GB525903A - Improvements in or relating to focal plane shutters for photographic cameras - Google Patents

Abstract

525,903. Photographic roller blind shutters. LEITZ GES. E. March 2, 1939, No. 6906. Convention date, June 2, 1938. Addition to 488,073. [Class 98 (i)] The shutter of the parent Specification is provided with improved means for braking the initial and final movements of the leading blind, comprising a cam, driven by said blind, and operating a brake, preferably of the internally-expanding type, acting on one of the wheels of the shutter mechanism. As shown, on the spindle 16 of the leading blind V<SP>1</SP> is a disc 1 having a projecting cam 2 and a snail cam surface 3. The brake is housed in a pinion 42 in the gear train between the spindle 16 and the take-up spool 19 of the film, and comprises an annular brake-drum 6 having a pin 7 engaging loosely in a slot 8 in the pinion, thereby permitting limited play between drum and pinion to facilitate winding of the shutter. The drum contains brake-shoes 9, 10, anchored by a pin 12 to the camera body 13, which shoes are expanded by a flat pin 11 on a lever 14 carrying a roller 15 engaging the disc 1. The shutter is set by the usual knob 22, and when released by depressing the button 29 to disengage the coupling 27, 28, the cam 2, by rocking the lever 14, turns the pin 11 to expand the shoes 9, 10 and thus checks the initial speed of the leading blind. During further movement of this blind, the cam surface 3 engages the roller 15 and the brake is again applied gently to eliminate shock as the blind completes its movement. The cam described may also be employed to co-operate with a spring-controlled brake-lever of the kind shown at 22 in Fig. 11 of the parent Specification.