Patent GB-991122-A (GB)
Title: Improvements in or relating to photographic cameras
IPC: G03B19/12
Filed: 1961-12-22
Abstract: 991,122. Reflex cameras. C. ZEISS-STIFTUNG, [trading as C. ZEISS], and COMPUR - WERK G.m.b.H. [trading as COMPUR-WERK G.m.b.H.& CO.]. Dec. 22, 1961 [Feb. 24, 1961],No. 46110/61. Heading G2A. In a single lens reflex camera having mechanism for moving the mirror into and out of the viewing position, and co-acting shutter-cocking mechanism, the said cocking mechanism comprises a blade actuating member adapted to co-operate with a drive member for the purpose of opening and closing the shutter, the co-operating elements of the drive member being situated, in the rest position, outside the path of the blade-actuating member so that the shutter can be opened and shut for viewing purposes, the blade actuating member also co-operating with an actuating element in driving connection with the mirror-moving mechanism and in guiding connection with a control device for moving said actuating element into and of engagement with the blade-actuating member in the rest position of the driving member. In the form shown, when film-winding knob 12 is turned to wind the exposed film on to spool 14, it engages at the same time a slide 16, pushing it to the right (Fig. 1) against the action of spring 216. The other end of slide 16 has a rack section 168, which engages a pinion 18 which in turn is linked to turn a further pinion 20a on the same shaft 20. Pinion 20a meshes with a transmission gear 22 which in turn meshes with a pinion 26 which drives the cocking shaft 280 of the shutter. Also fixed on shaft 20 is a crank disc 206 which is spring-biased in an anticlockwise direction (Fig. 3), but during the above cocking movement of slide 16 is turned clockwise. The parts are maintained in the cocked position by a pawl 30, one end 30a of which locks against an abutment 320 on disc 206. Within the camera body is a further slide 34, which can be moved to the right (Fig. 1) against the action of spring 134, and having a rack section 34a which engages a pinion 36. Pinion 36 has an extended hub 36a embracing a shaft 40. Mounted on hub 36a is a helical gear wheel 44 which can be linked with another helical gear wheel 46 to rotate shaft 48 on which the mirror 50 is mounted, and also a flap for covering the light-sensitive film. Fig. 2 shows the mirror in the inclined viewing position; when the mirror is tilted through 45 degrees to the horizontal position, the flap is tilted through 90 degrees, so uncovering the picture frame. The other end of slide 34 carries a lever 38 pivoted at 38a. One end 238 of this lever is spring-urged against a fixed pin 234 on the slide, and the other end 138 projects into the path of a pin 208 on the crank disc 206. Fig. 6 shows the shutter housing. Five shutter blades such as 152 are provided, each hingeing on a pivot pin 54a on a bearing ring 54. The blades are actuated with a conventional pin- and-slot arrangement by a ring 56. Thus if the bearing ring 54 is kept stationary, an anticlockwise rotation of actuating ring 56 opens the shutter, and a clockwise rotation closes it again. (This opening and shutting action occurs during the exposure.) On the other hand, if ring 56 is kept stationary, clockwise and anticlockwise rotation of ring 54 opens and closes the shutter. (This action is performed for viewing.) The rotary reciprocation of the actuating ring 56 is controlled by a driving member 58 mounted on the cocking shaft 280. Also mounted in the shutter housing is an iris diaphragm comprising five blades such as 64. Each blade is pivoted at 264, and actuated by a ring 66. Mounted on the front objective tube is a spring- loaded release ring 70, having teeth 270 meshing with a pinion 28a on the cocking shaft 28. To use the camera, knob 12 is turned, to wind on the film and drive across slide 16 to cock the shutter, viewing being possible throughout this operation. On releasing knob 12 and slide 16, which is then restored to its original position by spring 216, the gear train 22, 28a, 70 remains locked in the cocking position by the engagement of pawl 30 with disc 206; driving member 58 is also retained in the cocked position by a pawl 60. During the cocking movement, pin 208 has rotated past arm 138 of lever 38, and now bears against its rear face. Focus and shutter speed are now adjusted, the aperture set by ring 76 which moves ring 66, and the release button 32 pressed. This pushes down the arm 230 of pawl 30 to release the crank disc 206, which rotates anticlockwise under its restoring spring. Pin 208, which is engaged behind the arm 138 of lever 38, accordingly pushes the lever, and hence slide 34, to the right (Figs. 1 and 3). This causes the ring 66 to turn anticlockwise, so closing the shutter, and closing the diaphragm down to its selected value. An abutment 236 on pinion 36 actuates the mechanism causing mirror 50 and the flap to be raised into horizontal position. Locking pawl 60 is now tripped by the release ring 70 out of engagement with the driving member 58, which on release rotates to drive the shutter-actuating ring first anticlockwise and then clockwise, to open and close the shutter and so effect the exposure. Pin 208 eventually rotates clear of lever 38, so that slide 34 is released to return to its rest position. The mirror and flap are therefore lowered again into the light path, and the shutter and diaphragm opened again. Thus the object to be photographed can be viewed up to the time of making the exposure, and again immediately afterwards, the image on the viewing screen 51 disappearing only during the actual exposure period.