Patent GB-615116-A (GB)
Title: Improvements in or relating to separable magazine for the record tape of sound recording and/or reproducing machines, and the improved recording and/or record-reproducing machine including the improved separable magazine
IPC: G11B15/18
Filed: 1946-07-25
Abstract: 615,116. Recording and reproducing apparatus for magnetic tape. HELLER, H. S. July 25, 1946, No. 22168. Convention date, Aug. 3, 1945. [Class 40 (ii)] A recording and reproducing apparatus for magnetic tape having multiple sound tracks comprises two parts, the first part consisting of a main housing 1 containing the driving means, the translating and wiping magnet blocks 19, 20, automatic means for reversing the direction of travel at each end of the tape 16, and automatic means for moving the magnet blocks 19, 20 step by step transversely to the length of the tape, and the second part consisting of a separable magazine 3 containing the tape 16, spools 14, 15, and guides 67, 68, movable relative to the magazine and serving to locate the tape 16 accurately in position between magnet blocks 19, 20 by means of fixed abutment members 72 in the main housing 1. The magazine 3 is retained in position on the main housing 1 by three pins 13 thereon having slots or grooves which are engaged by a T-shaped member 81 mounted for sliding movement in the magazine 3. Movement of the member 81 is effected by means of a slot 94 which is engaged by a pin 95 on a disc 84 rotatable under the control of a hand lever 103, Fig. 10, on the main housing 1. The member 81 also serves to press the magnet block 19 toward the magnet block 20 when the hand lever 103 is released to its normal position, as shown in Fig. 1, so that the tape guides 67, 68 are gripped between them. Springs 61 urge the blocks 19, 20 apart when the magazine 3 is removed from the main housing 1. Attached to the member 81 are links 106 and levers 108 by which means tape-gripping members 110, 114 are moved, against the tension of spring 119, to the position shown in Fig. 10, in order that the tape 16 may be freed from driving rolls 17, 18. A reversible motor drives the rolls 17, 18 and the spool driving shafts by means of belts, Figs. 5 and 8 (not shown). Over-run clutches are incorporated on the spool driving shafts so that only one spool is driven, according to the direction of travel of the belts, frictional slip devices of a known type being also included. Automatic reversal is effected by the provision of thickened portions 196, Fig. 3, near the ends of the tape 16 which cause feelers 190, operating a lever 186, Fig. 12, to close a micro-switch 195 in circuit with a solenoid 146 controlling a plunger 149 which, by means of a ratchet 145, rotates a shaft 134 at each operation an amount corresponding to one tooth 156 on a wheel 151. The shaft 134 carries the wiper arms of switch decks 197, 198 which provide suitable switch contacts for reversal of the motor and for bringing into circuit one or other of the outer wiping magnets 78 when recording is taking place, the appropriate wiping magnets 78 being switched into circuit according to the direction of travel of the tape 16, i.e. the tape 16 is wiped by the first wiping magnets before passing between the centre transducing magnets. When the centre transducing magnets are switched to reproduce, the wiping magnets are open circuited as illustrated in the circuit diagram of Fig. 24 (not shown). At the same time that a reversal of direction takes place a cam disc 133 on shaft 134 causes the magnet blocks 19, 20 to be lifted one step until the highest position is reached after which it is returned to the lowermost position. Details are given of the operation of toothed jaws 179, Fig. 16, whereby the shaft 57 supporting the magnet blocks 19, 20 is locked in each position. Details are also given of an indicator device, Fig. 25 (not shown), which shows the amount of tape on the spools at any instant, and consists of a feeler arm which presses constantly on the periphery of one of the tape rolls, and is provided with a scale sector arm having suitable engraved indications thereon.