Patent GB-544584-A (GB)
Title: Sound on film
IPC: G11B15/00
Filed: 1940-10-10
Abstract: 544,584. Recording sound on film ; selective control controlling and actuating by sounds. KIEL, [nee RIPLEY, M.]. M. R: Oct. 10, 1940, No. 15121. [Classes 40 (i), 40 (ii) and 118. (ii)] An apparatus for recording and reproducing sound by means of styli running on a film or band is so arranged that the film from a feed reel 28, Fig. 2, to a take up reel 29 passes helically round a mandrel 21 so as to form substantially a complete cylindrical surface in the middle part of the mandrel where the recording and reproducing devices 26, 27 are situated. To avoid clicks in reproduction, the reproduction is cut off while the reproducing stylus crosses the line between the adjacent turns of the helix. Film feed.-The mandrel 21 is in one with cone flanges 19, 20 and fast with a transverse spindle 40 journalled at both ends in a frame 41. The reels 28, 29 are freely rotatable on the spindle 40. The film, on its way from one reel to the mandrel 21 and thence to the other reel passes through slots in the flanges 19, 20 and over several rollers 30, 37 all carried by the mandrel. In addition, the helical turns of the film on the mandrel are kept close against each other by means of fingers 147, 148 ; and the film is pressed against the rollers 33, 35 by spring urged rollers and on the mandrel 21 by a spring cushioned pad. The mandrel is driven by belts 17, 18. Fig. 1, and suitable gearing from a motor 12. So long as the reels are free, they rotate with the mandrel and there is no feed of the film from one reel to the other. To cause forward feed of film from feed reel 28 to take-up reel 29, a brake is applied to the take-up reel 29 to prevent its rotation relatively to the frame 41. This causes a pull on the film, drawing the film through and winding it up on the take-up reel. For backward feed, the takeup reel 29 is unbraked and a brake is applied instead to the feed-reel 28. The feed forward and backward may be helped by transmitting a drive to the rollers 33, 35 respectively through suitable gearing, when desired. The gearing for driving the roller 33 may give two slightly different speeds for recording and reproducing respectively to counter-balance the slight stretching of the film which takes place during recording. The position of the film in the apparatus can be seen by, means of numbers marked on the film and periodically illuminated by a fixed lamp 144, Fig. 3, through a slot 145 in the flange 20 and a fixed mirror 146. To facilitate the movement of the film, it may be. given a thin coating of wax by means of a solution thereof, and the side of the film bearing against the mandrel may in addition be dusted with a fine powder. Recording and reproducing heads.-The recorder 26 is pivoted at 113, Fig. 8, on the tangent at the recording point, and is urged against the film on the mandrel 21 by a spring 114. The recorder can be raised away from the film by means of a pin 116 co-operating with a face cam 115 on a shaft 22a. The reproducer 27 has a universal pivot mounting 127, 128 and is normally urged towards the film on the mandrel by gravity. The reproducer can be lifted by means of an arm 129 urged by a spring 134 against a pin 131 co-operating with a face cam 132 on the shaft 22a. Control device.-The operation of the apparatus is controlled by a handle 22, Fig. 1, which can be set to any of the positions indicated according to the operation desired, the operations 'being determined by cams and switches on the shaft of the handle. As shown in Fig. 8, this shaft 22a carries the cams 115, 132 for putting the recorder and reproducer in and out of action as desired, a cam 125 for operating the pad 119 which presses the film against the mandrel 21, and a multiple switch 140 for controlling the several circuits as required. As shown in Figs. 2 and 3, this shaft 22a also carries a cam 68 for controlling linkworks 65, 69; 70 on one side and 65a, 69a, 70a on the other side for controlling spring plungers in the ends of the spindle 40 for determining the drive or the de-clutching of the driving mechanism of the rollers 33, 35. In addition, the shaft 22a carries a cam 142 co-operating with a spring detent 144 for locating the several positions of the handle 22 and yieldingly holding the same in these positions. Push-button, control.-The control shaft 22a, Fig. 18, may be set to its several positions by a motor 237, under control of push-buttons 210b, Fig. 21. The motor drives the shaft through worm gearing 240, 241 ; and the shaft drives a rack 201 by means of pinion 200. The rack 201, Figs. 18 and 19, has a slot 205 finishing in a ramp 205a leading to the full face 206. A number of spring-urged fingers 207 are mounted on the fixed wall 202 and are connected to a corresponding set of centre contacts 210, Fig. 21, which are therefore brought against an external contact 209 or 211 on one side or the other except the centre contact corresponding to a pin 207 brought to the middle of the ramp 205a. When it is desired to turn the shaft 22a to a certain position, the corresponding push-button 210b is depressed. This causes any other depressed push-button to be released in a manner well known in push-button devices. If the.shaft 22a is already in the desired position, the corresponding centre contact 210 is free and the motor 237 remains out of action. If the shaft 22a is not in the desired position, the corresponding centre contact is against one of the external contacts, so that the depression of the corresponding push-button energizes relay 244 or 245 and the motor 237 is driven in the desired direction until the pin 207 corresponding to the depressed push-button reaches the middle of the ramp 205a when the corresponding centre contact 210 is moved to its free central position and the motor is stopped. Overdriving of shaft 22a is prevented in any known way, for example, by releasing a clutch 239, Fig. 18, at the same time that the motor 237 is switched off. Automatic control.-The apparatus may be made to start and stop automatically by sound. For this purpose, a switch 260, Fig. 21, is thrown over to the left to connect the control relays 244, 245 of motor 237 to contacts 266, 268 controlled by a relay 270 in the anode circuit of a valve 271 controlled by a rectifier 276 adapted to receive amplified currents from a microphone . 272 through an amplifier 273. When sound is received by the microphone, the relay 270 is de-energized and its contacts cause the motor 237 to be driven to set the shaft 22a in recording position. Failure of a valve produces the same result. A condenserresistance circuit 280, 281 between the valves 276, 271 prevents re-energization of relay 270 by short interruptions of sound. But cessation of sound for a sufficient time causes relay 270 to become operative, whereby the motor is switched on to drive the shaft 22a to neutral position.