Method and apparatus for making perforations continuously

Abstract: A perforator (10) has a rotary drum (11). A plurality of die sets (12) are arranged at regular intervals around the peripheral surface (16) of the drum and circulates along with the peripheral surface (16). Each of the die sets (12) has a pair of die (27) and punch (29). The die (27) is secured to a die holder (28) which is mounted to the peripheral surface (16), and the punch (29) is secured to a punch holder (30) which is linearly movable in a direction perpendicular to the peripheral surface (16) between a punch position where the punch (29) is fitted in the die (27) and a retracted position where the punch (29) is retracted away from the die (27). The sheet material (15) is brought into contact with the peripheral surface (16) within a predetermined range, and conveyed on the peripheral surface (16) in the same direction at the same speed as the die sets (12). An annular punch drive cam (13) disposed surrounding the peripheral surface (16) drives the punch holder (30) to move between the punch position and the retracted position. The punch (29) or the sheet material (15) is shifted into a relief position where the punch (29) cannot interfere with the sheet material beyond the predetermined contact range of the sheet material (15) with the peripheral surface (16).

Description: The present invention relates to a method and an apparatus for making perforations along a long strip of sheet material, while continuously conveying the long strip at high speed in a longitudinal directional. Successive perforating apparatuses have been known from JPA 2-109700, JPA 63-222787, JPA 63-191598, JPA 63-52998 (which corresponds to U.S.P. No. 4,747,895) and JPU 56-98597. JPU 56-98597 discloses an apparatus wherein a plurality of die sets, each having a pair of punch and die incorporated thereinto, are disposed on the outer periphery of a rotary wheel so as to endlessly circulate or rotate the die sets around a rotary axis of the wheel. A strip of photographic film is wound on the outer periphery of the rotary wheel so as to be successively perforated by the die sets. Each die set is comprised of a die holder having the die and a punch carrier arm having the punch. The die holder has a shaft orthogonal to the rotational axis of the wheel. The punch carrier arm pivots about the shaft coupled thereto at the middle portion thereof. The punch is integrally formed on one end of the punch carrier arm. The opposite end of the punch carrier arm is engaged in an annular stationary cam groove formed surrounding the wheel. The cam groove has a curve which causes the punch carrier arm to pivot between a punch position where the punch is fitted into the die and a retracted position where the punch is removed off the die. In this way, perforation are successively formed in the photographic film while the photographic film is conveyed by the wheel at the same speed as the rotating speed of the wheel by virtue of the engagement between the perforations and the punches. When perforating, it is required to make the cutting surfaces free from cracks or burrs. A proper or optimum clearance is essential for this requirement. However, in order to maintain the optimum clearance constant in the entire stroke of the punch, it is necessary to arch the shape of the punch and the cavity of the die because of the pivotal punching motion of the punch carrier arm. Such arched punch and die cavity are difficult to manufacture, so that the manufacturing cost thereof is increased. From FR-A-2 473 939 a method respectively an apparatus according to the preamble of claim 1 respectively of claim 2 is known, in which the punch and the die are moved together in integral fashion in parallel with the axial direction of the rotatable assembly while maintaining the relative position between the die and the punch unchanged so as to prevent the punch from interfering with the sheet material when said sheet material is approaching or leaving said peripheral surface. In the apparatus of US-A-1,559,987, the punch is swung while the die is stationary. The die is fixedly located on the rotatable assembly. It is difficult to position the punch with precision relative to the die as only the punch moves. The construction requires enlarging a gap in the die in the swinging direction of the punch, namely in the width direction of the punch. The perforation to be formed in the sheet material is likely to have a deviated position in the width direction of the sheet material. Summary of the Invention An object of the present invention is to provide a method of making successive perforations along a long strip of sheet material wherein the optimum clearance between a pair of punch and die