Can chuck and can manufacturing apparatus

Abstract

To provide a can chuck and a can manufacturing apparatus which can stably return an expansion ring to an original position before expansion, when the expansion ring is contracted.SOLUTION: A chuck peripheral wall 71 has a cylindrical body 74, an annular storage groove 75 which is recessed to radial outside from the inner peripheral surface of the cylindrical body 74, and an annular expansion ring 76 which is arranged in the storage groove 75 and is elastically deformable, wherein the storage groove 75 has a pair of groove side faces 75a, the expansion ring 76 has a pair of ring side faces 79 facing the pair of groove side faces 75a, a ring inner peripheral surface 81 capable of being brought into contact with a can trunk Wa, and an annular air chamber 82 arranged inside the expansion ring 76, wherein when air is supplied to the air chamber 82, the expansion ring 76 is expanded and can hold the can truck Wa by the ring inner peripheral surface 81, and in longitudinal cross-sectional view, a sum (W2+W4+W5) of radial dimensions of parts not contacting the groove side faces 75a in the ring side faces 79 are set to be larger than a sum (W1+W3) of radial dimensions of parts contacting the groove side face 75a in the ring side faces 79.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a can chuck and a can manufacturing apparatus.

Background Art

[0002] Conventionally, there is known a bottle can manufacturing apparatus (hereinafter sometimes referred to as a can manufacturing apparatus) that manufactures a bottle can (a threaded can) by performing various processes on the opening of a cylindrical can (DI can) as shown in Patent Documents 1 and 2 below.

[0003] The can manufacturing apparatus includes a holding table (turn table), a processing table (die table), a table indexing mechanism, and a crank mechanism. The holding table has a plurality of chucks (can chucks) that hold a plurality of cans. The processing table is arranged to face the holding table from the axial direction of the table. The processing table has a plurality of processing tools for performing processing on each can held by the holding table. The table indexing mechanism intermittently rotates and moves the holding table relative to the processing table around the table axis. The crank mechanism reciprocates the processing table relative to the holding table in the table axis direction.

[0004] The plurality of chucks of the holding table are arranged side by side around the outer periphery of the holding table around the table axis. Each can is held by each chuck in a posture with the opening facing the processing table side. The plurality of processing tools of the processing table are arranged side by side around the outer periphery of the processing table around the table axis. The plurality of processing tools include a plurality of die processing tools and a plurality of rotary processing tools. The plurality of die processing tools perform various die processes such as drawing (diameter reduction) and diameter expansion on the opening of the can. The plurality of rotary processing tools perform various rotary processes such as trimming, thread forming, curling, and slot (curl flattening) on the opening of the can.

[0005] The holding table and the processing table are repeatedly moved closer to and away from each other in the table axis direction by a crank mechanism, and are intermittently rotated relative to each other around the table axis by a table indexing mechanism. Specifically, the processing table repeatedly moves closer to and away from the holding table in the table axis direction, and during one stroke (reciprocating movement) of this approach and separation, the holding table rotates by a predetermined amount around the table axis relative to the processing table (intermittent rotation).

[0006] And for each stroke in which the tables approach and separate from each other, a predetermined process is performed on the can by a processing tool, and the can is moved to the processing position by the next processing tool. By repeating this operation, sequential processing is performed on the cans held by the holding table by a plurality of processing tools provided on the processing table, and when the processing by all the processing tools is completed, a bottle can having a predetermined shape is obtained.

[0007] In the can manufacturing apparatus described in Patent Document 1, a plurality of can body holding devices (can chucks) are fixedly provided annularly on a rotating plate (holding table). This can body holding device is composed of a can body holder fixed to a frame body, a can holder that sandwiches the body portion of the can by supplying air, and a can holder fixing tool that fixes the can holder.

[0008] Further, in the bottle can manufacturing apparatus described in Patent Document 2, a plurality of chucks (can chucks) are arranged along the circumferential direction of the table on the outer peripheral portion of the surface of the holding table facing the processing table side. The chuck has a peripheral wall and a bottom wall. An expansion and contraction ring that is elastically deformed by air pressure and detachably holds the can body of the can is provided on the peripheral wall of the chuck. Specifically, the expansion and contraction ring expands by supplying air into the expansion and contraction ring to hold the can body of the can, and contracts by stopping the supply of air to release the can body of the can.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] In a conventional can chuck, when the air supply is stopped and the expansion and contraction ring contracts, there are cases where the expansion and contraction ring cannot stably return to its original position before expansion. Specifically, when the expansion and contraction ring is moved radially inward during expansion and then returns radially outward due to subsequent contraction, the amount of movement may not be sufficient and it may not be able to return to the initial position before expansion (cannot return to the origin).

[0011] If the expansion and contraction ring cannot return to the origin, the expansion and contraction ring will protrude from the inner peripheral surface of the can chuck. Next, when the can supplied to this can chuck gets caught on the expansion and contraction ring, it will be processed while being held in an inclined state, resulting in processing defects, conveyance defects, or can dropping, which is not preferable.

[0012] An object of the present invention is to provide a can chuck and a can manufacturing apparatus in which the expansion and contraction ring can stably return to its original position before expansion when it contracts.

Means for Solving the Problems

[0013] To solve the above problems, the present invention provides the following means.

[0014] 〔Aspect 1 of the Present Invention〕 A can chuck having a bottomed cylindrical shape centered on a central axis, comprising a chuck peripheral wall into which the body of the can is inserted and a chuck bottom wall that contacts the bottom of the can. The chuck peripheral wall has a cylindrical body extending in the axial direction, an annular receiving groove that is recessed radially outward from the inner peripheral surface of the cylindrical body and extends over the entire circumference around the central axis, and an elastically deformable annular expansion and contraction ring disposed in the receiving groove. The receiving groove has a pair of groove side surfaces spaced apart from each other in the axial direction and a groove bottom surface disposed between the pair of groove side surfaces and facing radially inward. The expansion and contraction ring has a pair of ring side surfaces facing both axial sides and opposing the pair of groove side surfaces, a ring outer peripheral surface facing radially outward and opposing the groove bottom surface, a ring inner peripheral surface facing radially inward and capable of contacting the body of the can, an annular air chamber disposed inside the expansion and contraction ring and extending over the entire circumference around the central axis, and a communication portion that communicates the ring outer peripheral surface with the air chamber. When air is supplied to the air chamber through the communication portion, the expansion and contraction ring expands and can hold the body of the can with the ring inner peripheral surface. In a longitudinal sectional view along the central axis, the sum of the radial dimensions of the portions of the ring side surfaces that do not contact the groove side surfaces is larger than the sum of the radial dimensions of the portions that contact the groove side surfaces. Can chuck.

[0015] In the can chuck and can manufacturing apparatus of the present invention, when air is supplied into the air chamber through the communication portion by an air supply means or the like, the expansion and contraction ring elastically deforms and expands. Due to this expansion, the ring inner peripheral surface moves (displaces) radially inward and contacts the body of the can, and the expansion and contraction ring holds the body of the can. With the body of the can held by the expansion and contraction ring, processing by each processing tool is performed on the opening or the like of the can. After processing by each processing tool, when the supply of air to the expansion and contraction ring is stopped, the expansion and contraction ring restores and contracts. Due to this contraction, the ring inner peripheral surface moves (displaces) radially outward and separates from the body of the can, thereby releasing the holding state of the can by the can chuck. Thereby, the can can be pushed out in the axial direction by an extrusion piston or the like and taken out from the can chuck.

[0016] According to the present invention, in a longitudinal sectional view along the central axis of the can chuck, the sum of the radial dimensions of the portions of the ring side surface of the expansion and contraction ring that do not contact the groove side surface is larger than the sum of the radial dimensions of the portions that contact the groove side surface of the accommodation groove. Therefore, when the expanded expansion and contraction ring contracts, the frictional resistance between the ring side surface and the groove side surface is suppressed to be small, and the expansion and contraction ring can stably return to its original position before expansion.

[0017] Specifically, when the expansion and contraction ring is moved radially inward during expansion and then returned radially outward due to subsequent contraction, the frictional resistance is reduced, so that a sufficient amount of movement is ensured. As a result, the expansion and contraction ring can stably return to its initial position before expansion (that is, it can return to the origin).

[0018] Since the expansion and contraction ring can stably return to the origin, the state where the expansion and contraction ring protrudes from the inner peripheral surface of the cylindrical body is suppressed, and it is prevented that the can supplied to this can chuck next is caught by the expansion and contraction ring. For this reason, defects such as the can being processed while being held in an inclined state by the can chuck, resulting in processing defects, conveyance defects, or can dropping, can be suppressed. That is, the productivity of the can is stably increased.

[0019] From the above, according to the present invention, there is provided a can chuck and a can manufacturing apparatus in which the expansion and contraction ring can stably return to its original position before expansion when it contracts.

[0020] 〔Aspect 2 of the present invention〕 The can chuck according to Aspect 1, wherein the expansion and contraction ring has a recess that is recessed axially from the ring side surface and extends in the circumferential direction around the central axis.

[0021] In this case, by a simple structure in which the expansion and contraction ring is provided with a recess that is recessed from the ring side surface, the frictional resistance between the ring side surface and the groove side surface can be suppressed to be small. As a result, the above-described operational effects of the present invention are stably achieved.

[0022] 〔Aspect 3 of the present invention〕 The can chuck according to aspect 2, wherein the recess has an axial dimension smaller than a radial dimension.

[0023] In this case, by providing the recess, the contact area between the ring side surface and the groove side surface is reduced, and the frictional resistance between them is kept small, while the thickness of the expansion and contraction ring is ensured. Specifically, since the axial dimension of the recess is smaller than the radial dimension of the recess, a large wall thickness dimension is ensured between the deepest part in the axial direction of the recess and the air chamber. Thereby, breakage due to repeated expansion and contraction deformation of the expansion and contraction ring, aging deterioration, etc. is suppressed.

[0024] 〔Aspect 4 of the present invention〕 The can chuck according to any one of aspects 1 to 3, wherein the expansion and contraction ring has a corner portion disposed at a connection portion between the ring side surface and the ring outer peripheral surface, and the corner portion contacts the groove side surface.

[0025] In this case, since the corner portion is in contact with the groove side surface and frictional resistance is generated between them, when air is supplied to the air chamber and the expansion and contraction ring expands, the portion located radially inward of the corner portion is preferentially elastically deformed. When the expansion and contraction ring expands, the movement of the corner portion radially inward is suppressed (that is, the corner portion is in a fixed state). Therefore, an anchor effect is obtained by the corner portion, and when contracting after expansion, the expansion and contraction ring can return to the origin more stably.

[0026] 〔Aspect 5 of the present invention〕 A can manufacturing apparatus including a holding table that is intermittently rotated around a table axis and a processing table that reciprocates in the table axis direction with respect to the holding table, the holding table having a plurality of can chucks that hold a plurality of cans, the processing table having a plurality of processing tools that perform processing on each of the cans held by each of the can chucks, and the can chuck including the can chuck according to any one of aspects 1 to 4.

Advantages of the Invention

[0027] According to the can chuck and the can manufacturing apparatus of the above aspect of the present invention, when the expansion and contraction ring contracts, it can stably return to the original position before expansion.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0029] The can manufacturing apparatus 1 and the can chuck 7 of an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the can chuck 7 may sometimes be simply referred to as the chuck 7.

[0030] As shown in FIGS. 1 and 2, the can manufacturing apparatus 1 of the present embodiment is a so-called bottle necker (bottle can manufacturing apparatus) that manufactures a bottle can (product can) P having a predetermined shape by performing a plurality of types of forming processes including die processing and rotational processing on a cylindrical can (intermediate formed can) W that is a workpiece.

[0031] The can W supplied to the can manufacturing apparatus 1 as a workpiece is a DI can that has been subjected to processes such as DI (Drawing & Ironing) processing, printing, and painting in a previous process before the can manufacturing apparatus 1. The DI can is formed into a bottomed cylindrical shape by performing a capping process (drawing process), a DI process (drawing and ironing process), a trimming process, a printing process, a painting process, etc. on a disk-shaped blank punched from an aluminum alloy plate.

[0032] The can W includes a cylindrical peripheral wall (can body Wa) and a substantially disk-shaped bottom wall (can bottom Wb) (see FIG. 3). In the present embodiment, the central axis of the can W is referred to as the can axis, and the direction in which the can axis extends is referred to as the can axis direction. In the can manufacturing apparatus 1 of the present embodiment, necking is performed on the opening of the can W having a bottomed cylindrical shape, thereby forming a base portion and a shoulder portion. The base portion is the minimum diameter portion of the peripheral wall of the can W. The shoulder portion is disposed between the body portion, which is the maximum diameter portion of the peripheral wall of the can W, and the base portion, and has a tapered shape that gradually decreases in diameter as it extends from the body portion toward the base portion along the can axis direction.

[0033] In the bottle can P manufactured by processing the can W with the can manufacturing apparatus 1, in a post-process after the can manufacturing apparatus 1, the can P is filled with a content such as a beverage, and a cap is screwed onto the base portion to seal the can.

[0034] The can manufacturing apparatus 1 includes an apparatus main body 4, a holding table 3, a processing table 2, a shaft portion 5, a crank mechanism 8, a drive motor 11, a table index mechanism 9, a supply wheel 10, a discharge wheel 14, a wheel index mechanism 15, and a conveying means 12.

[0035] In the processing table 2 and the holding table 3, each table axis TA, which is the central axis of each table, extends in the horizontal direction, and these table axes TA are arranged coaxially with each other. The processing table 2 and the holding table 3 are arranged side by side in the direction in which the table axis TA extends and face each other.

[0036] In the present embodiment, the direction in which the table axis TA extends is referred to as the table axis direction. In each figure, the table axis direction corresponds to the X-axis direction. Among the table axis directions, the direction from the processing table 2 toward the holding table 3 (+X side) is referred to as one side of the table axis direction, and the direction from the holding table 3 toward the processing table 2 (-X side) is referred to as the other side of the table axis direction. Note that the table axis direction may be referred to as the front-rear direction. In this case, one side (+X side) of the table axis direction corresponds to the rear side, and the other side (-X side) of the table axis direction corresponds to the front side.

[0037] Also, the direction orthogonal to the table axis TA is called the table radial direction. Among the table radial directions, the direction approaching the table axis TA is called the inner side of the table radial direction, and the direction away from the table axis TA is called the outer side of the table radial direction. Also, the direction of orbiting around the table axis TA is called the table circumferential direction.

[0038] The apparatus main body 4 supports a holding table 3, a processing table 2, a shaft portion 5, a crank mechanism 8, a table index mechanism 9, a drive motor 11, a supply wheel 10, a discharge wheel 14, and a wheel index mechanism 15. The conveying means 12 extends outside the apparatus main body 4.

[0039] Although detailed illustration is omitted, the apparatus main body 4 has, for example, a base, a frame attached to the base, and an exterior member covering the base and the frame. The base is installed on the floor of a facility such as a factory. The frame is assembled on the base and fixed to the base by fastening members such as bolts or welding. The exterior member has a housing shape and includes a plurality of plate-like members. A part of the exterior member is a door portion that can be opened and closed, and is opened and closed during maintenance of the components of the apparatus.

[0040] The holding table 3 is called, for example, a turntable or an index table. The holding table 3 has a circular ring shape. The holding table 3 is, for example, a circular ring-shaped or disc-shaped table with a large diameter (for example, a radius of 650 mm or more).

[0041] On the outer peripheral portion of the surface facing the other side (-X side) in the table axis direction of the holding table 3, a plurality of chucks 7 arranged at equal pitches along the table circumferential direction are provided. That is, the holding table 3 has a plurality of chucks 7 arranged side by side in the table circumferential direction on the outer peripheral portion of the holding table 3. The plurality of chucks 7 hold a plurality of cans W.

[0042] Specifically, the bottom of each can W is held by each chuck 7. The "bottom of the can W" in the present embodiment includes the end portion of the can body Wa on the can bottom Wb side in the can axis direction and the can bottom Wb (see FIG. 3). The can W held by the chuck 7 has its opening facing the other side (-X side) in the table axis direction and facing the processing table 2. The detailed configuration of the chuck 7 will be described separately later.

[0043] The holding table 3 is intermittently rotated in the circumferential direction of the table by a table indexing mechanism 9. That is, the holding table 3 holds a plurality of cans W and is intermittently rotated around the table axis TA.

[0044] In the present embodiment, the direction in which the holding table 3 is intermittently rotated with respect to the processing table 2 in the circumferential direction of the table is called the holding table rotation direction R1, and the rotation direction opposite to this is called the direction opposite to the holding table rotation direction R1 or the reverse holding table rotation direction.

[0045] Note that the holding table rotation direction R1 is the same as the direction in which a plurality of processing tools 6 provided on the processing table 2, which will be described later, are arranged in the circumferential direction of the table in the order of processing the can W. For this reason, the holding table rotation direction R1 can be rephrased as the downstream side (or simply the processing order direction) of the processing order of the can W, and the direction opposite to the holding table rotation direction R1 (reverse holding table rotation direction) can be rephrased as the upstream side of the processing order of the can W.

[0046] The processing table 2 is called, for example, a die table. The processing table 2 has a circular annular shape. The processing table 2 is, for example, a circular ring-shaped or disc-shaped table with a large diameter. The diameter dimension (outer diameter dimension) of the processing table 2 is substantially the same as the diameter dimension of the holding table 3.

[0047] The processing table 2 is supported by the apparatus main body 4 via the shaft portion 5. The shaft portion 5 is fixed to the processing table 2 and extends in the table axis direction about the table axis TA. The shaft portion 5 penetrates the holding table 3 in the table axis direction. The shaft portion 5 is movable in the table axis direction with respect to the holding table 3. The shaft portion 5 is slidably supported by the apparatus main body 4 in the table axis direction, and one end portion of the shaft portion 5 on one side (+X side) in the table axis direction is connected to a connecting rod 18 of a crank mechanism 8 described later.

[0048] The processing table 2 is disposed to face the holding table 3 from the other side (-X side) in the table axis direction. The processing table 2 is reciprocated in the table axis direction with respect to the holding table 3 by the crank mechanism 8.

[0049] The processing table 2 has a plurality of processing tools 6 for performing processing on each can W held by each chuck 7. The plurality of processing tools 6 are arranged side by side in the table circumferential direction on the outer peripheral portion of the processing table 2. Specifically, the plurality of processing tools 6 are arranged at equal pitches along the table circumferential direction on the outer peripheral portion of the processing table 2, and are respectively disposed to face a plurality of cans W held by the holding table 3 from the other side in the table axis direction. The plurality of processing tools 6 are different from each other in type.

[0050] As shown in FIG. 1, the central axis (tool central axis) of each processing tool 6 extends parallel to the table axis TA. The central axis of the processing tool 6, the central axis C of the chuck 7 facing the processing tool 6, and the can axis of the can W held by this chuck 7 are coaxially arranged with each other during processing of the can W. Each processing tool 6 faces each can W from the other side (-X side) in the table axis direction. Then, with the central axis C of the chuck 7 and the can axis of the can W coinciding with the central axis of the processing tool 6, the can W is processed by the processing tool 6.

[0051] Although not particularly shown, the processing table 2 has mounting holes that penetrate the processing table 2 in the table axis direction (X-axis direction). A plurality of mounting holes are provided in the processing table 2. The plurality of mounting holes are arranged side by side in the circumferential direction of the table on the outer peripheral portion of the processing table 2. A plurality (a plurality of types) of processing tools 6 are mounted in each mounting hole in the order of processing on the can W along the holding table rotation direction R1.

[0052] The plurality of processing tools 6 include a plurality of die processing tools and a plurality of rotary processing tools. In the present embodiment, the die processing tools and the rotary processing tools are detachably mounted in the plurality of mounting holes of the processing table 2 in the order of processing on the can W. Note that an oiling tool for attaching oil to the processing planned portion of the can W may be detachably mounted in one or more of the plurality of mounting holes.

[0053] The plurality of die processing tools move in the direction in which the tool center axis (the center axis of the processing tool 6) extends with respect to the can W (the tool axis direction, that is, the can axis direction), and perform various die processes such as drawing (diameter reduction process) and diameter expansion process on the opening of the can W. One type (predetermined) of die process is performed on the can W by one die processing tool.

[0054] The plurality of rotary processing tools perform various rotary processes such as trimming, screw forming, curling, and slot (curling flattening) processes on the opening of the can W by a rotational movement that moves around the tool center axis (that is, around the can axis) with respect to the can W. One type (predetermined) of rotary process is performed on the can W by one rotary processing tool.

[0055] The crank mechanism 8 reciprocates the processing table 2 in the table axis direction with respect to the holding table 3. The crank mechanism 8 includes a drive shaft 16 to which rotation (rotary driving force) from the drive motor 11 is input, a crank shaft 17 that is connected to the drive shaft 16 and is rotated around the axis O of the drive shaft 16 as the drive shaft 16 rotates, and a connecting rod 18 that connects the crank shaft 17 and the shaft portion 5. The crank mechanism 8 converts the rotational motion around the axis O input from the drive motor 11 to the drive shaft 16 into a linear motion in the table axis direction and outputs it to the shaft portion 5. The drive motor 11 is, for example, an inverter motor or the like.

[0056] The table indexing mechanism 9 rotates and stops (intermittently rotates) the holding table 3 in the circumferential direction of the table every one stroke of the reciprocating movement along the table axis direction of the processing table 2. The table indexing mechanism 9 has a structure that intermittently rotates the holding table 3 around the table axis TA with respect to the processing table 2 according to the crank angle around the drive shaft 16 of the crank mechanism 8.

[0057] Therefore, the holding table 3 and the processing table 2 are repeatedly moved closer to and away from each other in the table axis direction by the crank mechanism 8, and are intermittently rotated relative to each other in the circumferential direction of the table by the table indexing mechanism 9. Specifically, the processing table 2 moves closer to and away from the holding table 3 in the table axis direction, and during one stroke (reciprocating movement) of this approach and separation, the holding table 3 rotates (intermittently rotates) by a predetermined amount in the circumferential direction of the table with respect to the processing table 2.

[0058] And for each stroke in which the processing table 2 and the holding table 3 approach and separate, predetermined processing is performed on the can W held by the chuck 7 of the holding table 3 by each processing tool 6 of the processing table 2, and the holding table 3 moves the can W to the downstream side (holding table rotation direction R1) in the processing order to the processing position by the next (another) processing tool 6. By repeating this operation, sequential processing is performed on the can W held by the holding table 3 by a plurality of processing tools 6 provided on the processing table 2, and when the processing by all the processing tools 6 is completed, a bottle can P having a predetermined shape is obtained.

[0059] As shown in FIG. 2, the supply wheel 10 supplies the cans W to the holding table 3. The supply wheel 10, which is also called the infeed wheel, has a substantially cylindrical shape. The supply wheel 10 receives the cans W supplied from the outside of the can manufacturing apparatus 1 (the previous process than the can manufacturing apparatus 1) to the shooter 13, and transfers the cans W to the holding table 3. The supply wheel 10 has a wheel axis SA, which is its central axis, extending parallel to the table axis TA, and is supported by the apparatus main body 4. The supply wheel 10 is rotated in the wheel rotation direction R2 about the wheel axis SA.

[0060] The discharge wheel 14 discharges the processed cans W (bottle cans P) from the holding table 3. The discharge wheel 14, which is also called the discharge wheel, has a substantially cylindrical shape. The discharge wheel 14 receives the cans W (bottle cans P) processed by the can manufacturing apparatus 1 from the holding table 3, and transfers (discharges) them to the conveying means 12. The conveying means 12 conveys the bottle cans P toward the outside of the can manufacturing apparatus 1 (the subsequent process than the can manufacturing apparatus 1). The discharge wheel 14 has a wheel axis DA, which is its central axis, extending parallel to the table axis TA, and is supported by the apparatus main body 4. The discharge wheel 14 is rotated in the wheel rotation direction R3 about the wheel axis DA.

[0061] The supply wheel 10 has a plurality of concave pockets 23 capable of holding the peripheral wall of the can W. The plurality of pockets 23 are arranged at equal pitches in the wheel circumferential direction about the wheel axis SA on the outer peripheral portion of the supply wheel 10. Further, the discharge wheel 14 has a plurality of concave pockets 24 capable of holding the peripheral wall of the can W (bottle can P). The plurality of pockets 24 are arranged at equal pitches in the wheel circumferential direction about the wheel axis DA on the outer peripheral portion of the discharge wheel 14. In FIG. 2, the illustration of each of the pockets 23 and 24 is partially omitted.

[0062] These pockets 23, 24 are formed in a concave curved surface shape with a cross-section perpendicular to the wheel axes SA, DA being a concave arc shape corresponding to the cylindrical shape of the peripheral wall of the can W. Further, suction holes communicating with an air suction source (not shown) are opened on the inner surfaces of the pockets 23, 24. The pockets 23, 24 can hold the can W by the air suction force of the air suction source acting on the peripheral wall of the can W through the suction holes.

[0063] The wheel indexing mechanism 15 intermittently rotates and moves the supply wheel 10 and the discharge wheel 14 around the respective wheel axes SA, DA in synchronization with the intermittent rotation of the holding table 3 around the table axis TA.

[0064] Specifically, the supply wheel 10 and the discharge wheel 14 are intermittently rotated by the wheel indexing mechanism 15 in wheel rotation directions R2, R3 (clockwise around the respective wheel axes SA, DA in the example of FIG. 2) that are reverse to the holding table rotation direction R1 (counterclockwise around the table axis TA in the example of FIG. 2).

[0065] When the supply wheel 10 rotates intermittently and the can W held in the pocket 23 of the supply wheel 10 is disposed at a position overlapping with the chuck 7 of the holding table 3 (directly above the chuck 7) as viewed from the table axis direction, a pushing portion (not shown) provided on the processing table 2 pushes this can W toward one side (+X side) in the table axis direction. Thereby, the can W is transferred from the pocket 23 to the chuck 7 and held by the chuck 7.

[0066] Also, the can W held by the chuck 7 of the holding table 3 is transferred in the holding table rotation direction R1 for each stroke of the processing table 2. After all the processing is completed, when the can W is arranged at a position overlapping with the pocket 24 of the discharge wheel 14 (directly below the pocket 24) as viewed from the table axis direction, an extrusion piston 73 (see FIG. 3), which will be described later and is provided in the chuck 7, pushes out this can W (the bottle can P of the product subjected to all the processing) toward the other side (-X side) in the table axis direction. As a result, the can W (bottle can P) is transferred from the chuck 7 to the pocket 24 and held by the pocket 24.

[0067] The bottle can P held by the pocket 24 is transferred around the wheel axis DA as the discharge wheel 14 rotates intermittently, is released from the pocket 24, and is transferred to the conveying means 12.

[0068] The drive motor 11, the crank mechanism 8, the table index mechanism 9, and the wheel index mechanism 15 are mechanically connected to each other so as to be synchronizable, for example, by gears, belts, joints, etc. That is, by the rotational driving force of the drive motor 11, the crank mechanism 8, the table index mechanism 9, and the wheel index mechanism 15 are driven synchronously with each other.

[0069] Next, the chuck (can chuck) 7 of the present embodiment will be described in detail. As shown in FIG. 3, the chuck 7 has a bottomed cylindrical shape centered on the central axis C. Also, as shown in FIG. 1, the central axis (chuck central axis) C of the chuck 7 is coaxial with the central axis (tool central axis) of the processing tool 6 facing the chuck 7 in the table axis direction and extends parallel to the table axis TA. Further, the central axis C of the chuck 7 is also arranged coaxially with the can axis of the can W held by the chuck 7.

[0070] In this embodiment, the direction in which the central axis C of the chuck 7 extends is referred to as the axial direction. The axial direction is the same as the table axial direction and corresponds to the X-axis direction in each figure. In this embodiment, one side in the axial direction corresponds to one side (+X side) in the table axial direction, and the other side in the axial direction corresponds to the other side (-X side) in the table axial direction. Note that the axial direction may also be referred to as the front-back direction. In this case, one side (+X side) in the axial direction corresponds to the rear side, and the other side (-X side) in the axial direction corresponds to the front side.

[0071] Also, the direction orthogonal to the central axis C is referred to as the radial direction. Among the radial directions, the direction approaching the central axis C is referred to as the inner radial direction, and the direction away from the central axis C is referred to as the outer radial direction. Also, the direction of orbiting around the central axis C is referred to as the circumferential direction.

[0072] Note that the axial direction may also be referred to as the chuck axial direction for the purpose of distinguishing it from the aforementioned table axial direction. The radial direction may also be referred to as the chuck radial direction for the purpose of distinguishing it from the aforementioned table radial direction. The circumferential direction may also be referred to as the chuck circumferential direction for the purpose of distinguishing it from the aforementioned table circumferential direction.

[0073] As shown in FIG. 3, the chuck 7 includes a chuck peripheral wall 71, a chuck bottom wall 72, and an extrusion piston 73. The chuck peripheral wall 71 and the chuck bottom wall 72 are fixed to the outer peripheral portion of the holding table 3. The extrusion piston 73 is configured to be movable in the axial direction with respect to the chuck peripheral wall 71 and the chuck bottom wall 72.

[0074] The chuck peripheral wall 71 has a substantially cylindrical shape centered on the central axis C. Inside the chuck peripheral wall 71, the can body Wa of the can W is inserted. The chuck peripheral wall 71 includes a cylindrical body 74 extending in the axial direction, an annular accommodation groove 75 that is recessed radially outward from the inner peripheral surface of the cylindrical body 74 and extends over the entire circumference in the circumferential direction around the central axis C, an air supply port 78 that extends inside the chuck peripheral wall 71 and opens into the accommodation groove 75, an elastically deformable annular expansion and contraction ring 76 disposed in the accommodation groove 75, and an accommodation cylinder 77 disposed inside the expansion and contraction ring 76.

[0075] The cylindrical body 74 is cylindrical with the central axis C as the center. The cylindrical body 74 is made of metal. The accommodation groove 75 is a circular annular groove centered on the central axis C. The accommodation groove 75 opens at an intermediate portion located between both axial ends on the inner peripheral surface of the cylindrical body 74. The accommodation groove 75 has a pair of groove side surfaces 75a arranged at intervals in the axial direction, and a groove bottom surface 75b arranged between the pair of groove side surfaces 75a and facing radially inward.

[0076] The pair of groove side surfaces 75a are arranged at both axial ends of the accommodation groove 75. The pair of groove side surfaces 75a face opposite sides in the axial direction and are spaced apart from each other. The pair of groove side surfaces 75a are each planar and extend in a direction (surface direction) perpendicular to the central axis C.

[0077] The groove bottom surface 75b is arranged at the radially outer end of the accommodation groove 75. The groove bottom surface 75b has a cylindrical surface shape (inner peripheral surface shape of a cylinder) parallel to the central axis C. Both axial ends of the groove bottom surface 75b are connected to the respective radially outer ends of the pair of groove side surfaces 75a. The pair of groove side surfaces 75a and the groove bottom surface 75b each have a metal surface.

[0078] The air supply port 78 forms part of an air supply passage extending inside the chuck peripheral wall 71. The air supply passage is connected to air supply means (not shown) provided outside the chuck 7 via a tube, pipe, or the like. The air supply port 78 is arranged at the downstream end of the air supply passage (the downstream end in the direction of air flow) and opens at the groove bottom surface 75b of the accommodation groove 75.

[0079] The expansion and contraction ring 76 is made of an elastic member such as an elastomer or rubber. In this embodiment, the expansion and contraction ring 76 is made of, for example, ethylene propylene diene rubber (EPDM). The expansion and contraction ring 76 is integrally formed by a single member. The expansion and contraction ring 76 is accommodated in the accommodation groove 75.

[0080] As shown in FIGS. 3 and 4, the telescopic ring 76 has a front-back inversion symmetry shape (axial inversion symmetry shape) in the axial direction. Specifically, the telescopic ring 76 has a mirror symmetry shape with respect to a virtual plane (not shown) that extends in a direction perpendicular to the central axis C through the axial center of the telescopic ring 76.

[0081] The telescopic ring 76 has a pair of ring side surfaces 79, a ring outer peripheral surface 80, a ring inner peripheral surface 81, an air chamber 82, a communication portion 83, a corner portion 85, a concave portion 84, a contact portion 87, and a step portion 86.

[0082] The pair of ring side surfaces 79 are arranged at both axial ends of the telescopic ring 76. The pair of ring side surfaces 79 face opposite sides in the axial direction. Specifically, of the pair of ring side surfaces 79, one ring side surface 79 is arranged at the end on one axial side (+X side) of the telescopic ring 76 and faces one axial side. Of the pair of ring side surfaces 79, the other ring side surface 79 is arranged at the end on the other axial side (-X side) of the telescopic ring 76 and faces the other axial side. The pair of ring side surfaces 79 face both sides in the axial direction and face the pair of groove side surfaces 75a. The pair of ring side surfaces 79 are in contact with the pair of groove side surfaces 75a.

[0083] The ring outer peripheral surface 80 is arranged at the radially outer end of the telescopic ring 76. The ring outer peripheral surface 80 has a cylindrical surface shape (outer peripheral surface shape of a cylinder) parallel to the central axis C. The ring outer peripheral surface 80 faces radially outward and faces the groove bottom surface 75b. The ring outer peripheral surface 80 is in contact with the groove bottom surface 75b.

[0084] The inner peripheral surface 81 of the ring is disposed at the radially inner end portion of the expandable and contractible ring 76. The inner peripheral surface 81 of the ring faces radially inward and can contact the can body Wa. Specifically, when the expandable and contractible ring 76 expands by the supply of air as described later, the inner peripheral surface 81 of the ring moves (displaces) radially inward and adheres to the can body Wa. In FIGS. 3 and 4, a state where the expandable and contractible ring 76 is not expanded (a state when not expanded) is shown. In this state, the inner peripheral surface 81 of the ring is disposed radially outside the inner peripheral surface of the cylindrical body 74 and does not contact the can body Wa. Although not particularly shown, in a state where the expandable and contractible ring 76 is expanded (a state when expanded), the inner peripheral surface 81 of the ring protrudes radially inward from the inner peripheral surface of the cylindrical body 74 and is pressed against the can body Wa.

[0085] The inner peripheral surface 81 of the ring has a pair of convex curved surface portions 81a disposed at both axial ends of the inner peripheral surface 81 of the ring, and a straight portion 81b disposed between both axial ends of the inner peripheral surface 81 of the ring.

[0086] As shown in FIG. 4, in a longitudinal sectional view along the central axis C, each of the pair of convex curved surface portions 81a has a convex curved shape. The pair of convex curved surface portions 81a are connected to the radially inner end portions of the pair of ring side surfaces 79. The straight portion 81b has a cylindrical surface shape (inner peripheral surface shape of a cylinder) parallel to the central axis C. That is, the straight portion 81b extends in the axial direction parallel to the central axis C.

[0087] The air chamber 82 is disposed inside the expandable and contractible ring 76 and has an annular shape extending over the entire circumference in the circumferential direction around the central axis C. In the longitudinal sectional view shown in FIG. 4, the air chamber 82 has a substantially D-shaped inner surface shape. Specifically, the air chamber 82 has a pair of inner side surfaces 82a, a pair of receiving surfaces 82b, and an expansion surface 82c. The pair of inner side surfaces 82a, the pair of receiving surfaces 82b, and the expansion surface 82c constitute the inner surface of the air chamber 82.

[0088] The pair of inner surfaces 82a are arranged on the inner surface of the air chamber 82 with an axial spacing from each other. The pair of inner surfaces 82a are arranged at both axial ends of the air chamber 82. The pair of inner surfaces 82a face opposite sides in the axial direction and face each other with a spacing therebetween. Each of the pair of inner surfaces 82a has a planar shape extending in a direction (plane direction) perpendicular to the central axis C.

[0089] The pair of receiving surfaces 82b are arranged at the radially outer ends of the air chamber 82 and each faces radially inward. The pair of receiving surfaces 82b are arranged on the inner surface of the air chamber 82 with an axial spacing from each other. Each of the pair of receiving surfaces 82b has a cylindrical surface shape (inner peripheral surface shape of a cylinder) parallel to the central axis C. The pair of receiving surfaces 82b are connected to the respective radially outer ends of the pair of inner surfaces 82a.

[0090] The expansion surface 82c is arranged on the inner surface of the air chamber 82, connects the radially inner ends of the pair of inner surfaces 82a, and faces radially outward. The expansion surface 82c is arranged in the radially inner part of the air chamber 82. As shown in FIG. 4, in a state where no air is supplied to the air chamber 82 (state when the expansion and contraction ring 76 is not expanded), the entire expansion surface 82c has a concave curved surface shape. Specifically, in the longitudinal sectional view shown in FIG. 4, the expansion surface 82c has a curved shape that is concave radially inward over its entire area. Also, in this embodiment, in this longitudinal sectional view, the radius of curvature of the expansion surface 82c is larger than the radius of curvature of the convex curved surface portion 81a.

[0091] The communication portion 83 is arranged in the radially outer part of the expansion and contraction ring 76. In the longitudinal sectional view shown in FIG. 4, the communication portion 83 extends radially and has a slit shape that opens to the ring outer peripheral surface 80 and the air chamber 82. The communication portion 83 communicates the ring outer peripheral surface 80 and the air chamber 82. Also, the communication portion 83 has an annular shape extending over the entire circumferential direction around the central axis C.

[0092] A part of the circumferential direction of the communication part 83 faces the air supply port 78 in the radial direction. Thus, the communication part 83 and the air supply port 78 are connected and communicate with each other. Air is supplied to the air chamber 82 from air supply means (not shown) through the air supply port 78 and the communication part 83. When air is supplied to the air chamber 82, the expansion and contraction ring 76 elastically deforms and expands, and the can body Wa can be held by the ring inner peripheral surface 81.

[0093] In the present embodiment, the communication part 83 has a constant axial dimension (slit width) over the entire radial direction. The axial dimension of the communication part 83 is equal to or less than half of the axial dimension of the air chamber 82. Thereby, when the expansion and contraction ring 76 expands, it is more likely to elastically deform preferentially around the air chamber 82 disposed radially inside the communication part 83, and the holding state of the can body Wa by the expansion and contraction ring 76 becomes more stable.

[0094] The corner part 85 is disposed at the connection part between the ring side surface 79 and the ring outer peripheral surface 80. Specifically, the corner part 85 is disposed at the ridge line part where the radially outer end part of the ring side surface 79 and the axial end part of the ring outer peripheral surface 80 are connected. A pair of corner parts 85 are provided at the radially outer end part and both axial end parts of the expansion and contraction ring 76. The pair of corner parts 85 are in contact with the pair of groove side surfaces 75a.

[0095] The recessed part 84 is disposed at the outer part in the radial direction of the ring side surface 79. Specifically, the recessed part 84 is disposed adjacent to the corner part 85 inside the corner part 85 in the ring side surface 79. The recessed part 84 is recessed axially from the ring side surface 79 and extends in the circumferential direction around the central axis C. In the present embodiment, "being recessed axially from the ring side surface 79" means being recessed axially from the most axially protruding part (the part in contact with the groove side surface 75a) of the ring side surface 79.

[0096] The recess 84 is an annular groove extending over the entire circumference in the circumferential direction around the central axis C. The recess 84 is arranged so as to overlap the communication portion 83 when viewed in the axial direction. Also, in the present embodiment, the recess 84 is not arranged so as to overlap the air chamber 82 when viewed in the axial direction. A pair of recesses 84 are provided at both axial ends of the expansion and contraction ring 76.

[0097] Each recess 84 has an axial dimension D smaller than the radial dimension W2. The radial dimension W2 of the recess 84 is twice or more the axial dimension D of the recess 84, and is, for example, about four times in the present embodiment. Specifically, in the present embodiment, the radial dimension W2 of the recess 84 is set to about 2 mm, for example, and the axial dimension D of the recess 84 is set to about 0.5 mm, for example. Note that the radial dimension W2 of the recess 84 may be referred to as the groove width dimension W2, and the axial dimension D of the recess 84 may be referred to as the groove depth dimension D.

[0098] The radial dimension W2 of the recess 84 is made larger than the radial dimension W1 of the corner portion 85. The radial dimension W2 of the recess 84 is 1.5 times or more the radial dimension W1 of the corner portion 85, and is, for example, about twice in the present embodiment. Specifically, in the present embodiment, the radial dimension W2 of the recess 84 is set to about 2 mm, for example, and the radial dimension W1 of the corner portion 85 is set to about 1 mm.

[0099] The contact portion 87 is arranged at a substantially central portion in the radial direction of the ring side surface 79. The contact portion 87 is arranged adjacent to the recess 84 on the radially inner side of the recess 84 in the ring side surface 79. A pair of contact portions 87 are provided at both axial ends of the expansion and contraction ring 76. The pair of contact portions 87 are in contact with the pair of groove side surfaces 75a.

[0100] The step portion 86 is arranged in the inner portion in the radial direction of the ring side surface 79. Specifically, the step portion 86 is arranged adjacent to the contact portion 87 on the radially inner side of the contact portion 87 in the ring side surface 79. The step portion 86 is recessed axially from the ring side surface 79 and extends in the circumferential direction around the central axis C. The step portion 86 forms an annular shape extending over the entire circumference in the circumferential direction around the central axis C.

[0101] The axial dimension of the stepped portion 86 is smaller than the axial dimension D of the concave portion 84. In other words, the axial dimension D of the concave portion 84 is larger than the axial dimension of the stepped portion 86. In the present embodiment, the axial dimension D of the concave portion 84 is made larger than the axial dimension of the stepped portion 86 in a range of, for example, 2 times or more and 4 times or less.

[0102] The stepped portion 86 is arranged so as to overlap with the expansion surface 82c of the air chamber 82 when viewed from the axial direction. A pair of stepped portions 86 are provided at both axial ends of the expansion and contraction ring 76. Each radially inner end of the pair of stepped portions 86 is connected to the pair of convex curved surface portions 81a.

[0103] Here, since the pair of convex curved surface portions 81a are located at the connection portions between the ring inner peripheral surface 81 and the pair of ring side surfaces 79, it can be said that they constitute both axial ends of the ring inner peripheral surface 81 as described above, or that they constitute the radially inner ends of the pair of ring side surfaces 79. The pair of convex curved surface portions 81a are arranged at intervals in the axial direction from the pair of groove side surfaces 75a.

[0104] Thus, in the present embodiment, a plurality of portions of the ring side surface 79 that contact the groove side surface 75a are provided. The contacting portions are the corner portion 85 and the abutting portion 87. Also, a plurality of portions of the ring side surface 79 that do not contact the groove side surface 75a are provided. The non - contacting portions are the concave portion 84, the stepped portion 86, and the convex curved surface portion 81a.

[0105] And in the present embodiment, as shown in FIG. 4, in a longitudinal sectional view along the central axis C, the sum of the radial dimensions (W1 + W3) of the portion of the ring side surface 79 that contacts the groove side surface 75a is smaller than the sum of the radial dimensions (W2 + W4 + W5) of the portion that does not contact the groove side surface 75a. Specifically, among the ring side surface 79, the sum of the radial dimension W2 of the concave portion 84, the radial dimension W4 of the stepped portion 86, and the radial dimension W5 of the convex curved surface portion 81a that do not contact the groove side surface 75a is larger than the sum of the radial dimension W1 of the corner portion 85 and the radial dimension W3 of the contact portion 87 that contact the groove side surface 75a. In the present embodiment, even if it is only the sum (W2 + W4) of the radial dimension W2 of the concave portion 84 and the radial dimension W4 of the stepped portion 86 (that is, even when the radial dimension W5 of the convex curved surface portion 81a is not included in the sum), it is larger than the sum (W1 + W3) of the radial dimension W1 of the corner portion 85 and the radial dimension W3 of the contact portion 87.

[0106] As shown in FIGS. 3 and 4, the housing cylinder 77 is housed inside the air chamber 82. The housing cylinder 77 has a cylindrical shape centered on the central axis C and extends in the axial direction. The housing cylinder 77 is made of metal or the like. A pair of end faces facing both axial sides of the housing cylinder 77 are in contact with a pair of inner side faces 82a. Also, the outer peripheral surface facing the outer side in the radial direction of the housing cylinder 77 is in contact with a pair of receiving faces 82b. The housing cylinder 77 is arranged overlapping a pair of contact portions 87 when viewed from the axial direction.

[0107] The housing cylinder 77 has through holes 77a that penetrate the peripheral wall of the housing cylinder 77 in the radial direction. A plurality of through holes 77a are provided at intervals in the circumferential direction. Each through hole 77a communicates the communication portion 83 with the inside of the air chamber 82.

[0108] As shown in FIG. 3, the chuck bottom wall 72 has a substantially annular plate shape centered on the central axis C. The bottom wall Wb of the can W contacts the plate surface of the chuck bottom wall 72 facing the other axial side (-X side).

[0109] The extrusion piston 73 has a columnar shape centered on the central axis C and extends in the axial direction. The extrusion piston 73 is inserted into the chuck bottom wall 72. The end of the extrusion piston 73 on the other axial side (-X side) faces the can bottom Wb from the one axial side (+X side). By moving to the other axial side, the extrusion piston 73 pushes the can bottom Wb to the other axial side and discharges the can W from the chuck 7.

[0110] In the can chuck 7 of the present embodiment described above and the can manufacturing apparatus 1 equipped with the same, when air is supplied into the air chamber 82 through the air supply port 78, the communication portion 83, and the through hole 77a by the air supply means, the expansion and contraction ring 76 elastically deforms and expands. Due to this expansion, the inner peripheral surface 81 of the ring moves (displaces) radially inward and contacts the can body Wa of the can W, and the expansion and contraction ring 76 holds the can body Wa. With the can body Wa held by the expansion and contraction ring 76, processing by each processing tool 6 is performed on the opening of the can W. After processing by each processing tool 6, when the supply of air to the expansion and contraction ring 76 is stopped, the expansion and contraction ring 76 restores and contracts. Due to this contraction, the inner peripheral surface 81 of the ring moves (displaces) radially outward and separates from the can body Wa of the can W, thereby releasing the holding state of the can W by the can chuck 7. As a result, the can W can be pushed axially by the extrusion piston 73 and taken out from the can chuck 7.

[0111] According to the present embodiment, in a longitudinal sectional view along the central axis C of the can chuck 7, the sum of the radial dimensions (W2 + W4 + W5) of the portion of the ring side surface 79 of the expansion and contraction ring 76 that does not contact the groove side surface 75a is larger than the sum of the radial dimensions (W1 + W3) of the portion that contacts the groove side surface 75a of the accommodation groove 75. Therefore, when the expanded expansion and contraction ring 76 contracts, the frictional resistance between the ring side surface 79 and the groove side surface 75a is suppressed to be small, and the expansion and contraction ring 76 can return stably to its original position before expansion.

[0112] Specifically, when the expansion and contraction ring 76 is moved radially inward during expansion and then should return radially outward due to subsequent contraction, the frictional resistance is reduced, so that a sufficient amount of movement is ensured. As a result, the expansion and contraction ring 76 can stably return to its initial position before expansion (that is, it can return to the origin).

[0113] Since the expansion and contraction ring 76 can stably return to the origin, it is suppressed that the expansion and contraction ring 76 protrudes from the inner peripheral surface of the cylindrical body 74, and it is prevented that the can W supplied to the can chuck 7 next is caught by the expansion and contraction ring 76. For this reason, defects such as the can W being processed while being held inclined by the can chuck 7 resulting in processing defects, conveyance defects, or can dropping can be suppressed. That is, the productivity of the can W(P) is stably increased.

[0114] As described above, according to the present embodiment, there are provided a can chuck 7 and a can manufacturing apparatus 1 in which the expansion and contraction ring 76 can stably return to its original position before expansion when it contracts.

[0115] Further, in the present embodiment, the expansion and contraction ring 76 has a concave portion 84 that is recessed axially from the ring side surface 79 and extends in the circumferential direction around the central axis C. In this case, by the simple structure of providing the concave portion 84 recessed from the ring side surface 79 in the expansion and contraction ring 76, the frictional resistance between the ring side surface 79 and the groove side surface 75a can be suppressed to be small. As a result, the above-described operational effects of the present embodiment are stably achieved.

[0116] Further, in the present embodiment, the concave portion 84 has an axial dimension D smaller than its radial dimension W2. In this case, by providing the recess 84, the contact area between the ring side surface 79 and the groove side surface 75a is reduced, and while suppressing the frictional resistance therebetween to a small value, the wall thickness of the expansion and contraction ring 76 is ensured. Specifically, since the axial dimension D of the recess 84 is made smaller than the radial dimension W2 of the recess 84, a large wall thickness dimension is ensured between the deepest part (groove bottom) in the axial direction of the recess 84 and the air chamber 82. Thereby, breakage due to repeated expansion and contraction deformation or aging deterioration of the expansion and contraction ring 76 is suppressed.

[0117] Also, in the present embodiment, the expansion and contraction ring 76 has a corner portion 85 disposed at the connection portion between the ring side surface 79 and the ring outer peripheral surface 80, and the corner portion 85 contacts the groove side surface 75a. In this case, since the corner portion 85 contacts the groove side surface 75a and frictional resistance is generated therebetween, when air is supplied to the air chamber 82 and the expansion and contraction ring 76 expands, the portion located radially inward of the corner portion 85 is preferentially elastically deformed. When the expansion and contraction ring 76 expands, movement of the corner portion 85 radially inward is suppressed. That is, the corner portion 85 is fixed in a state where it is connected to the corner where the groove side surface 75a and the groove bottom surface 75b are connected. For this reason, an anchor effect by the corner portion 85 is obtained, and when contracting after expansion, the expansion and contraction ring 76 can return to the origin more stably.

[0118] Also, in the present embodiment, the radial dimension W2 of the recess 84 is made larger than the radial dimension W1 of the corner portion 85. With the above configuration, when the radial dimension W2 of the recess 84 is larger than the radial dimension W1 of the corner portion 85, the expansion and contraction ring 76 is more likely to expand in the region radially inward of the corner portion 85, and the expansion and contraction ring 76 is more likely to return to the origin stably.

[0119] Further, in the present embodiment, in a longitudinal sectional view along the central axis C of the can chuck 7 with no air supplied to the air chamber 82, the expansion surface 82c of the air chamber 82 forms a curved shape that is concave radially inward over its entire area. That is, the expansion surface 82c is formed in a concave curved surface shape over its entire area. In the present embodiment, no bent portions or the like that would serve as crack initiation points are formed on the expansion surface 82c, and local stress concentration due to expansion is also less likely to occur. Therefore, even if the expansion and contraction ring 76 repeatedly expands and contracts and aging deterioration progresses beyond a certain level, defects such as cracks occurring starting from a part of the expansion surface 82c and the expansion and contraction ring 76 being damaged are suppressed. For this reason, the can W can be stably held by the expansion and contraction ring 76 over a long period, and the component life of the expansion and contraction ring 76 is extended.

[0120] From the above, according to the present embodiment, it is possible to suppress cracks from occurring in the air chamber 82 due to repeated expansion and contraction of the expansion and contraction ring 76 and aging deterioration, etc., and maintain the can holding performance of the expansion and contraction ring 76 well over a long period and extend the component life.

[0121] Also, in the present embodiment, the ring inner peripheral surface 81 has a straight portion 81b that extends parallel to the central axis C. In this case, the straight portion 81b of the ring inner peripheral surface 81 can stably hold the can body Wa of the can W. While extending the component life of the expansion and contraction ring 76 as described above, the holding force of the can W by the expansion and contraction ring 76 can be increased.

[0122] Note that the present invention is not limited to the above-described embodiment. For example, as described below, configuration changes and the like are possible without departing from the spirit of the present invention.

[0123] In the foregoing embodiments, the can manufacturing apparatus 1 was exemplified by a bottle can manufacturing apparatus that manufactures a bottle can P by performing various processes on a bottomed cylindrical can W. However, the present invention is not limited to this. The can manufacturing apparatus 1 may be, for example, an aerosol can manufacturing apparatus that manufactures an aerosol can by performing various processes on the can W, or a can manufacturing apparatus that manufactures other cans other than bottle cans and aerosol cans.

[0124] The present invention may combine the respective configurations described in the foregoing embodiments, modification examples, etc. within a range not departing from the gist of the present invention. Further, addition, omission, substitution, and other changes of the configuration are possible. The present invention is not limited by the foregoing embodiments, etc., and is limited only by the scope of the claims.

Industrial Applicability

[0125] According to the can chuck and the can manufacturing apparatus of the present invention, when the expansion and contraction ring contracts, it can stably return to the original position before expansion. Since the expansion and contraction ring can stably return to the origin, it is suppressed that the expansion and contraction ring protrudes from the inner peripheral surface of the can chuck, and it is prevented that the can supplied to this can chuck next is caught by the expansion and contraction ring. For this reason, defects such as the can being processed while being held in an inclined state by the can chuck, resulting in processing defects, conveyance defects, or can dropping, can be suppressed. That is, the productivity of the can is stably increased. Therefore, it has industrial applicability.

Explanation of Reference Numerals

[0126] 1... Can manufacturing apparatus, 2... Processing table, 3... Holding table, 6... Processing tool, 7... Chuck (can chuck), 71... Chuck peripheral wall, 72... Chuck bottom wall, 74... Cylindrical body, 75... Accommodation groove, 75a... Groove side surface, 75b... Groove bottom surface, 76... Expansion and contraction ring, 79... Ring side surface, 80... Ring outer peripheral surface, 81... Ring inner peripheral surface, 82... Air chamber, 83... Communication portion, 84... Concave portion, 85... Corner portion, C... Central axis, D... Axial dimension, TA... Table axis, W... Can, W1, W2, W3, W4, W5... Radial dimension, Wa... Can body, Wb... Can bottom

Claims

1. A can chuck having a bottomed cylindrical shape centered on a central axis, comprising: a chuck peripheral wall into which the body of the can is inserted; and a chuck bottom wall that contacts the bottom of the can. The chuck peripheral wall includes: a cylindrical body extending in the axial direction; an annular accommodation groove that is recessed radially outward from the inner peripheral surface of the cylindrical body and extends over the entire circumference around the central axis; and an elastically deformable annular expansion and contraction ring disposed in the accommodation groove. The accommodation groove has: a pair of groove side surfaces spaced apart from each other in the axial direction; and a groove bottom surface disposed between the pair of groove side surfaces and facing radially inward. The expansion and contraction ring has: a pair of ring side surfaces facing both axial sides and opposing the pair of groove side surfaces; a ring outer peripheral surface facing radially outward and opposing the groove bottom surface; a ring inner peripheral surface facing radially inward and capable of contacting the body of the can; an annular air chamber disposed inside the expansion and contraction ring and extending over the entire circumference around the central axis; and a communication portion that communicates the ring outer peripheral surface with the air chamber. When air is supplied to the air chamber through the communication portion, the expansion and contraction ring expands and can hold the body of the can by the ring inner peripheral surface. In a longitudinal sectional view along the central axis, the sum of the radial dimensions of the portions of the ring side surfaces that do not contact the groove side surfaces is larger than the sum of the radial dimensions of the portions of the ring side surfaces that contact the groove side surfaces. A can chuck.

2. The expansion and contraction ring has a recess that is recessed axially from the ring side surface and extends in the circumferential direction around the central axis. The can chuck according to claim 1.

3. The recess has an axial dimension smaller than a radial dimension. The can chuck according to claim 2.

4. The expansion and contraction ring has a corner portion disposed at a connection portion between the ring side surface and the ring outer peripheral surface. The corner portion contacts the groove side surface. The can chuck according to any one of claims 1 to 3.

5. A holding table that is intermittently rotated around a table axis; and a processing table that reciprocates in the table axis direction with respect to the holding table. The holding table has a plurality of can chucks for holding a plurality of cans. The processing table has a plurality of processing tools for processing each of the cans held by each of the can chucks. The can chuck includes the can chuck according to any one of claims 1 to 3. A can manufacturing apparatus.

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