GB1298226A - Improvements in or relating to phonograph with radial arm - Google Patents

Abstract

1298226 Radial arm gramophone E G NORRIS 15 Dec 1970 [15 Dec 1969] 59443/70 Heading G5R In a gramophone using a pick-up assembly of the type described in Specification 1,298,225 which comprises a pick-up unit 16 slidably mounted on an arm 17 which can be pivoted between a rest position and a position over the gramophone turn-table, the unit and arm are controlled by a single cam member to operate in a single record playing mode. Operation of a push button switch 60 energizes cam drive motor 48 momentarily and during this period the motor drives cam disc 40 which via cam member 45 closes switch 64 connected in parallel with switch 60 so that the motor drive continues. Vertical pin 66 now engages part 67A of a member 67 made fast with the mounting spindle of the pick-up arm assembly so that the arm 17 is rotated to its record playing position over record 10 on turn-table 13. Thereafter tip 34A of shaft 34 rides up cam member 43 and when it reaches its uppermost position shaft 34 has rotated member 17B of the pick-up arm about member 17A to a position which is free of pick-up unit 15 which has thus rotated to move its stylus into playing contact with the record. At this time cam member 45 opens switch 64 and the cam motor drive ceases. At the end of record play a magnet 28 on the pick-up head actuates reed switch 27 again energizing motor 48 and this again stays energized through the action of switch 64. As the shaft 34 is lowered by cam member 43 the arm member 17B again rotates about member 17A lifting the pick-up from the record so that an endless cord 30 is engaged by a lug 15A on the pick-up unit via a longitudinal slot in member 17B. Drive wheel 34B on shaft 34 now engages the inner surface of cam member 44 so that shaft 34 is rotated, rotating pulley 31 to reel the pick-up member back to its initial position at stop 67. Thereafter vertical pin 91 engages part 67B of member 67 rotating shaft 34 and bringing the arm 17 back to its initial position. Finally cam member 45 opens switch 64 returning the assembly to its initial position. This return can be initiated at any time during play by operation of push button 6D. Lever 80 forms a pause control to interrupt playing of the record. On being moved vertically it rotates twin arm 84 about pivot 85 whereby arm 84B engages the cam surface 90A of a cam block 90 on the cam disc 40 to rotate this anticlockwise and arm 84A pivots motor 48 so that its drive wheel 50 is disengaged from the cam disc periphery. The rotation of the disc causes shaft 34 to ride down the leading edge of cam member 43 so that pick-up member 15 is rotated out of engagement with the record and the cam drive motor is energized ineffectively via cam operated switch 64. On lowering the lever the motor engages the cam disc and drives this to the position occupied before the lever was operated in which the pick-up re-engages that part of the record from which it was raised.