GB208753A - An automatic stopping device for talking machines of disc type - Google Patents

Abstract

208,753. Findlay, R. M. Sept. 1, 1922. Starting and stopping.-Relates to devices of the kind in which a spring-operated brake is automatically applied to the machine when movement of the tone-arm across the record ceases, the release of the brake occurring when a circuit is closed through two contacts, one of which is carried by a motor-driven part, and the other being moved by connection with the tone-arm at a speed which is not less than that of the other contact. The mechanism comprises a disc A intermittently or continuously driven from the machine motor C<1> (for example by gearing C - - B) through a light friction clutch, which as shown in Fig. 2 may be constituted by pressing together the parts A, B by a spring B<2>. The disc has an arm A<1> carrying a contact A<2>, adapted to coact with a contact finger D'. This is mounted on an insulating arm D, on which is pivoted a link F having a pin-and-slot connection with the tonearm G. The contacts A<2>, D<1> are arranged in circuit with an electromagnet K<3>, controlling a detent N for the brake L<2>, contacts j, J<1>, one of which is fixed and the other carried bv the tone-arm, being also included in the circuit. In the arrangement shown, additional contacts K<1>. K<2> are also provided, the member K<2> being a hand-lever which, when moved to the contactclosing position shown, takes the brake off and shifts a part N<2> of the brake-mechanism into engagement with the detent N. On swinging the tone-arm clear of the turntable, and then placing the stylus on the record, the link F first causes the contacts D', A<2> to be drawn round together and then separated, the contact A<2> being left behind. During the playing of the record, the contact A<2> follows the contact D<1>, but does not overtake it until the movement of the tone-arm ceases. Meanwhile the contact J<1> has come into engagement with J. When the circuit is finally established at A<2>, D<1>, the magnet K<3> is energized, the detent N is attracted, releasing the part N<2>, and the bra.ke L<2> is moved by spring L<3> so as to stop the motor. In a modification, an electromagnet normally holding the brake is short-circuited when the contacts are closed. The Provisional Specification refers also to the use of similar mechanism to that described above for stopping the motor mechanically.