Patent GB-218384-A (GB)
Title: An instrument for testing cinematograph films or like strips
IPC: G03B21/32
Filed: 1923-04-04
Abstract: 218,384. Imray, O. Y., (Film Inspection Machine Co., Inc.). April 4, 1923. Kinematograph picture films. - The machine tests the film for abnarmally located apertures, strip material, and slits, so that when such defects are encountered the feed of the strip is automatically arrested. A strip supply reel 5, Fig. 1, rotates wiht the shaft 4 fitted with a brake actuaed by the rod 7 articulated with a weighted lever 8 rocking about a pivot 9. The take-up reel 23 rotates with a shaft 22 driven from a motor 24 through gearing involving a slip clutch. The strip passes between spring-pressed feed rollers 50, 51 rotated by gearing from a shaft 27 driven from the motor 24. The roll 50 is recessed for a large part of its length in order to avoid contact with the picture. Tension and guiding rollers 75, 76 very similar to the feed rollers are provided and may be rotated either by the strip or by means of a belt from the feed rollera. Fig. 4 shows the detector pin 92. Two spring-pressed pins are arranged radially in a roller 91 over which the film passes and project into the line of feed of the sprocket holes 85 in the edges of the film strip. Normally the tension of the film is suffieient to keep the pins 92 down against the tension of the springs 93, but should an abnormal opening occur, such as would be caused by a slit 86, 87 and 88, Fig. 11, the pin projects through the film and is carried with it. To detect faults such as bad joints the film is passed over a roller 97 loose on a shaft 98, Fig. 6, and provided with spaced feeling teeth 99 which mesh with the holes in the edges of the strip. Firmed to the shaft 98 at each end of the roller is a block 104 through which passes loosely a rod 100, a lug 101 of which overlies but does not quite contact with the edge of the strip. When a hole is absent due to a bad joint, the film is raised and with it the rod 100. The detectors 92, 99 operate, the following mechanism to stop the motor 24 and apply a brake to the shaft 4. The motor drives a dynamo 119 which supplies current through leads 122, 123 to an electromagnet 121. This circuit is normally made through a contact 127 and a contact 135, Fig. 3, carried by insulated arms 131 rocking about a. pivot 138. The armature 140 of the magnet 121 is carried by a rod surrounded by a spring 145 and connected by links to an arm 141 on the shaft 110 of the detector pin mechanism 92. Another arm 150 on the shaft projects between lugs 152, 153 on a rod 151 which carries a fork 154, 155 by which the motor switch 118 and the brake lever 8 are moved. The handle 111 is provided for resetting the pins 92. Normally the rods 100, 138 underlie, the arms 131 and the contacts 127, 135 engage each other. When either contact device 92 or 99 becomes operative tlwough meeting a defect, the rod 138 or 100 is raised and consequently the lever 131 is raised to break the contacts 127, 135. This de-energizes the magnet. In a modification, the dynamo, magnet, and rods 100, 138 are omitted. In this form the rod 151 is actuated by a lever which is tripped when pivoted fingers riding above and just clear of the film strip are raised by means of the projections 92 or 99. In another form, the armature of the magnet is mounted on an arm mounted on the shaft 110 and the generator 119 is omitted, the electromagnet being thrown. into and out of circuit with the mains supplying the motor and the. lever 118 operating to de-energize the magnet and to break the motor switch.