Patent GB-394326-A (GB)
Title: Improvements in and relating to automatic record-transferring devices for gramophones and like apparatus
IPC: G11B17/02
Filed: 1931-12-14
Abstract: 394,326. Magazine gramophones. MITCHELL, F. A., Bendon Valley, Garratt Lane, Wandsworth, London, and ELECTRIC & MUSICAL INDUSTRIES, Ltd., Blyth Road, Hayes, Middlesex. Dec. 14, 1931, No. 34658, [Class 40 (ii).] In a magazine gramophone in which a recordtransferring device is automatically set into operation by an increase in the rate of inward movement of the reproducer arm, means are provided positively to prevent automatic reactuation of the record-transferring device while the arm is being moved rapidly inwards to commence playing the transferred record. In the construction shown in Fig. 1, a pile of records is supported over the turntable by means of a stepped pin (not shown) engaging in the central holes of the records, and a movable stepped ledge J<1> on which the edge of the pile rests. During the playing of a record, the slow inward movement of the pick-up arm T causes a lever B to move until a chamfered hook B<1>thereon is brought into the path of a rotating cam C. Each engagement of the cam with the hook B<1> produces a set-back of the lever B, in the manner described in Specification 332,004, [Class 40 (ii), Phonographs &c.], until an accelerated movement of the pick-up arm occurs, for example, as a result of the needle entering a spiral groove of large pitch terminating the record groove. When this takes place, the cam C pulls the lever B endwise, moving with it a lever H on which B is pivoted. The lever H actuates a clutch L, whereby a motor-driven shaft D is clutched to a shaft L<1>which is geared to a shaft F. A cam F<1> on this shaft causes the pick-up arm to be raised, swung outwardly and subsequently brought into a position for beginning playing a fresh record, which has meanwhile been dislodged from the pile and dropped on to the turntable. The discharge of the record is brought about by a lateral push effected by the member J<1>, moved by a lever J which is actuated by a cam F3 on the shaft F. During these operations, a grooved cam L<3>, integral with the slidable member of the clutch L, coacts with a pin P<1> to hold the clutch in engagement until the whole sequence of operations is ended, the cam groove causing separation of the clutch members after one revolution of the shafts D, Ll has occurred. A pin H<1> on the lever H holds the lever B clear of the cam C while the clutch is in engagement. By these means. undesired reactuation of the record-transferring mechanism by the inward movement of the pick-up arm to the initial playing position is prevented. The cams F<1>, F<3> may be adjusted along the shaft F by operating a knob K, to enable the machine to deal with either 10-inch or 12-inch records. Means are provided to enable a record to be repeated by putting the transfer mechanism out of action, or to prevent interengagement of the lever B and the cam C, or to bring the transfer mechanism into operation at any time by manual control. A switch E in the motor circuit may be automatically opened when the last record of the pile has been played. A modification is described (Fig. 3, not shown), in which a member moving with the pick-up arm carries an inertia weight which co-operates with contacts so as to close the circuit of a magnet actuating the clutch L when the pick-up arm moves at an increased rate at the end of reproduction of a record. Modified means for adjusting the mechanism for records of two different sizes, for stopping automatic reproduction after the last record has been played and for manual control of repetition and record-changing are embodied in this construction. A further modification, similar to that last described, comprises a dashpot instead of an inertia weight. Fig. 5 shows another construction in which a control switch G<3> is adapted to be actuated by the acceleration of a pawl B<2>, moved by the pick-up arm, relatively to a screw C<2> with which it engages. the screw being driven by the turntable spindle at such a speed that it tends to feed the pawl slightly faster than its normal rate of advance by the pick-up arm. In still another modification, Fig. 6, a clutch member D<3> is controlled by a sprocket-like wheel C, the member D3 being slidably keyed on a shaft D driven from the turntable, and the wheel C being frictionally mounted on the shaft. Normally the part D<3> drives the wheel C by engagement of a projection C3 in a notch, the engagement being maintained by a spring-actuated fork V. During the playing of a record, the movement of the pick-up arm T causes a lever B3 to be pushed by a lever A<2> into the path of the teeth of the sprocket, but the lever is intermittently shifted back by the teeth until accelerated movement of the arm T occurs. Thereupon, the lever B<3> moves farther inwards, and stops the sprocket wheel, so that the projection C<3> causes the clutch member D<3> to slide into engagement with and to drive a clutch member L<4>. By this means cams F<5>, F<6> are rotated, and operate respectively to raise the pick-up arm and to swing it outwardly. The swinging movement is effected through a lever X, which also indirectly actuates a lever X<3> to discharge a fresh record on to the turntable. The cycle of operations is completed during one revolution of the clutch, in which period the member V prevents accidental reactuation of the transfer mechanism by locking the wheel C. At the end of a revolution, the spring acting on the member V restores the various parts to their original position. A lever K<1> enables the mechanism to be adjusted for records of different sizes. M<2> is a button for enabling the transfer operation to be started at will. In order to stop the machine after the playing of a predetermined number of records, a switch E is provided, which is controlled by a ratchet wheel 0<3>, adapted to be set to any desired position, the wheel being rotated step by step, by means of the cam F<6>. The switch may be associated with a cam which, in a certain position, causes a lever M<3> to lock the lever A<2>, thus putting the automatic mechanism out of action. A subsidiary contact may be provided, whereby the pick-up may be automatically disconnected from the amplifier during transfer operations. Means such as a cam or spring are preferably provided to lower the pick-up gently and push the needle into the starting point on the record. Specification 191,413, [Class 40 (ii), Phonographs &c.], is referred to.