Improvements in or relating to Aerial Photography.

摘要

128,609. Brock, A. Jan. 3, 1917. Cameras for roll-films with connected action, between shutter and changing- mechanism; aeronautical apparatus.- A camera for taking a series of photographs from aircraft has an intermittently-operating motor for operating the film-feeding mechanism and the shutter, and timing-mechanism for starting the motor at regular intervals. The timing-mechanism is regulated by means operable from the pilot's seat. The motor for operating the film feed and shutter comprises four spring drums J1 - - J4 Fig. 6, the drum J' carrying a spur-wheel j14 for driving the film mechanism and a second spur-wheel j15 engaging the spur-wheel j1, Fig, 2, of the timing-mechanism, by which the tension of the spring j19 is maintained. The film-winding mechanism comprises spur-wheels M, F1, Fig. 5, which drive the winding-roll F through a friction clutch F2, F3,Fig. 6. Engaging with the pinion F1 is a spur-wheel L' engaging gearing M2, E1 which drives a measuring-drum E for measuring the required amount of film for each exposure, and also drives the roller blind mechanism. The spurwheel L1 carries on its axle ratchetwheels L which are released in turn by pawls K2, the timing of which is controlled by the timing-gear. The timing-gear comprises a spring drum j19 wound by means of a handle j31 driving an escapement-wheel j1 engaged by an anchor escapement j9 attached to an adjustable pendulum j11, j12. The axle of the spring drum j18 carries cams j20 which engage the levers K by which the pawls K2 are moved. In the form shown in Figs. 2 and 5, the adjustable pendulum comprises a lever j11 carrying a pin j13 engaging a slot in the heavy disk j12 mounted on the pivoted arm j16. The timing is regulated by altering the distance of the disk j12 from the lever j11 by means of a cam j24 operated by a worm and worm-wheel. The worm may be rotated through a flexible shaft by means of a handle on the aeroplane. In the form shown in Fig. 10, the adjustable pendulum comprises a lever j110 a slot in which engages a pin carried by the lever j120 carrying weights j123, the position of which is varied by means of a right and left handed screw j124. The shutter arrangement comprises a roller-blind shutter G moving in the focal plane, and a safety shutter R opened immediately before and closed immediately after an exposure is made. The roller-blind shutter is wound up by means of gearing M2, E', M3 - - M‹ from the spur-wheel L, and is held against return by means of a ratchet-wheel and pawl I4. When sufficient film is wound and the shutter set, the cam j21 on the timing-gear engages the lever N, which trips the pawl I4 and releases the shutter. Immediately before the release of the shutter G, the safety shutter R is opened by means of a cam L3 engaging a lever R bearing against the short lever R2. For use on aircraft, the apparatus is suspended in gimbals provided with dash-ports, as described in Specification 128,593. In order to prevent the winding of the film from the supply to the take-up spool from disturbing the centre of gravity of the apparatus, the counterweight S7, Fig. 9, is mounted on a lever S5 connected through link-work to a roller S2 kept in contact with the film on the roll C by a spring S'.