Patent GB-144203-A (GB)
Title: Improvements in or relating to gramophones and the like
IPC: G11B3/095
Filed: 1919-12-11
Abstract: 144,203. Cotton, A. F. R., and Cotton, S. H. Dec. 11, 1919. Sound-boxes, raising, positioning, and lowering; returning sound-box to starting-point.-Electrical apparatus for automatically raising the sound-box and returning the tone-arm to enable records to be repeated comprises two switch members adjustably supported on an horizontal bar so as to be operated by the tone-arm at each end of its travel, the switch at the finishing point being combined with a hold-on electro-magnet, so that the magnet for lifting the sound-box is maintained energized, whilst the tone-arm is returned by a spring or weight. Bells, buzzers, or the like may be sounded during the return movement of the tone-arm. The machine may be arrested by sliding one of the switches into such a position that the sound-box needle falls clear of the record on to a brake-lever. A bar e<1> arranged axially of and beneath the tone-arm e moves between two stops f, g adjustable along a bar d and held frictionally in position by springs. The stop f carries a switch arm f<1> which is arranged to open a battery circuit against the action of a spring when the bar e strikes a pin f<2>. The stop g carries a switch arm g<1> which is arranged to close the battery circuit against the action of a spring when the bar e<1> strikes a pin g<2>. The battery circuit includes in series the switch f<1>, bar d, switch g<2>, hold-on magnet i, and an electro-magnet l for raising the sound-box. During the playing of a record, the circuit is open at the contact g<1>. When the tonearm reaches the desired point for repetition, the switch g<1> is closed by the arm e<1> and is held closed by the magnet i, and the sound-box is raised by the magnet l. The tone-arm is then returned to the starting position by a spring, a weight n, or other means. When the bar e<1> strikes the pin f<2>, the circuit is opened, and the sound-box descends on to the record for another reproduction, cushioning being effected by the residual magnetism of the magnet l or by a dash-pot. The magnet l for raising the sound-box preferably has a centre pole l' and two lateral pole-pieces l<2>, and is carried, on an arm m pivoted at m<1> to a bracket e<2> clamped on the tone-arm e. An armature k<2> is secured to the sound-box rim, and the gap is adjustable by a screw m<3>. Alternatively, the magnet l may be mounted on a bracket on the tone-arm socket, and its armature may be connected to the sound-box by a cord or lever. During the interval in which the sound-box is elevated, bells or buzzers may be sounded in time with the record music. For this purpose, an electrical buzzer q<1> may be connected in circuit with a battery B<1> and a commutator r on a shaft of the spring motor t. The circuit also includes a switch controlled by the circuit of the magnet l, or by the raising of the. sound-box. A succession of bells, buzzers, or other instruments may be similarly operated. The commutator r may be rotated by an electric or other motor, and its speed may be adjusted preferably by a rheostat connected to the governor of the spring motor t. When it is desired to stop the machine, the adjustable stop f is moved out. wards so as to allow the tone-arm, in its return movement, to pass beyond the turntable rim. When the stop is engaged, the sound-box falls until the needle rests on a rubber pad on one end of a lever, the other end of which applies a brake to the turntable rim.