Patent GB-330555-A (GB)
Title: Improvements in sound reproducing apparatus
IPC: G11B17/00
Filed: 1929-03-02
Abstract: 330,555. Marshall, N., and Marshall, C. March 2, 1929. Starting and stopping; turntables; multiple machines; gramophones associated with kinematographs.-Relates to gramophones of the kind in which a sound record is held out of contact with a rotating turntable by an axially displaceable member, the record being lowered by the said member into driving engagement with the turntable when required. According to the invention, the turntable 1 is driven by worm gearing 3, 4, and has a recess 1<a> in its upper face to accommodate an axially displaceable recordholder 6, cam mechanism being provided to raise or lower the record holder. In the construction shown, the record holder is carried by a spindle 7, the lower end of which bears on a rotatable cam 8 coacting with a fixed cam 8<1>. When sound-reproduction from the record is required, the cam 8 is rotated by means of a handle 9, so that the holder 6 is lowered into the recess in the turntable, and the record is driven. Instead of a rotatable cam, a slidable, one may be employed. The worm 4 is fixed on a shaft 5 which may be driven by an electromotor, and which may drive other similar turntables through worm gearing. With this multiple arrangement, one record may be started as soon as a previously played record has been raised from its turntable. Figs. 4 and 6 show means whereby a number of records may be brought into action automatically in succession or in any predetermined combination or order, under the control of a kinematograph apparatus. The arm 9 operating the record raising and lowering cam for each turntable is acted upon by a spring 9<a> under the control of two detents 17, 17a, these being withdrawn in turn when solenoids 16, 16<a> are successively energized. The arrangement is such that when the arm 9 is held by the detent 17, as shown in Fig. 6, the record support controlled by the arm is raised. The arm is moved against the detent 17a when the detent 17 is withdrawn by the solenoid 16, allowing the record to, be lowered into operative position; further movement of the arm, whereby the record is raised again, occurs when the solenoid 16a withdraws the detent 17a. For energizing the respective solenoids at the proper times, a circuit-closing device is provided, comprising a drum 14 carrying appropriately arranged contacts 15. The drum is rotated step by step by ratchet mechanism 13 operated by an electromagnet 12, the circuit through which is closed at predetermined intervals by pegs 10<a> adjustably fixed on a disc 10. This disc is rotated by the kinematograph. Automatically Making and breaking circuit of electric pick-up by mechanism associated with gramophone.-When an electric pick-up is used for reproducing, its circuit is not completed until the record by which it is operated is brought into action. For this purpose, a contact arm may be provided on the rotatable cam 8 which effects the raising and lowering of the record. A dash-pot or the like may be provided on the spindle of the record holder to complete the pick-up circuit only after the record has attained the proper speed. Locating particular parts of records.-To enable a pick-up to be set so that the playing of a record may begin at any predetermined part of the sound-groove, an indicating finger 20, Fig. 4, moving over a scale, may be provided on the pick-up carrier 19.