Patent GB-331339-A (GB)
Title: Improvements in and relating to phonograph apparatus
IPC: G11B17/00
Filed: 1929-05-27
Abstract: 331,339. Loughridge, M. H. May 27, 1929. Multiple-machines, mechanical.-A number of turntables with co-operating pick-ups are arranged to be driven from a common driving shaft and may be used for making duplicates from a record on one of them, or for playing a number of records in continuation, in which case circuit controls are provided whereby reproduction from each pick-up is controlled from the one preceding it. Provision is also made for selecting the turntable to be driven, for repeating records and for controllling from a distance. A machine with similar features is described in Specification 320,924. Driving, starting, and stopping. The turntables are mounted on spindles 26, Figs. 3 and 4, on arms 24 pivoted to brackets 21 spaced apart vertically on upright supports 13, and are driven by friction wheels 19 on a vertical motor-driven shaft 15. Each turntable is yieldingly pressed against the friction wheel by a spring 31 controlled by a dash-pot 30 and operating on an arm 27 fixed to the arm 24. An initial rotation is given to the turntable as it moves into driving engagement with the friction wheel by a pinion 38 connected to the spindle through a ratchet clutch and engaging a fixed quadrant 37 on the bracket 21. A cam 33 operated by a handle 35 and engaging the arm 27 serves to withdraw the turntable, the handle also acting through a rod and levers 80, 79, and 78 to lift a crossbar 77 and thereby raise the pick-up arm 65. The relative speeds of the turntables can be adjusted by making their peripheries, and also those of the friction wheels 19, slightly conical and providing for small adjustment of the wheels 19 along a spline on their driving shaft 15. This adjustment may be effected by regulating clamping nuts on each side of the wheels, or by cams operating on a lever engaging a grooved boss on the wheel. Feed-mechanism; raising, lowering, and positioning pick-up. The pick-up arm 65 is pivoted, with adjustment by a screw and spring for positioning, on a bracket 60 adapted to slide on a splined shaft 56, and having an extension 61 supporting an electromagnet 67 which acts on an armature on a pivoted arm so as to engage and disengage, against gravity action, a part-nut with a feeding screw 53 driven from the vertical shaft 15. A lug fixed to the nut arm. acts through links 71 to raise and lower the pick-up arm when the nut is disengaged from or engaged with the feed screw. All of the pick-up supporting brackets may be returned to starting position simultaneously by lugs 86 on rods 85 connected to a common vertical operating rod 88 and arranged to slide through bearings 83 which are hinged to the frame of the machine so that the returning mechanism can be swung out of position. The pick-ups of the several turntables may be connected to a common amplifier and loudspeaker through contact switches actuated so that, on completion of reproduction from one turntable, circuits are controlled to disconnect its pick-up and excite its feed-control magnet 67, and also to complete the necessary circuits to the pick-up and feed-control magnet of the next turntable. For this purpose, an adjustable rod 92, Fig. 3, set to suit the length of the record is moved by the feed carriage to rock a pivoted spring-controlled lever 94 so as to break a circuit at 100 and make it at 101. This causes, through the circuits shown in Fig. 12, the magnet 67 to disengage the feed-head of the pick-up of turntable A and to engage that of turntable B, which then proceeds to play, its pick-up having been lowered by the engagement of the feed-nut and its output circuit connected. So long as the circuit remains made at the contact 100 to control playing by turntable A a circuit is completed through the magnet 67 pertaining to turntable B whose feed-arm is thus held inoperative. When however the contact is made at 102, as shown in Fig. 12, the circuit to the magnet 67- of turntable B is opened so that its pick-up comes into operation; and the circuit to the magnet 67 of turntable A is closed so that its pick-up is brought out of action, this circuit also actuating a relay 135 so that on returning the pick-up to starting position, whereby it closes a switch 138, the parts are in position to be started up by the completion of playing from the last turntable. Provision is made for playing from any desired turntable selectively, as by coin-controlled mechanism, and the selection can be controlled from a distance. 'For this purpose, an electromagnet is excited to actuate a selector switch to complete the desired circuit for starting the turntable. A gear may be provided on the driven shaft 15 for coupling to a kinematograph for synchronous working.