GB810598A - Improvements in and relating to sound reproducing apparatus - Google Patents

Abstract

810,598. Automatic gramophones. BIRMINGHAM SOUND REPRODUCERS Ltd. June 5, 1957 [April 20, 1956], No. 12193/56. Class 40 (2). In an automatic gramophone wherein the setting-down position of a pick-up is controlled by a movable stop which is operated by a detent member tripped by a record falling to the turntable and is abutted by a locator member connected to the pick-up arm, the need to unclutch the locator member from the pick-up arm (to allow the latter to swing further inwards during record playing) is avoided by provision of means to space the stop clear of the locator member after the pick-up has been located. As applied to the apparatus described in Specification 766,048, the resetting lever 42 of that Specification is replaced by a lever 52, Fig. 4, moved outwards against its spring 55 by a cam pin 54 on the usual one-revolution gapped control gear 9 as soon as the pick-up has been set down, whereby a spring extension 56, overriding the spring 41, Fig. 10, moves the stop lever 38 to the position of Figs. 10 and 17 clear of all abutments 25 ... 27 of the locator member 24, which is permanently fixed on the vertical pick-up arm spindle (the Provisional Specification refers to a pin-and-slot connection here). The detent 42 is stepped as in Specification 810,599. General operation.-A cam 10 on the onerevolution gear 9 reciprocates a plate 8 by engagement with lugs 11; during record-playing the lever 52 and cam pin 54 hold the gear 9 in its inoperative position with the plate 8 at its right-hand extremity. As soon as the gear 9 is engaged with its drive, the edge 16 of a slot in the plate 8 is withdrawn from the upper arm of an L-shaped lever 13 whereby a spring 14 lifts its lower arm 17 to lift the pick-up arm by means of a push-rod 23; the stop 38 is released by the lever 52 and assumes its innermost position as in the earlier Specification; the edge 35 of a slot 29 in the plate 8, engaging a pin 28 on the locator member 24, swings the pick-up arm outwards; and a friction bar 31, pressed against the plate 8 by a leaf-spring on the ends of guide pins 32 slidable along a slot in the plate 8, is held by a fixed bracket 12 so that it moves to the right-hand end of the slot. The stop 38 is then set as before by the falling record, and as the plate 8 moves to the right, the friction bar 31 pushes the pin 28 until stopped by the appropriate abutment 25 ... 27 meeting the stop 38, whereafter the plate 8 slides over the bar 31. Finally, as the edge 16 contacts the lever 13 to lower the pickup on to the record, the cam pin 54 engages the lever 52 to retract the stop 38.