Patent GB-862442-A (GB)
Title: Improvements in or relating to photographic camera shutters
IPC: G03B9/10
Filed: 1957-03-12
Abstract: 862,442. Photographic shutters. KABUSHIKI KAISHA KOPARU KOKI SEISAKUSHO. March 12, 1957 [Sept. 7, 1956], No. 8137/57. Class 98(1) A photographic shutter of the pivoted blade type comprises a shutter blade operating ring, an eccentric cam rotatably mounted upon a shaft and in engagement with the shutter blade ring so as to reciprocate it, a first pinion mounted on the shaft and in driving connection with the cam, a gear in meshing engagement with the first pinion, a tension spring connected to the gear-and operative, when stressed, to apply a torque to the pinion and the cam, a manually operable lever arm coupled to and adapted to rotate the gear in a direction to stress the spring, a second pinion in driving connection with the gear, said second pinion being provided with a releaseable stop means by which it may be held arrested when the spring has been stressed and thereby prevent restoration movement of the gear and the first pinion and cam until release of the stop means, and a rotatable setting ring arranged for rotational setting movement in one direction against the action of restoring spring means also by said lever arm and carrying trip means for releasing said stop means during return movement in the opposite direction. In the form shown in Fig. 1, the shutter is set by anti-clockwise rotation against a power spring 49 of a ring 1 operable by a lever 7, integral with a pinion 6 having a pin and slot connection 10, 11 with freely rotatable gear 9. The consequent rotation of gear 9 is imparted to a meshing gear 20 having a pin 24 which snaps behind a hook 24 on a spring biased lever 23, the arm 23a of which is in the path of a projection 50 on ring 1. Anticlockwise rotation of gear 9 by a spring, which is wound up as ring 1 moves to set position, is thus prevented. The gear 17 is also rotated in such direction that the bevelled end of a pin 18 depending from gear 17 rides out of a notch in a rotatable member, having a cam 15 for reciprocating blade ring 14, and so does not rotate this member. When spring 49 has been tensioned, a hook 51a on a shutter release lever 51 snaps behind a projection 4 of ring 1 to prevent premature clockwise rotation thereof, Rotatable around the shutter housing is a member (not shown) for simultaneous or selective actuation of pawls 56, 57 and 58. In all, except the M setting, pawl 56 is moved clockwise to position E so that a pallet 38 is removed from a star wheel 37 and the running down motion of ring 1 will not be braked by a pinion 36 integral with wheel 37 as it is in the M setting. Pawl 57, except in the M setting, is positioned at F so that the finger 30 of pivoted lever 29 will not be struck by a lug 5 on setting ring 1 during the running down and finger 31 will not therefore close flash contacts 53, 52 (these contacts are, however, closed by a lever 54 operated by a pin 55 on the blade ring when the shutter blades open). Pawl 58 usually occupies position A but for self exposures is moved to D so that hook 41 on a lever pivoted to ring 1 engages a pin on a gear 47 and a backing device is brought into use. Release is effected by anti-clockwise rotation of lever 51 so that ring 1 starts to run down and pin 50 thereon releases gear 20 whereby pinion 9 is free to move, under the action of a spring in the direction necessary for gear 17 to rotate cam 15 and thus reciprocate the blade ring 14. Instead of spring 49, ring I may be driven by a spring powered pinion which is slidable on a shaft so that it may be disengaged from setting ring 1 before being rotated to vary the tension of the power spring (Fig. 7, not shown). The retarding mechanism may be combined with the braking device formed by the pallet 38 and star gear 37, a gear driven by setting ring 1 being movable out of mesh with the retard mechanism by a lever carrying said gear (Figs. 8 to 10, not shown). As shown in Fig. 11, the braking device may alternatively comprise a pinion 80 provided with a restoring power spring and meshed with the teeth 3 on the setting ring 1. Pinion 80 also meshes with a gear 146 on a lever 147, which is pivoted at 148 and operable by a pawl 151 and carries a gear 149, the latter meshing with gear 145 and with a gear 150 on the shaft of a gear 154 forming part of a differential gear train. A lever 171, Fig. 13, operable by a pawl 152. has a lug 172 for engaging a gear 157 in this gear train. By different settings of pawls 151, 152, three values of delaying time between the instant of shutter release and the operation of the shutter blades can be obtained.