Patent GB-1216202-A (GB)
Title: Improved in or relating to cameras
IPC: G03B17/42
Filed: 1968-07-17
Abstract: 1,216,202. Camera mechanisms. AMERICAN OPTICAL CORP. July 17, 1968 [Aug.7, 1967], No.33967/68. Heading G2A.  A camera has a shutter comprising a single rotatable disc 42, with latch means 74 for preventing double exposures. As shown, the shutter disc 42 is mounted on an axle on the front wall of an exposure chamber 20 which has an aperture 36 aligned with the camera lens 38. Disc 42 has two diametrically-opposed openings 54, 56, either of which, when aligned with aperture 36 and lens 38, allows an exposure to be made on the photosensitive film 26, there being only a single fixed shutter speed. Disc 42 also has two hooked lugs 44 extending at diametrically-opposed positions. Secured to the front of the shutter disc is a cam 62, whose ends 72 curve to a peak 70. A wire spring 64, secured at one end to the front plate 16 of the camera, has its other end bearing normally, under tension, against a flat side of cam 62, in the position shown in Fig. 3. Lugs 44 extend externally of the camera, and to effect an exposure, one of them is pressed downwards from the position of Fig.3. Spring 64 thus rides over the peaked end 70 of the cam and down the adjoining curve end 72, thereafter taking control of the shutter movement, until approximately 180 degrees rotation has been made, during which time an exposure will have been made.  The latch means 74 comprises a rod 82 having at one end a flat foot 84 terminating in a sloping surface. At the other end of rod 82 is a head 80 having an arm 78 with a latching pin 76. Rod 82 is urged towards the film 26 by a spring 89. As film 29 is wound on, when one of a regular series of perforations 90 aligns with foot 84, the latter enters the perforation, under the action of spring 89 (position of Fig.4). An exposure has just been made, by anti-clockwise rotation of shutter 42, and this can not be moved any further because lug 44 is obstructed by pin 76. The locking of lug 44 by pin 76 is designed to occur just before disc 42 has completed its full 180 degress rotation under the action of spring 64. Thus a further exposure can not be made in this position. When the film is now wound on, in the direction of arrow 28, the sloping end of foot 84 rides out of the perforation 90 and along the surface of the film until it engages in the next perforation (90<SP>1</SP>). During this time, pin 76 has been moved out of the path of lug 44, and disc 42 completes its rotation. Thus by the time the foot 84 moves back into engagement with perforation 90<SP>1</SP>, and pin 76 moves back into the path of movement of lug 44, it is not in front of the lug but behind it (position of Fig.6). It therefore no longer intercepts lug 44, and shutter disc 42 is now free to carry out another 180 degrees rotation, i.e., another exposure can be made. The camera, which is intended to be of a lowcost disposable type, is made of a moulded plastics material, the casing having a key slot 96, Fig. 9, (not shown) into which a blade can be inserted and twisted, so causing the end of the camera to be broken off Fig. 10 (not shown) to extract the reel of exposed film. A view-finder frame 110, Fig. 2, (not shown) can fold down, when not in use, to prevent accidental actuation of the shutter