GB793502A - Improvements in record-changing apparatus for phonographs - Google Patents

Abstract

793,502. Automatic gramophones. TESLA RADIO CORPORATION OF SOUTH AFRICA (PROPRIETARY), Ltd. - July 9, 1956 [July 10, 1955; July 26, 1955], No. 21225/56. Class 40 (2). An automatic record player is provided with preset means to select any playing position, or any one of a number of positions, from the centre of the turntable. The first embodiment is described comprising a modification of the apparatus in Specification 693,594 in which the correct setting down starting position for the pick-up at the start of one of three different sizes of records is automatically effected by a stopmember set in accordance with the size of the particular record falling to the turntable. Such a stop-member, as illustrated in Figs. 2 and 7 of the present Specification, remains in its initial position if a record of smallest size falls to the turntable, or is tripped to one of two other vertical positions by the engagement of said records with a trip-lever 25 if the record of the larger two sizes falls to the turntable. The different vertical positions of stop-member 38 cause a stepped abutment 29 thereon to arrest a similarly stepped sector arm 30 on the pick-up arm spindle 33 on the inward traverse of the pick-up over the edge of the record. By means of the present invention the stop-member 38 is drawn below the path of sector arm 30 so that the pick-up arm may continue to traverse inwardly until the said sector arm is arrested by an adjustable stop-member 58 preset in accordance with a desired setting down position on the record. The lowering of the stop-member 38 to render it ineffective is accomplished by the manual operation of clutch knob 26 which, through a linkage 50, Fig. 2, shaft 52, forked arm 66 on a pin 67 on the member 38, Figs. 2 and 5, causes the said member 38 to be drawn downwardly against the tension of spring 40, Fig. 7. At the same time, the adjustable stop-member 58, Fig. 5, is lifted into the path of the sector arm 30 by a member 62 linked to shaft 52 by a bell-crank and a linkage 60, 61. The presetting of the adjustable stop-member 58 is effected through a linkage 95, 56, 55 and a toothed sector 54 by means of a graduated control 27, Fig. 1. A second embodiment is described wherein a known make of record changer, having a feeler arm which tests the size of the next record to be played in order to determine the normal setting down position, is modified in accordance with the aforementioned methods of the invention.