Patent GB-699836-A (GB)
Title: Devices for synchronizing flashlights with the opening of photographic roller-blind camera shutters
IPC: G03B9/70
Filed: 1951-06-15
Abstract: 699,836. Synchronizing flashlights with photographic roller blind shutters. LEITZ GES., E. June 15, 1951 [July 8, 1950], No. 14225/51. Class 98 (i). A flashlight synchronizer for a roller-blind camera shutter in which allowance is made both for the type of lamp used and the exposure time chosen, comprises .a knob for setting the shutter exposure time and rotatable by one of the shutter blinds on tensioning and releasing the shutter, and two members for closing contacts in the flashlight circuit, adjustable relatively to the camera casing, one member being connected to the time-setting knob and being together with the latter adjustable in dependence on exposure times and the other being adjustable in dependence on types of flashlights, the arrangement being such that the one member rotates with the time-setting knob on release of the shutter and the flashlight is ignited when the two members reach a predetermined position relative to each other. Preferably the one member is integral with the time-setting knob and comprises a cylindrical spindle which is engaged by a cam on a pivoted lever comprising the said other member, the flashlight contacts being closed when the cam drops into a recess on the spindle. As shown, a setting disc 3 disposed coaxially of the timesetting knob 2 of the shutter is provided with a recess 4 for reading off a scale 1a of flashlight factors corresponding to different kinds of lamps and carries a lever 6 pivoted at 5 and urged clockwise by a spring 7 but held by a cam 9 on the lever bearing against the shaft 2a of the knob Z so that a contact 8 on the lever is normally clear of an insulated contact carried by the disc 3. On operating the shutter trigger, a switch 16 is closed and when the leading blind is released the shaft 2a rotates, whereupon at a position determined by the setting adjustments of the knob 2 and disc 3, the cam 9 drops into the recess 2b in the shaft so that the contacts 8, 10 engage to effect synchronization, the cam 9 resting on the far side of the recess in the rundown position. During setting, closure of the contacts 8, 10 is prevented from exciting the lamps 15 since the switch 16 is open. In a modification dispensing with this switch, Fig. 4, the disc 3 carries a second lever 26 pivoted at 27 and urged anti-clockwise by a spring 28. During the exposure movement, the operation is as in the previous embodiment with the addition that a projection 9b on the cam 9 engages a cam 29 on the lever 26 and holds the cam 29 out of the recess 2b. On setting the shutter, the cam 29 drops first into the recess and the complementary surfaces 9a, 29a on the cams 9, 29 engage, thereby holding the cam 9 out of the recess so that the contacts 8, 10 remain open. In modifications, the springs 7, 28 may be dispensed with by making the levers 6, 26 inherently resilient. The disc 3 instead of being directly adjusted by hand may be rotated by axially displacing against a return spring a sleeve coaxial with the knob 2, teeth on the sleeve being arranged to engage teeth on the disc 3. The knob 2 may carry a scale of exposure times which is set against a fixed mark and the disc 3 may also carry a scale of exposure times, the same value on the disc scale as that indicated on the knob scale by the fixed mark being set against a selected value on the flashlight scale on the shutter body to determine the initial distance between the cam 9 and the recess 2b. Alternatively the knob 2 may carry a scale of lamp types and the body may carry a scale of exposure times. In another form, the knob carries a sleeve bearing leading lines against the outer end of the appropriate one of which the chosen flashlight scale value on the disc 3 is aligned. In yet another form the knob 2 is set against a fixed mark on the camera body as before while the disc 3 is replaced by two relatively-movable but frictionally coupled discs 3a, 3b, Fig. 11 (not shown). One disc 3a bearing a scale of exposure times is set so that the value chosen by the knob 2 is registered with chosen lamp type setting on disc 3b, and both discs are then rotated together to bring this lamp factor against another fixed mark on the camera casing. In a modification of this form, the two discs are replaced by a disc 3 and a frictionally coupled sector 3c, Fig. 12 (not shown), having a reading window which is set to surround the chosen exposure time value on the disc. The disc and sector are then rotated together to place the chosen lamp type setting on the sector against the second fixed mark. If desired, by suitable choice of scales a single fixed mark on the camera body may be used instead of two as above described.