GB817509A - Improvements in or relating to gramophone record changers - Google Patents

Abstract

817,509. Automatic gramophones. PLESSEY CO. Ltd. Dec. 28, 1956 [Feb. 29, 1956], No. 6349/56. Class 40 (2). In a record changer having a feeler member which is differentially actuated by differentsized records for controlling the setting-down position of the stylus, said feeler member is utilized for controlling the speed at which the turntable is driven. The embodiment is directed to means for playing mixed 33 1/3 r.p.m. and 45 r.p.m. microgroove records and takes advantage of the fact that 45 r.p.m. records are 7 inches in diameter. The apparatus is provided with means for manually setting the speed at 78, 33 1/3 or 16 r.p.m., but when set for 33 1/3 r.p.m. the speed is automatically changed to 45 r.p.m. if a 7-inch record falls to the turntable. The feeler member may be a toothed sector-shaped plate 16 as shown in Fig. 4, which assumes one of three different positions, according to whether a 7-inch, 10-inch or 12-inch record falls to the turntable 8, and rotates a shaft or pin 21 having an ear 11 which is thereby set in the path of teeth 13, 14 or 15 on a lever 6 secured to the shaft of the pick-up and controlling the setting- down position of the stylus in well-known manner. The three alternative speed positions are set by rotation of a shaft 48 bearing a disc 36 having three notches 37, 38, 39 arranged at progressively increasing radial positions and which are engaged by a follower 34 on a lever 30 pivoted at 29 on a bar 26 and acting on a spring- loaded rod 31 controlling a speed-changing means 32. The notches 37, 38, 39 correspond to speed settings of 78, 33 1/3 or 45, and 16 r.p.m. respectively. When set to notch 38 and a 7-inch record falls to the turntable, the lever 6 is swung to the extreme position in which a pin 25 thereon moves the bar 26 about pin 28 and produces additional movement of lever 30 and sets the speed-changing means from 33<SP> 1</SP>/ 3 to 45 r.p.m. Return movement of lever 6 at the end of a record causes the bar 26 to be restored to its initial position by the engagement of a pin 25a with a sloping surface 49 on the bar 25. The additional movement of lever 30 is prevented when disc 36 is set for 16 r.p.m., by means of a pin 43 thereon which engages the hooked end 44 of bar 26. A similar pin and hook may be arranged for the 78 r.p.m. setting, but this is not shown in the Figures. Specification 817,510 is referred to.