GB404683A - Improvements in studio camera backs and shutters - Google Patents

Abstract

404,683. Photographic cameras. STOKES, C. J., 65, Myddelton Street, Clerkenwell, and BENNETT, A., 274, Oxford Street, London. June 22, 1932, No. 17626. [Class 98 (i).] In a camera back especially for use with studio cameras, in which a carriage bearing a focusing screen and a plate holder side-by-side, is mounted to slide in a frame so that either can be brought into register with the exposure opening, coacting means are provided on the carriage and frame for rewinding or resetting a shutter also mounted on the carriage. In the form shown the shutter comprises an apertured blind 9, Fig. 5, carried by rollers 10, 11, the latter being spring-actuated. The shaft of the roller 10 is extended upwards to form an axle 14 for a cord 15 attached to a shoe 16 and carries also a collar 21 formed with a projection 20. When the carriage is slid to the right the shoe remains stationary and the cord rotates the shaft thereby winding the shutter, a spring urged pawl 18 falling behind the projection 20 to maintain the shutter in tension. At the same time a projection on the frame 4 engages the shutter of the dark slide which is thus withdrawn. Pressure on the operating member removes the pawl 18 from the path of the projection 20 to make the exposure. To vary the time of exposure a dashpot 61, Fig. 4, is provided, the plunger of which is connected to a pivoted plate 59 having an upstanding pin 63 which engages one end of a pivoted arm 70, the opposite end of which is formed as a catch 69 and projects into the path of the shoe 16. On its return movement the shoe is arrested by the catch, with the shutter open, until the arm 70 moving under the control of the dashpot has rotated sufficiently to move the catch 69 clear of the shoes. The travel of the plunger is governed by the setting of a bevelled plate 64, which on forward movement of the carriage permits a plate not shown to engage a pin 62 on the plate 59 so as to wi thdraw the plunger until the bevelled portion of the plate 64 is reached, when the pin 62 is freed. For bulb exposures, a plate 43 mounted below the operating member is moved by a pin-and-slot 50 operated by an external pointer, to bring a projection 71 behind the arm 70, the shoe 16 being thus held by the catch 69 until release of the operating member allows the projection 71 to rise clear of the arm 70. A rack and pinion may be used in place of the cord 15 and the rate of movement of the shutter blind may be regulated by a dashpot 49. A sliding plate may be substituted for the blind 9.