor for detecting the lower end of the shaft 54. The position of the lower end of the digital gauge 57 according to the type of the empty can P is selected by the sensors 61.

Next, each of the above mechanisms operates as follows in accordance with a command from a microcomputer (control mechanism) not shown.

That is, when the trim height measurement of the empty can P is started, first, the master gauge 28 moves to below the digital gauge 23 and is placed on the turntable 11. Next, the disk 27 descends and the tracing stylus 23a contacts the upper surface of the master gauge 28, and the microcomputer stores the measured value at this time. Next, the disk 27 rises and the tracing stylus 23a also rises.

Next, the robot hand A is moved to one of the can stockers B
Is selected, the empty can P is taken out therefrom, and the height measuring mechanism C is selected.
On the turntable 11. Then, the push piece 14 moves forward and comes into contact with the side of the empty can P, the axis of the empty can P is made to coincide with the axis of the turntable 11, and the vacuum can is suctioned from the through hole 11a to hold the empty can in the shape of the turntable 11. I do. At the same time, the guide ring 19 is lowered and inserted into the empty can P, and the deformation of the empty can P is corrected to be a perfect circle. As a result, the axis of the empty can P completely coincides with the rotation center of the turntable 11. Next, the disk 27 descends and the tracing stylus 23a contacts the upper edge of the side plate portion of the empty can P. At the same time, the turntable 11 rotates,
The tracing stylus 23a moves up and down according to the trim height of the empty can P.
Then, the microcomputer counts the number of steps of the stepping motor 8 stored in advance, and reads the measured value of the trim height by the digital gauge 23 for each set rotation angle position of the turntable 11. Then, when the empty can P rotates once, reading of the measured values of all points of the empty can P is completed, and the microcomputer adds the measured value of the master gauge to the read measured value and stores this value.

Next, the robot hand A takes out the empty can P from the height measuring mechanism C, and causes the chuck 37 of the thickness measuring mechanism D to grip the empty can P. At this time, the chuck 37 is at a position shifted from the mandrel shaft 39 in the horizontal direction, so that the empty can P can be easily transferred from the robot hand A. Next, the chuck 37 moves forward of the mandrel shaft 39 and advances rightward in FIG. 3 to cover the empty can on the mandrel shaft 39. Next, the pusher 42 descends and presses the empty can P toward the mandrel shaft 39 to bring the inner periphery of the empty can P into contact with the contact 40. Next, the disk 46 descends, and the stylus 43a
Descends and comes into contact with the side plate portion of the empty can P. The microcomputer stores the value measured by the digital gauge 43 at this time. Next, the chuck 37 rotates by a predetermined angle. Then, the thickness of the side plate portion is measured in the same manner as described above, and the thickness is measured at a plurality of locations in this manner.

When the thickness measurement at all points of the empty can P is completed, the chuck 37 retreats to the left, and the robot hand A moves the empty can P
From the chuck 37. Then, the empty can P is placed on the frame 50 of the depth measuring mechanism E. At this time, empty can P
It is positioned by the can guide 60. Here, the digital gauge 57 is set to zero by the master gauge 59 before the depth measurement of the concave portion Pa. Then, when the empty can P is placed on the frame 50, the support 53 is moved to the left,
The digital gauge 57 is lowered. Then, the stopper 58
Abuts against the bottom of the empty can P, and the distance from the lower surface of the stopper 58 to the concave Pa of the empty can P, that is, the depth of the concave Pa is measured. When the measurement is completed, the digital gauge 57 is raised, and the empty can P is taken out by the robot hand A and inserted into a predetermined storage container.

The above measurement result is determined by the microcomputer, and an alarm is issued when the measurement value deviates from a predetermined range. Further, the measured values stored in the microcomputer are totaled every day or every month, and the result is printed out.

In this embodiment, the stockers B..., The height measurement mechanisms C and C, the thickness measurement mechanisms D and D, and the depth measurement mechanisms E and E are sequentially connected in a clockwise direction. These stockers B ... and each measuring mechanism CC, D, D, E
-The order of E is not limited to this. Further, in this embodiment, the order of measurement is height measurement, thickness measurement,
Although the order of the depth measurement has been described, the order of the thickness measurement and the depth measurement may be reversed. In short, the height measurement may be performed prior to the thickness measurement and the depth measurement.

In the above-mentioned inspection apparatus, the above-mentioned stockers B...
・ C, D ・ D, EE ・ E are arranged in an annular shape in plan view, and the measurement of trim height and measurement of thickness with many measurement points are performed.
Since the microcomputer reads the measurement results of the digital gauges 23 and 43 while the empty can P makes one revolution (one rotation) of the stockers B and the measuring mechanisms C, D and E, the dimensional inspection of the empty can P is performed. Can be performed automatically in a very short time. In addition, the number of measurement points can be set arbitrarily, and the measurement of trim height and thickness can be performed with extremely high accuracy without any variation in measurement positions or reading errors. Can be improved.

