GB588841A - Improvements in and connected with kinematograph projectors - Google Patents

Abstract

588,841. Kinematograph film feed apparatus. CHEESEMAN, L., and MOY, Ltd., E. F. Nov. 9, 1944, No. 22071. [Class 97 (i)] A kinematograph projector has an intermittent film-feeding sprocket arranged above the projection gate to push the film therethrough, and strain on the film is reduced by causing a pressure pad to press the film against the gate aperture during the period when the film is stationary in the gate and to move away from the film during the shift periods. Provision may be made for adjusting the film masking and for maintaining synchronism between the movement of the feed, pressure pad and shutter mechanisms during the adjustment. In one form, Figs. 1 and 3, in which the pressure pad is moved parallel to the aperture plate, the gate consists of an aperture plate 2 fixed to the projector body 1 and a front plate 3 which is hinged to the body at 4 and is held against the aperture plate by a spring-urged pin 28 engaging in a hole in a fixed quadrant 31, the gate being opened by transferring the pin to engage a second hole in the quadrant. The plate 3 carries a floating pressure pad 5, having outside the path of the film four lugs 6 fitted with pins 7 engaged by leaf springs 8, the lugs being engaged by crossconnected parallel - motion linkages 9, 10 actuated by a cam 15 on a shaft 40 driven in synchronism with an intermittent film-feed sprocket 17 to produce the desired intermittent movement of the pressure pad. The cam 15, sprocket 17 and shutter (not shown) are gear driven from a power-driven wheel 55, the cam through pinion 39 and helical gears 37, 33, the shutter by pinion 63, Fig. 6, on the cam-shaft, and the sprocket by pinion 54 actuating Maltese cross mechanism 50, 51, the mechanism being enclosed in a gear-box 62 rotatable about the shaft 52. To secure synchronism, the pinions 39, 54 and helical gears 33, 37 all rotate at the same speed. Correct masking is effected by rotating a knob 56 which through lever and quadrant gearing rotates a pinion 60 causing the gear-box 62 to turn about the shaft 52 and, in so doing, to rotate the sprocket 17 sufficiently to move the film up or down the required amount. Correct phasing of cam 15, pin-wheel 50 and shutter is maintained during the masking adjustment by causing the pinion 60, through a threaded shaft 66 carrying a fork 65 embracing the helical gear-wheel 33, to displace this wheel along the cam to which it is slidably keyed so that the shaft 40 and therefore also the cam 15 and shutter-driving gear are adjusted by an amount corresponding to that of the pin-wheel 50. In a modified form, the pressure pad is pivoted at its upper end on the hinged front plate and a barrel cam, driven and adjusted in away similar to that described above, actuates lever'mechanism to rock the pressure pad which, as before, is spring-biassed towards the aperture plate. The aperture plate in this form is provided with a yieldable lateral film guide.