Patent GB-325875-A (GB)
Title: Improvements in or relating to automatic gramophones
IPC: G11B17/16
Filed: 1928-11-22
Abstract: 325,875. Pittman, G. H. Nov. 22, 1928. Magazine gramophones; ; starting and stopping; repeating mechanism.- An automatic gramophone comprises a magazine for a stack of records, a turntable arranged at one side of the magazine, and means for delivering the records successively through the bottom of the magazine, conveying them to the turntable and, after playing, discharging them into a receptacle. Means are also provided for setting the machine for ordinary manual operation, or for automatic repetition. Records, storing and transferring.- The magazine, Fig. 2, is a cylindrical casing 14, with a lateral recess 24 to allow the operator's hand to be inserted. At the bottom of the magazine is an annular casting 25, with a crescent-shaped ledge 26 which serves, in conjunction with a platform 30, to support the stack of records 15. During " magazine operation,'" a reciprocating slide 27, indirectly actuated by a cam shaft 36, pushes each record in turn clear of the ledge 26 so that it can be lowered by the platform 30 on to conveyer belts 31. The record is carried forward until it meets a stop 120, which has been temporarily raised, and which retains the record directly over a turntable 17. The latter, which is in continuous rotation, then rises, lifting the record off the conveyer belts into engagement, with the reproducing needle 22, whereupon playing of the record begins. The platform 30 rises to its original position simultaneously with the rise of the turntable, the stop 120 having meanwhile fallen back to an inoperative position, and when these actions have occured, the movement of the cam shaft 36 and of the belts 31 is automatically stopped. At the end of the playing of the record, the shaft 36 is again rotated, causing the turntable to be lowered so that the played record is deposited on the belts 31, which are again set in motion. The record is then carried along until it slides down a shoot 84, into a felt-lined receptacle 16. The tone-arm is automatically returned to the starting position, and the cycle of operations recommences with the delivery of a fresh record from the magazine. Driving-mechanism.-A spring motor, not shown, drives the turntable spindle, and also drives a wheel 61 which gears with a wheel 54. Figs. 4 and 5, loose on a shaft 53. The wheel 54 is clutched to its shaft when a clutch member 56 is lowered. whereupon the shaft 53 drives the cam shaft 36 through gearing 46, 47, 48 and 50, 52. The wheel 47 drives through a clutch 66 a pulley 68 which, through a belt 75, is adapted to rotate a shaft 77 by which the conveyer belts 31 are driven. A transversely slidable bar 42 is connected to a bar 34 to which the record ejector 27 is attached, and the bar 42 can be moved so that the bar 34 is coupled through a tongue 40 to a slide 38. This is reciprocated by a cam 35 on the shaft 36 when the latter rotates, thus causing the requisite movements of the ejector. The bar 42, when in the position in which it puts the parts 34, 38 into engagement, also holds the clutch 66 in action, by means of an arm 71. Control of tone-arm, turntable, and record platform.-As. the tone-arm swings towards the centre of a record which is being played, it moves, by means of a connecting member 90, Fig. 4, a trip bar 92 which when the cam shaft 36 has been set in motion, as subsequently described, is acted upon by a cam 95. The cam first draws the tone-arm further inwards, to allow clearance for the played record as it is tilted on to the shoot 84; then the cam pushes back the bar 92, by which the tone-arm is returned to the starting position, ready for the next record. The bar 92 carries at one end a setscrew 96, which serves to start the cam shaft 36 in operation in the following manner. A U- shaped lever 62, pivoted on the shaft. 36 carries a yoke 64, Fig. 5, engaging the clutch member 56, and the lever 62 is normally held up, with the clutch inoperative, by a trigger 99, Fig. 4. When the screw 96 strikes a trip arm 97, the trigger 99 is moved so as to allow the lever 62 to drop, whereupon the clutch 56 is engaged and the cam shaft 36 is driven by the mechanism described above. - The turntable is mounted on a sleeve slidably keyed to a shaft driven by the spring motor, and is raised and lowered by a connection between the sleeve and a pivoted frame L<1>. This frame has a transverse member carrying a roller 111 and engaging parallel arms of a lever L which is linked to the support 100 for the platform 30. A cam 112 on the shaft 36 normally presses down the roller 111 so that both the turntable 17 and the platform 30 are held in the elevated position. When, however, the shaft 36 rotates, the cam 112 allows the members 17, 30 to fall, and afterwards raises them again when a record-changing operation has been completed. As the frame L<1> raises the turntable, the trigger 99, which is mounted thereon, and which has meanwhile re-engaged the lever 62, raises the latter. By this means the clutch 56 is disengaged and the cam shaft 36 is stopped. The movements of the recordpositioning stop 120 are effected by means of a slidable bar 124 acted upon by a pin on the wheel 46. Setting the machine for various modes. of operation.-A notched disc 143 on a spindle 140, Figs. 4 and 5, which can be set in different positions by rotating it by means of a knob 141, controls two bell-crank levers 148, 149 which respectively determine the positions of the. bar 42 and of an arm 178. The bar 42 enables the rotation of the cam shaft 36 to occur either with or without consequent operation of the record delivery and transfer mechanism, by the means described above, and an arm 232 on the bar 42 serves to look the platform in the raised position when the members 34, 38 are disengaged. The arm 178 is adapted to be moved, by suitably rotating the disc 143, into a position in which it engages under the lever 62, and so prevents this lever from dropping and starting the rotation of the cam shaft 36 when the arm 97 is tripped by the screw 96. Thus the control knob 141 enables the machine to operate with successive automatic transfer of records from the magazine to the turntable, or allows the playing of any record to be repeated indefinitely, or enables the automatic mechanism to be thrown out of action altogether, so that the machine can then be operated manually in the ordinary manner. Means are provided for preventing the control knob from being turned whilst a cycle of automatic operations is occurring. Starting and stopping the turntable.-A friction brake 162, Fig. 2, adapted to engage the underside of the turntable, is carried by an arm 164 secured to a lever 165. This is operable by hand, and when it is moved to apply the brake, a support 173, connected by a system of levers to the member 165, is moved forward to prevent the lever 62 from falling. Automatic application of the brake occurs at the end of a record, when the knob 141 has been set for manual operation of the machine, this is brought about by the indirect action upon the member 173 of a part projecting from a sleeve 180, Fig. 4, the sleeve having been set by means of the arm 178 and a lever 182 into such a position that it can be rotated by the trip arm 97. A modification is described (Figs. 13, 14, not shown), wherein means are provided for automatically applying the brake when the last record in the magazine has been played. This mechanism comprises a member which normally is moved by each record as it is carried along by the conveyer from the magazine to the turntable, so as to prevent application of the brake. When the magazine is empty, so that this preventive action cannot occur, a cam disc on the main shaft 36 is enabled to effect the application of the brake at the termination of the last cycle of operations. Automatic winding of spring motor.-When the cam shaft 36 rotates, a, member carried thereon rocks a lever which operates a, switch in circuit with an electromotor (not shown), this motor being geared to the winding arbor of the spring motor. ' The circuit of the electromotor is kept closed for a predetermined period during each rotation of the cam shaft.