Patent GB-483819-A (GB)
Title: Improvements in and relating to intermittent feed mechanism for cinematograph apparatus
IPC: G03B1/22
Filed: 1936-08-28
Abstract: 483,819. Kinematograph apparatus. HILLMAN, A. G., and JOHNSON, G. H. Aug. 28, 1936, Nos. 23659/36 and 6236/37. [Class 97 (i)] Intermittent-feed mechanism comprises a member which carries a feeding tooth and is rocked by a slide moving in an orbital path, and spring means for imparting to the member sudden rectilinear movements with respect to the slide, to cause the tooth to travel through the film perforations in a substantially straight path ; means may be provided for positively operating a film-registering tooth in synchronism with the movements of the feeding tooth, and for removing both teeth from the film track to facilitate threading. As shown in Fig. 3, the feeding tooth 1 is carried by a rod 2 which is mounted in a slide 11 suspended from the pin 12 of a rotating crank, and also in a guide 4 rocking about a spindle 5. A rack 10, formed on the rod 2 is engaged by a toothed segment 9 secured to the spindle 5 and turned by the spring means, at the ends of the rocking movements of the rod, to move the tooth 1 into or out of a film perforation ; the turning movement may take place during about 10‹ of movement of the crank pin 12. Fig. 8 shows diagrammatically a means for turning the segment 9. The spindle 5 carries an arm 56 connected by a link 55 to a lever 38 turning on a fixed pivot 44 under the control of a cam follower 37, carried by it, and cams 33, 34. The turning movement is effected by a blade spring 39 engaging a slot 42 at the lower end of the lever 38 and secured to an arm 43 rocked about the pivot 44 by cams 47, 48 engaging cam followers 45, 46 on its ends. Rotation of the cams 47, 48 rocks the arm 43 and stresses the spring so that the cam follower 37 moves rapidly to right or left when permitted to do so by the stepped parts 40, 41 of the cams 33, 34. In a modification. Fig. 10, the spring 39 is replaced by coil springs 49, 50 connected to levers 51, 52 having followers 53, 54 engaging the cams 47, 48. The cams are rotated by intermeshed gears 35, 36 of which the gear 36 is fast on the shaft 13 of the crank 12 and is driven, through worm gearing and a variable speed coupling, from the main shaft. The variable speed coupling comprises a pin rotating round one shaft, and engaging a slotted arm on a shaft parallel to, but not coaxial with, the pin shaft, and produces an accelerated film-feed movement. A registering tooth 25 is connected by a link 29 to a lever 22 turning about a trunnion 24 and pivoted on an arm 20 secured to the spindle 5. The two teeth 1, 25 are respectively inserted into and withdrawn from film perforations simultaneously, but may be both withdrawn simultaneously, to facilitate threading, by movement of the trunnion 24 from a position engaging a bearing 30, in a spring-pressed arm 31, to a recess 32a in the arm. Modifications are described in which the lever 22 is connected by a rod to a roller &c. held by a spring in alternative recesses, or to a spring-controlled lever held in alternative positions on opposite sides of a deadcentre. The film track may be curved to correspond to the operative claw path, and a guide 75, arranged so that the film closely follows it but does not impact with it, may be provided; meta] pads 76, 77, Fig. 3, may engage one edge of the film when a single feed tooth is provided. The mechanism may be used for feeding several (e.g. three) image-heights at a time in apparatus for taking colour records in accordance with the process described in Specification 483,817.