GB636971A - Improvements in and relating to automatic gramophone apparatus - Google Patents

Abstract

636,971. Automatic gramophones. PREARIS, M. Oct. 4, 1947, No. 26754. [Class 40 (ii)] A gramophone pick-up arm which is normally supported in an inoperative. position above a record and moves to its operative position when an electromagnet is actuated by the operation of a switch, is automatically raised at the end of the record and returned to its initial position under gravity. A gramophone pick-up arm d, Fig. 3, is normally held with the needle f of the pick-up f out of engagement with a record g on a turntable b by a lever l urged to its upper position by a counterweight j. When it is desired to play the record, coin operation of a switch (not shown) momentarily energizes an electromagnet k to pull down lever l, Fig. 4, and lower the pick-up to the start of the record. Lever l is retained in its lower position by a spindle m which is normally below lever l, Fig. 3, but which is moved to the right by the extremity of lever l, during descent of the latter, to rotate a lever n about its pivot o, a counterweight q returning lever n with spindle m above lever l, Fig. 4, when the latter is in its lower position. The gramophone motor is also started when the switch is operated so that reproduction of the record commences. Towards the end of the recording, engagement of pick-up arm d and a stop r, Fig. 4, moves lever n to the right until, at the end of the recording, spindle m is out of engagement with lever l and the latter rises to lift the pick-up off the record, Fig. 5. The pick-up arm d then returns under gravity down the sloping portion of lever l until arrested by a stop s at its initial position where it remains unless the switch is again operated to repeat the cycle. An alternative arrangement in which the electromagnet is normally energized and the pick-up is lowered on to the record upon de-energization is referred to. A plurality of switches controlling a plurality of pick-ups is referred to. The Provisional Specification refers to : (a) means for returning the pick-up arm before completing the playing of a record ; (b) a switch operated by the pickup arm, when it returns to its initial position, to operate the electromagnet and replay the record automatically ; (c) rectification of the output of an amplifier associated with the pickup to bias a thyratron which, at the end of the record, initiates return of a push-button operated to select a record and stops the gramophone motor ; (d) pictures automatically rendered visible when the pick-up arm engages the record.