GB645285A - Improvements in or relating to devices for synchronising flashlights with photographic camera shutters - Google Patents

Abstract

645,285. Time switches; momentary contact switches. DAWE INSTRUMENTS, Ltd., and DAWE, F. W. Jan. 28, 1948, No. 2588. [Class 38(v)] [Also in Group XX] A control device for operating a flashlight in synchronism with a photographic camera shutter has a spring-loaded member which, when the device is operated, is released to actuate a shutter release mechanism and to impart an impulse to a flywheel to set it in motion, the said flywheel serving to close electric contacts in the flashlight circuit at a predetermined point in its travel. One contact may be carried by the flywheel and the other which is stationary carried by a pivoted insulated plate is adjusted by a manually rotatable screw-threaded rod engaging in a boss pivoted on said plate. As shown the device is set, a lever 3 of channel section pivoted at 9 on a bracket 10 being retained by .the hooked nose of a T-shaped lever latch 20, pivoted at 21 on a bracket 22, which passes through a slot 27 in the lever 8. On depressing the trigger 25 the latch 20 rotates clockwise against a leaf spring 23 releasing the lever 8 which turns clockwise under its wire driving spring 11, Fig. 1, (not shown), which is wrapped round the pivot 9 and has one end engaging the side 1 of the casing while the other passes into a' hole in the lever 8. This clockwise movement of the lever (i) trips the shutter by moving the release cable 38, which is secured by an adjustable screw 37, Fig. 1, to a sleeve 35 slidably mounted in a bush 36 and screwed into a threaded boss 34 held in the end of the lever 8 by the bent-over channel walls forming a.portion of square section; and (ii) completes the flashlight circuit through an electric discharge lamp by engaging a stop 51 on a heavy disc 44 which it rotates against the action of a coiled spring to move a spring contact arm 52 on the disc against a stationary contact 56 on an insulated disc 55 adjustable to allow for different lamp lags by a screw and nut drive 63, 64, the extent of the lag being indicated in a window 60 by a numeral on a strip 58 carried by the disc. To reset the device a plunger 16 is depressed, when the lever 8 is returned to the position shown, the leaf spring 18 serving to return the plunger to its rest position. For synchronizing the flashlight with shutters of different inertias the spring 11 controlling the lever 8 may be replaced by a spring of different strength.