Patent GB-489228-A (GB)
Title: Improvements in or relating to photographic cameras
IPC: G03B7/12
Filed: 1937-01-19
Abstract: 489,228. Photographic cameras. RAUCH, C. Jan. 19, 1937, No. 1603. Convention date, Jan. 20, 1936. [Class 98 (i)] A photographic camera comprises a photo - electric lightmeasuring device, a detection member by means of which the deflection of the device can be transmitted to means for regulating the exposure-conditions, and a change-over device by the adjustment of which the deflection can be selectively transmitted to means for regulating the exposure period or to means for regulating the stop. The change-over device may comprise a member which, when adjusted for automatic setting of the exposure period. regulating means, moves over a stop-scale and when adjusted for an automatic setting of the stop-regulating means, moves over an exposure period-scale, and which in its adjustment over these scales pre-sets the stop and the exposure period respectively. The arrangement may be applied to plate cameras. As shown, the movement of the shutter-release button A is transmitted by a wire D attached to which is a control-plate p which removes a cover P from the light-measuring cell M by a cranked lever b. The wire D carries with it a slipping clutch R, a wire d and a stop-pin T until the stop-pin T engages a stepped cylinder C, which is secured on the spindle a of a coil E rotating in the field of an electromagnet F energized by the current from the cell M. If the light is insufficient, the clutch R is arrested by the top of the cylinder C and the movements of the wire d, a bolt i and a locking wire s are also stopped. The wire D then moves until the stop S encounters the locking wire s resting on counterstop G<2>, and the shutter remains unreleased. If the light is sufficient, the cylinder C is turned, the stop T encounters a lower part of the cylinder, and the stop S moves unhindered through an opening in G<2> and a stop v mounted on the wire D causes the objective shutter V to be released. The change-over member H is set to the exposure period on the segment n and the arm K then presses on the wire d<1> and transmits the required period to the timeregulating device Z and at the same time the arm k presses on the cranked arm W which adjusts the extent of uncovering of the lightsensitive cell M by a disc O through a wire d<3> to the extent necessary for the predetermined exposure period. On depressing button A, the wire d pushes the bolt i out from the member H to press on the arm n and adjusts the stop aperture. The wire D then releases the shutter V. The cover of the objective may be removed in the movement. The setting of the timeregulating device Z or the stop-device B is effected directly by hand or by a spring brought into action on actuation of the release button A. Alternatively, the member H may be set to the required stop number on the segment N connected to the wire d<1> and the arm k presses on the wire d<2> and adjusts the stop B to the required extent while the arm K effects uncovering of the cell M by means of the arm W. On depressing the button A, the bolt i presses on the arm N to set the correct exposure period. The sensitivity of the material may be taken into account by a disc or dense grey filter in front of the cell M or a resistance in the electrical circuit. The filter-factor may be taken into account by covering the objective and cell M with the same filter or separate filters or having parts on the filter frames uncovering part of the cell M. A light-intensity indicator or the cylinder C is visible from the top or back of the camera. Devices indicating the setting may be visible in or near the view-finder. The film-feeding means may be coupled with the shutter-setting movement, and both the film feeding and shutter-setting may be effected by the element D. In a modification, the operations may be effected separately by several side-by-side buttons or levers, or the button A may be depressed twice. The movement may be controlled to permit movement of the cylinder C by the provision of an air-brake or dash-pot. A slidable cylinder and rotatable stop may be used. The film-feeding and shutter-setting means may be connected to and operated by the movement of the member H.