Patent GB-964024-A (GB)
Title: Magnetic recording and reproducing apparatus
IPC: G11B15/44
Filed: 1961-09-25
Abstract: 964,024. Feeding record tapes; accidental erasure, preventing. RADIO CORPORATION OF AMERICA. Sept. 25, 1961 [Oct. 26, 1960], No. 34318/61. Heading G5R. A cassette-loading tape recorder is provided with toggle joint means for maintaining the manual positioning of a belt drive mechanism in record/ playback or rewind positions, characterised in that a portion of the belt is in driving engagement with a take-up driving member in the record/playback position, but is stretched and disengaged from said member during rewinding and brought into engagement with a rewind drive member. The manually controlled toggle means comprises a knob on a control shaft 71 to which is secured a cam plate 74, rotation of which in a clockwise direction for record or playback causes a toggle plate 79 thereon to be swung outwardly until spring 80 between plates 74 and 79 passes over a dead centre and same become locked in that position; this outward swing of the plate 79 moves an arm 85, and a bellcrank 44, spring loaded and hinged thereto, and carrying a capstan pressure 34, in to engagement with the capstan 33. The movement of the bellcrank 44 also allows a spring-loaded bellcrank 46 to permit a sliding plate 21, carrying pressure pads 17, 18 to move until the said pads engage the tape and press it against the record/playback head 12 and erase head 13 respectively. The rotation of cam plate 74 also longitudinally moves a bar 97 linked to a brake lever 92 so that a brake pad 94 is removed from the disc 53 carrying the feed spool. During this time a two-step pulley on the motor shaft 56 drives the flywheel 40 on the capstan shaft 33 by means of a belt 58 which engages the edge of a disc 52 carrying the take-up spool. If a " record" operation is required, rather than "playback", a switch 65 is operated by a knob on a shaft 14, a catch lever rigid with said shaft latching with another spring-loaded lever 111 to retain said switch in position. To prevent erasure of a prerecorded tape, the cassette has a break-out portion, which if not removed engages a cranked portion 114a of a control rod 114 to prevent its rotation. The crank at the opposite end then inhibits movement of the link 116 and this prevents rotation of the "record" switch control arm 110. The control shaft 71 may be returned to the neutral position manually, but should the end of the tape on the supply spool approach, the tension of the tape acting on a guide pin 91 on brake lever 92 causes the toggle action of the toggle spring 80 to be tripped and the control shaft 71 to be returned to the normal position, the resulting leftward movement of bar 97 causing the "record" switch 65 to be released, should it have been set. When a rewinding operation is required the control shaft 71 is rotated counter-clockwise, whereby an arm 76 thereon longitudinally moves a bar 64 coupled to a lever 61 pivoted on the axis of take-up drive member 52 and carrying pulleys 59, 60, so that the belt 58 is pushed out of contact with drive member 52 and into contact with supplyspool member 53, and a rewind effected. The control shaft 71 is retained in this position by the toggle action of spring 84 until the control is manually returned to the neutral position or the tension on a guide pin 90, acting through lever'98 and a rod 99 causes the tripping of toggle spring 84.