Patent GB-655985-A (GB)
Title: Improvements in or relating to apparatus for playing gramophone records
Inventor: METCALFE CLIFFORD
IPC: G11B17/04
Filed: 1948-03-13
Abstract: 655,985. Automatic gramophones. ELECTRIC & MUSICAL INDUSTRIES, Ltd. March 13, 1948, No. 7681. [Class 40 (ii)] A gramophone comprises a cabinet, a platform supporting the turntable and pick-up or tone arm movable between an enclosed position in the cabinet and an outer position in which a record can be placed on the turntable and a cam, carried by the cabinet, engaging spring-controlled mechanism on the turntable, whereby the pick-up or tone arm is automatically moved into or out of operative position on the margin of a record when the platform is moved into or withdrawn from the cabinet. The cam controls springs tending to move the pick-up or tone arm to an inward operative position. Actuating mechanism operated by a stepped cam 11 in the side of the cabinet engaging a pin 14, Fig. 2, on a rotary disc 12 underneath the platform first swings then lowers automatically the tone arm on to the margin of the record, finally a teasing-in lever sliding the arm and stylus against the sound track. Mounted on an extension of the tone arm spindle 9, Figs. 3 and 5, are an actuating lever 18, an arm 17, a bell-crank lever 16 and a teasing-in lever 19, all but arm 17 of which are freely rotatable on the spindle 9. A spring 20 biasses the levers 18, 17, 16, 19 and tone arm to an inward position when permitted by a further pin 30 on the disc normally holding back levers 19, 16 and by a latching arm 35, since lever 18 abuts a pin 23 on lever 16, and a projection 24 on lever 16 abuts a projection on arm 17. A fixed stop 49 controls this inward movement to the margin of a 10-inch record, but further rotation of the disc 12 with pin 30 is made by the cam 11 so that a spring 31 moves the teasing-in lever 19 to abut and move forward stop 23 by an amount limited by the engagement of stop 33 on the teasing-in lever 19 with an abutment on the actuating lever 18 so that levers 16 and 17 are further moved to slide the stylus on to the record. Prior to the teasing-in a cranked supporting arm 57, Fig. 3, for the tone arm descends into a groove on the disc 12 to lower the stylus by gravity on to the record margin. A latching arm 35, Fig. 2, controlled through linkage from a feeler gauge 41 prevents movement of the pin 23 on the lever 16, Fig. 5, and operation of the tone arm unless a record has been put on the turntable so moving the gauge 41. Before reaching the stop 49, Fig. 5, the lever 18 abuts a pin 45 on a stop disc 44 rotating the latter and slightly moving the linkage so that the gauge 41 is moved clear of the record rim. For a 12-inch record the gauge 41 and stop disc 44 are further moved so that a stop 46, Fig. 2, on the disc limits the inward movement of the actuating lever 18 and tone arm. As before, the lever 18 gives a further movement to the stop disc to move the gauge 41 clear of the record rim. A switch 62, Fig. 2, operates the turntable drive after inward movement of the tone arm. A tap-tap brake mechanism switches off the motor drive after a record is played. Specification 554,530 is referred to.