Patent GB-1523746-A (GB)
Title: Photographic camera
IPC: G03B15/04
Filed: 1975-11-27
Abstract: 1523746 Cameras with flash EASTMAN KODAK CO 27 Nov 1975 [29 Nov 1974 10 March 1975] 48844/75 Heading G2A In a camera in which a flash is fired by a firing member striking a Piezo-electric crystal, the film advance mechanism is coupled to the said firing member to move it to a latched position during film advance, means also being provided for preventing the return of the film advance mechanism to its rest position before the firing member is moving to its latched position. As shown, the Piezo-electric generator 10, comprising a crystal 12 with first and second anvils 14, 15, is connected to the flash unit 58 by two contacts 60 and 62. Contact 60 is integral with a strip 66 having a spring finger 68 biased into contact with anvil 15. Contact 62 is integral with a spring strip 70 having a contact end 74 and a spring end 76. The firing spring 20 is supported in a flexed position by a pin 25 and a knife-edge 27. A latch 30, pivotably mounted on a pin 32, has three arms, 36, 40, 46. In the Fig. 2 position the end 76 of spring 70 engages a lug 34 on latch 30 and urges the latch anti -clockwise. It is restrained in this movement by engagement of a latch surface 44 on arm 40 of the latch with end 28 of spring 20. Thus the tendency of latch 30 to move anti-clockwise holds the end 28 bent upwards as in Fig. 2, so that it is latched against its firing movement. When an exposure is to be made, a shutter actuator 80 is moved downwards from the Fig. 2 position. During this movement it engages a cam edge 38 on arm 36 of latch 30, and pivots the latch clockwise, until latch surface 44 disengages from end 28 of firing spring 20. The spring is now free to move from its tensioned Fig. 2 position to the Fig. 4 position. A hammer 26 at the end of spring 20 strikes the first anvil 14, so generating energy by the crystal 12. The electrical pulse produced is presented across the contacts 60, 62, and so fires the flash. The latch 30 is now free to pivot anti-clockwise under the action of spring end 76 into the Fig. 4 position, in which a pawl 48 at the end of arm 46 is brought into engagement with a rack gear 54 on a film advance slider 52. For subsequent operation, slider 52 is moved to the right, against a spring 56, to advance the film. Pawl 58 and rack 54 will allow movement in this direction, but not in the reverse direction. This film advance movement is also coupled with the shutter actuator 80 to move it upwards again from the Fig. 4 position. It first engages arm 36, which flexes to allow actuator 80, which has an inclined edge (82), Fig. 3 (not shown), to pass. Further movement of actuator 80 brings it into engagement with end 28 of spring 20 and forces it upwards. It engages with arm 40 of latch 30, and pivots the latch clockwise, against the action of spring end 76. This clockwise movement of latch 30 also disengages pawl 48 from rack 54, so that the slide 52 can now be drawn by spring 56 back into the rest position. When shutter actuator 80 moves the spring end 28 clear of arm 40, spring end 76 urges latch 30 anti-clockwise again, so that latch surface 44 engages spring end 28 again, and the latched position of Fig. 2 is reached once more. In the embodiment of Figs. (not shown) 7-12 there is a slight difference in the arrangement of the mechanical parts.