Patent GB-718611-A (GB)
Title: Photographic cameras having shutter-cocking means interconnected with an exposure-counting and a film-winding mechanism
IPC: G03B17/42
Filed: 1951-11-06
Abstract: 718,611. Photographic twin-lens camera. GRANGE, A. Nov. 6, 1951 [Jan. 26, 1951], No. 26006/51. Class 98(1) A photographic twin lens camera includes a shutter-cocking device interconnected with exposure-counting and film-winding mechanisms, the shutter mechanism including a disc mounted coaxially with the shutter and operatively connected to a release lever of the shutter mechanism for angular movement therewith, a projection on the disc adapted to engage a lever to release the exposure-counting mechanism, the film-winding mechanism operating a cam and lever arrangement adapted to drive a member disconnectably mounted on a shutter-controlling spindle so as to cock the shutter each time a picture area on the film has entered the operative position, the spindle and projection extending perpendicular to the plane of the shutter and through the wall of the camera case to engage respectively with the exposure-counting and film-winding mechanisms, thus permitting the use of interchangeable lens boards on the camera. As shown, the film 1 is wound from the supply spool 2 to a take-up spool 3 by a crank 4 geared through the gearing 5, 6 and 7 to the spool 3, and rotates the roller 8 and thereby an indicator wheel 9 having associated therewith discs 10, 11 as described in Specification 717,334. Normally engaging the periphery of the disc 10 is a lug 26<SP>2</SP> on a spring-urged lever 26 having a slot 26<SP>1</SP> engaged by a pin 25<SP>1</SP> on a bell-crank 25 engaged by a two-armed lever 24 adapted to engage a projection 21<SP>2</SP> on the shutter housing. Keyed to the spindle of the crank 4 is a cam 12 having a projection 12<SP>1</SP> engageable with a lever 13 normally spring- urged into contact with the stop 15 but engageable with a lever 16 connected by the slotted socket 16<SP>1</SP> to a rotatable pin 17 connected to the shutter. A notch 12<SP>2</SP> in the cam 12 is normally engaged by a spring-loaded catch 18, a slot 18<SP>2</SP> in which is engaged by a pin 19<SP>1</SP> on a spring-urged bell-crank 19 having a lug 19<SP>2</SP> adapted to engage the end of the lever 13. The shutter housing has rotatably mounted thereon a disc 21 having a curved slot 21<SP>1</SP> for the reception of the pin 17. On release of the shutter, the disc 21 rotates, the projection 21<SP>2</SP> pivots the lever 24 and rocks the levers 25, 26 to release the lug 26<SP>2</SP> from a notch in the disc 10, and also, due to rocking of the lever 26, to release the film-winding mechanism as described in Specification 717,334, The crank 4 is rotated to wind the film and to move the wheel 9, and the consequent rotation of the cam 12 urges the catch 18 outwardly and allows the lever 19 to move to cause the lug 19<SP>2</SP> to contact the end of the lever 13. At the same time, the lug 26<SP>2</SP> engages the periphery of the disc 10. The projection 12<SP>1</SP> on the cam 12 pivots the lever 13' to move the lever 16 to set the shutter and the lug 19<SP>2</SP> moves under the end of the lever 13 and holds it fast. Shortly afterwards the lug 26<SP>2</SP> engages another notch in the disc 10 and arrests film-winding. The crank 4 is then rotated in the opposite direction to allow the catch 18 to re-engage the notch 12<SP>2</SP> and move back the lever 19 to release the lever 13 to re-engage the stop 15. The lever 16 is released when the shutter is operated. The lens board may be changed as described in Specification 707,665.