Patent GB-329289-A (GB)
Title: Improvements in and relating to automatic record changing mechanism for gramophones
IPC: G11B17/16
Filed: 1929-02-08
Abstract: 329,289. Whitman, R. B. Feb. 8, 1929. Magazine gramophones; returning sound-box to starting point; turntables; stopping. - Relates to magazine gramophones of the kind in which a pile of records is supported centrally by a stepped pin and peripherally by a ledge, the records being dropped one at a time, upon supports carried by a turntable and, when in this position, after being played being allowed to fall to a lower level. According to the invention, the turntable is provided with three movable supports for holding a record in the playing position, which supports are adapted to be automatically displaced one at a time to release the record, after being played, so that it falls down on to the rotating turntable. A portable machine is described and shown. The turntable spindle 23, driven by an electromotor 44, is extended to meet a pin 28 depending from a bracket 29 secured to a yoke 30 which is hinged to the motorboard. A plate 90 is secured to a horizontal support on the bracket 29, and co-operates with an offset end of the pin 28, on which a pile 27 of records is threaded, to support the pile. The outer edge of the plate on which the records are supported peripherally is preferably an arc having a greater radius than that of a record. When a record is being played, it rests upon three supports 26, pivoted at 80 on the turntable, Fig. 8. Each member 26 is normally held by a spring 83 in the position shown in full lines, but when the record on the supports has been played, and the tone-arm has been automatically lifted and swung outwards, the supports are tilted in turn, by means described below, and the played record falls down on to the turntable itself. The lowest record in the pile 27 is then pushed off the cupport 90 by a finger 92, Fig. 7, so that it clears the offset end of the pin 28, and can fall down the spindle 23 on to the supports 26, which have meanwhile resumed their normal position. On the motor-board, beneath the turntable, the mechanism shown in Fig. 2 is provided for effecting the necessary movements of the tonearm when a record has been played, and for changing the record. Two interengaging levers 60, 42 are mounted respectively on ball-andsocket pivots 61, 52, the lever 42 having at one end a cam 42<1> engaging with a pin 40 adjustably rnounted on the tone-arm 33, Fig. 6. The levers 60, 42 are controlled by a pin 63 and a cam 62 on a wheel 58 which is mutilated in two places 58<1>, 58<2>. During the playing of a record, the wheel 58 remains in the position shown in Fig. 2, with the gaps in the teeth adjacent to pinions 51 and 57. The wheel 51 is constantly driven through gearing by the motor spindle. When the end of a record is reached, the sound-box is rapidly moved towards the centre of the record by means such as a large.-pitch spiral groove on the record, and thereupon the pin 40 engages and moves a lever 54. This causes the pinion 57 to rotate the wheel 58 sufficiently to gear with the pinion 51, which consequently drives the wheel 53 through one revolution. The cam 62 and pin 63, acting successively, first of all cause the lever 60 to tilt and to swing about its pivot 61, these movements being transmitted to the lever 42. Thus, through the action of the cam 42<1> on the pin 40, the tone-arm is raised and swung outwardly, with the needle clear of the record. At this stage a pin (not shown) on the wheel 58 strikes a lever 66, shifting it so as to cause a plate 77, Figs. 2 and 8, to ride up an inclined rail member 78. This action is effected through a lever 73, bearing a spring-controlled trigger 71 with which the lever 66 engages. Each record support 26 carries a downwardly extending pin 79, and these in turn engage the raised plate 77, causing the supports 26 to be tilted successively, so that the record that has just been played is allowed to fall down from the position shown at 27' to that shown at 27<2>, Fig. 6. When this action has occurred, further movement of the lever 66 causes a lever 84 to operate the finger 92, Fig. 7, through a Bowden wire 87, so that another record falls down on to the supports 26 from the upper pile. Subsequently, the lever 66 is passed by the actuating pin on the wheel 58, and a spring 69 returns it to the normal position; another spring, not shown, has meanwhile moved the member 77 back to its original position. Before the wheel 58 has completed a revolution and again come to rest, the pin 63 and the cam 62 cause the levers 60, 42 to move again in such a manner that, through the engagement of the tone-arm pin 40 with the cam 42<1>, the tone-arm is swung inwardly and lowered, until the soundbox needle rests on the fresh record to be played and is gently urged into the beginning of the sound groove. Some further downward movement of the cam 42<1> occurs after the sound-box needle has engaged the record, so that the pin 40 no longer rests on the cam. After the last record has been played, however, there is no record on the supports 26 when the tone-arm is fed inwardly, and consequently the pin 40 remains in engagement with the cam 42<1> for a longer period, so that the sound-box moves further inwards and downwards than would be the case if a record were in position for playing. These movements mav be utilized to operate a switch to break the circuit of the driving motor and thus to stop the operation' of the whole mechanism. The positions of the ledge 90 and of the supports 26, and the effective length of the pin 40, may be adjusted to enable records of various sizes to be used in the machine. For any particular setting, however, a group of records which are alike in size must be used. Modifications in details of the mechanism for initiating the movement of the wheel 58, in the construction of the record-supports carried by the turntable, and in the mechanism for tripping the supports to release a played record, are described.