Patent GB-726767-A (GB)
Title: Improvements in or relating to a web perforator
IPC: B26F1/00
Filed: 1953-12-15
Abstract: 726,767. Perforating webs. KODAK, Ltd. Dec. 15, 1953 [Dec. 19, 1952], No. 34898/53. Class 31 (2). A web perforator comprises guideways including a die 12 and a stripper 13 between which the web F is fed, a punch mechanism including a punch 15, Fig. 3, adjustably-mounted on a carrier 14, means 80, Fig. 1, for mounting the punch mechanism such that the punch may be moved substantially orthogonally of the web by means 90, 91 for reciprocating the punch mechanism, and spring means opposing movement of the punch mechanism and having, together with the punch mechanism, a natural frequency equal to or substantially equal to the frequency of reciprocation of the means 90, 91 such that the force required to reciprocate the punch mechanism is supplied mainly by the spring means. As applied to perforating kinematograph film F, a pair of punches 15 and a locating pin 36 are mounted on the carrier 14 by a clamp 37 and a screw 43 respectively, and the carrier is wholly supported at its ends by the pair of flat springs 80 which oppose its movement, one spring extending above and the other below the carrier. The punches are located longitudinally by screws 40, which engage a block 41 and a lug on the carrier, and locked after adjustment by pressure applied to the block 41 by a further screw; a similar adjustment is provided for the pin 36. The film is fed in steps by a feeding mechanism, of the shuttle type, from a supply reel (not shown) and delivered to a further reel both of which are supported from a table which carries the vertical plate 10 of the machine, guide means (not shown) also being provided for forming free loops L, L<SP>1</SP> in the film above and below the punches. The feed steps are produced by a cam 20 acting through a follower 18 which has a claw 29 to engage successive perforations in the film and is pivoted on a spring-pressed lever 24 mounted on the plate 10. The claw acts in a slot in a plate 5 which forms, with a hinged plate 6, a shoot to guide the film, a slot also being provided in the plate 6 if required. A pair of dies 12 and strippers 13 pass through a clearance hole o, Fig. 2, in the punch carrier 14 which allows oscillation of the carrier by an eccentric 90 and a connecting-rod 91 attached to the carrier by a pivotal bearing or a flexible reed and synchronized with the drive of the cam-shaft 21 of the feeding device by a belt 96 and pulleys 22, 95 so that perforating operations are effected between feed steps. The dies 12 are each clamped by two pairs of bolts 54, Fig. 2, having square shanks, and can be adjusted laterally and axially by set-screws 55, 58, 60 locked by screws 59, lateral adjustment being effected against the influence of a spring plunger (not shown) between the dies. Sideplates 67 are provided for the V-opening between the dies 12 and stripper 13, and four sapphire buttons 70, 72 guide the edges of the film at the perforating station, the inside buttons 70 being mounted on the ends of spring arms 71 adjustably-supported from the plate 10 and the outside buttons 72 being adjustably-mounted in sleeves 74 on a fixed part of the structure. Instead of the punch carrier 14 being supported by the flat springs 80, it may be supported in a guideway and can have other forms of spring-urging means. A short length of previously-perforated film is attached to the film to be perforated and co-operates with the claw 29 to lead the unperforated film to the punching station where it is engaged by the locating pin 36 during punching operations, the punched-out pieces falling through a shoot 100 which may have a removable cap. Reference is made to the length of travel of the punch, its frequency of operation and the accelerating force required.