Patent GB-930083-A (GB)
Title: Improvements in pivoted blade photographic shutters
IPC: G03B9/70
Filed: 1959-12-01
Abstract: 930,083. Shutter delay mechanism. AGFA A.G. Dec. 1, 1959 [Dec. 20, 1958], No. 40849/59. Class 98 (1). A pivoted blade shutter including delayedaction mechanism and flashlight ignition retarding mechanism has a fully rotating master member for operating the blade ring which engages members of the delay and retard mechanism, the contacting surfaces of the master member and said elements of the delay and retard mechanism being so shaped as to engage and disengage smoothly. As shown in Fig. 1, the master member 1 is pivoted at 8 for rotation on shutter release in the direction 81 to reciprocate the blade ring 14. Initially, a stop lever 2 pivoted at 9 and having three bent-up lugs 4, 18 and 19 engages by means of lug 4 a projection 5 on the master member. As the shutter is tensioned, by means not shown, the lever 2 is pivoted clockwise against spring loading into the position shown thereby bringing lug 4 out of engagement with projection 5 thus allowing a slight rotation of the master member 1 before a projection 6 on the lever 2 engages surface 57a of a stepped recess 57 on the member 1 and holds it in tension, lever 2 being itself constrained by the engagement of lug 19 with one arm 21 of a threearmed release lever 22 pivoted at 23. Movement of lever 22 in the direction 80 disengages arm 21 and lug 19 on lever 2 and the latter will now tend to pivot anti-clockwise under its return spring loading 3 and bring lug 18 to bear against the push-rod 20 which can be moved within the limits of slots 65 thus causing a pin 49 at its other end to bear on a lug 48 thereby pivoting the " M.X.V " setting lever 37 about pin 36 from a " V "-setting 78 (as shown) into the " X " position 77. At the same time, the third arm of lever 22 terminating in a lug 24 pivots lever 26 about a pin 27 until the recess 32 engages a pin 34 and an escapement 30 engages the escapement wheel 35 of a delayed-action mechanism having gearing 47, 46, 45, 43, 44 in mesh with a rack 38 integral with the lever 37 whose movement under the influence of the push-rod 20 is yieldingly resisted thus allowing the lever 2 to pivot only very slowly. The projection 6 on lever 2 finally disengages the recess 57a on the master member and the shutter is operated, the cam 11 at the instant of disengagement being so oriented that no motion is being transmitted to the blade ring. The rotation of the master member is arrested by projection 5 engaging lug 4 of the lever 2. If the lever 37 had originally been set to " X " (position 77), there would be no engagement of push-rod 20 with the lever 37 and the shutter would be operated immediately. As the lever 37 is pivoted within the " X "-" V " range (77-78) a cylindrical cam surface 50 formed on a lug 52 of lever 37 is engaged by a member 72 rigidly attached to both flash contacts 66, 67 the position of which does not, therefore, change and which will be closed by means of a projection 17 on the blade ring during shutter release. When lever 37 is moved to the " M " position (76), the portion 51 of the cam comes into contact with member 72, and the flash contacts, which in the " X "-setting had been resiliently held inwards, now move into the dotted position 66<SP>1</SP>, 67<SP>1</SP> out of the path of the projection 17 and into the path of a pin 63 on a gearwheel 62 which together with gear-wheel 59 and the member 54 forms the retarding mechanism for the shutter release (about 15 milliseconds). The member 54 is pivoted at 53 and has a projection 56 engaging under-spring-loading a recess 576 (axially stepped with respect to 57a) on the master member 1, and a rack 55 engaging a pinion 58 on the gear-wheel 59. Rotation of master member 1 sets in motion the rack and gear-wheels which cause pin 63 to close the flash contacts before projection 56 clears the recess and the master member rotates further to operate the shutter. The surfaces 57a, 57b on the master member 1 are shaped to give smooth disengagement with projection 56 of member 54 and projection 6 of lever 2. In " X "- setting, where the retarding mechanism is inoperative as far as the closing of the flash contacts is concerned, it may be uncoupled from the master member by pivoting member 54 out of the recess 57b, as described in a further embodiment, by means of an arcuate cam member 1 attached to the " M.X.V " setting lever 37 by a pin and slot connection. In yet a further embodiment, in order to prevent spurious closing of the flash contacts by pin 63 when the shutter is retensioned with the lever 37 in the " M " position, the setting ring is provided with a cam surface co-operating with the member 72 in such a manner that during tensioning of the shutter the flash contacts are moved out of the path of pin 63.