Patent GB-1328711-A (GB)
Title: Apparatus for releasing the shutter of a photographic camera
IPC: G03B9/64
Filed: 1971-06-23
Abstract: 1328711 Reflex cameras NIPPON KOGAKU  K K 23 June 1971 [30 June 1970 29428/71 Heading G2A A single lens reflex camera has a self timer used as a long exposure timing escapement mechanism, a shutter-release-button 142, a roller blind shutter having a front curtain and a  rear curtain, and a mirror moving lever 161, wherein upon depression of the shutter-releasebutton it is locked in a depressed position, the mirror moving lever is released which releases the front curtain and starts the timing mechanism and wherein the shutter-release-button is released when any set time of the timing mechanism has elapsed. Upon depression of the shutterrelease-button, a spring 145 engages a slot in  the shaft of the button to lock the button in a depressed state. The lower end 142b of the button engages a projection 150a of a lever 150 pivotally mounted on a shutter-release-button interlocking member 126 which slides on a base plate (not shown) by the provision of pins 171 and slots 126e. A rod 134, engaging a projection 126f also slides down to lock a rear curtain moving pawl 138 by a rear curtain retaining lever 135. The interlocking lever then allows, by a mechanism (not shown), the movement of a mirror retaining lever 164 to allow mirror driving lever 161 to rotate in the direction of the arrow. Mirror 160 is moved to an exposure position and an arm 161c of lever 161 engages an arm 167a of a front curtain interlocking lever 167 to rotate the lever 167 so that a front curtain retaining lever 131 fixed thereto moves to free a front curtain retaining pawl 133 and so that an arm 167b of lever 167 engages arm 121b of the self timer start lever 121, which lever rotates in the direction of the arrows shown. A leaf spring 118 is moved to free a projection 118a thereof from engagement with a limit lever 116 which rotates under action of a spring 117, the free end of the spring releasing the anchor of the escapement mechanism to start the timing action. The other arm of lever 116 engages and rotates an interlocking member 111 pivotally mounted on a lever 114 which has on end fixed to a shaft 115. An engaging portion 111a of member 111 engages a cam 113 rotating under action of the self timer mechanism at the end of the set time of which the cam pivots shaft 115 in the counter clockwise direction. Auxiliary lever 150 is pivoted clockwise so that engagement between surfaces 142b and 150a is lost to allow interlocking member 126 to slide upwards under action of compression spring 127. Rod 134 is thus moved upwards to free the rear curtain retaining pawl 138. During use of the self timer in the ordinary manner, the leaf spring 118 is moved by depression of member 119, and at the end of the set time counterclockwise rotation of lever 107 enables an arm 107b thereof to engage projection 126g of interlocking member 126 which slides down to make an exposure. A prior art camera is described in which continued manual depression of the shutter release button prevents closure of the shutter even after the end of the set time, and in which the set time depends; upon the extent to which the button is depressed. Both these disadvantages are avoided in the instant camera.