Patent GB-438658-A (GB)
Title: Improvements in gramophones and like sound-reproducing apparatus
IPC: G11B17/16
Filed: 1934-04-09
Abstract: 438,658. Magazine gramophones. DOWNS, A. R., 8, St. Nicholas Road, Brighton, Sussex. April 9, 1934, No. 10663. [Class 40 (ii)] In a magazine gramophone, a swinging arm is provided with means for picking up each record when in a storage position by engagement with its central hole, and is adapted to transfer the record to a playing position in which it may be rotated whilst suspended ; means are also provided whereby the record may be played on both sides in turn without being inverted, after which it is released and the swinging arm returns to transfer the next record from the storage position. Fig. 1 shows the general arrangement of the operative parts, A being the arm for transferring records from the storage position B to the playing position C, where each is rotated by means of a motordriven spindle 28 so that reproduction can be effected by means of pick-ups 34, 35 mounted so as to coact with the upper or the lower side of the record respectively. The unplayed records, either 10-inch or 12-inch, are stored in any order on a platform 40, Fig. 5, which is adapted to be raised a distance equal to the thickness of a record after each removal of a record. The raising movement is effected by a nut 44, threaded on a hollow screwed spindle 42 on which the platform is mounted. A record-centring rod 60 is automatically pushed up through the spindle 42 each time a record is removed from the magazine. The nut 44 is driven by gearing from a cam shaft 51, which makes a single revolution during the whole cycle of operations concerned in the playing of both sides of a record. The cam shaft is driven at predetermined intervals by a motor that is separate from that driving a record for playing. For transferring the records from storage to the playing position, the swinging arm A has at its outer end a gripping device, which picks up the top record by engagement with its central hole. The arm A is pivoted at 2 on a bracket at the top of a column 5, means being provided to enable the arm to rise and fall about the pivotal axis 2, and to swing about the vertical axis of the column 5. The gripping device comprises pivoted claws 18, Fig. 4, adapted to be protruded by spring action so as to engage the edges of the hole in the record and to pull the record up tightly against a friction surface 31 on a disc 32. This disc is attached to a sleeve 13, rotatably mounted in a bearing carried by the arm A. A tube 12, having an extension which forms a mounting for the claws 18, and which has a slotted rod 25 projecting therefrom, is fitted in the sleeve 13. When a record has been picked up, and the arm A has been swung so as to carry the record into playing position over the motor driven spindle 28, the arm is lowered to effect engagement between a tongue 27 on the spindle 28 and the slot in the rod 25. This connection enables the sleeve 13 to be driven, and by the frictional contact at 31, to rotate the record. The arms carrying the pick-ups 34, 35 are each pivoted at 36 on a hollow spindle passing through a standard 37. Each of these spindles has at its lower end a cam 95, Fig. 5, coacting with mechanism under the control of the cam shaft 51 for swinging the pick-up arm outwardly when necessary and then inwardly to a starting position depending on the size of the record in use. Such swinging movements are in each case preceded and followed by a raising or lowering of the pick-up relatively to the record surface, by means of rods 123 under the control of cams on the main shaft 51. A lever 39 protruding through the base-board 6 is so arranged that a 12in. record as it is being carried by the arm A to the playing position moves the lever, while a 10-in. record passes clear of it. This movement of the lever 39 shifts a set of levers which co-operate with cams on the shaft 51 in such a manner as to determine the extent of inward movement of the pick-ups during resetting. Switches adapted to control the record-driving motor 125 and the cam-shaft driving motor 52 are connected as shown in Fig. 12. The switch 125<a> is for reversing the direction of the motor 125 after one pick-up has been in use, before the other one comes into operation. The switch 135 is controlled by both pick-up arms ; it opens automatically when the playing of either side of a record is completed and closes when a pick-up has been returned to the outermost position, after playing. The switches 141 and 130 are in parallel in the circuit of the motor 52, 141 being mechanically connected to 135 so that either is open when the other is closed, whilst 130 is controlled by a cam on the shaft 51. The switches 142 and 143 are manually controlled, and are used for initiating the operation of the machine, which is as follows. Beginning with the switches 130 and 135 closed and the switch 141 open, the motor 52 is started and drives the cam shaft 51. The first effect is that one of the cams causes a rod 88 to be pulled down and rock the arm A about its pivots, Fig. 5, thus raising from the magazine a record with which the gripping members are engaged. The centring spindle 60 then moves upward through the holes in the stored records. A cam 73, acting through a rod 77, causes the arm A to swing and carry the record to the playing position, whereupon the arm is lowered and the rod 25, Fig. 4, is caused to engage the driving spindle 28, Fig. 1. Cams on the shaft 51 cause the upper pick-up to be positioned over and lowered on to the starting point of the record, after the reversing switch 125<a> has closed and so started the gramophone motor 125. Shortly afterwards, the switch 130 opens and stops the motor 52, the cam shaft having made half a revolution. When the upper side of the record has been played, the upper tone-arm causes the switch 135 to open and at the same time the switch 141 to close. The motor 125 therefore stops and the motor 52 starts. Again the cam shaft is driven, causing the upper pick-up to be returned to the outermost position, while the lower pick-up is brought into action by the release of a counterweight. The switch 125<a> then closes, reversing the direction of the motor 125, and the motor 52 is stopped by the opening of the switch 130. On completion of the playing of the underside of the record, the switch 135 is again actuated, to cut out the motor 125 and switch on the motor 52. Cams on the shaft 51 cause the lower pick-up to be returned to the outer position, and the played record is then released so that it can drop down a sleeve 38 surrounding the spindle 28. The release takes place when Bowden-wire mechanism, operated by a cam on the shaft 51, actuates a lever 29 and causes the claws 18 to be retracted, Fig. 4. Finally, the arm A is swung back over the pile of records on the storage platform, which has meanwhile been automatically raised a distance equal to the thickness of a record.