Patent GB-757353-A (GB)
Title: Improvements in photographic shutters with flashgun operating means
Inventor: HUNTER DOUGLAS GORDON
IPC: G03B9/70
Filed: 1953-11-25
Abstract: 757,353. Photographic shutters. BARNET ENSIGN, Ltd. Nov. 25, 1954 [Nov. 25, 1953], No. 32734/53. Class 98 (1). A lens panel shutter assembly for a photographic camera includes at least two flash-gun cable plug sockets mounted on the shutter body, each socket having a contact in electrical connection with the shutter body and an insulated contact connected to a contact arm insulated from the shutter body, and during the shutteractuating movement of the shutter mechanism, which is electricallyconnected to the shutter body, one member of the mechanism makes contact with the insulated contact arm of one of the plug sockets to complete the circuit between the two contacts of the socket before the shutter is actuated and at a later stage of the movement another member of the shutter mechanism causes the insulated contact arm of the other or another plug socket to be electrically connected to the shutter body to complete the circuit between the two contacts of the other sockets. As shown, the shutter body 11 has a cover plate 12 in which are disposed the leaves 13, and carries two flash-bulb plug sockets 1, 2 adapted to receive flash-bulb plugs of the concentric contact type. The shell of each socket, which contacts the outer contact of its plug, is electrically connected to the casing 11, and the central contacts of the sockets 1, 2 are insulated from the shell and connected to contact arms 3, 4 terminating respectively in a.bent-up flange 3a co-operating with a spring 5 anchored to the shutter body and having a hooked end 5a and in an insulated arm 4 having a bared end 4a. The shutter setting member 9 is moved clockwise to set the shutter, and on disengagement of the pawl at the end of lever 15 from the notch 16 in the member 9, the member 9 is returned to its original position, in so doing effecting exposure, by the spring 17. The member 9 carries a pivot 7 on which is mounted a rocker 6, and a master member 8 having a lug 8a and a pin 10 is pivoted at 14 on the shutter body. The rocker 6, which is in electrical contact with the casing 11, is spring-biased counterclockwise and its cam-like upper edge is engageable by the lug 8a, the master member 8 being biased clockwise by a stronger spring 20. The lug 6a on the rocker 6 co-operates with the cam slot 18 and the face 19 formed in the shutter body. When the member 9 is rotated clockwise, the rocker 6 is rocked counterclockwise by the lug 8a to bring the lug 6a into the slot 18, where it is guided to bring the upper edge of rocker 6 clear of the lug 8a. When the pawl at the end of the lever 15 engages notch 16 at the end of the clockwise movement of the member 9, the left-hand end of the rocker 6 is just to the right of the end 4a of arm 4 and well clear of lug 8a, and the lug 6a has reached the right-hand end of the slot 18 and allowed the rocker 6 to rock clockwise so that its left-hand end is in position to engage the end 4a of arm 4 on the return counterclockwise movement of member 9 on release of the shutter. This engagement closes the circuit through the socket 2. Further movement of the member 9 causes the left-hand end of rocker 6 to engage the lug 8a to rock counterclockwise the master member 8, counterclockwise rocking of the rocker 6 being prevented by the engagement of the lug 6a with the face 19. The pin 10 thus engages the end 5a of the spring 5 and bends the spring to engage the contact arm 3 and to close the circuit through the socket 1. When the highest point of the cam-like upper edge of rocker 6 has passed the lug 8a, the master member 8 rocks clockwise to its former position, and the to- and-fro rocking of the member 8 thus produced effects the opening and closing of the shutter leaves in known manner. The closing of the circuit through the socket 1 coincides with the maximum opening of the shutter leaves 13. Socket 2 is intended for use with flash-bulbs requiring an appreciable delay (e.g. 15 milliseconds) in shutter opening, while socket 1 is intended for use with flash-bulbs of the electronic type requiring no delay. The sockets 1 and 2 may be used as alternatives or both may be used at the same time, and may be differently marked, suitably coloured, or designed to receive plugs of different size or shape to ensure connection to the appropriate flash-bulbs. The time lag obtainable by use of one or more of the sockets may be adjustable.