GB914802A - Improvements in or relating to multi-speed mechanisms - Google Patents

Abstract

914,802. Change-speed friction gear. ELECTRIC & MUSICAL INDUSTRIES Ltd. April 15, 1959 [April 16, 1958], No. 12045/58. Class 80 (2). [Also in Group XXXVIII] In a gramophone change-speed friction drive in which the friction disc 3 is engageable with a stepped driving spindle 1 and the turntable 2, the lateral and axial movements of the disc are imparted to a bracket arm 12, on which the disc is mounted, by a pair of cams integral with a rotary speed-selector 4. The latter has appropriate indicia 8 on its rim, and when one of them is visible in a cut-out in the base-plate 6 a pin 25 carried by a spring-loaded arm 24 in engagement with arm 12 engages one of a series of detent recesses 10 in the circumference of a circular cam-plate 9 secured to selector 4, thus allowing disc 3 to engage the spindle and turntable. Rotation of member 4 to change speed causes pin 25 to ride on the periphery of cam 9, rotating arm 24 about a pivot-pin 22 to disengage arm 12 from disc 3. The vertical position of disc 3 is determined by the setting of a heart-shaped cam-slot in the face of disc 9, which is engaged by a pin 20 carried by a vertically movable bracket 17 on which the arm 12 is mounted. In the arrangement shown in Fig. 3 the selector 4 is of conoidal form 30, on which a helical line 32 operates in conjunction with indicia 33 on base-plate 6.