can always be maintained constant without the need for expensive constructions. Another object of the present invention is to provide a perforator for executing the method. These objects are achieved by providing for a method according to claim 1 respectively an apparatus according to claim 2. According to the the present invention, the punch is moved linearly toward the die in a direction perpendicular to the sheet material conveyed on a rotating surface along with the die sets, when perforating the sheet material. Thereby, the optimum clearance is maintained constant in the entire stroke of the punch, and it is unnecessary to arch the punch and the die cavity. Dependent claims 3 to 6 define preferred embodiments of the apparatus according to the invention. Brief Description of the Drawings Other objects and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment when read in connection with the accompanying drawings, wherein like reference numerals designate like or corresponding parts throughout the several views, and wherein: Figure 1 is a front view of a perforator, with parts broken away for clarity; Figure 2 is a vertical sectional view of the perforator taken along line II-II in Fig.1, with parts broken away for clarity; Figure 3 is a front view of a die set of the perforator shown in Fig.1, partly in cross section; Figure 4 is a view of the die set in the direction of the arrow C in Fig.1 or 3; Figure 5 is a sectional detail view taken along line V-V of Fig.1, illustrating the die set in its punch position; Figure 6 is a sectional detail view taken along line VI-VI of Fig.1, illustrating the die set in its relief position; Figure 7 is a side view, partly in cross section, of a die set according to an embodiment of the invention, illustrating a standby position thereof; Figure 8 is a view similar to that of Fig.7 and illustrates the die set in its relief position; Detailed Description of the Preferred Embodiment Figures 1 to 6 illustrate a perforator respectively a method for making perforations which do not constitute an embodiment of the present invention, but which are useful for understanding the same. Referring to Figs.1 and 2, a successive perforator 10 is constituted of a rotary drum 11, a plurality of die sets 12 each having a pair of punch and die incorporated therein, an annular punch drive cam 13 and a cylindrical die drive cam 14. The rotary drum 11 has a film convey surface 16 formed around the outer periphery thereof. A pair of path rollers 17 and 18 whose spindles extend parallel to the rotary axis of the drum 11 are disposed in the vicinity of the drum 11. Through these path rollers 17 and 18, a loop of a long strip of sheet material, for instance, a photographic filmstrip 15 is tightly wound around the film convey surface 16 of the drum 11 by a predetermined contact angle, so that the photographic filmstrip 15 is not deflected sideways from the film convey surface 16. An initial contact position where the filmstrip 15 comes into contact with the film convey surface 16, and an final contact position where the filmstrip 15 gets off the film convey surface 16 are disposed within an angular range shown by 1 in Fig.1. By virtue of the punch drive cam 13 and the die drive cam 14, the die sets 12 are set in their relief positions in this angular range 1 where the punch and die pairs do not interfere with the filmstrip 15, as will be described in detail below. The rotary drum 11 is constituted of a substantially cylindrical frame 20 and a bottom cover 21. A rotary shaft 22a of a drive motor 22 is coupled to the rotational center of the frame 20. The frame 20 has a plurality of stepped recess portions 20a disposed at regular intervals around the periphery of the inner frame 20, each for receiving one of the die sets. In Fig.1, the bottom cover 21 and a part of the punch drive cam 13 are omitted or broken away for clarity. As shown in detail in Figs.3 to 6, the die set 12 is constituted of a base 26 secured to the stepped recess portion 20a, a die 27, a die holder 28 having the die 27 secured thereto, a punch 29, a punch holder 30 having the punch 29 secured thereto, a punch drive member 31 and a die drive member 32. The die holder 28 is coupled to the base 26 through a slide guide 28a which permits the die holder 28 to move relative to the base 26 in a direction parallel to the rotary axis of the drum 11. A pair of guide rods 34 extending in a direction perpendicular to the film convey surface 16 of the drum 11 and in parallel to each other, are secured at their one ends to the die holder 28. The other ends of the guide rods 34 are fitted into bearings 36 which are securely mounted in the punch holder 30 so as to permit the punch holder 30 to move along the guide rods 