Patent GB-334637-A (GB)
Title: Improvements in or relating to photographic cameras
IPC: G03B15/00
Filed: 1929-06-17
Abstract: 334,637. Stringer, H. B., and Elliott, A. J. June 17, 1929. Aeronautical apparatus; magazine cameras with connected action between shutter and changing mechanism; lens fittings; roll-film dark slides; shutters, roller-blind, - Camera apparatus, more particularly for use on aircraft, having the film or plate changing and shutter setting mechanism operated from a hand or power drive, has a gear unit connected to the shutter so that they can be applied to or removed from the camera body as a single unit. The camera may comprise as complete and separate units a camera body, a film or plate unit, and a gear and shutter unit. The timing and sequence of all operations except the shutter release are effected by the gear unit. Fig. 2 shows the units assembled in a camera according to the invention. The shutter 2 is inserted into the rectangular metal camera body 1 and secured by the screw 172, the gear unit 3 to which the shutter is attached lying along the front side of the body. The film unit 4 with its casing 5 is placed on the top of the camera body 1 and secured by the lug 179 and spring bolt 181. The lens 165 is mounted in a sleeve 163 carried by a lens cone 6 screwed to the bottom of the camera body. An iris diaphragm 166 is adjusted by an arm 168 having a spring catch which engages notches on a scale on the lens cone. The gear unit comprises a. base plate 12 carrying a fixed spindle 14 on which is mounted a spur wheel 17 driven through a oneway clutch 20 by the handle 19 or through a worm wheel 24 and worm 21 by a motor or air-screw as described in Specification 222,548. A further spindle on the plate 12 carries a sleeve 26 on which are mounted a main spur wheel 18, meshing with the wheel 17 and having three teeth missing so that the drive is interrupted once in each revolution, and a main spur wheel 25 having twenty-four teeth missing at 31. At one end of their gaps the wheels 18 and 25 have each a spring tooth to facilitate re-engagement of the teeth. The wheel 25 drives spur wheels 33, 34, and 35 operating respectively the capping blind of the focal plane shutter, the exposure blind, and the film changing mechanism. The wheels 18 and 25 are formed integrally with one another, and have a smooth cylindrical portion 28 between them. To lock the wheels 18 and 25 after completion of a cycle of operations, a slot 29 on the surface 28 is engaged by a pawl 55 on a release lever 54 pivoted on the spindle 350. A spring- pressed pawl 57 on the lever 54 is adapted to engage the spur wheel 34 when the lever is in the locking position. The sleeve 26 also carries a cam 66 adapted to rock a pivoted arm 69 by which a pressure plate is operated. The shutter unit, which is screwed to, and forms a single unit with, the gear box, comprises capping and exposure blinds actuated by helical driving springs in the spindles to which the blinds are attached. The film unit 4 includes a pressure plate 67 pivoted at 77 to a lever 76. The pressure plate is normally pressed down on the film by the bell crank 93 and spring 92, the tension of which may be adjusted, but is intermittently raised by the engagement of the lever 69 with the end 75 of the lever 76. Means are provided for automatically locking the lever 76 when the film unit is moved from the camera body. The film is led from the supply roller which is braked by a spring washer, under the pressure plate and over a spiked measuring roller to the takeup spool, which is driven from the measuring roller by a friction clutch. The spindle of the measuring roller carries a disc, on which are mounted two pins, and is driven by the engagement of the pins with a diametrical arm on the spindle 43, Fig. 24, of a spur wheel 42, which is driven from the spur wheel 35. A spring-urged roller 49 resting on a cam 48 on the spindle 43 is adapted when the drive is broken, to reverse the motion of the diametrical arm through a small angle so that the arm rests freely between the pins, thus facilitating separation of the units. Indicators for showing when film is being fed and the number of photographs taken are driven through gearing from the supply spool and measuring roller respectively. Instruments such as a watch and counter operated from the lever 69 are mounted in the casing 103, Fig. 2, illuminated, and reflected by the prism 104 on to the film. The operation of the camera is controlled by a slider 58, Fig. 25, having a sloping portion 60 which, when the slider is depressed, engages an arm on the lever 54 and rocks the latter, withdrawing the pawls 55, 57. The slider 58 may be depressed by an electromagnet 63 operated through a remote control box as described in Specification 222,548 or by Bowden wire control. In operation, the pawl 57 is first withdrawn from the wheel 34 releasing the exposure blind to effect an exposure. The pawl 55 is then withdrawn causing the lever 69 acting through the cam 66 to rotate the main spur wheel until it engages and is driven by the spur wheel 17. The wheel 25 engages first the wheel 33 drawing the capping blind in front of the film and then the wheel 34, re-setting the shutter. Meanwhile the cam 66 causes the lever 69 to raise the pressure plate whilst the wheel 25 drives the wheel 35 drawing a fresh section of film across the exposure aperture. When the wheels 18 and 25 have completed one revolution, the wheel 18 disengages the wheel 17 and the pawl 55 re-engages the slot 29. The invention includes cameras using plates or pack films. The Provisional Specification describes means for universally mounting the camera or aircraft.