Patent GB-421575-A (GB)
Title: Improvements in automatic gramophone mechanisms
IPC: G11B3/085
Filed: 1933-06-15
Abstract: 421,575. Gramophones. COLLARO, C., 84, Portsdown Road, Maida Hill, and COLLARO, Ltd., Culmore Road, Peckham, both in London. June 15, 1933, No. 17144. [Class 40 (ii)] Relates to gramophones in which a " gate " is provided through which the records are passed when they are to be placed on the turntable, the diameter of each record determining the extent to which the gate is opened, and thereby controlling mechanism which effects the placing of the pick-up or sound-box in the starting position appropriate to the size of the record. According to the invention (which is particularly applicable to a gramophone having a lateral slot in the casing, through which the records are inserted for playing without opening the casing, as described in Specification 406,311, but which may also be applied to magazine and other gramophones), means are provided for holding the gate open, after a record has passed through it, for a time sufficient to allow the pick-up to be brought automatically to the starting position before the gate closes. Fig. 3 shows the mechanism beneath the motor board 4 as seen from below. The gate, which is located behind a slot in the casing, comprises two rollers 7 (only one of which is shown), carried by two pivoted interconnected arms. The spindle on which one of these arms is mounted carries, below the motor-board, a sector-shaped plate 13, having three notches which co-operate with a spring-pressed pawl 12. When a record is passed through the gate, it pushes the rollers further apart, and the pawl 12 engages in one or other of the notches in the plate 13, according to the size of the record, so as to hold the gate open. The record also engages a pin 15 on an arm 16, pivoted on one of the arms of the gate, and causes the pin to rock a lever 18, which thereupon releases a spring-actuated bar 14, Figs. 3 and 7. The bar 14 is connected at one end by a rod 22 to a lever 28, Fig. 6, pivoted in a record-carrier arm 30 which is rotatably mounted at 31. When the bar 14 is released, the rod 23 rises and rocks the lever 28, so that a plunger 32 at its end descends on to the smooth central part of the record. At the same time, a pin 25 on the bar 14, which engages in a groove 26 in a cam drum 27, Figs. 3 and 9, moves down from A to B. As the record is pushed further in through the slot, its central hole allows the plunger to pass down into contact with the turntable ; the pin 25 moves down to position C, Fig. 9, and at the same time an end 144 of the bar 14 throws over a switch 36, closing the circuit of a motor 38. As shown in Fig. 13, the motor is adapted to drive either the turntable spindle 46 or a spindle 39 actuating the mechanism for placing the record and pick-up arm in position, through two clutches 68, 69 respectively. These clutches are specially designed to prevent jamming, and to eliminate chatter. The drive from the motor to the clutches is effected through worms 70, 71, and the arrangement is such that whenever one clutch is in engagement the other is disengaged. Normally, the clutch 69 is engaged, so that when the motor is first started, as described above, a pinion 40 on the spindle 39 drives the cam drum 27. The drum is connected through a link 43, Fig. 3, to a bellcrank lever 44, which is fixed to the stem 140 of the carrier arm 30, Fig. 6. Starting from the rest position shown in full lines in Fig. 3, the link 43 moves to the chain-line position as the drum rotates anti-clockwise through half a revolution, and thereby the bell-crank 44 is caused to swing the carrier arm inwards to centre the record on the turntable. The plunger 32 thereupon drops into a socket 45 formed at the top of the turntable spindle 46, Fig. 6. At this point, the pin 25 moves from D to E in the cam groove 26, as shown in Fig. 10. At the same instant, a spring-actuated pivoted bar 66, Fig. 13, controlling the clutches 68, 69, is released, as described below, to throw out the clutch 69 and to put the clutch 68 in action, so that the spindle 39 driving the cam drum 27 is stopped and the motor begins to drive the spindle 46 of the turntable, on which the record is then in playing position. The release of the bar 66 is effected when one end of a bell-crank lever (not shown), connected to the bar, enters a notch in the cam drum. Meanwhile, the setting of the pick-up arm to the position appropriate to the size of the record has been effected by the action of mechanism comprising a bar 52 which is pivoted to the bell-crank 44 and coacts with a cam 50. The operation of this mechanism and also the action of means comprising a bar 57 controlled by the cam drum 27 for lowering the pick-up on to the edge of the record, are described in Specification 421,638. Whilst the cam drum 27 is stationary, the playing of the record proceeds as usual, until the needle passes from the end of the sound groove into a run-off groove. Thereupon, stop mechanism of the " tap-tap " kind is brought into action to effect the stopping of the turntable, discharge of the record, and the outward movement of the pick-up arm. The stop mechanism (Fig. 2, not shown), comprises an arm constantly urged towards the turntable spindle by the action of the moving pick-up arm and repeatedly moved back by a rotating cam until the rapid run-in of the pick-up occurs. The effect of the final movement of this arm is to actuate a trigger, which releases a spring-controlled lever whereby a further combination of levers 93, 94, 97, 101, Fig. 3, is shifted to enable an eccentric on the turntable spindle to exert a thrust against an arm 102, Fig. 13, projecting from the clutch bar 66. The bar 66 is thus rocked, declutching the turntable spindle 46 and clutching in the spindle 39. The cam drum 27 then rotates through another half-revolution, during which (1) movement of the bar 57 by the cam drum lifts the pick-up arm ; (2) the pin 25 moves from F to G in the cam groove 26, Fig. 10, thereby withdrawing the plunger 32 from the socket 45, Fig. 6; (3) the bell-crank 44 actuates the bar 52 to move the pick-up arm outwards, as described in Specification 421,638 and also swings the arm 30, so that the record is carried outwards ; (4) the pin 25 on the bar 14 moves into the position H, Fig. 9, rocking the bar so that the plunger 32 is lifted from the hole in the record, and at the same time the bar 14 operates the switch 36 to stop the motor, whilst the catch 18 passes beneath an end of the bar 14 and holds it up. As the record moves out through the gate, it engages the pin 15, Fig. 3, and causes it, through a link 17, to release the plate 13 from the pawl 12 and allow the gate to close. In order to stop the playing of a record at will, and to cause it to be ejected, the projection 102 on the clutch bar 66 may be acted upon by a manually operated lever, connected to a rod projecting through the casing. A door is provided in one side of the casing, to allow the pick-up to be swung outwardly for needle-changing, as described in Specification 421,639.