34, that is, in the radial direction of the drum 11 relative to the die holder 28 (see Fig.3). By virtue of the guide rods 34, the punch holder 30 also moves in the axial direction of the drum 11 in cooperation with the die holder 28. It is to be noted that the direction perpendicular to the film convey surface 16 is equivalent to the radial direction of the drum 11 of the drum 11 under the conditions that the drum 11 is cylindrical. Therefore, a direction perpendicular to the film convey surface 16 will be hereinafter referred to as a radial direction of the drum 11 throughout the description of the perforators shown in the drawings, although direction perpendicular to a film convey surface is not always radial. The bearing 36 for rectilinear motion of the punch holder 30 may be a ball-and-roller bearing or a plain bearing. It is possible to use a single guide rod if the guide rod has such a construction that prevents rotation of the punch holder 30 about the axis of the guide rod, for example, a key groove or if the guide rod is of a rectangular shape. The end of the punch holder 30 that is opposite to the punch 29 is linked to the punch drive member 31 through a linkage between a slider 30a of the punch holder 30 and a slit 31a of the punch drive member 31. The slit 31a extend in the axial direction of the drum 11, the punch holder 30 can move in the axial direction relative to the punch drive member 31. The punch drive member 31 is slidable through a slide guide 37 along a pair of radial projections 20b formed on the periphery of the frame 20 in association with each stepped recess portion 20a. A shaft 38 extending in the axial direction of the drum 11 is secured to the punch drive member 31 at the opposite end from the slit 31a, and a roller 40 is rotatably mounted on the shaft 38 through a bearing 39. Elements designated by 33 and 41 in Figs.3 and 4 are set screws. The roller 40 is engaged in an annular cam groove 13a formed in the punch drive cam 13 which is stationary disposed surrounding the drum 11. When the drum 11 is rotated, the roller 40 slides along the cam groove 13a. Because the cam groove 13a has a small radius of curvature in an angular range shown by 2 in Fig.1 than in the angular range 1, the roller 40 is caused to move radially inwardly in the range 2 relative to the range 1. The punch drive member 31 transmits the radial motion of the roller 40 to the punch holder 30, thereby to move the punch holder 30 rectilinearly along the guide rods 34. In result, the punch holder 30 is brought into a punch position in the range 2 where the punch 29 is fitted in the cavity of the die 27, as is shown in Fig.5. While in the range 1, the punch holder 30 is in a retracted position where the punch 29 is removed off the die 27, as is shown in Figs.2 and 6. The die drive member 32 is mounted on the frame 20 of the drum 11 through a slide guide 32a so as to be slidable on the periphery of the frame 20 in the axial direction of the drum 11. A shaft 42 extending in a radial direction of the drum 11 is secured to one end of the die drive member 32, and a roller 44 is rotatably mounted on the shaft 42 through a bearing 43. The opposite end of the die drive member 32 is linked to the die holder 28 through a linkage between a radial slit 32b of the die drive member 32 and a roller 28c of the die holder 28. Thereby, the die holder 28 can move in the axial direction in cooperation with the die drive member 32. The roller 44 is engaged in an circular cam groove 14a formed in the die drive cam 14 in coaxial with the drum, so as to slide along the cam groove 14a with the rotation of the drum 11. The die drive cam is secured to a stationary outer frame 46 of the perforator 10. The course of the cam groove 14a curves in the axial direction so that the roller 44 changes its axial location while sliding along the cam groove 14a. The die drive member 32 transmits the axial motion of the roller 44 to the die holder 28. Thereby, the die holder 28 and thus the punch holder 30 are axially displaced between the relief position shown in left hand side of Fig.2 or in Fig.6 and a standby position shown in right hand side in Fig.2. In the standby position, the punch 29 and the die 27 are disposed on the opposite surfaces of the photographic filmstrip 15 which is in contact with the film convey surface 16. From this standby position, the punch holder 30 is moved radially inwardly into the punch position as shown in Fig.5, and maintained in the punch position in the range 2, by virtue of the punch drive cam 13. In order to eject chips subsequent upon the die-punching of the photographic filmstrip 15, holes 28a, 26a and 20c are formed through the die holder 28, the base and the stepped recess portion 20a of the