Patent GB-599863-A (GB)
Title: Improved apparatus for controlling the operation of camera shutters in relation to that of flash bulbs
IPC: G03B15/04
Filed: 1945-09-07
Abstract: 599,863. Photographic cameras combined with flashlights. FOX, C. R., FOX, R. W. H., and YEOMANSON, E. W. Sept. 7, 1945, No. 23156. [Class 98 (i)] Apparatus in which the interval between the firing of the flash bulb and opening of the shutter is adjustable, comprises a guided member, movable e.g. rectilinearly or angularly by a spring whose driving force is adjustable, and bearing a cam for actuating the shutter mechanism and also bearing means cooperating with adjustable contact means for closing the flash bulb circuit ; and a trigger for holding the movable member in a cocked position. As shown in Fig. 2, the movable member is a slide 4 guided horizontally by means of an inverted U-shaped guideway 5, a roller 6 and a guide sleeve 8. The slide is retained by a projection 14 on it engaging a trigger 12 in a position in which the spring 11, held between a surface in the interior of the sleeve 8 and a corresponding surface on the slide 4 is compressed, the amount of compression and hence speed of the slide on release, being variable by a screw-threaded adjustment for the guide sleeve 8. On pressing the trigger release 15, the trigger pivots about a vertical axis allowing the slide to move to the right. In so doing, the cam 16 engages a roller carried by a lever 17 which is pivoted at 18 and whose free end operates either a pushrod 20, or a Bowden cable carrying a plate which is held in position by nuts 33, to depress the shutter release button. As the slide continues its movement, its right-hand end 25 completes the flash bulb circuit by engaging a spring-mounted contact pin 26 adjustable by a micrometer head 27, the movement of the slide being finally arrested by a buffer 30. The lateral thrust of the slide may be compensated for bv means of a similar member connected to it and moving in the opposite direction. In Fig. 7, the movable member is a rotatable cylinder. The cylinder 44 carried by a shaft 45 is rotated by turning a milled head 49 to tension a spiral spring 52 which is attached between a sleeve 47, adjustable by a milled head 50 to one of three positions in which it is retained by a set-screw 53, and a sleeve 51 attached to the shaft 45, the sleeve 51 being held by a trigger 57 when the tensioning is complete. On releasing the trigger by depressing the button 59, a roller 65 carried by a lever 67 which operates the shutter release button, rides along a cam 64 on the end of the cylinder 44, thus tripping the shutter and a contact arm on the sleeve 51 engages a contact adjustable by a screw 62. The cylinder is then arrested by a projection 69 engaging a buffer 70. In both embodiments, the end of the lever which presses the shutter release button may carry an adjustable screw as at 68 (Fig. 7). Fig. 11 shows the electrical circuit for use with the embodiment of Fig. 2. The frame 1 of the apparatus is connected to the contact 25 carried by the slide 4, to one contact 1<1> of the stem of the flash bulb holder 3 and to a contact 78, while contacts 38, 77 are connected to contact 71. One side of the battery 41 is connected to contact 72 and the other to the adjustable contact member 26. To fire the flash-lamp carried by 3, a plug 79 is used to close contacts 71, 72, whilst to fire a distant flash-lamp which may have a series booster battery, a plug 73 connected to this lamp is used to engage contacts 71, 72 and the plug 79 is inserted to close contacts 77, 78, the flashlamp unit 3 being removed. A lamp 42 for lighting the object when focusing and a switch 43 therefor are arranged across the battery in parallel with the flash lamp circuits. Caps fitting on to tubular shields surrounding the contacts 71, 72 and 77, 78 may be provided to enclose them when not in use.