In addition, since the inspection results are compiled by the microcomputer, data processing within a specific period can be compiled for each can-making line and each can type, so that the quality control situation of empty cans can be immediately listed. And quality control can be performed very easily. In the inspection device, since the stocker B and the measurement mechanisms C, D, and E are arranged in a ring around the robot hand A in plan view, the space of the entire device can be saved. Since the transport path of the empty cans P is simple, an effect is obtained that the structure of the robot hand A may be simple.

Further, in the above-described inspection apparatus, when measuring the trim height, the measuring element 23a of the height measuring mechanism C is directly
The upper edge (edge) of the side plate portion of the empty can P is extremely susceptible to dents and deformation as compared with, for example, the bottom portion of the empty can P or the center portion of the side plate portion. When a dent or the like occurs, there is a problem that an accurate measurement of the trim height cannot be performed. In this regard, in the above inspection apparatus,
Prior to the thickness measurement mechanism D and the depth measurement mechanism E, the robot hand A removes the empty can P taken out of the stocker B,
Because it is controlled to transfer to the height measurement mechanism C,
The upper edge of the side plate of the empty can P is a mandrel shaft 39 or frame
An effect is obtained in that there is no possibility that a dent or the like occurs due to the contact with the 50 (can guide 60), and accurate measurement of the trim height cannot be performed. Further, in the above-described inspection apparatus, the measurement location in the thickness measurement mechanism D is the third location.
As shown in the figure, since it is near the lower edge of the side plate portion of the empty can P,
Even if a dent or the like occurs in the upper edge of the side plate portion of the empty can P, the measurement is not affected, and the depth measuring mechanism E measures the distance from the stopper 58 to the concave portion Pa of the empty can P. In addition, even if a dent or the like occurs in the upper edge of the side plate portion of the empty can P, the measurement is not affected.

Further, in the above-described inspection apparatus, the height measuring mechanism C and the depth measuring mechanism E are respectively provided with the digital gauges 23 and 57.
Since each of the master gauges 28 and 59 for zero setting is provided, it is possible to automatically suppress the occurrence of errors in each measuring device, thereby realizing high-precision dimensional measurement automation. .

Further, in the above inspection apparatus, the height measuring mechanism C
However, a sensor 20 for detecting the lowering position of the guide ring 19 ...
Is provided, it is possible to select the lowering position of the guide ring 19 according to can types having different lengths (for example, 500 ml cans and 350 ml cans). In particular, as described above, the upper edge of the side plate portion of the empty can P is liable to generate dents and deformation, and once dents and the like occur once, accurate measurement of the trim height becomes impossible. Is provided, so that the guide ring 19 does not descend unnecessarily to cause the upper edge of the side plate portion of the empty can P to be dented or deformed.

[Effect of the Invention] As described above, the height from the bottom to the upper edge of the side plate portion of the empty can having a bottomed cylindrical shape and having a concave portion which is depressed toward the opening at the bottom center is defined as the above-mentioned empty space. A height measuring mechanism for measuring by contacting a vertically movable measuring element with the side edge while rotating the can, and sandwiching the side plate portion with another vertically movable measuring element while rotating the empty can. A thickness measurement mechanism for measuring the thickness, a depth measurement mechanism for inserting another vertically movable measuring element into the recess to measure the depth, and a storage mechanism for storing empty cans for each type. And a transport mechanism for taking out the cans from the storage mechanism, transferring the cans to each measuring mechanism, and taking out the measured empty cans from the measuring mechanism, and judging the quality of the empty cans based on the measurement results by the measuring mechanisms. And a control mechanism for totalizing each measurement result As a result, the inspection of the dimensions of empty cans can be completely unmanned, and the inspection can be performed in a very short time. Further, there is no variation in the measurement position and no reading error of the measured value, so that the reliability of the inspection can be greatly improved, and further, the effects of processing the inspection results can be extremely easily obtained. In addition, although the apparatus for inspecting the size of an empty can according to the present invention has a simple mechanical structure, the height of the empty can, the thickness and the depth of the side plate can be accurately measured. .

Further, in the present invention, since the storage mechanism and the measurement mechanisms are arranged in a ring around the transfer mechanism in plan view, the space of the entire apparatus can be saved, and the transfer path of the empty can can be reduced. Because of the simplicity, an effect is obtained in that the structure of the transport mechanism may be simple.

