Patent GB-245942-A (GB)
Title: Improvements in or relating to cameras for aerial photography
IPC: G03B19/02
Filed: 1925-01-20
Abstract: 245,942. Rushen, P. C., (Brock & Weymouth, Inc.). Jan. 20, 1925. Aeronautical photography and apparatus.-A pendulous, gimbal-suspended, aircraft camera, having a plate magazine, has two compartments C<2>, C<3>, Fig. 4, one of which contains a horizontally arranged apertured plate R in the exposure plane and the lens Y with its optical axis vertical, the other compartment being provided with vertical guides C<4>, C<5> for the plate magazine E which is vertically movable and has horizontal plate-supporting ledges together with a fixed and a movable shutter f, F adapted to form, when separated, a slot for passage of a plate near the exposure plane of the camera. Hand operated means for lifting the magazine so as to bring each plate successively into registry with the slot and for drawing it through the slot to the exposure position on the apertured plate R and then returning it to the magazine are also provided. As shown. the camera C, Fig. 1, is pivotally mounted on a gimbal ring B<3> pivoted on uprights B<1> secured to a turntable B rotatably mounted in guides A<4> on the aeroplane &c. so as to be rotatable about the axis of the lens, apertures being provided below the lens Y and a slotted view-plate W. The magazine chamber C<3> of the camera has a pivoted lid D<1> which is locked by means of a cam d<12>, actuated by a handle d<11>, operating, against springs d<19>, Fig. 6, a bar d<14> engaging locks d<20>. The magazine E is formed with ledges E<4> Fig. 12, for the plates, and has a vertical slot E<5> terminating at each end in apertures E<7> having light-tight packing E<8> and adapted to take a cover-plate F, Fig. 4. The magazine E has guide wheels E<2> cooperating with the guides C<4>, C<5> on insertion in the camera. Lateral racks E<3> on the magazine then engage with pinion wheels G<1>. on each side of the camera, secured to ratchet wheels G<2>, rotation of the wheels G<1> being permitted in order to lower the magazine into position by the release of spring-controlled pawls H<1>, J from each wheel G<2> by rotation of the cam M<2> through contact of the rack E<3> with a spring-controlled finger L pivoted on an arm K<2> of a lever K<1>, which is then rotated, causing rotation of the cam M<2> through levers M, M<1>. The pawl J is pivoted on a bar I which is reciprocated, to cause rotation of the wheel G<2> and consequent raising of magazine E, by a two-armed lever N<1>, pivoted at one end thereto and at the other end having a roller N<3> engaging in a closed cam slot in a disc O<4> secured to a shaft O<3> rotated through gear wheels O<1>, O<2>, Fig. 1, from a handle O. The spring-controlled pawl H<1> retains the wheel G<2> during return movemnt of the pawl J. On insertion of the magazine E into the camera, the fixed plate f enters the slot E<7> and pushes out the slide F. On closing and looking the lid D<1> of the chamber C<3>, a projection d<13> on the cam d<12> contacts with a projection d<6> on a plate d<4>, pivoted at d<3> to the lid D<1>, rocking the plate against the action of springs d<7>. Levers d<1> pivoted at the sides of the camera and contacted by the plate d<4> are then rocked, their ends d<2> engaging under projecting portions at the top of the slide F to raise the slide slightly against the action of spring-pressed plungers d<10> on the lid, leaving an aperture between the slide. F and the plate f, approximately in the focal plane of the lens. The plates have carrier frames R<4>, Fig. 3, which surround them while allowing freedom for their vertical adjustment, and are drawn successively through this aperture into the exposure plane, where they are supported by four pins R<2> on an apertured plate R, by engagement of pins Q<5> on levers Q<4> with slots R<6> in the frames. The levers Q<4> are pivoted on a carriage Q reciprocated on guides C<6>, C<7> by means of two levers P<4> pivoted to the camera and actuated from the shaft O<3>. To each of the levers P' a lever P is pivoted, having at one end a roller P<1> engaging in a groove in a cam disc 0<5> on the shaft O<3>, and pivoted at the other end to a lever P<2> pivoted to the camera. Movement of the pins Q' into and out of the slots R' is obtained by means of spring-controlled bars Q<7> pivoted at one end to the end Q<6> of the levers Q<4>, and bearing at their other ends on a cam Q<8> which has four symmetrically disposed recesses. Cam Q<8> is secured to the shaft of a ratchet wheel Q<10> which is given the rotation required to give the necessary movement of the pins Q<5> by its engagement with stop-fingers q<10>, Q" on each side of the exposure chamber C<2>, on reciprocation of the carriage Q. The setting lever S<8> of the shutter is also actuated from the shaft O<3> through an arm S', secured to a shaft S, engaging in the groove of a cam on the shaft O<3>, shaft S, and arm S<2> on shaft S which engages with one arm of a lever S<5>, the other arm S<7> of which actuates the shutter setting lever S'. The shutter is released for exposure by depressing a rod T<5>, Figs. 1, 3, which bears on one arm T<3> of a spring-controlled lever, the other arm T' of which bears on the shutter release pin T. When a plate has been drawn into the exposure position, the shaft O<3> is locked against the return movement by the engagement of a spring-controlled detent U<1>, Fig. 9, with a finger piece U on the gear-wheel O<2>. The detent U<1> and the shutter can be simultaneously released by closing a switch V' to actuate electromagnets V, V<1>, attracting their armature plates V<2>, V<3> which contact with and operate the shutter release rod T<5> and the release pin U<5> of the detent U<1>. The handle 0 can then be turned to operate the shaft O<3> and cause return of the plate to the magazine. In order to hold the plate F, Fig. 4, in position when the magazine E is being withdrawn from the camera, a plate D<5> is moved into contact with the top thereof, against the action of a spring D<7>, by operating a cam D<4> by means of a handle D'.