Patent GB-924668-A (GB)
Title: Improvements in or relating to photographic shutters
IPC: G03B9/58
Filed: 1961-02-09
Abstract: 924,668. Photographic shutters. ALFRED GAUTHIER G.m.b.H. Feb. 9, 1961 [March 2, 1960], No. 4783/61. Class 98 (1). In a photographic shutter including a latch device-as at 29, 32-a retaining device-as at 23-and a driving part-as at 4-having a main spring-as at 5-and an additional spring- as at 6-urgingly connected to a rotatable member-as at 10-the retaining device is arranged to retain the rotatable member in a position in which the additional spring has maximum tension (cf. Fig. 1) and, when actuated by the shutter release (not shown), to release the rotatable member before the driving part is released from the cocked state thereof, and the rotatable member is arranged to rotate after release into a predetermined position defined by a settable cam-as at 34a-the latch device including a latch-as at 29-one end of which is pivotally connected to one end of an actuator-as at 32a-the other end of which actuator is adapted to arrest the rotatable member in the predetermined position, the actuator having a stop pin-as at 340- arranged to make contact with the setting cam and to serve as a fulcrum about which the actuator is pivotable by the action of the additional spring upon the rotatable member, such pivotal movement causing the free end of the latch to release the driving part and the actuator to contact a stationary stop-as at 41-preventing further movement of the actuator. The tension of the additional spring is thus adjusted prior to each exposure to correspond to the setting of the cam 34a. The main driving part 4 is coupled to a blade driving ring 16 through a spring-urged pawl 13 pivoted on the part 4 and engaging with a pin 15 on the ring 16. The additional spring 6 is wound around a bushing 9 on the cocking shaft 3 of the part 4, one end of the spring being fixed to an abutment 10a of the member 10 and the other end engaging a turned-up portion 4a of the disc 4. The cam 34a is formed in an exposure time setting member 34 which also carries a cam 34b (Figs. 9 and 10-not shown) for co-operation with a conventional gear retard mechanism (not shown) co-operating in known manner with the lug 4a of the part 4 for supplementing the control effect of the additional spring 6. The shutter operates as follows, starting from the cocked position of Fig. 1. On pivoting a spring- urged release lever 20 (coupled to a body release lever by means not shown) in the anticlockwise direction about its fixed pivot 21, a spring- urged retaining lever 23 is pivoted by a link 26 in the anticlockwise direction about its fixed pivot 24, whereby the member 10 is freed to rotate in the anticlockwise direction under loading of the additional spring 6. Rotation of member 10 is followed by actuator 32 which has a forked end 32a engaging over a pin 33 on the member 10-until the stop pin 340 thereon engages with one of the steps of the cam 34a. Rotation of the actuator about pivot 40 then stops, but the actuator continues to rotate about the pin 340 until its pivot 40 engages the stationary stop 41. During this last rotation, latch 29 (which is connected to actuator 32 at 40) is pivoted so as to release projection 4b of the part 4 for exposure. Near the end of the running down of the disc 4, portion 4a thereof collects projection 10b of member 10 and moves it into its initial position ready for the next exposure.