Patent GB-1517049-A (GB)
Title: Magnetic recording and reproducing apparatus
IPC: G11B15/02
Filed: 1975-08-29
Abstract: 1517049 Cassette recorder BELTEK CORP 29 Aug 1975 [13 Sept 1974] 35643/75 Heading G5R In a twin-reel cassette recorder incorporating an auto-reverse arrangement in which when a first track of the tape has been fully recorded or played back in a first direction by a first head and the end of the tape has been detected the direction of the tape drive is reversed and a second head records or plays back from a second track on the tape, the tape is driven by a single motor driving a single capstan and a single idler coupleable to the tape reels for transducing in both directions and for fast forward wind or rewind. On insertion of a cassette in receptacle 46 it engages a sensing part 56 of a slide 51 and moves the slide, against the action of spring 54 in the insertion direction. A pin 57 on the slide moves along a cam part 58 of a member 60 secured to the recorder chassis until stopped by a stop 132 when adjacent the vertical slot 75 in the member. At this point part 77 of the slide 51 engages part 76 of a latch member 72 to release part 75 of the latch from an aperture 68 in a spring loaded slide 65 formed with a cam slot 62 in which a pin 61 carried by the receptacle is engaged. On release of the slide it is moved towards the front of the recorder thereby moving the receptacle and cassette downwards to the record/play back position. During this movement the receptacle support 47 and the receptacle pivot on plate springs 48, 49 and a further resilient member 134 acts via an aperture 135 in the receptacle to urge the cassette into engagement with the receptacle base. The movement of slide 65 also moves a pin 80 carried thereby along a cam slot 79 in head plate 9 to allow this to be pivoted by spring 11 to bring the head 8 and pinch roller 7 into tape engaging positions. On movement of ejecting lever 66 inwards from the front of the recorder a part 70 thereon engages a part 71 on the slide 65 to move this inwardly to its latched position during which the receptacle is raised by pin 61 assisted by the plate springs 48, 49 to its upper position from which the cassette is ejected by movement of slide 51 by spring 54. Drive motor 15 is coupled by belt to flywheel 16 driving capstan 6. The flywheel is also coupled by belt 18 to a fixed pulley 22 which is friction coupled to an idler 4 which is supported to be movable into friction drive engagement with one or other of the hubs of reel drive spindles 2 and 3. By virtue of the idler's engagement with pulley 22 its movement is automatic on change of direction of drive of the motor so that in dependence on the direction of tape drive the required spindle is driven as the take up reel drive spindle. The end of tape is detected by a switch SW2 which co-operates with a printed disc 24 rotating with one of the reel drive spindles. The disc has conducting and insulating portions 24b, 24a which co-operate with the switch contacts to provide a pulse signal when the disc is rotating, i.e. when the tape is moving. This pulse train keeps a trigger circuit A, e.g. a one-shot multivibrator, in its "on" state during tape movement. When the tape reaches its end the pulse train ceases, the multivibrator drops back to its other state and the change is detected by circuit C which supplies an output to a motor normal-reverse control circuit D to change the direction of rotation of the motor and hence the direction of tape drive. Simultaneously with the change in direction a head change-over circuit G is operated to enable the head scanning the other track. When power is initially switched on a circuit H ensures that the tape is driven in a fixed direction. The tape direction of movement can be switched manually by operation of a switch SW3. During recording or play-back a switch SW4 operated by a lever 25 is in a mid position and the tape speed is controlled by a constant speed control circuit E. Fast forward feed and fast rewind are obtained by moving the switch to the a and b positions in which the circuit E is cut off and the motor runs at a fast rate. The switch lever 25 is interlocked with the head plate 9 to raise the tape heads and pinch roller driving fast speed operation. When reel drive spindle 2 is used as take up reel drive the pull on the tape as this leaves the capstan 6 is reduced because of the braking effect of the head 8. To prevent this causing entanglement of the tape the clutch coupling the drive from this spindle hub to the spindle is adjusted to give a greater torque to spindle 2 than that to spindle 3. Further means to avoid any entanglement consist of the brake 128 on reel spindle 3 to provide restraint when the reel of the spindle is the feed reel-this is not necessary on spindle 2 because of the braking action of the head and also the provision of tape edge guidance on the tape guides 131.