Patent GB-555885-A (GB)
Title: Improvements in photographic cameras
IPC: G03B19/04
Filed: 1942-06-19
Abstract: 555,885. Roll-film cameras; Rontgen-ray apparatus. WATSON, W. June 19, 1942, No. 8434. [Class 98 (i)] [Also in Group XXXVII] The film take-up spool of a camera suitable for mass-radiography is driven by a motor 19 which also rotates a disc 14, into locking relationship with which a pivoted member 11 is urged by a spring 16 or by gravity. When moved by electrical means (shown as a solenoid 21) the member 11 unlocks the disc 14, starts the motor (for example by closing a switch 22) and operates a trip device 25, 28 which breaks the circuit of the solenoid 21 or other means for moving the member 11, so that when the disc 14 moves again into locking relation with it, at the end of the winding operation, the member returns to the position shown and stops the motor. In the construction shown a projection 13 on the member 11 enters one of three notches 15 in the disc in the locking position, and rides on the periphery of the disc during the winding operation. A film sprocket is mounted on the same shaft 17 as the disc. When the member 11 is rocked by the solenoid it depresses the member 25 which opens contacts 23 in the solenoid circuit and closes contacts 24 which are connected to the relay circuit energizing the X-ray tube, and also if desired to the circuit of a device for illuminating an identification card. The member 25 is held in this position by a pivoted catch 28 until the exposure has been made, this resulting in the energization of a solenoid 27 which rocks the catch 28 and allows the member 25 to return to the position shown. This ensures that exposures and film movements must occur alternately. The movements of the member 11 operate a rock-shaft 36 carrying an arm (not shown) which moves a spring-urged pressuregate when the film is being wound. A roller (not shown) bearing on the film moves when the film is exhausted and opens a switch to prevent further operation of the film-winding means. The camera is provided with removable film-boxes, Fig. 4, having a slidably mounted side 46 which is moved against the closing action of springs 68, to form a slot for the passage of the film, by the engagement of projections on the back of the camera with push-rods 70 when the back is put on. Fig. 7 shows a modification in which the switch controlling the motor circuit is formed by contacts 78, 76 respectively, carried directly on the pivoted member 11 and on a sleeve 74 which is slidable on it and carries a projection 80. When the projection engages a slot in the disc 14 slight further rotation of the disc moves the sleeve to a stop pin 82, opening the contacts and stopping the motor. In order that the film may be cut and removed after a predetermined series of exposures, the apparatus causes a double-winding of the film at the end of the series. For this purpose a star wheel 83 is moved at each winding operation through one tooth by pins 86 on the disc 14, and carries a projection 87 which in one position of the wheel engages a projection 88 on the member 11, which is thus prevented from returning to locking position until a double winding has occurred. Trip mechanism as described in connection with Fig. 1 is employed, but not shown.