Patent GB-1199347-A (GB)
Title: A Shutter Mechanism for Photographic Cameras
Inventor: NOACK ROLF
IPC: G03B9/70
Filed: 1968-07-04
Abstract: 1,199,347. Shutter mechanism. PENTACON DRESDEN KAMERA-UND KINOWERKE, VEB. July 4, 1968, No.31902/68. Heading G2A. In a camera having a normal shutter and an additional shutter used for flash operation only, if, after the additional shutter has been cocked, it is not required, it can be uncocked without wasting an exposure. As shown, the additional shutter, comprising blades 1, is operated by a drive ring 4, itself actuated by a drive lever 7 which has a fork portion 6 entraining a pin 5 on ring 4. Lever 7 is urged anti-clockwise by a spring 8, and the pivoting of lever 7 on its spindle 9 opens or closes the shutter. A drive ring 13 is mounted coaxially with ring 4, and urged clockwise by a spring 14. Similarly concentric with ring 4 is a setting ring 25, urged clockwise by a spring 29. When a daylight exposure is to be made, so that the additional shutter is not required, ring 25 is turned to the "daylight" position Fig.3, (not shown). In this position a dog 28 on ring 25 engages a catch lever 26 and pivots it out of the path of ring 13, and another dog 27 on ring 25 engages lever 7 and pivots it into the "shutter blades open" position, so that the shutter takes no part in the subsequent exposure. If a flash exposure is required, the setting ring 25 is rotated out of the "daylight" position into the cocked position S . In this movement, ring 25 entrains drive ring 13 by means of respective dogs 32 and 31, and cocks it against its spring 14. At the same time dog 27 disengages from drive lever 7 which then, under the action of spring 8, pivots the shutter blades into the "closed" position. During continued movement of ring 25 and ring 13 into position S, drive lever 7 is rotated once more to open the shutter blades. When setting ring 25 is released, it is returned by spring 29 into the "flash" position it actually occupies in Fig.2 and Fig.1 (not shown), being retained there by a latch lever 30. Ring 13 is now retained in the position of Fig.1 (not shown) by the catch lever 26, which is spring-urged anti-clockwise so that it intercepts a tab 21 on ring 13. When the camera release is actuated, catch lever 26 is pivoted out of engagement with tab 21, thus allowing ring 13 to run down clockwise. Drive lever 7 is disengaged, allowing it to close the shutter again under spring 8. The normal shutter (not shown), set for a long time exposure, is now opened, ring 13 being delayed by an escapement mechanism until it is fully open. An opening lever 17 attached to ring 13, engaging lever 7 briefly, causes the shutter to open once more for the duration of the flash. This is fired by the engagement of an abutment tab 20 on ring 13 with a switch 35, closure of which energizes the flash bulb 38. If, after the additional shutter 1 has been cocked, it is decided not to use it, latch lever 30 is pivoted to release setting ring 25, which then returns under spring 29 into the "daylight" position Fig.3, (not shown), in which position the dog 28 disengages the catch lever 26 from tab 21 of ring 13, so releasing the latter to run off, and so opening the shutter blades 1 again.