Patent GB-1362749-A (GB)
Title: Single-lens reflex camera
IPC: G03B13/02
Filed: 1972-07-13
Abstract: 1362749 Reflex cameras NIPPON KOGAKU KK 13 July 1972 [15 July 1971] 32861/72 Heading G2A  A single lens reflex camera has a diaphragm inter-locking lever 28 engageable with a diaphragm lever 29 on shutter operation, the reflex mirror also being liftable independently of shutter operation. As shown, a mirror charge lever 4 is mounted by a pivot 5 on the mirror box 3, and can be pivoted clockwise by a lever 6, in response to a wind-up operation, against the action of a spring 21, until it is retained by the end 7a of a lever 7 Fig. 4 (not shown). Spring 21 is linked to lever 4 by a hook 11. A mirror drive lever 12 is pivoted on a shaft 13 and has one end 12a which can engage a pin 1a studded in the mirror 1 and another end 12b which can engage the shutter release 14. A connector lever 15 has one end pivoted at 16 to lever 12 and the other end pivoted at 17 to a lever 18, which has a holder pin 20 against which one end of spring 21 bears. The diaphragm inter-locking lever 28 is pivoted on the same shaft 13 as lever 12, and has a pin 28a studded therein. This pin is engaged by a spring 30 secured on shaft 13, which spring also engages a pin 12d on lever 12, so that levers 12 and 18 are urged together by spring 30. A separate mirror-actuating lever 31 is pivoted on a shaft 32, and can engage pin 1a to move the mirror independently of lever 12. It is actuated by a slider 33 having a lower portion 33c which, on downward movement of the slider, engages a pin 31a on lever 31 and so causes it to pivot and engage pin 1a, so raising the mirror 1. In normal operation, lever 4 is pivoted by lever 6 into the Fig. 4 (not shown) position, so that spring 21 is tensioned. Lever 12 is retained in its original position by a spring-loaded locking lever 25. When the shutter release button is pressed, lever 25 releases lever 12 which is then pivoted clockwise by spring 21 acting through levers 18 and 15. End 12a raises the mirror 1 by the pin 1a, and end 12b actuates the shutter lever 14. At the same time pin 12d on lever 12 pushes down lever 28, allowing the spring-loaded diaphragm lever 29 to stop down the diaphragm aperture to a predetermined value. When the shutter closes, lever 4 is released by lever 7 so that it is now pivoted anti-clockwise by spring 21, which movement is transmitted also to lever 12 because of interengaging pins 4b and 12c. Mirror 1 is thus allowed to be lowered again (by spring 2) and lever 28 is pivoted anti-clockwise to engage lever 29 and open up the diaphragm aperture once more. When a picture is to be taken with the mirror fixed in its upper position, the slider 33 is moved downwards (position of) Fig. 5 (not shown). Its upper arm 33a latches in front of the end 30a of spring 30 and prevents it from moving. Its central arm 33b engages pin 28a to pivot lever 28 clockwise to allow the lever 29 to stop down the diaphragm, and its lower arm 33c pivots lever 31 clockwise to engage pin 1a and so raise the mirror 1. When the shutter release button is pressed, the mechanism acts as described above, but when the shutter closes again and lever 12 is pivoted anti-clockwise, it does not have to act against the spring 30 since this is already held back by arm 33a.