Patent GB-340006-A (GB)
Title: Improvements in or relating to gramophones
IPC: G11B17/16
Filed: 1929-08-16
Abstract: 340,006. Cowey, L. E. Aug. 16, 1929. Multiple machines; mandrels or turntables; brakes, arrangement and disposition of.-Relates to magazine gramophones having a series of disc records piled upon the turntable so that each record can be played when those above it have been removed. According to the invention, the record-changing mechanism which is movable step by step through a series of positions so as to tilt, during each movement, the uppermost record so that it is discharged from the turntable, is connected, through ratchet mechanism, to a rotary actuating member which also operates cam mechanism for returning the tone-arm to the starting position. The arrangement is such that a single operation of the actuating member moves the record-changing mechanism through one step and at the same time causes the cam mechanism to lift the tone-arm and swing it outwardly until the tone-arm, or a member connected thereto, engages a fixed stop and finally to lower the tone-arm until the reproducer bears upon the uppermost record remaining upon the turntable. The machine illustrated employs six records, each carried by a tray 1, 2, which are piled upon the turntable 3. Each tray 2 has a peripheral flange 9 adapted to be engaged by one of six fingers 10 on a vertical shaft 11 slidably and rotatably carried in frame plates 12, 13. The shaft 11 is rotated step by step by a reciprocating strap 18 and pin wheel 20 so that during each movement the uppermost tray 2 is discharged into a receiver, as described in Specification 339,973. The strap 18 is driven by an eccentric 14 on a shaft 15. When the final tray has been discharged into the receiver, a brake-pad 27 on an arm 26 fixed to the shaft 11 engages the turntable and brakes it. The tone-arm 31 is ball-jointed to the sound conduit 32 and can swing vertically on a pivot 33, the conduit 32 being rotatably carried in the frames 12, 13. A rod 35 pivoted to links 36, 37, pivoted to the conduit 32, carries a tappet plate 34. When the stylus reaches the end of a record groove, a cam 43 on a sleeve 42 on the shaft 15 engages the plate 34 to lift it, move it transversely, and then lower it, this movement causing the stylus to be re-positioned ready to reproduce the next record. Outward movement of the tonearm 31 is limited by an adjustable stop (not shown). The mechanism for returning the tonearm to the starting position is more fully described in Specification 340,225 [Group XXXVIII]. The actuating shaft 15 is driven by a motor 51 through gears 54, 35, 56, the gear 56 being connected by a finger 58 to a disc 57 fixed to the shaft 15. A disc 59 fixed to the eccentric 14 carries a sliding plate 60 having a finger 61 engagable with teeth 62 on the disc 57. The plate 60 has a cranked finger 64 engaging a radial slot 65 in the disc 59. A spring 66 urges the finger 61 towards the teeth 62. The slot 65 has a shoulder 67 which can engage the finger 64 to hold the finger 61 away from the teeth 62. The strap 18 has a cam surface 68 which engages the finger 64. The sleeve 42 is coupled to the shaft 15 by a light frictional coupling consisting of a plate spring 70. The shaft 15 is capable of limited axial sliding movement and has a worm 71 meshing with a worm wheel 72 frictionally carried by the sound conduit 32. The rotation of the worm 71 tends to feed the shaft 15 to the right, Fig. 2, but the rotation of the, worm wheel 72 due to the movement of the tone-arm when the stylus is tracking the record groove cancels the feeding movement of the worm 71. A groove 79 in the shaft 15 engages a tappet lever 80 on a rock-shaft 81 which also carries an arm 82 having a roller 83 normally positioned in the path of an arm 84 extending from a boss 85 rotatably mounted on the base-plate 16<a>, Fig. 4. Mounted co-axially with the boss 85 is a toothed wheel 86 meshing with a toothed wheel 87 fixed to the shaft 53. The boss 85 is connected to the wheel 86 by a spiral spring 88 fixed at one end to the boss 85 and frictionally engaged at its other end by a casing 89 carried by the wheel 86 so that as the wheel 86 is rotated the spring 88 will be wound up and then slip relatively to the wheel 86. Operation of the machine. When at rest the cam 43 