frame 20, respectively, in alignment with one another. Through these holes, the chips are gathered in an interior 11a of the drum 11, and ejected therefrom to the outside of the perforator 10 through a suction hose 48 which is connected to the rotation center of the bottom cover 21 through a bearing 49. The operation of the above-described perforator is as follows: First, the photographic filmstrip 15 is wound around the drum 11 along the film convey surface 16 by way of the path rollers 17 and 18. When the motor 22 is driven in this situation, the drum 11 is rotated in a direction shown by an arrow in Fig.1. At a position indicated by P1 in Fig.1, that is, a position immediately after the initial contact position in the rotating direction of the drum 11, the die drive cam 14 causes the die drive member 32 to move in the axial direction of the drum 11 so as to move the die holder 28 and thus the punch holder 30 in the axial direction from the relief position into the standby position preparing for the die-punching. At a position indicated by P2 in Fig.1, the punch drive cam 13 causes the punch drive member 31 to move radially toward the rotational center of the drum. Thereby, the punch holder 30 moves along the guide rods 34 into the punch position where the punch 29 is fitted in the die 27. In this way, the photographic filmstrip 15 is successively perforated at the position P2 while being conveyed by the drum 11. Because each pair of the die holder 28 and the punch holder 30 is incorporated into the die set 12, the relative position of the pair is maintained unchanged in the rotating direction of the drum 11. By virtue of the punch drive member 31, the motion of the roller 40 in the rotating direction of the drum 11 is prevented from being transmitted to the punch holder 30, the punch 29 is moved radially rectilinearly into the die 27. Therefore, it is easy to maintain the optimum clearance constant throughout the entire stroke of the punch 29. Because it is unnecessary to arch the punch 29 or the cavity of the die 27, the manufacturing cost can be low. Because the punch holders 30 are kept in the punch position throughout the angular range 2, the photographic filmstrip 15 is nipped between the punches 29 and dies 27 in this range 2. Thereby, the photographic filmstrip 15 is exactly conveyed at the same speed as the rotational speed of the drum 11. Accordingly, the position of the photographic filmstrip 15 relative to the film convey surface 16 is maintained unchanged in the contact range from the initial contact position to the final contact position, so that the pitch or interval of the perforations is maintained precisely constant. At a position indicated by P3 in Fig.1, that is, a position immediately after the angular range 2 in the rotating direction of the drum 11, the punch drive cam 13 causes the punch drive member 31 to move the punch holder 30 radially outwardly from the drum 11 along the guide rods 34. Thereby, the punch 29 is removed off the die 27. At a position indicated by P4 in Fig.1, that is, a position immediately before the final contact position in the rotating direction of the drum 11, the die drive cam 14 causes the die drive member 32 to move the die holder 28 and thus the punch holder 30 in the axial direction of the drum 11 into the relief position. Thereafter, the photographic filmstrip 15 is removed off the film convey surface 16, as is shown in Fig.6. Thus, the relative position of each pair of the punch holder 30 and the die holder 28 is maintained unchanged also in the axial direction, so that the optimum clearance is maintained constant also in the axial direction. Figs.7 and 8 illustrate an embodiment of the invention, wherein a die holder is pivotally displaced between the standby position and the relief position. A punch holder 50 holding a punch 29 is coupled to a die holder 52 through a pair of guide rods 51 which extend in a radial direction of a drum 11 and in parallel to each other. The guide rod pair 51 are secured at their one ends to the punch holder 50, while the other ends of the guide rod pair 51 are slidably fitted in bearings which are securely mounted in the die holder 52. One end of the die holder 52 is pivoted on a shaft 54 which extends orthogonal to the guide rod pair 51 and substantially parallel to a film convey surface 16 of the drum 11. The other end of the die holder 52 is linked to a die drive member 55. The die drive member 55 is mounted on a radial projection 20b formed on the periphery of a cylindrical frame 20 of the drum 11, and is slide radially thereon through a slide guide 55a, while a roller 56 slides along an annular cam groove 57a of a die drive cam 57 with the rotation of the drum 11. Thereby, the die holder 52 is