Patent GB-800843-A (GB)
Title: Magnetic recording and reproducing machine
IPC: G11B5/004
Filed: 1955-11-18
Abstract: 800,843. Magnetic record apparatus. DUKANE CORPORATION. Nov. 18, 1955 [Feb. 24, 1955], No. 33051/55. Class 40 (2). A magnetic record apparatus comprises a flexible pre-grooved belt record 299 mounted on spaced horizontal mandrels 24, 25 supported at one end only, clutches for selectively driving said mandrels, and disposed parallel to said mandrels a guide rod 181 on which a transducer 272, mounted on a slidable carriage, engages a part of the record belt passing over the top of one of the mandrels. The mandrels 24, 25 are provided with axles 31 revolving in bearings 34 rigidly mounted in a partition 33. Freely rotatable pulleys 39, 39<SP>1</SP>, Figs. 7 and 8, mounted on the axles of mandrels 24, 25, respectively, are rotated by a continuously moving belt 90 driven by a motor 12 via a belt 92 and pulleys 87, 86. Tension of the belt is maintained by a spring-loaded pulley 83. A drive is established between one or other of the axles 31 and either the small pulley 39 or the larger pulley 39<SP>1</SP>, according to whether a fast reverse or a normal forward drive is required, respectively, by means of coil spring clutches 64, which are rendered effective by bell cranks 65 acting as expanding members under the influence of buttons 67 pressed inwardly by one or other of actuators 79 cortrolled by solenoids 76, 76<SP>1</SP>, Fig. 7a. A jockey roller 100, Fig. 5, is provided to tension the record belt 299 and is tiltable by an eccentric screw at one end to maintain the belt in its lateral position against shoulders 29, 30, Fig. 7, on the mandrels 24, 25. The roller 100 is mounted on a rocking plate 105, Fig. 5, pivotally mounted on a rod 112 and biased towards the record belt 299 by a torsion spring 114 arranged about the said rod 112. The roller 100 may be pushed down out of engagement by pressing a finger plate 118, Fig. 12, downwardly, in which position it becomes locked by means of a spring- loaded pulley 124 which latches with a surface 137, Fig. 6, of an aperture 135 in the partition 33. The pulley 124 is unlatched when a pivoted plate 150 extending across the width of the record belt and coupled to a bell crank 142, is pressed downwardly by the pivoted plate 150 to the position shown in Fig. 19. The upward movement of the plate 150 is limited by means of a curved edge 153 which engages a tongue 219 projecting from a part 218 of a plate 214 forming part of the transducer carriage and resting on the plate 150 during a transducing operation. In the event of the roller 100 being in the inoperative position while the machine is switched on ready for use, or the roller is in the operative position and no record belt is in the machine, an alarm is sounded by means of a micro-switch 172, Fig. 5, closed by plate 105 when said plate is in other than its normal position, i.e. when roller 100 is engaging a record belt. Means are also provided to operate the micro-switch when the transducer reaches the edge of the record belt. The transducer carriage comprises inner and outer tubes 184, 200, respectively, Fig. 20, independently rotatable with regard to each, other and to the transverse rod 181 on which the inner tube is free to slide, the outer tube carrying the plate 214, and the inner tube having clamped to it, through a window 201 in the outer tube, a bracket 202 carrying the transducer 272. The transducer 272 is provided with a guide tongue 297, Fig. 2 (not shown), which engages a helical. groove in the record belt. The plate 214 is provided with an extension carrying a device 222 whereby indication markings may be made on a card or sheet on a plate 226 extending over the record belt. The device 222 is provided with finger plates 237, 238 pressure on which causes a stylus to be moved forwardly over the plate 226 to produce a line the length of which is dependent on the particular finger plate pressed and would indicate such information as, for instance, the end of a letter and a correction. An erazing head is provided in form of a permanent magnet in the form of a bar 302, Fig. 2a, extending the full width of the record belt and having a U-sectioned pole piece embracing its full length to produce a rapid alternation of magnetization of the record belt as the belt passes the pole surfaces. The erazing head is carried by a bar 306, Fig. 1, having end forming pivot plates enabling the head to swing upwardly towards the record belt to an erazing position such that the leading edge of the pole surface is nearer to the record than the trailing edge so that the initial polarization is stronger than the reverse direction of polarization immediately following. Details are given, with reference to a circuit diagram, Fig. 21 (not shown), showing the manner in which by means of relays, the various operations of Record, Playback and Reverse are effected by means of hand controls 328, 329, Fig. 1, on a handset 20 which also comprises a combined microphone and loud-speaker. Interlock means between the controls 328, 329 on the handset 20 to prevent simultaneous Record and Reverse operation. Specifications 800,841, [Group XXXV], and 800,842, [Group XVI], are referred to.