Patent GB-820429-A (GB)
Title: Improvements in recording and reproducing apparatus
IPC: G11B3/36
Filed: 1957-07-24
Abstract: 820,429. Dictating machines. SOUNDSCRIBER CORPORATION. July 24, 1957 [Aug. 24, 1956], No. 23413/57. Class 40 (2). A dictating-machine using a disc record is built on a chassis 10 (Fig. 4) on which is mounted a motor 13 which drives a pulley 112 through a belt 116. The shaft of the pulley 112 drives by friction an idler pulley 119 which in turn drives the rim of the turntable 12. The turntable spindle 60 incorporates a worm which meshes with a worm-wheel 64 which is free to rotate on a lead-screw 63. Secured to the lead-screw is a collar 70 and between the collar and the worm-wheel 64 is a friction washer 65. A similar friction washer 66 and the washers 67 and 68 with the nut 69 together form an adjustable friction clutch. A recording-arm 14 (Fig. 9), carries a stylus 39, the downward pressure of which is adjusted by a screw 48 moving the slide 49 to which one end of the spring 47 is anchored. The arm pivots about a pin 33 (Fig. 4), has a leaf-spring hinge 32 near the pivot and has a downward extension 36 (Fig. 9) supporting a knife-edge 37 which engages the lead-screw 63. Freely mounted on the outer end of the lead-screw is a ratchet-wheel 74, the rotation of which is limited by a crosspin 75 engaging two shoulders 77 and 78. A spring 76 urges the wheel 74 in the direction in which the lead-screw normally rotates (clockwise in Fig. 9). The recording-arm is lifted and lowered by a bar 85 which pivots about the leadscrew and is operated by a " talk-listen " button 88. The operative end of the bar engages a nylon strip 41 attached to the underside of a flexible lifting lever 40. When the button is depressed the recording arm is lifted until the abutments 42 and 43 engage. Further movement of the button to enable the notch 93 to engage the chassis results in flexing of the lifting lever. The recording arm can still be moved manually through its normal range of movement when in the raised position. A pin 86 on the bar 85 engages a slot 91a in a bell-crank lever 91 which rotates about a pivot 90. When the button 88 is pressed down to the " listen " position, the lever 91 rotates and moves a latch 82 into engagement with the ratchet wheel 74 which stops immediately. The lead-screw continues to turn until the pin 75 reaches the shoulder 77 and this rotation of the lead-screw corresponds to slightly more than one revolution of the turntable so that when recording starts again there will be a safety gap between the recordings. The bell-crank lever 91 also moves the slider of a switch 89 which makes the appropriate circuit changes in the amplifier. An index lever 79 (Fig. 11) pivots about the outer end of the lead-screw 63 and carries a pivoted pawl 80 which engages the teeth of the ratchet wheel 74. Operation of the lever 79 overdrives the lead-screw and advances the recording arm, leaving a visible space. As the recording arm approaches the end of the record a flexible reed 55 (Fig. 4) is struck repeatedly by a pin 56 projecting from the pulley 112 and gives an audible warning. A playback arm 15 is mounted on a horiontal pivot-pin 131 and a vertical pivot-pin 129. A counter-balance weight 128 is provided. When not in use the arm rests behind the shoulder of a cone 134, which facilitates sliding the arm 15 downwardly and also drops the stylus 140 at the starting- point of the record. It is retained in the rest position by a spring 133. A switch actuator 136 is attached to the arm 15 and controls a warning circuit which warns the operator when the machine is not in the recording position. Scales 51 and 139 indicate the position of the recording and replay stylii respectively. A circuit diagram of the amplifier is given. Specification 723,564 is referred to.