caused to pivot about the shaft 54 between a standby position as shown in Fig.7 and a relief position as shown in Fig.8. A coil spring 58 is provided on each guide rod 51 between the punch holder 50 and the die holder 51, so as to urge the punch holder 50 toward the retracted position, that is, to the direction to remove the punch 29 away from a die 27. Therefore, it is unnecessary to provide such a cam surface in a punch drive cam 59 that causes the punch holder 50 to move into the retracted position. The punch drive cam 59 may have only a cam surface 59a for bringing the punch holder 50 radially into the punch position where the punch 29 is fitted in the die 27. Accordingly, the punch drive cam 59 may be manufactured at a less cost. In this embodiment, those elements which may be equivalent to the first described perforator are designated by the same reference numerals so that the detailed description thereof can be omitted for brevity. The above embodiment is also preferable because it is possible to minimize the stroke of the punch holder, which contributes to the precision of fitting between the punch and die. Although the above described embodiment relates to such a case where perforations are made along one side of the photographic filmstrip 15, it is possible to provide perforations along both lateral sides of the filmstrip 15 by disposing die sets on opposite lateral sides of the film convey surface 16. The perforator of the invention may be applicable to perforate any kind of long strip of sheet material other than photographic filmstrip. In order to achieve the sharpness and accuracy of the die-punching, it is necessary to give stable tension on the long strip to be perforated. For this purpose, it is preferable to control the rotation of supply and take-up reels of the long strip according to the fuzzy control method on the basis of the rotational speed and the acceleration of the rotary drum 11, the displacement of dancer, the change rate of the displacement of dancer, the diameters of the rolls of the long strip coiled around the supply reel and the take-up reels, and other parameters as input data. While the present invention has been described in detail with respect to the embodiment shown in the drawings, the present invention should not be limited to this embodiment, but on the contrary, various modifications of the present invention can be effected without departing from the scope of the appended claims.

Claims: A method for making perforations along a long strip of sheet material (15) while continuously conveying said sheet material (15) in a longitudinal direction thereof, said method comprising: continuously rotating a rotatable assembly (11) about an axis extending in a first direction, the rotatable assembly (11) having a peripheral surface (16) around which a plurality of die sets (12) are arranged at regular intervals, the die sets (12) rotating along with the rotatable assembly (11), each of said die sets (12) having a die (27) and punch (29) pair, each punch (29) being linearly movable relative to the peripheral surface (16) in a second direction which is perpendicular to the peripheral surface (16); continuously conveying the sheet of material (15) through a loop in which the sheet material (15) is wound around a portion of the peripheral surface (16) of the rotatable assembly (11) and is in contact therewith, the sheet of material (15) being conveyed at such a speed, that the relative speed between the sheet of material (15) and the peripheral surface (16) is zero; the sheet of material (15) being die-punched by subsequently moving each of the punches (29) along the second direction into the corresponding die (27) relatively shortly after the rotatable assembly has rotated through the position in which the sheet of material (15) initially comes into contact with the portion of the peripheral surface (16) at which the corresponding die (27) is arranged, each of the punches (29) being retracted away from the die (27) by reversely moving it in the second direction relatively shortly before the rotatable assembly (11) rotates into the position in which the sheet material (15) runs off of the portion of the peripheral surface (16) at which the corresponding die (27) is arranged, the sheet of material (15) being clamped between the punches (29) and dies (27) while they are engaged; characterised by pivoting said die sets (12) in a plane traversing said peripheral surface (16) while maintaining the relative position between said die (27) and said punch (29) unchanged in each die set (12), so as to prevent said punch (29) from interfering with said sheet material (15) when said sheet material (15) is approaching or leaving said peripheral surface (16). An apparatus