Patent GB-564937-A (GB)
Title: Improvements in photographic cameras
IPC: G03B19/04
Filed: 1943-04-16
Abstract: 564,937. Roll-film cameras. BOLSEY, J. April 16, 1943, No. 6135. Convention date, March 6, 1942. [Class 98 (i)] A roll-film camera is provided with a magazine comprising two film chambers 22, 23 connected by a member 24 and having a resilient pressure member 25 secured to it and arranged in the space between the chambers so that, when the magazine is in position on the camera, it presses the film against the surface 16 of the camera surrounding the exposure aperture. In the construction shown the member 24 connecting the film coil containers 22, 23 is of channel section, and the pressure member consists of a plate 25 and leaf spring 26 secured to the channel member. The film passes through slots 27 from the supply to the take-up chamber, where it is caused to coil upon itself by a spiral spring 30. A similar spring may, as shown, be provided in the supply chamber 23, which may then be loaded by pushing a film strip into it through the slot 27. The magazine is divided into separable halves in a plane parallel to the top and bottom walls, and is provided with flanges (not shown) engaging in grooves in the camera body to form light traps. The camera is formed with recesses 14 to receive the magazine chambers 22, 23. The film is fed by the movement of a member 38 extending through a slot in the camera front and rigidly secured to a slidably-mounted apertured plate 49 which guides it so that it remains parallel to itself. During the forward movement a claw 41 at the end of the member 38 engages in a marginal slot in the film, and feeds the film. During the return movement the claw slides over the film, the pressure-plate yielding to allow this, or the claw being arranged to yield in one direction for the same purpose. The movement of the member 38 also sets a shutter comprising a plate 33 with an aperture 36 slidably mounted in front of the lens. The member 38 passes through a slot 37 in the plate, and during its forward movement moves the plate against the tension of a helical spring 35 until the plate is latched in the set position by the engagement of a projection 45 on it with a corresponding projection 44 on a shutter-release member 43. During setting the plate 49 masks the exposure aperture. The spring 35 passes round a drum 52 which may be adjusted to vary the exposure by altering the spring tension. Further, for slow automatic exposures the drum may carry a pivoted segment 61 on which is a pin 59 which may be moved by adjustment of the drum more or less into the path of a pin 65 on the shutter plate 33. The plate is thus arrested in the open position until the sector has been turned under the restraint of escapement mechanism 62, 63, 64 to a position in which the pin 65 is freed, when the plate 33 completes its movement. A direct-vision viewfinder is provided, comprising a frame 68 carrying front and rear lenses 66, 67 and carried by hollow pillars 69 housing springs so that the finder and supporting pillars may be lowered into recesses in the camera when out of use, in which position they are retained by the engagement of a hook 76 which engages the operating member 38 or a pin in the shutter 49. When the shutter is set the hook is released and the springs raise the view-finder to the operative position. In a modification, the front lens of the finder is pivoted to the front of the camera and held against a spring in a downturned out-of-use position by a hook member which is released when the shutter is set.