Patent GB-433657-A (GB)
Title: Improvements in and relating to power driven photographic cameras
IPC: G03B17/42
Filed: 1934-05-22
Abstract: 433,657. Photographic cameras. GROVES, W. W., 30, Southampton Buildings, Chancery Lane, London.-(Folmer Graflex Corporation; 154, Clarissa Street, Rochester, New York, U.S.A.) May 22, 1934, No. 15305. [Class 98 (i)] A motor-driven roll-film camera, which may for example be used for recording in rapid succession the readings of meters in telephone exchanges, is provided with means, preferably electrically-operated, for intermittently feeding the film, and with signalling means operated by structural variations in the film to control an electric circuit for signalling that a sensitive part of the film strip is in position for exposure, or is about to be moved into such position, or that the whole of the film has been exposed. A second signalling device operated by the motor drive may be provided for indicating that an exposure is being made. As shown, the camera comprises a body 1, Fig. 11, housing a removable film magazine 21 secured by a screw 22, the body being detachably bolted to a chamber 2 which is provided at its base with a panel 18 supporting a lens 16 mounted in a shutter-casing 17, at its inclined wall with an inverting mirror 11, and at its front with an extension 7 provided with lamps 10 for illuminating the object. The chamber 2 has a carrying handle on each side, and is secured in known manner to the body 1 by sliding bolts. The lens panel 18 carries a solenoid whose core is pivoted to the shutter trigger, and two signal lamps 52 visible through windows one clear and one red, in the inclined wall of the chamber 2. The magazine 21 comprises (1) chambers 25, 26, Fig. 9, in which the film supply-spool 27 and the take-up spool 29 respectively are trunnioned, the chamber 26 enclosing also a spiked film measuring-roll 37, a film guide roll 40, and a gate member 42 which is pivoted at 43 to facilitate threading of the film and carries film guide rolls 39, 41 and a plate 44 which engages the back of the film in the focal plane 24 when the gate member is closed and secured by a spring latch ; and (2) a chamber housing the motor 56 which drives through worm gearing a shaft 59 for operating the camera mechanism. The wiring of the various parts is completed through contact members which engage one another when the body 1, chamber 2, and magazine 21 are assembled. The lamps 10 remain continuously in circuit when a plug socket on the body 1 is connected to the mains. The white signal lamp 52 is included in a circuit containing a pair of spring contacts 97, Fig. 9, bearing on the margins of the film guide roll 3 which is of conducting material. As the film F is driven along, it insulates the roll 39 from the contacts 97 and the lamp 52 remains unlit until a pair of marginal slots formed in the tail end of the film leader strip reach the roll 39. The lamp circuit is then completed through the roll 39, indicating that the first picture area of the film is in the focal plane 24. The lamp is extinguished during the subsequent feed movements of the film until similar marginal slots in the tail end of the sensitive portion of the film reach the roller 39, when it lights up again to indicate that the last picture area has been exposed. To facilitate threading of the film, the spindle of the take-up spool 29 is also hand-operable by a knob 99 on the side of the magazine casing. After the first picture area has been brought into the focal plane 24 by hand winding of the knob 99, or by the motor, the first exposure is made by pressing a button to start the motor, whereafter a cam driven from the shaft 59 actuates contacts to complete circuits through the shutter-operating solenoid on the lens panel 18 and through the red signal lamp 52, which remains lit for the duration of the exposure. Thereafter, film is fed forward to bring the next picture space into the focal plane, and the cycle of operations is repeated after each pressure on the starting button.