Patent GB-797406-A (GB)
Title: Improvements in or relating to flashlight ignition devices for photographic shutters
IPC: G03B9/70
Filed: 1956-05-17
Abstract: 797,406. Photographic shutters and flashlamp synchronizers. BURGER, M. May 17, 1956 [May 20, 1955], No. 15467/56. Class 98(1) [Also in Group XXXVII]- In a flash lamp synchronizer, elements provided to close an electrical contact in the lamp circuit move in the same direction on operating the shutter and, after a predetermined time delay, one element is arrested, the relatve movement between the elements, due to the continued movement of the unarrested element, being used to close the contacts. Preferably, the unarrested element is driven by the shutter mechanism and drives the other element by friction In one form contact is made between the two elements in the form of plates 15, 16 when one of projections 28, 29 on an insulating plate 17 separating plates 15,.16 is arrested by contact with the end 30 of a lever 32. Continued anticlockwise movement of plate 15 brings lug 25 on plate 16 into electrical contact with stepped portion 44 of the plate 15 (Fig. 3). Plate 16 is electrically connected by sliding spring contact 27 to the flash lamp terminal insulated from the shutter casing and plates 17 and 15 are retained in frictional engagement by plate spring 19. Plate 15 is driven by pin 23 on blade ring 3 and on the return movement to close the shutter blades plates 15, 16 and 17 are driven in a clockwise direction until projection 29 strikes abutment 45 when plates 16, 17 are arrested and the continued clockwise rotation of plate 15 removes lug 25 from part 44 and breaks the flash lamp circuit. Shutter release lever 10 retains lever 32 by means of pin 34 during the setting of the shutter so that end 30 of lever 32 does not contact projections 28 or 29 as the blade ring 3 oscillates during this operation. The flash contacts thus remain open as setting lever 7 is moved anticlockwise about pivot 6 against tension spring 8 and heel 42 is engaged by lever 12 which is freely pivoted on release lever pivot 11. On turning shutter release lever 10 anticlockwise about pivot 11 to release the shutter, first lever 32 moves about pivot 31 under tension spring 33 until arm 35 abuts one of surfaces 39, 38 or 43 on lever 36. End 30 of lever 32 is accordingly positioned to intercept neither or either projection 28, 29. Thereafter pin 14 moves lever 12 anticlockwise to release heel 42 and tension spring 8 turns lever 7 to operate the shutter and synchronizer. In another form, Figs. 4-6 (not shown), the relative rotation of two plates due to the continued rotation of one after the arrest of the other moves the arrested plate axially with respect to the other by the interaction of inclined surfaces of punched up lugs or wedges on the unarrested plate with apertures left by similar lugs on the arrestable plate. The axial movement is used to close two contacts separately mounted on an insulating block fixed to the shutter casing. In a further setting of the synchronizer the blade ring may be arrested for a predetermined time interval by a known device after it has closed the contacts but before it has opened the shutter blades. A cover blade system is provided.