Patent GB-696971-A (GB)
Title: Improvements relating to photographic cameras with focal-plane shutters and built-inflashlight contact devices
IPC: G03B9/70
Filed: 1951-03-08
Abstract: 696,971. Photographic cameras combined with flashlamps; shutters; cameras with connected film and shutter winding. DECKEL, H., and DECKEL, F. W. March 8, 1951 [July 19, 1950], No. 5640/51. Class 98 (i). A camera includes a focal plane shutter, an auxiliary shutter of the pivoted blade-type adjacent the objective, means operated by mechanism controlling the auxiliary shutter for closing an electric switch for a flashlamp in synchronism with the opening of said shutter, and interconnected control means for selectively conditioning either shutter for determining the duration of an exposure and for causing the other shutter to be open during the entire time of the exposure as determined by the shutter selected for making the exposure. As shown, the tapes of the leading blind of a roller blind shutter are wound up on pulleys 14, 16 and the trailing blind is wound on a drum 10 coaxial with the pulleys, the two blinds running off to make an exposure on to spring-driven take-up drums 40, 42 respectively. A second shutter having two pivoted blades 54, 56, operated by a pin 62 which is mounted on a bell-crank lever 64 and engages in slots in the blades, is provided to control the lens aperture 48. On rotating the film-winding knob 20, a sprocket 22 driven by the film drives a gear 28 by means of pins 24, 26 on the sprocket and gear respectively, the gear 28 in turn driving a spur wheel 30 which drives both a gear 32 on the shaft of the setting means of the roller blind shutter and a rack 96 on a slide 86 which is thereby moved to the left, the extent of these winding movements being limited by a fixed pin 34 engaging the end of an arcuate slot 36 in the spur wheel 30. By this movement of the slide 86 a catch 84 thereon engages a lug 82 on a second slide 70 and moves it too to the left, tensioning a spring 76, in which position it is latched by a nose 104 on a pivoted pawl 100 engaging behind the lug 82. During the setting movement of the slide the lug 82 moves past the arm 150 of a bell-crank lever 144 which forms the moving contact of a flashlamp synchronizing switch, springs 152, 154 serving normally to hold the lever 144 in the position shown in Fig. 1, clear of the stationary contact 138. If a flashlight exposure is to be made a lever 114 having a slot engaged on a fixed pin 112 is moved to the position shown in Fig. 2, this being possible only provided the roller blind exposure selecting knob 44 has been set to " T " or " B," when it presents a recess 136 to a projection 134 on a rod 133 rotatable on the pin 112 and secured to an arm 132 having a fork 130 engaging a lug 128 on the lever 114. On depressing the shutter button 38, the leading blind runs off on to the drum 42 fully opening the exposure aperture 50 and the rotation of the pulleys 14, 16 moves via gears 32, 30, 98 and rack 96 the slide 86 to the right so that at the end of its travel its projection 108 trips the latching pawl 100 and the slide 70 moves to the right, whereupon its lug 82 rocks the bell-crank lever 144 anticlockwise to close the flashlight synchronizer switch and also a cam 80 on the slide engages the pin 62 to open and close the blades 54, 56. Upon releasing the button 38 (for B exposures) or operating it a second time (for T exposures), the trailing blind is wound off on to its drum 40 to close the exposure aperture. If photographs without flashlight are to be taken, the blades 54, 56 are permanently held open and the slide 70 is rendered inoperative. For this purpose the lever is moved to the left and caused to engage in a recess 156, Fig. 4, when a lug 126 on the lever 114 presses the slide 70 towards the camera front so that the cam 80 engages the pin 62 to hold the blades open and the connection between the slides 70, 86 is broken, whereby the setting of the shutter tensions only the roller blind shutter. If the shutter has already been set, the movement of the lever 114 releases the connection between the slide 70 and the pawl 100 so that the slide moves to the position as above.