GB555143A - Improvements in or relating to photographic shutters - Google Patents

Abstract

555,143. Photographic shutters. KODAK, Ltd. July 31, 1942, No. 10768. Convention date, Sept. 6, 1941. [Class 98 (i)] The blade ring of a multiple-blade photographic shutter is operated by a prime mover comprising a Geneva driver tensioned by a spring between it and a winding member and so located in this condition that upon its release by the shutter trigger it is substantially accelerated by the spring before engaging a Geneva driver member connected to the blade ring. As shown, the shutter blades 5, which make a single revolution at each exposure, are operated by a gear ring 8 engaging pinions 7 on the shafts carrying the blades. The gear ring 8 forms part of a Geneva driven member 9 operated by a driver 12 carried on a plate 13 extending radially from a disc 14 which engages one of the curved surfaces 11 of the member 9 to lock it except during its operation by the member 9, when a cut-away portion of the disc allows it to be moved one step. The driver 12 is actuated by a spring 38, which is wound by a knob 16. To limit the setting movement of the knob to a single turn a pin 27 which is carried by an arm 26 on a sleeve 25 secured to the Geneva driven member forms a stop which is engaged by a pin 28 on the knob. Fig. 1 shows the parts after an exposure ; in re-setting the shutter the knob is rotated anti-clockwise, the stop 27 following the pin 28 until a lug 30 on a plate 24 secured to the Geneva driving member is engaged by a lug 42 on the pivoted release member 32, Fig. 7, so holding it and the stop 27 against further rotation. Further movement of the knob finally causes the pin 28 to engage the other side of the stop. A ratchet device prevents return movement of the knob. On movement of the release arm 32 the Geneva driving member is released and moves anticlockwise through approximately 100 degrees before the driver 12 engages a slot in the driven member 9. After the exposure the parts are again in the position shown in Fig. 1. The lug 42 prevents operation of the release arm 32 by engaging a flange 40 on the knob during winding of the shutter, but may pass into a slot 41 in the flange when the shutter is fully wound. Specification 555,144 is referred to.