Patent GB-121526-A (GB)
Title: Improvements in Roll Film Cameras.
Inventor: WORKMAN HAROLD
IPC: G03B19/04
Filed: 1917-12-20
Abstract: 121,526. Workman, H. Dec. 20, 1917. Cameras with connected action between shutter and changing-mechanism; aeronautical photography and apparatus.-In roll film cameras having mechanism for automatically winding the film and setting and releasing the shutter, mechanism is provided for pressing the film against a transparent plate in the focal plane during exposure; the camera may be used on aircraft, and the mechanism may be driven continuously by any convenient source of power to take a series of photographs at regular intervals, or may be stopped automatically after each exposure and released manually for the next exposure. The mechanism may be contained in a box d, Fig. 2, secured to a casing e forming a roll-film attachment which is detachable from or hinged to the camera, and has removable ends so that it mav be loaded in daylight. As shown in Figs. 3 and 4, a spindle or barrel a is mounted in the sides d<1>, d<2> of the box d and bears wheels and cams by which the mechanisms are operated, the spindle being driven by a worm-wheel b from a shaft c. The film is drawn across the exposure aperture by mangle-rollers e<1>, e<2>, Figs. 1 and 2, and is fed to a take-up spool l<1>. The mangle-roller e' is driven intermittingly by a wheel h on the spindle a which has teeth round about three quarters of its circumference and gears with a wheel i, a locking rim h<1> extended round the untoothed part of the wheel h and one or more locking sectors k of the Maltese cross type on the side of the wheel i ensuring that the roller e<1> is stationary during exposure. Proper meshing between the wheels h, i may be ensured by the provision of pins at each end of the untoothed part of the wheel h which engage the radial parts of the locking sector k. The motion of the wheel i is communicated to the roller e<1> through a wheel j which engages a wheel j<1> on the shaft of the roller. The take-up spool e' is driven through a friction drive from a wheel o on the spindle a, the drive being through a friction clutch to a wheel p having a crank s on its spindle which engages a radially slotted arm s<2> on the spindle of the spool. The shutter may be of the focal plane type, and may be adjusted in the usual manner for varying the exposure. It is set through the medium of a partially toothed wheel t on the spindle a which drives a wheel t' through a friction drive. A star wheel w on the side of the wheel t<1> is engaged by a finger w<1> when the wheels are about to mesh to ensure proper meshing. The shutter is released while the wheels t, t<1> are out of mesh by the operation of a cam x upon the end of a lever y which moves a lever y<1> connected to the shutter release. Alternatively, the shutter may be of the between-lens type and be set and released through Bowden wires from levers operated by a cam or cams on the spindle a The film is pressed against a transparent plate m. during exposure by a plate 1 which is raised against spring pressure during the film-shift by means of levers 2 and links 3, the spindle 9 and a spindle 6 being connected by means of an arm 7 bearing a pin, and a slotted arm 8 on the spindle 9, and the spindle 6 being turned through a lever 5 by a cam 4. A punch 22 for perforating the film between exposed parts may be provided, and may be operated through a bell-crank 23 fastened at one end to a spring z and linked at the other end to a lever 2. Means for indicating the number of exposures made may be driven by a pin 11 cr by a lever and cam, and a counter dial may be mounted in front of the pilot's seat when the camera is used on an aeroplane and be operated by a Bowden wire from the camera. Means for stopping the mechanism after each exposure may comprise a pin on the wheel b in the path of which a stop may normally project, the stcp being capable of being withdrawn when desired by a hand-grip release operating through a Bowden wire. A slipping friction-drive may be arranged between the motor and the wheel b. According to the Provisional Specification, means may be provided for automatically stepping the mechanism when a roll of film has been completely exposed, such as a trip-lever throwing out a spring clutch in the motor drive, or means for breaking the circuit of the current to the motor; the film may be shifted by mechanism which starts its movement slowly and gradually increases its velocity until it attains a maximum and then gradually decreases; and the shutter may be set by a pawl and ratchet mechanism.