Patent GB-937528-A (GB)
IPC: G03B9/22
Abstract: 937,528. Camera shutters. CARL ZEISS-STIFTUNG, and A. H. LOMB, [trading as COMPUR-WERK FRIEDRICH DECKEL oHG]. Jan. 22, 1962 [Feb. 8, 1961], No. 2197/62. Class 98 (1). A camera shutter has a cocking lever arrestable in a cocked position by a spring-loaded pawl, and arranged on the one hand to provide an anchorage for a first spring which acts on a movable bladeactuating member to open the shutter, and on the other hand to form a driving element driven by a second spring to act on the blade-actuating member to close the shutter, the said member being shaped so as to engage with the trigger release for actuating the shutter, and also so as to disengage the pawl. The form shown in Fig. 1 has several segmental shutter blades 5, only one being shown, actuated by a ring 3 in conventional manner. The shutter is opened by the action of a spring 12, attached at one end to a pin 10 secured to a radial lug 11 of the actuating ring 3, and anchored at the other end to a pin 14 on a cocking lever 13. This lever pivots on a fixed pin 15, and is rotated anticlockwise to tension spring 12 and thus cock the shutter. It is retained in the cocked position by a locking pawl 19 biased anti-clockwise by a spring 20; a tooth 21 on the pawl co-operates with a tooth 22 on the cocking lever. The actuating ring 3 is retained in the cocked position by a tooth 37 on a release lever 7 which engages a lug on the ring. Fig. 1 shows the closed shutter in the cocked position. When release lever 7 is pressed, ring 3 is released to rotate under the action of spring 12, to open the shutter. As ring 3 rotates, the lug 11 pushes the end 24 of pawl 19 to turn it clockwise and so disengage from cocking lever 13. Lug 11 then strikes against a stop 23, so terminating the movement of ring 3. At the same time, a further lug 25 on ring 3 strikes against an abutment 26 on lever 13. The shutter is closed by the action of a second spring 17, secured at one end to the cocking lever 13 and at the other end to a fixed pin 16. The lever 13 is now pulled anti-clockwise by spring 17, and so drives the ring 3 back into the " shutter closed " position by reason of the abutment 26 engaging against lug 25. The closing movement is terminated by lug 25 striking against stop 23. The reversal of the opening to the closing motion of the ring 3 is quickened by the rebound as lug 11 strikes stop 23. The retarding action is provided by a racking lever 28 pivoted at 27, whose position can be adjusted by suitable shutter speed setting mechanism. An arm 29 of this lever extends into the path of pin 14 on the cocking lever as the latter turns during the shutter.closing movement. When the pin 14 strikes against arm 29, it rides along it until it rides off the end. The motion of the cocking lever is thus braked until pin 14 is clear of the arm 29, the actual closing motion of the blades not beginning until then. The greater or lesser degree to which the pivotable arm 29 of the racking lever 28 extends into the path of pin 4 determines the retardation and hence the shutter speed. The spring 20 may have an elongated end for closing a flash contact (Fig. 4, not shown). Fig. 6 shows another embodiment having a single blade shutter 38 fixed to a support 40 which can slide on a rod 42. The release lever 48, locking pawl 50, cocking lever 52, shutter-opening spring 54, and shutterclosing spring 56, correspond to the similar members 7, 19, 13, 12, 17 respectively of Fig. 1.