Patent GB-799595-A (GB)
Title: Improvements in or relating to roller-blind camera shutters
IPC: G03B9/34
Filed: 1956-09-06
Abstract: 799,595. Photographic roller-blind shutters incorporating flashlight synchronizers. LEITZ GES., E. Sept. 6, 1956 [Sept. 15, 1955], No. 27287/56. Class 98(1) A roller-blind shutter having two successively releasable blinds incorporates a flashlight synchronizing device comprising a plurality of tappets for actuating the flashlight ignition switch, the tappets being movable on movement of the leading blind which is released first, a member for releasing the subsequently released lagging blind, and a disc releasably interconnected with the release member and movable by the leading blind for setting the release member to travel in different planes and through paths of different lengths relatively to abutments on a releasable latch for the lagging blind, the abutments being arranged for co-operating with the release member, the tappets being allocated to different exposure times or groups of exposure times and each being capable of being set into and returned from a position such that a set tappet, when moved on movement of the leading blind, moves in a path for actuating the ignition switch during the running down of the shutter, the setting disc carrying a plurality of control cams for moving the tappets into their set positions. As shown, the leading blind is wound off the tape rollers 1 on a shaft 2 on which the drum 10 for the lagging blind is freely rotatable. After setting the shutter, the lagging blind is held fast by a latch 13, having abutmets 14, 15 of different heights, which latch engages a projection 12a on a disc 12 freely rotatable on the shaft 2 and connected to the drum 10 by a pin 11 passing through an annular slot 1a in one tape roller. This latch is releasable by a projection 6a on a carrier 6 coupled with a knob 7 graduated in exposure times and, during the shutter release and setting movements, connected with a disc 3 on the shaft 2 by the engagement of a lug depending from the projection 6a with one of several holes 4, 4a or 4b (Fig. 4) in the disc 3. The projection 6a thus rotates during the release movement of the leading blind and is adapted to release the lagging blind by engaging one or other of the abutments 14, 15 on the latch 13. The abutment which is engaged and the distanc travelled before the projecting 6a engages this abutment (and hence the exposure time) depends upon which of the holes in the disc 3 is engaged by the lug depending from the projection 6a. This hole is selected by first lifting the knob 7 and the carrier 6 to withdraw the lug, rotating them until the selected exposure time marked on the knob registers with an index, and then releasing the knob so that the lug engages the hole corresponding to this exposure time. The holes 4 are of a larger diameter than the hole 4a and 4b and the lug has portions 6b, 6c of different diameters so that, if a hole 4a or 4b is engaged by the lug, the projection 6a lies above the disc 3 and will contact the abutment 15 whereas with a hole 4 engaged, the projection and the disc are in contact and the other abutment 14 will be engaged. Radially extending from the disc 3 are cams 5 for engagement with tappets 26 pivotally held by a spring 22 in radial slots in the carrier 6. Depending upon the selected exposure time, one of these cams will engage a corresponding tappet to move it outwardly so that, during the release movement of the leading blind and a predetermined time after release of the lagging blind, the tappet will pivot a lever 31 (Fig. 3), and through lever 28 close the contacts 25, 26 of the flashlight ignition switch. Closure of the contacts during the setting operation is prevented by the provision of an abutment 29 which stops movements of the lever 28 in the opposite direction. To allow for the use of different types of flashlight. the two exposure times defined by the holes 4b are the same as two of those defined by the holes 4. The hole 4a corresponds to an exposure time of 1/1000 second to avoid overcrowding of elements associated with the short exposure times.