GB1188645A - Improvements in Tape Recorders - Google Patents

Abstract

1,188,645. Magnetic tape recorder drives. BSR Ltd. 29 Aug., 1967 [7 June, 1966], No. 25219/66. Heading G5R. The invention relates to a magnetic tape recorder of the type having a supply and a takeup spool, an assembly including magnetic erase, recording and reproducing heads, and a capstan spindle associated with a pressure roller. A take-up drive for such a tape recorder comprises: (a) a pivotable carrier member having two pulleys connected by an endless belt, the first pulley being driven from the capstan spindle through a slipping clutch and the second pulley being adapted to have driving relationship with the take-up spool to supply drive thereto, (b) spring means acting on the carrier member to move it in a direction for engagement of the second pulley with the take-up spool, and (c) link means, connected between the carrier member and a manually-operable control of the tape recorder, to retract the carrier member in the opposite direction and hold it, against the pressure of the spring means, in the position where the second pulley is out of engagement with the take-up spool. As shown in Fig. 1, the capstan structure includes, between a flywheel 18 and spindle 14, a disc portion 29 of intermediate diameter, the purpose of which is to drive the take-up spool 11 by means of a driving disc 39, 40 (see also Fig. 2) and an endless rubber belt 38 forming part of the take-up drive 30 according to the invention. The driving disc 39 and a pulley 32 are freely rotatable on a spindle mounted near one end of a flat carrier plate 31, near the other end of which a second pulley 33 is freely mounted; disc 39 has a rubber tyre 40, and the rubber belt 38 passes round pulleys 32 and 33. The plate 31 is pivoted at 34 to one end of a jockey arm 35, whose other end is pivoted at 36 to the tape deck. A link 41 for moving the carrier plate 31 is pivoted to the plate at 42, the pivot connection being located between pivot 34 and pulley 33 and also between pivots 34 and 36. A control 26 is provided which, when depressed, operates through appropriate linkage to cause clockwise movement of an arm 23 about its end 24 from the position shown to a position in which pressure pads 22 press the tape (not shown) into engagement with transducer heads 13, and a pressure roller 15 presses the tape against the capstan spindle 14, for recording or playback. This movement of arm 23 permits link 41 (which has a peg 43 engaging a flange 44 on arm 23) to be moved upwards (in the plane of the Figure) by a spring 37, fixed at one end and attached at its other end to carrier plate 31 in a position to rotate it counterclockwise. Thus, tyre 40 is brought into contact with the capstan disc 29, and belt 38 into contact with take-up spool 11. In order to allow for the progressive reduction in rotational speed of spool 11 as the diameter of the tape coil increases, a slipping clutch is provided between driving disc 39 and pulley 32. This takes the form of two arcuate brake shoes 48, Fig. 2, which are pressed radially outwardly by springs 50 having their ends engaging over lugs on the shoes; each shoe has a pad of brake material 49 and engages a flange 47 extending downwardly from pulley 32 into disc 39. Each shoe is engaged by a peg 46 projecting upwardly from disc 39. When the stop control (not shown) is operated, arm 23 moves anti-clockwise, thus retracting link 41. The link 41 rotates carrier plate 31 clockwise and jockey arm 35 anti-clockwise, until jockey arm 35 engages a fixed peg 45, whereupon carrier plate 31 is rotated further, to bring tyre 40 out of engagement with disc 29. Thus, during fast re-wind or fast forward transport of the tape, the take-up drive 30 is completely disconnected.