Patent GB-392182-A (GB)
Title: Improvements in photographic cameras
IPC: F41G3/26
Filed: 1931-10-05
Abstract: 392,182. Photographic cameras for gunnery training. STRINGER, H. B., Royal Aircraft Establishment, South Farnborough, Hampshire. Oct. 5, 1931, No. 27608. [Class 98 (i).] A camera of the single-shot type for photographing a target when an operation representing the firing of a gun is performed comprises in combination, (1) shutter-setting and release levers 16, 17, Fig. 8, rotatable about the same axis 141, the shutter being set by movement of the lever 16 in one direction and subsequent movement of the lever 17 in the opposite direction releasing the shutter and resetting the lever 16, and (2) film-changing mechanism in which a free-wheel clutch on the film-spool spindle is driven by a reversible pinion 56, Fig. 1, this pinion and the setting-lever being operated from a common toothed wheel 27, Fig. 17, which is actuated by means such as a Bowden cable 32 when an operation representing the cocking of the gun is performed. The bracket shown in plan in Fig. 17, which is adjustably mounted on the plane of an aircraft, supports the camera shown in Fig. 1 by the engagement of apertured lugs 6 in the camera with corresponding lugs 9 on the bracket. The setting-lever 16 is actuated by the upstanding member 19 moved by the wheel 27, and the release-lever 17 by the member 41 operated by a Bowden cable 46 when a member representing the firing-trigger is pulled. The camera can be readily removed from the bracket without disturbing the cocking and firing mechanism. The camera shown in Fig. 1 includes (1) a forward lens compartment A with semicylindrical lens-capping members 63, 64, (2) a compartment B carrying the shutter mechanism on a removable plate 18, and a watch-face time recorder, (3) a compartment C for the film spools, and (4) a rear compartment D having a readily removable door 92 to permit of a through-view for alignment purposes. The shutter mechanism shown in Fig. 8 operates a louvre shutter 3 of the kind described in Specification 365,224 which is released when a bracket 131 is moved upwardly by a crank 132 the crank pin 142 of which normally rests in a recess 138<x> in the bracket and occupies a long slot 133 in a lever 134 depending from a fixed pivot 135. To set the shutter, the parts are moved to the position shown by lever 16, bell crank 153, link 137 and lever 134 against the action of an adjustable timing spring 78, the crank pin 142 moving into a short slot in the lever 134 and the parts being retained by a catch 150 engaging a projection 148 on the link 137. To release the shutter, an arm 152 is moved by the lever 17 to raise the catch 150 about its pivot 152<x>, the lever 134 flies forward, and the crank pin 142 being retained by the short slot, the bracket 131 rises to operate the shutter. The releaselever 17 operates through a bifurcated arm 73 engaging radial slots 71 in discs 65 to open the semicylindrical lens-capping members 63, 64 which may be retained open, when viewing the target through the end door 92, by a catch 122 engaging a notch 121 in the arm 73. The shutter-release is controlled by a dashpot 162 having a switch as described in Specification 370,721, [Group XXXVII], to close contacts 160, 161 so that the time which elapses between pulling and releasing the trigger can be ascertained from the watch-faces reproduced on the film. A graticule marked with concentric circles and vertical and horizontal diametral lines is provided for use when aligning the camera with the gun sights. In a modification, Fig. 21, the same shutter and film-feed mechanism is embodied in a practice gun of the Lewis type, the setting-lever 16 and film-changing pinion being operated by the cocking-handle 166 and the release-lever 17 being connected with the trigger 165. In this construction, the gun is straddled by a removable magazine 173 carrying compartments for two spare filmcarriers which can be used to replace the carrier 104.