Patent GB-357998-A (GB)
Title: Improvements in automatic gramophones
IPC: G11B17/24
Filed: 1930-05-28
Abstract: 357,998. Automatic gramophones. DEHN, F. B., 103, Kingsway, London.- (Mills Novelty Co. ; 4100, Fullerton Avenue, Chicago, U.S.A.) May 28, 1930, No. 16505. [Class 40 (ii).] An automatic gramophone of the type described in Specification 324,693, [Class 40 (ii), Phonographs &c.], has the records supported radially on a rotary carrier movable to bring the records successively into playing position in relation to a swinging arm carrying a pick-up, such arm being capable of swinging across the record during playing and of being rocked upwardly after playing, to permit the carrier to bring a fresh record into playing position, under the control of a cam carried by and extending around the record carrier. Provision is made whereby any desired record in the carrier can be selected for playing, and the machine may be coin-controlled. Each record 19, Fig. 1, is supported on a bevel-edged disc 34 provided with a spindle 27 mounted for rotation in an arm 10 of a record carrier secured to a shaft 13 geared by a chain 38 with a motor 36 by which the records are brought successively into a horizontal position. At each such movement a cam 59 fixed to the record carrier and acting on a bowl 63 on a pivoted lever 64 permits, due to a recess 62 in the cam, the lever 64 to rock under the action of a spring and thereby rock a pivoted support 40 to which the pick-up arm 41 is pivoted for movement in both a horizontal and a vertical plane. The pickup 42 is thus lowered on to the record, which is already being driven by the engagement with its bevel edged supporting disc 34 of a friction wheel 73 on the spindle of a constantly driven pivoted motor 71 which has been rocked into driving position by the movement of the lever 64 on a bowl 88 on the motor frame. The pick-up arm 41 is partially supported from the support 40 by an adjustable spring 55 which avoids shock when the pick-up is lowered on to the record. The lowered pick-up is pushed over the blank margin to engage the first groove of the record by a spring-influenced lever 139, Fig. 2, pivoted to the support 40. During playing, a pawl 109, Fig. 2, on an arm 112 extending from the pick-up arm rides over a rack 108 on a pivoted switch arm 105, Fig. 8, and the terminal grooves of the record, whether of the eccentric type or of the continuing spiral type, effect rocking of the arm 105 to engage one or other of contacts 116, 121, thereby completing a circuit to a motor 36 to drive the record carrier, the cam 59 on which acts through the lever 64 to rock the pick-up support 40 and thus raise the pick-up and also to rock the motor 71 to disengage the friction wheel 73 from the disc 34. As the pick-up is lifted, the switch arm 105 is released and fails to complete the circuit to the motor 36 but this circuit is now maintained by a spring-influenced switch 126 which has been released by the movement of the lever 64, and the motor continues to rotate until the next record is in playing position unless arrested before this by a cut-out switch 101, 102 arranged in the main circuit and controlled by the insertion of coins in the machine or otherwise. As the next record is brought into position the cam 59 operates the lever 64 to lower the pick-up arm support 40, which is checked by a yieldingly-supported pivoted lever when the pick-up is lowered into playing position, and to open the switch 126 so that the motor 36 is stopped. The speed of the motor 36 is controlled automatically during record changing, for which purpose a switch 160, Figs. 2 and 8, on the pick-up arm is provided to vary a resistance 198 in a shunt circuit including a switch 166 across the armature of the motor. The switch 160 is open to include all the resistance in the shunt circuit so that the current mainly passes through the armature when the motor 36 is started to change a record and lift the pick-up arm as already described. When, however, the arm has been lifted and swings back against its support 41 it closes the switch 160 to short-circuit the part 198a of the resistance so that less current goes through the armature, and shortly after this the switch 166 is moved by the rocking of the motor 71 to open the circuit so that the motor is accelerated until on lowering of the pick-up arm the shunt circuit is again completed whereby the new record is brought into final position slowly, the motor being then stopped by the opening of switch 126. Any desired record can be selected for playing, as described in Specification 357,997, for which purpose the lever 64, Fig. 1, can be held clear of operation by the cam 59 by means of a latch 146 controlled by an electromagnet 148, and a dial 156 marked to correspond with the records is mounted on the shaft 13 aligned with the shaft of the record carrier whereby a disc 154, Figs. 2 and 8, can be set in relation to a disc 153 so that a circuit through the discs to the magnet 148 is broken to release the lever 64 only when the desired record is moving into playing position. Provision is made for controlling the volume output from each record automatically as described in Specification 355,744, for which purpose adjustable tappets on the record carrier can be set to vary a resistance in the output circuit from the pick-up 42 to a loud-speaker 213 when the corresponding record is being played. To provide for coin control, the circuit from a main supply plug 175 includes carbon contacts 184, 185, 186 of the coin control device : this coin control is described in Specification 354,442, [Group XXXVII]. Turntables.-The records 19, Fig. 1, are secured on the turntables 34 by a slotted cross-bar 22 engaging a transverse pin 24 in the protruding head of the turntable spindle 17 and held in position by a spring plunger in the turntable spindle.