Patent GB-460502-A (GB)
Title: Improvements in or relating to automatic gramophone mechanisms
IPC: G11B3/28
Filed: 1936-07-16
Abstract: 460,502. Gramophones. COLLARO, C., and COLLARO, Ltd. July 16, 1936, No. 19778. [Class 40 (ii)] Automatic gramophone mechanism is furnished with a member 33 connected to the pick-up arm 1 and an actuator which is driven along a predetermined path to brush past the member 33 when the pick-up needle is on the smooth edge of a record to be played, thereby urging the needle into the playing groove, while a resilient or yielding connection interposed in the transmission between the driving source and the pick-up arm yields when the needle enters the groove, the actuator being arranged immediately afterwards, and without any substantial alteration in its path of movement, to snap past and leave the said member and consequently cease to exert a force tending to move the pick-up. The member 33 is constituted by a tongue which is pivoted at 34 to a plate 25 carried on a curved plate 4 movable with the pick-up arm 1. The actuator is constituted by a pin 5 on an arm 6 which is driven by a shaft 8. The pick-up arm 1 is mounted on a rotatable vertical tube 3 which carries the plate 4 at its lower end. The mechanism embodies a shaft 7 which,. after the playing of a record, is clutched automatically to an electric motor and makes one complete revolution during a record changing process. During the first stage in the revolution of the shaft 7, a cam 10, Fig. 4, carried by the shaft actuates a bell-crank lever 12 engaging a nut 15 on a rod 16 so as to swing the pick-up arm 1 upwardly about its pivot 17<a>. The shaft 8, which is driven by gearing 9 from the shaft 7, then causes the pin 5 to act upon the plate 4 so as to swing the pick-up arm outwardly. The pin 5 is carried by the arm 6 which is pivoted at 19 to a plate 20 rigidly fixed to the shaft 8, and the arm 6 and plate 20 are normally held in such a position that a pin 22 on the arm 6 is in contact with an edge of the plate 20 by a spring 21 connected between the pin 22 and a pin 23 on the plate 20. During the first movement of the arm 6, while the pick-up arm is being raised, a pin 30 on the arm 6 engages a cam 30<a> so that the arm 6 yields about its pivot against the action of the spring 21. The further movement of the arm 6 causes the pin 5 to move the curved plate 4 and thereby the pick-up arm outwardly to its outermost position. The pin 5 then moves out of contact with the plate 4 and continues in a circular path while a new record is being fed to the turntable. After this operation, the pin 5 engages the edge 24 of a place 25, which is fixed to the plate 4 by means of pins and slots 26 and a set-screw 27, so that the plate 4 is moved in an anti-clockwise direction and the pick-up arm is moved inwardly to a position above the smooth edge of the record to be played, this movement of the plate 4 and pick-up arm ceasing when the pin 30 contacts with the edge 31 of a pivoted plate 28. The pick-up arm is again moved inwardly when the pin 5 engages the tongue 33 pivoted to the plate 25, such movement taking effect after the pick-up needle has been lowered on to the smooth outer edge of the record by the action of the cam 10 and lever 12. The tongue 33 is loaded by a spring 42 so that it tends to rotate in anticlockwise direction as seen in Fig. 1, within the limit allowed by a stop 43. The action of the pin 5 on the tongue 33 is to urge the plate 4 and pick-up arm 1 about the axis of the tube 3 until the needle enters the outer end of the playing groove of the record. The spring 42 provides the resilient or yielding connection referred to above. The pin 5 subsequently snaps past the tongue 33 and is brought to rest at the conclusion of one revolution of the shaft 7. The distance which the pick-up arm 1 has to be moved inwardly towards the new record on the turntable depends upon the diameter of this record, and is controlled by the position of the pivoted plate 28 which is engaged by the pin 30 to stop the inward movement of the pick-up arm 1. The plate 28 may be set in three different positions corresponding to three different sizes of records and is adapted to be latched in the selected position by a latch 35 engaging one of three notches 38, 38<a>, 38b. Normally, the latch 35 engages the notch 38 corresponding to the smallest size of record. If a larger size of record is to be played, feelers engaging the record move the plate 28 outwardly through the medium of a bar 39 so that one of the other notches 38<a>, 38<b> is engaged by the latch 35, and the stopping action of the pin 30 occurs correspondingly later. Specifications 317,703, [Class 40 (ii)], 439,106, and 460,501 are referred to.