Further, in the present invention, when measuring the trim height,
The measuring element of the height measuring mechanism is brought into contact with the upper edge of the side plate of the empty can.The upper edge of the side plate of the empty can, for example, is significantly dent or deformed compared to the bottom of the empty can or the center of the side plate. There is a problem that once a dent or the like is generated there, an accurate measurement of the trim height cannot be performed. In this regard, in the present invention, since the transport mechanism is controlled to transfer the empty can taken out of the storage mechanism to the height measuring mechanism prior to the thickness measuring mechanism and the depth measuring mechanism, the empty can is An effect is obtained that there is no possibility that an accurate measurement of the trim height cannot be performed due to, for example, the upper edge of the side plate portion being dented during thickness measurement or depth measurement. In addition, since what is measured by the thickness measuring mechanism is the thickness of the side plate portion of the empty can, even if a dent or the like occurs at the upper edge of the side plate portion of the empty can, there is no effect on the measurement,
Also, the depth measurement mechanism measures the depth of the concave portion of the empty can,
Similarly, even if a dent or the like occurs in the upper edge of the measuring plate portion of the empty can, the measurement is not affected.

Further, in the above-described inspection apparatus, at least one of the height measurement mechanism and the depth measurement mechanism includes a master cage for performing zero setting of each of the measuring elements. It can be suppressed automatically, and thus, high-precision automation of dimension measurement can be realized.

Further, in the above inspection device, the height measuring mechanism
Since the sensor for detecting the descending position of the guide ring is provided, it is possible to select the descending position of the guide ring according to can types having different lengths (for example, a 500 ml can or a 350 ml can). In particular, as described above, the upper edge of the side plate portion of the empty can is susceptible to dents and deformation, and once dents or the like occur there, it becomes impossible to accurately measure the trim height. This prevents the guide ring from descending more than necessary and causing the upper edge of the side plate portion of the empty can to be dented or deformed.

[Brief description of the drawings]

1 to 6 are views showing an embodiment of the present invention, wherein FIG. 1 is a plan view showing a dimension inspection apparatus for empty cans, and FIG. 2 is a view showing a height inspection mechanism in FIG. FIG. 3 is a view in the direction of the arrow II, FIG. 3 is a view in the direction of the arrow III in FIG. 1 showing the thickness inspection apparatus, FIG. 4 is a view in the direction of the arrow IV in FIG. 3, and FIG. FIG. 1 is a view taken in the direction of the arrow V in FIG. 1, and FIG.
FIG. 6 is a view taken in the direction of arrow VI in FIG. A: Robot hand (transport mechanism), B: Can stocker (storage mechanism), C: Height measuring mechanism, D: Thickness measuring mechanism, E: Depth measuring mechanism, P: Empty can, Pa …… Recess,
23a ... contact point, 43a ... contact point, 57a ... contact point.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-53-41252 (JP, A) JP-A-56-128401 (JP, A) JP-A-51-93249 (JP, A) 161683 (JP, U)

Claims (4)

(57) [Claims] The height from the bottom to the upper edge of the side plate portion of the empty can (P) having a bottomed cylindrical shape and having a recess (Pa) depressed toward the opening side at the center of the bottom is formed. While rotating the empty can (P), the probe (23
a) A height measuring mechanism (C) for measuring by bringing the side plate into contact with a measuring element (43) while rotating the empty can (P).
Thickness measurement mechanism (D) that measures the thickness between a)
A depth measuring mechanism (E) for inserting a tracing stylus (57a) into the recess (Pa) and measuring the depth thereof; and a storing mechanism (B) for storing empty cans (P) for each type. Take out the empty cans (P) from the storage mechanism (B), sequentially transfer them to each measuring mechanism (C, D, E), and remove the measured empty cans (P) from the measuring mechanism (C, D, E). A transport mechanism (A) to be taken out, and a control mechanism for judging pass / fail of the empty can (P) based on the measurement result by each of the measurement mechanisms (C, D, E) and totalizing each measurement result. , The storage mechanism (B) and each of the measurement mechanisms (C, D, E)
Is a dimension inspection device for empty cans, which is arranged in an annular shape with the transport mechanism (A) as the center of a circle in plan view. 2. The apparatus for inspecting dimensions of an empty can according to claim 1, wherein said transport mechanism (A) removes the empty can (P) taken out of said storage mechanism (B) into said thickness. An apparatus for inspecting dimensions of empty cans, which is controlled so as to be transferred to the height measuring mechanism (C) prior to the measuring mechanism (D) and the depth measuring mechanism (E). 3. An apparatus for inspecting dimensions of an empty can according to claim 1 or 2, wherein said height measuring mechanism (C) or said depth measuring mechanism (E).
At least one of them comprises a master gauge (28, 59) for performing zero setting of each of the measuring elements (23a, 57a). 4. The empty can size inspection device according to claim 1, wherein the height measuring device (C) is inserted into the empty can (P) from above. A guide ring (19) that corrects the deformation at the upper end of the empty can (P) to form a perfect circle, and a sensor (20 ...) that detects the lowered position of the guide ring (19). An empty can dimensional inspection device, characterized in that: