Perforated panel conveying mechanism

Abstract

To provide a perforated panel conveying mechanism that can prevent a perforated panel from being deformed due to forward and backward movements of a conveying pin, by restricting the conveying pin from wobbling when moving the conveying pin up and down to and from a transparent hole formed in the perforated panel.SOLUTION: A hitch feeding mechanism 24, as a perforated panel conveying mechanism, is provided with: a reciprocating body 25 having a concave hole 25A formed on an upper surface thereof, which is arranged in a conveying direction of a metal belt-like body 81; a conveying pin 27 in which an energizing member 27C whose upper end part contacts an inner surface of an upper bottomed-part of an upper bottomed-cylindrical body and whose lower end part contacts the concave hole 25A is stored and which intrudes into a transparent hole 89 of the metal belt-like body 81; and an upper surface plate 28 mounted on an upper surface of the reciprocating body 25, which has an insertion hole 28A through which the conveying pin 27 is inserted. In the conveying pin 27, plane parts 27A are formed in a required range in a circumferential direction on a side peripheral surface thereof. A flange part 27B is formed at a lower end part of the plane part 27A. An opening part at a lower surface side of the insertion hole 28A is formed in a turning restriction hole, and the conveying pin 27 is retained by the flange part 27A.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a mechanism for transporting a perforated plate. [Background technology]

[0002] A mechanism for transporting a perforated plate having through holes formed therein is disclosed in Patent Document 1 (Japanese Patent No. 5505911). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5505911 (paragraph 0006, Figures 5-6, etc.) Summary of the Invention [Problem to be solved by the invention]

[0004] The perforated plate conveying mechanism disclosed in Patent Document 1 intermittently conveys a perforated plate by reciprocating conveying pins inserted into holes formed in the perforated plate and biased upward by a biasing member in the conveying direction of the perforated plate. After conveying the perforated plate to a predetermined position, the conveying pins return in the opposite direction to the conveying direction while sinking into the conveying surface against the biasing force of the biasing member, thereby preventing deformation of the perforated plate due to the conveying pins. However, there is no disclosure of a configuration for restricting rotation of the conveying pins about a horizontal plane, which may result in rotation of the conveying pins about a horizontal plane (vibration during lifting and lowering). Therefore, when conveying a thin perforated plate, if vibration occurs during lifting and lowering of the conveying pins, there is a problem in that the perforated plate may be deformed due to the inertial force of the conveying pins. [Means for solving the problem]

[0005] The present invention is therefore intended to solve the above problems, and has the following object: to provide a perforated plate transport mechanism that can prevent deformation of the perforated plate due to the advancement and retreat of the transport pins by restricting rotation about a horizontal plane (vibration during the lifting and lowering) of the transport pins when they are raised and lowered into the through-holes formed in the perforated plate.

[0006] As a result of intensive research by the inventors to solve the above problems, the inventors have come up with the following configuration: That is, the present invention is a perforated plate conveying mechanism for conveying a perforated plate having a through hole formed therein, comprising: a reciprocating movable body that reciprocates in the conveying direction of the perforated plate and has a recessed hole formed on its upper surface; an upper bottomed cylindrical body, in which a biasing member is housed so that the upper end of the biasing member abuts against the inner surface of the upper bottomed part of the upper bottomed cylindrical body and the lower end of the biasing member abuts against the inner bottom surface of the recessed hole; a conveying pin that is supported by the biasing member and can move up and down and enters the through hole when raised; and a conveying pin attached to the upper surface of the reciprocating movable body. and an upper surface plate having an insertion hole through which the conveying pin is inserted, wherein the conveying pin has a flat portion formed from the upper end over a required height range at a portion corresponding to a chord in a required circumferential range of the side surface, and a flange portion is formed at the lower end of the flat portion by a non-flat portion-forming portion, and at least the opening of the insertion hole on the lower surface side of the upper surface plate is formed as a rotation restriction hole that restricts the rotation of the conveying pin around the insertion hole, and the flange portion prevents the conveying pin from coming out.

[0007] This restricts the rotation around the horizontal plane (vibration during lifting and lowering) of the conveying pin when it is raised and lowered into the through hole formed in the perforated plate, thereby making it possible to prevent deformation of the perforated plate due to the advance and retreat of the conveying pin.

[0008] Also, a perforated plate transport mechanism for transporting a perforated plate having a through hole formed therein includes a reciprocating body that reciprocates in the transport direction of the perforated plate, a base attached to the upper surface of the reciprocating body and having a recessed hole formed on the upper surface, an upper bottomed cylinder in which an urging member is housed so that the upper end of the urging member abuts against the inner surface of the upper bottomed part of the upper bottomed cylinder and the lower end of the urging member abuts against the inner bottom surface of the recessed hole, and a transport pin that is supported by the urging member and can move up and down and enters the through hole when raised, and a transport pin attached to the upper surface of the base. There is also an invention for a perforated plate transport mechanism, which comprises an upper surface plate attached to the conveying pin and having insertion holes through which the conveying pins pass, and an upper surface plate having a flat portion formed from the upper end over a required height range at a portion corresponding to a chord in a required circumferential range of the side surface, and a flange portion formed at the lower end of the flat portion by a non-flat portion-forming portion, and at least the opening of the insertion hole on the lower surface side of the upper surface plate is formed as a rotation restriction hole that restricts the rotation of the conveying pin around the insertion hole, and the flange portion prevents the conveying pin from coming out.

[0009] This restricts the rotation of the conveying pins about the horizontal plane when they are raised and lowered into the through holes formed in the perforated plate (vibration during raising and lowering), thereby making it possible to prevent deformation of the perforated plate due to the advance and retreat of the conveying pins. Furthermore, simply replacing a portion of an existing perforated plate conveying mechanism can be converted into the perforated plate conveying mechanism of the present invention. Furthermore, the conveying pins and urging members, which are consumables, can be easily replaced.

[0010] Preferably, a bushing is embedded in the upper opening of the insertion hole, allowing the arc-shaped portion of the side peripheral surface of the conveying pin to slide.

[0011] This allows the conveying pins to move up and down smoothly.

[0012] Preferably, the flat portions are formed with the same dimensions at opposing positions on the side circumferential surface, and the rotation restricting hole is racetrack shaped.

[0013] This makes it easier to process the conveying pin and the rotation restricting hole. [Effects of the Invention]

[0014] According to the configuration of the present invention, by restricting the rotation around the horizontal plane (vibration during lifting) of the transport pins when they are raised and lowered into the through holes formed in the perforated plate, it is possible to prevent deformation of the perforated plate due to the advance and retreat of the transport pins. Furthermore, simply by replacing a part of an existing perforated plate transport mechanism, it can be modified to the perforated plate transport mechanism of the present invention. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a heat exchanger fin manufacturing apparatus having a perforated plate transport mechanism according to the present invention. [Figure 2] FIG. 2 is a plan view of a heat exchange fin. [Figure 3] FIG. 2 is a plan view showing a partial area of ​​the metal strip (perforated plate). [Figure 4] FIG. 2 is a plan view showing a portion of a perforated metal strip. [Figure 5] FIG. 2 is a plan view of a part of the width of the product-length metal strip. [Figure 6] FIG. 2 is a plan view of the hitch feed mechanism according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 7 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 1A is a plan view of a conveying pin, FIG. 1B is a front view of a conveying pin, and FIG. 1C is a side view of a conveying pin. [Figure 10] FIG. 8 is a view equivalent to FIG. 7 of a hitch feed mechanism according to a second embodiment. [Figure 11] FIG. 10 is a view equivalent to FIG. 8 of a hitch feed mechanism according to a second embodiment. [Figure 12] 10A is a plan view showing a modified example of an insertion hole in the first embodiment, (B) is a cross-sectional view taken along line BB in the plan view, and (C) is a cross-sectional view taken along line CC in the plan view. DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a schematic diagram of a heat exchanger fin manufacturing apparatus 100 having a perforated plate conveying mechanism according to the present invention. The heat exchanger fin manufacturing apparatus 100 in this embodiment includes an uncoiler 10, a press forming section 20, a buffer section 30, a perforation slit forming machine 40, a cutoff machine 50, a suction section 60, a stacking section 70, and an operation control section 200. The operation control section 200 controls the operation of the uncoiler 10, the press forming section 20, the perforation slit forming machine 40, the cutoff machine 50, and the suction section 60. The operation control section 200 may be configured as a known device having an operation control program stored in a storage section (not shown) and a computing section, such as a CPU, that operates based on the operation control program.

[0017] The uncoiler 10 unwinds the aluminum sheet 80, which is the material for the heat exchange fins 88, from a coil 11 wound around a bobbin (not shown), and may have a known configuration. The press-forming unit 20 includes an oil supply unit 21, a press die 22, a press mechanism 23, and a hitch feed mechanism 24 as a perforated plate transport mechanism. The aluminum sheet 80, to which processing oil has been applied by the oil supply unit 21, is processed into a metal strip 81 as a perforated plate of a predetermined shape by the press die 22, which is brought into contact with and separated from the press mechanism 23. The metal strip 81 is intermittently fed from the press-forming unit 20 by the hitch feed mechanism 24 in synchronization with the operation of the press mechanism 23. The buffer unit 30 in this embodiment is a space for allowing the metal strip 81 fed from the press-forming unit 20 to sag downward, thereby buffering the difference in the forming length and cutting length per cycle between the press-forming unit 20 and the cut-off machine 50 (described later). The buffer portion 30 may also be configured by a guide means or the like that makes the metal strip 81 have a predetermined sagging shape.

[0018] The perforation slit forming machine 40 has an upper rotary blade 41 and a lower rotary blade 42 that faces the upper rotary blade 41 below the upper rotary blade 41 and clamps the metal strip 81. The perforation slit forming machine 40 forms perforation slits 90 to facilitate dividing the metal strip 81, which is the final product shown in FIG. 2, into a long body having multiple rows of heat exchange fins 88 in the width direction (a direction perpendicular to the feeding direction in the same plane), into product widths. FIG. 3 is a plan view showing a portion of the metal strip 81 in the longitudinal direction. At least one perforation slit 90 is formed in the metal strip 81 in the product width direction, and cutting lines 91, which are cutting portions, and connecting portions 92, which are uncut portions, are formed at required intervals along the product length. The perforated metal strip 82 (see FIG. 4), on which the perforation slits 90 have been formed by the perforation slit forming machine 40, is intermittently fed at the product length by the conveying device 51 disposed in the cutoff machine 50, and is suction-held on the suction surface 61 of the suction section 60 disposed downstream of the cutoff machine 50. At this time, the length of the perforated metal strip 82 protruding from the cutoff blade 52 of the cutoff machine 50 is equal to the product length.

[0019] In this manner, the perforated metal strip 82 is cut to the product length by the cutoff blade 52 with the leading end portion of the metal strip 82 held by suction on the suction surface 61. As shown in FIG. 5 , the product-length metal strip 83 cut to the product length by the cutoff machine 50 has a plurality of heat exchange fins 88 connected in the product width direction by connecting portions 92. A stacking unit 70 is disposed below the suction surface 61 in the suction unit 60. The stacking unit 70 has a stacking table 72 on which stacking pins 71 are installed in alignment with the positions of through-holes 89 for intubation formed in the product-length metal strip 83 held by suction on the suction surface 61. When the operation control unit 200 temporarily stops the suction device (not shown) of the suction unit 60, the product-length metal strip 83 falls from the suction surface 61 and is stacked in the thickness direction on the stacking table 72 with the stacking pins 71 inserted through the through-holes 89. When a preset number of product-length metal strips 83 are stacked in the stacking unit 70, the stacking unit 70 is transported to the next process by an operator or the like. The blank stacking unit 70 is then aligned with the suction unit 60 and the above operations are repeated.

[0020] Next, a first embodiment of a hitch feed mechanism 24 as a perforated plate transport mechanism of the present invention will be described in detail. As shown in Figures 1 and 6 to 8, the hitch feed mechanism 24 in this embodiment is disposed on a transport path for a metal strip 81 along the width direction of the metal strip 81. The hitch feed mechanism 24 includes a reciprocating body 25 that reciprocates in the transport direction of the metal strip 81 and has recessed holes 25A formed on its upper surface, transport pins 27 that advance and retract into through holes 89 in the metal strip 81, and an upper surface plate 28 that has insertion holes 28A through which the transport pins 27 pass.

[0021] The reciprocating body 25 intermittently transports the metal strip 81 in the transport direction by a so-called hitch action, in which the reciprocating body 25 moves back and forth along the transport direction of the metal strip 81. A plurality of recessed holes 25A for erecting (accommodating) the transport pins 27 are formed on the upper surface of the reciprocating body 25. A known configuration can be adopted for such a reciprocating body 25, and therefore a detailed description thereof will be omitted here.

[0022] Conveying pin 27 is formed as an upper, bottomed cylindrical body, as shown in FIG. 9 . A flat surface 27A is formed on the side surface of conveying pin 27 over a required height range from the upper end of conveying pin 27 at portions corresponding to two opposing chords in a required circumferential range, and a flange portion 27B is formed at the lower end of flat surface 27A by a non-flat surface portion. A biasing member 27C is accommodated in the internal space of conveying pin 27. The upper end of biasing member 27C abuts against the inner surface of the upper, bottomed portion (ceiling portion) of conveying pin 27, and the lower end abuts against the inner bottom surface of recessed hole 25A of reciprocating body 25. In addition, as shown in FIG. 9 , upper end surface 27D of conveying pin 27 in this embodiment is preferably formed as an inclined surface that gradually becomes lower as it approaches the upstream side in the conveying direction of metal strip 81.

[0023] Insertion holes 28A formed in top plate 28 are used to insert conveying pins 27. Top plate 28 is fixed to the top surface of reciprocating body 25 by a known method, with conveying pins 27, which are provided in recessed holes 25A of reciprocating body 25 together with biasing members 27C, inserted through insertion holes 28A. In this embodiment, insertion holes 28A have a racetrack shape in plan view, which is the cross-sectional shape of the portion of conveying pin 27 where flat portion 27A is formed. As shown in FIGS. 6 to 8, the inner periphery of insertion hole 28A in this embodiment abuts against the side periphery of conveying pin 27, but this is not limited to this. The inner periphery of insertion hole 28A may also be formed so as to be located outward from the side periphery of the upper end of conveying pin 27 and inward from flange portion 27B. These upper surface plates 28 prevent the conveying pins 27 from coming off the upper surface plate 28, restricting the rotation (vibration) of the conveying pins 27 around the horizontal plane (around the insertion hole) and guiding the lifting and lowering movement of the conveying pins 27.

[0024] Furthermore, because flange portion 27B, which serves as a retaining portion for conveying pin 27, is formed by flat portion 27A, which is a so-called D-cut, conveying pin 27 is made smaller and lighter, and the biasing force of biasing member 27C housed in conveying pin 27 can also be weakened. This is advantageous in that damage to metal strip 81 caused by inertial force and biasing force when conveying pin 27 moves up and down can be significantly reduced.

[0025] In this way, the hitch feed mechanism 24 of this embodiment restricts rotation (vibration) around the horizontal plane when the conveying pins 27 are raised and lowered, allowing the conveying pins 27 to always advance and retreat in the same posture relative to the through-holes 89 of the metal strip 81. This is advantageous in that damage to the metal strip 81 (particularly the through-holes 89) by the conveying pins 27 can be prevented, improving product yield. Another advantage is that an existing hitch feed mechanism 24 can be modified to the hitch feed mechanism 24 of the present invention by simply replacing the conveying pins 27 and the upper panel 28.

[0026] Next, a hitch feed mechanism 324 in a second embodiment will be described with reference to Figures 10 and 11. The hitch feed mechanism 324 in this embodiment includes a reciprocating body 325 that reciprocates in the conveying direction of the metal strip 81, a conveying pin 327, a base 328 attached to the upper surface of the reciprocating body 325, and an upper surface plate 329 attached to the upper surface of the base 328.

[0027] The reciprocating body 325 in this embodiment is formed in a known shape such as a block, plate, frame, etc. The reciprocating body 325 reciprocates along the transport direction of the metal strip 81, similar to the first embodiment.

[0028] The transport pin 327 moves up and down, entering and leaving the through-hole 89 of the metal strip 81, due to the reciprocating movement of the reciprocating body 325 and the biasing force of the biasing member 327C housed in the internal space of the transport pin 327. The transport pin 327 in this embodiment can be one formed in the same shape as the first embodiment. That is, two flat portions 327A and two flange portions 327B are formed, and the biasing member 327C is housed in the internal space.

[0029] In this embodiment, a plurality of recessed holes 328A capable of accommodating flange portions 327B of conveying pins 327 are formed in the upper surface of base 328. Attached to the upper surface of base 328 is upper plate 329 having insertion holes 329A aligned with the planar positions of recessed holes 328A. In this embodiment, insertion holes 329A are formed as circular holes 329B within a required depth range on the upper surface side of upper plate 329, and as racetrack-shaped rotation restriction holes 329C within a required depth range (lower surface opening) on ​​the lower surface side of upper plate 329. Furthermore, this embodiment facilitates the replacement of biasing members 327C of conveying pins 327, improving the manufacturing efficiency of heat exchanger fins 88.

[0030] By employing insertion hole 329A in this embodiment, bushing B1, which slides the arc-shaped portion of conveying pin 327, can be accommodated in circular hole 329B, which is the upper opening of top plate 329, thereby facilitating smooth lifting and lowering of conveying pin 327. Furthermore, because rotation-restricting hole 329C is formed at the lower opening of top plate 329, rotation of conveying pin 327, which is erected together with biasing member 327C in recessed hole 328A of base 328, around the insertion hole can be restricted. Such base 328 and top plate 329 are advantageous in that they can prevent damage to metal strip 81 caused by the lifting and lowering of conveying pin 327 during conveyance.

[0031] Furthermore, by reducing the thickness of upper surface plate 28 in the first embodiment and base 328 and upper surface plate 329 in the second embodiment, the height dimension of conveying pin 27 (327) can be reduced. Furthermore, by reducing the size and weight of conveying pin 27 (327), the inertial force of conveying pin 27 (327) can be significantly reduced. Furthermore, by reducing the size and weight of conveying pin 27 (327), the biasing force of biasing member 27C (327C) can also be weakened. This is advantageous in that damage to metal strip 81 (particularly through hole 89) when conveying pin 27 (327) enters and leaves through hole 89 of metal strip 81 can be significantly reduced.

[0032] In the first embodiment, insertion hole 28A drilled in top plate 28 is formed to have the same cross-sectional shape in the depth direction, but this is not limited to this. As shown in FIG. 12, insertion hole 28A may have a circular shape in plan view in required depth range 28X on the top surface of top plate 28, and a racetrack-shaped hole in plan view in required depth range 28Y on the bottom surface of top plate 28 to restrict rotation of conveying pin 27 (not shown in FIG. 12). When this configuration is adopted, accommodating bushing B1 in required depth range 28X on the top surface of top plate 28 of insertion hole 28A improves the slidability of the arc-shaped portion of conveying pin 27, which is advantageous in that it allows smoother lifting and lowering of conveying pin 27.

[0033] In the second embodiment, a configuration in which a bush B1 is housed in an insertion hole 329A formed in an upper surface plate 329 is exemplified, but the present invention is not limited to this configuration. The insertion hole 329A in the upper surface plate 329 may be formed to have the same cross-sectional shape in the depth direction as the insertion hole 28A in the first embodiment, and a configuration in which the provision of the bush B1 is omitted may also be employed.

[0034] Furthermore, in the above embodiment, the planar shapes of conveying pin 27 (327) and insertion hole 28A (329A) are both formed in a racetrack shape, but this is not limited to this. A configuration in which flat surface 27A (327A) is formed in only one location or in three or more locations within a required circumferential range on the side surface of conveying pin 27 (327) may also be adopted. The planar shape of insertion hole 28A (329A) may not only be a shape that matches the planar shape of conveying pin 27 (327), but may also be a planar shape that utilizes flat surface 27A (127A) to restrict rotation of conveying pin 27 (327) around insertion hole 28A (329A).

[0035] Furthermore, the heat exchanger fin manufacturing apparatus 100 in this embodiment is exemplified as having a perforation slit forming machine 40 disposed between the press forming section 20 and the cut-off machine 50, but is not limited to this configuration. It is also possible to adopt a configuration in which an inter-row slitting device is disposed instead of the perforation slitting machine 40. Note that the configuration of the inter-row slitting device is well known, so a detailed description thereof will be omitted here.

[0036] In addition to the modifications described above, it is also possible to adopt a form in which the modifications described in the embodiment are appropriately combined. [Explanation of symbols]

[0037] 10: Uncoiler 11: Coil 20: Press molding section 21: Fuel supply section, 22: Press die, 23: Press mechanism, 24: Hitch feed mechanism, 25: reciprocating moving body, 25A: recessed hole, 27: conveying pin, 27A: flat surface, 27B: flange portion, 27C: biasing member, 27D: upper end surface, 28: upper surface plate, 28A: Insertion hole, 28X: Required depth range on the upper surface, 28Y: Required depth range on the lower surface 30: Buffer section 40: Perforation slit forming machine 41: Upper rotary blade, 42: Lower rotary blade 50: Cut-off machine 51: Conveyor device, 52: Cut-off blade 60: Suction section 61: Adsorption surface 70: Stack section 71: Stack pin, 72: Stack table 80: Aluminum sheet 81: Metal strip, 82: Perforated metal strip, 83: Product length metal strip, 88: Heat exchange fin, 89: Through hole 90: Perforated slit 91: Cutting line, 92: Connection part 100: Heat exchanger fin manufacturing equipment 200: Operation control unit 324: Hitch feed mechanism, 325: Reciprocating body, 327: Conveying pin, 327A: Flat portion, 327B: Flange portion, 327C: Pressing member, 328: Base portion, 328A: Recessed hole, 329: Upper surface plate, 329A: Insertion hole, 329B: Circular hole, 329C: Rotation restriction hole B1: Bush

Claims

1. A perforated plate conveying mechanism for conveying a perforated plate having through holes formed therein, a reciprocating movable body that reciprocates along the conveying direction of the perforated plate and has a recessed hole formed on its upper surface; an upper bottomed cylindrical body, the upper end of which a biasing member is housed so that the upper end of the biasing member abuts against the inner surface of the upper bottomed portion of the upper bottomed cylindrical body and the lower end of the biasing member abuts against the inner bottom surface of the recessed hole, and a conveying pin which is supported by the biasing member and is vertically movable so that it enters the through hole when raised; an upper surface plate attached to an upper surface of the reciprocating body and having an insertion hole through which the conveying pin is inserted; The conveying pin has a flat portion formed over a required height range from an upper end portion at a portion corresponding to a chord in a required range in the circumferential direction of the side peripheral surface, and a flange portion formed at a lower end portion of the flat portion by a non-flat portion-forming portion, A perforated plate transport mechanism characterized in that at least the lower opening of the upper plate of the insertion hole is formed as a rotation restriction hole that restricts the rotation of the transport pin around the insertion hole, and the flange portion prevents the transport pin from coming out.

2. A perforated plate conveying mechanism for conveying a perforated plate having through holes formed therein, a reciprocating body that reciprocates along the conveying direction of the perforated plate; a base portion attached to an upper surface of the reciprocating body and having a recess formed on the upper surface; an upper bottomed cylindrical body, the upper end of which a biasing member is housed so that the upper end of the biasing member abuts against the inner surface of the upper bottomed portion of the upper bottomed cylindrical body and the lower end of the biasing member abuts against the inner bottom surface of the recessed hole, and a conveying pin which is supported by the biasing member and is vertically movable so that it enters the through hole when raised; an upper surface plate attached to an upper surface of the base and having an insertion hole through which the conveying pin is inserted; The conveying pin has a flat portion formed over a required height range from an upper end portion at a portion corresponding to a chord in a required range in the circumferential direction of the side peripheral surface, and a flange portion formed at a lower end portion of the flat portion by a non-flat portion-forming portion, A perforated plate transport mechanism characterized in that at least the lower opening of the upper plate of the insertion hole is formed as a rotation restriction hole that restricts the rotation of the transport pin around the insertion hole, and the flange portion prevents the transport pin from coming out.

3. 3. The mechanism for transporting a perforated plate according to claim 1, wherein a bushing is embedded in the upper opening of the insertion hole, allowing the arc-shaped portion of the side peripheral surface of the transport pin to slide.

4. 3. A perforated plate transport mechanism according to claim 1, wherein said flat portions are formed with the same dimensions at opposing positions on said side peripheral surface, and said rotation restricting holes are racetrack shaped.

5. 4. A perforated plate transport mechanism according to claim 3, wherein said flat portions are formed with the same dimensions at opposing positions on said side peripheral surface, and said rotation restricting holes are racetrack shaped.

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