Patent GB-347798-A (GB)
Title: Improved trip mechanism for phonographs
IPC: G11B17/02
Filed: 1930-02-24
Abstract: 347,798. Gramophones. TECHNIDYNE CORPORATION, 644, Broadway, New York, U.S.A.- (Assignees of Piazze, T. E.; 7311, 4th Avenue, Brooklyn, New York, U.S.A.) Feb. 24, 1930, No. 6108. Convention date, Sept. 18, 1929. [Class 40 (ii).] Stopping; record changing. - A trip mechanism for initiating record changing or repeating operations in, or for stopping gramophones, comprises a rotatable member frictionally driven from the driving mechanism, and means for preventing rotation of the member during playing of a record but permitting its rotation at the end of the record whereby a resulting trip movement is attained. The trip may actuate a further trip to liberate stored energy to effect the desired operation. In accordance with the invention a worm 16 on the turntable spindle drives through a worm wheel 18 and gears 20, 22 a smooth cylinder 14 on which is frictionally mounted a split sleeve 12 carrying a pin 26, and a finger 34 moving with the pivoted arm 30 carrying the pick-up R co-operates with the pin 26 to arrest rotation of the sleeve and cause it to creep along the cylinder during normal tracking of the record, even though such tracking may involve small variations in speed of traverse due to intentional variations in pitch of the record grooves. At the end of a record the stylus may enter an eccentric groove or a rapid spiral groove, thereby accelerating the movement of the arm 30 and finger 34 so that the finger passes clear of the pin 26, or the stylus may merely remain in a concentric groove in which case the movement of the arm and finger is arrested and, due to a slight sloping of the end of the finger, the pin 26 continues to traverse until it escapes from the finger 34. In either case, the sleeve 12 can now be rotated by its frictional engagement with the roller 14 and the pin 26 is carried against a projection 42 on a lever 44 which it rocks about a pivot 46, causing the other end of the lever to trip a toggle mechanism, and the pin 26 is then carried farther around and rides against a cam edge 92 on a fixed cylinder 90 whereby the sleeve is moved longitudinally into starting position, and the finger 34 and arm 30 moved back ready to play the next record or repeat. The Figures show the application to the automatic recordchanging gramophone described in Specifications 338,820, 338,821, [both in Class 40 (ii), Phonographs &c.], and 340,169 wherein the turntable A is mounted on a tilting frame F carried on pivots 80 in a support C, the tilting being effected by mechanism designated D whose movement is initiated by the trip mechanism of the present invention which causes a trigger 54 to operate a single revolution clutch so as to engage a crank 50, with the gear 20. The trigger 54 is fixed to a slidable shaft 56 carrying a spring 58 compressed by a toggle link 60, 62, and the toggle is broken, to allow the spring to act, by the end 74 of the pivoted lever 44 when this is rocked by the pin 26 on completion of playing of a record. The end 74 acts on a pin 72 projecting from a trunnion of one of the toggle levers for this purpose, and the trigger mechanism is reset by another pin 82 on the trunnion, which pin on breaking of the toggle is moved to the position 82<1> and on tilting of the frame F is carried against a fixed cam surface 86 on the support C. The toggle may also be reset at any time by a manually operated plunger 78 operating on another pin 76 extending from the trunnion through a slot 77 in the frame F.