for making perforations along a long strip of sheet material (15) while continuously conveying said sheet material (15) in a longitudinal direction thereof, said apparatus comprising: a rotatable assembly (11) having a peripheral surface (16), the axis of rotation of the rotatable assembly (11) extending in a first direction; a plurality of die sets (12) arranged at regular intervals around said peripheral surface (16) of said rotatable assembly (11) and rotating along with said rotatable assembly (11), each of said die sets (12) having a die (27) and punch (29) pair, each die (27) being secured to a die holder (52) which is mounted to said peripheral surface (16), each punch (29) being secured to a punch holder (50) which is linearly movable relative to the peripheral surface (16) in a second direction, which is perpendicular to said peripheral surface (16), between a punch position where said punch (29) is fitted in said die (27) and a retracted position where said punch (29) is retracted away from said die (27); roller means (17, 18) disposed outside said peripheral surface (16), for looping said sheet material (15) around a predetermined portion of the peripheral surface in such a manner, that the sheet material (15) is in contact with said peripheral surface (16), so as to convey said sheet material (15) on said peripheral surface (16) in such manner, that the relative speed between the sheet of material (15) and the peripheral surface (16) is zero; and punch drive means (40, 59) coupled to said punch holder (50) so as to subsequently drive each punch holder (50) to move in said second direction relatively shortly after the rotatable assembly (11), in use, has rotated through the position in which the sheet of material (15) initially comes into contact with the portion of the peripheral surface (16) at which the corresponding die (27) is arranged, the punch drive means (40, 59) being further adapted to subsequently retract each punch holder (50) away from the die (27) by reversely moving it in the second direction relatively shortly before the rotatable assembly (11), in use, rotates into the position in which the sheet material (15) runs off of the portion of the peripheral surface (16) at which the corresponding die (27) is arranged, the punch drive means (40, 59) being further adapted to keep the punch (29) in the engaged position, in between of its engagement and its retraction, over a predetermined rotational angle so as to keep the sheet of material (15) clamped between the punches (29) and dies (27) while they are engaged; characterised by shift means (54, 55-57) for pivoting said die sets (12) relative to said sheet material (15) in a transverse direction with respect to said peripheral surface (16) into a relief position where said punch (29) cannot interfere with said sheet material (15) when said sheet material (15) is approaching or leaving said peripheral surface (16), a relative position between said punch holder (50) and said die holder (52) remains constant while said shift means (54, 55-57) pivots said die sets (12). An apparatus as recited in claim 2, wherein said punch drive means comprise a punch drive cam (13, 59) stationary disposed along said peripheral surface and a cam roller (40) coupled to said punch holder (30, 50, 63) and sliding along said cam while said die sets are circulating along with said peripheral surface. An apparatus as recited in claim 2 or 3, wherein said punch drive means further comprises a sliding member (31, 64) disposed in each of said die sets and slidable in said second direction, said sliding member coupling said cam roller to said punch holder, so as to transmit only such motions of said cam roller to said punch holder that causes said punch holder to move in said second direction. An apparatus as recited in any one of claims 2 to 4, wherein said die set further has at least a guide rod (34, 51, 65) for guiding said punch holder linearly in said second direction, one end of said guide rod being slidably fitted in a bearing (36, 53, 67) securely mounted in one of said punch holder and said die holder. An apparatus as recited in any one of claims 2 to 5, wherein said die set further has a spring (58) urging said punch holder (50) toward said retracted position.

Inventors: SEIKAI HIROSHI, SUZUKI MITSURU, TAKAHASHI KOICHI, TSUZAKI HIROSHI, SEIKAI, HIROSHI, SUZUKI, MITSURU, TAKAHASHI, KOICHI, TSUZAKI, HIROSHI, SEIKAI, HIROSHI, C/O FUJI PHOTO FILM CO., LTD., Suzuki, Mitsuru, c/o Fuji Photo Film Co., Ltd., TAKAHASHI, KOICHI, C/O FUJI PHOTO FILM CO., LTD., Tsuzaki, Hiroshi, c/o Fuji Photo Film Co., Ltd.
Applicants: FUJI PHOTO FILM CO LTD, FUJI PHOTO FILM CO., LTD.
Application year: 1993
Main classification: B26F1
IPC codes: B26F1, B26D5