GB563351A - Improvements in or relating to recording apparatus for producing sound grooves for gramophone records - Google Patents

Abstract

563,351. Gramophones. PHILCO RADIO & TELEVISION CORPORATION. Dec. 1, 1942, No. 17092. Convention date, Jan. 7, 1942. [Class 40 (ii)] [Also in Group XXIV] The arm 13 supporting a recording device 14 over a gramophone turntable 11 is moved by a ratchet gearing during the recording operation. The arm 13 is mounted bv an horizontal hinge on a socket 18 attached to a vertical shaft 17 to which is also attached an arm 19. The outer end 40 of the arm 19 is arc-shaped concentrically about the shaft 17, and this arc 40 is frictionally gripped by a grooved pinion 27 fast with a spindle 26 and a ratchet wheel 28. The spindle 26 is carried by a swing plate 23 which is pivoted at 22 on the frame plate 20 and is influenced by a spring 25 to press the grooved pinion 27 against the arc 40. A lever 31 loose on the spindle 26 carries a spring- urged pawl 35 in engagement with the ratchet wheel 28, and has a bent extension 32 carrying a roller 33 in engagement with an eccentric or cam 34 on the hub of the turntable. This arrangement is such that during half of each rotation of the turntable, the lever 31 is turned in one direction and transmits movement through the ratchet and the grooved pinion to the arm 19 to feed the recording arm 13 inward ; and during the second half of each rotation of the turntable, the lever 31 is turned back by a spring 37, while the ratchet wheel 28 is held in position by a one-way gripping device comprising a cork disc 29 on the wheel 28 pressed against a metal disc 30 formed with bent-up teeth and attached to the swing plate 23, these parts being pressed together by a spring 55 held on the end of the spindle 26 by lock nuts 54. To put this mechanism out of operation when the recording arm 13 is moved to its off position outside the turntable, the end of the arc 40 has a recess 44 followed by a ramp 47 leading to a notch 43. When the recording arm 13 is moved outwards, the ramp 47 engages the pin 41, causing the lever 31 to turn away from the cam 34, and when the notch 43 reaches the pin 41, the pin is retained by the notch with the lever 31 away from the cam 34 and the recess 44 opposite the grooved pinion 27 until the recording arm is again forcibly moved inward by hand. While the recorder is out of action, a reproducer may be used, and the circuits may be switched over from recording to reproducing by a switch 45 operated by the outward movement of the recording arm to its off position.