holds the tone-arm in its raised position and the brake-pad 27 engages the turntable. The trays 1, 2 containing records are stacked upon the turntable and the latter is started by depressing and turning the shaft 11 to disengage the brakepad 27 from the turntable. The sleeve 42 is driven by the shaft 15 so that the cam 43 swings the tone-arm out to the starting position and lowers it on to the top record. The cam surface 68 then retracts the plate 60 and engages the finger 64 with the notch 67, after which the sleeve 42 is arrested by the engagement of a pin 76 thereon with a spring stop-plate 77. When the inward feeding movement of the tone-arm ceases at the end of reproduction, the shaft 15 moves to the right, Fig. 2, rocking the arms 80, 82 and releasing the arm 84. The latter is rotated by the spring 88 and trips the finger 64 to disengage it from the notch 67, and the finger 61 then engages the teeth 62. The sleeve 42 then rotates with the shaft 15 so that the cam 43 lifts the plate 34 so as to replace the tone-arm in a position to recommence reproduction. During the outward movement of the tone-arm, the strap 18 rotates the shaft 11 through one step so that a finger 10 engages the flange 9 of the tray containing the played record and lifts it so that it is discharged into the receiver by the rotation of the turntable. The cam surface 68 then disengages the finger 61 from the teeth 62 and engages the parts 64, 67, and the sleeve 42 is then arrested by the plate 77. During the rotation of the sleeve 42, a ball. 75 thereon engages a fixed plate 74 to move the shaft 15 to the Left. Fig. 2, and thus move the arm 82 into the path of the arm 84. The succession of events is then repeated for the second record, and so on. When the last record has been played, the brake-pad 27 engages the. turntable and the shaft 15 is held in the position of Fig. 2 by the engagement of the ball with the plate 74 so that the tone-arm will be held in the raised position by the cam 43. To permit reproduction from any record to be stopped at will, electromagnetic or other means may be provided for moving the finger 61 into engagement with the teeth 62 so that the tonearm is lifted and returned to the starting position whilst the record is changed. To repeat a record, means may be provided to retract the strap 18 from engagement with the pin wheel 20 so that no record-changing movement will occur when the sleeve 42 rotates. The means for stopping or repeating a record may be controlled electrically from a distance. In a modification illustrated in Figs. 5 and 7, the shaft 15 cannot move longitudinally. The finger 64 has a tooth 97 adapted to be engaged by teeth on the upper face of a wheel 98 which is mounted for a rotary and a limited axial movement. The wheel 98 is held depressed by a spring 99 and has on its lower face projections 100a which co-operate with spring urged balls 100, so that at regular intervals during its rotation the wheel 98 tends to rise to bring the face teeth into the range of the tooth 97. A detent 101 on a swinging arm 102 is adapted to project through a slot in a fixed bar 100b, and into engagement with a pin 103a, so that the members 97 and 98 cannot mutually engage. The wheel 98 carries a series of pins 98a adapted to engage a roller 102a on the arm 102 and arranged to disengage the members 101, 103<a> once after each successive engagement of the balls 100 with the projections 100a. A pin 104 on a lever 103 frictionally connected to the sound conduit 32 engages the arm 102 so that, during reproduction, the detent 101 is moved into engagement with the pin 103a. The cam plate 43 has rollers 43a at its end which can engage a depressed portion 34<a> of the tappet plate 34. The operation of this modification is as follows :-As the shaft 15 rotates during reproduction, the sleeve 42 is first arrested by the engagement of the roller 43a with the part 34a of the plate 34. As the tone-arm moves inwardly, the part 34a moves clear of the roller 43a so that the sleeve 42 can rotate until the finger 64 lies within range of the wheel 98. By this time the detent 101 has been moved into engagement with the pin 103a. The repeated engagement of the pins 98a with the roller 102a disengage the detent 101 and pin 103a, but so long as the tonearm moves the lever 103 will operate to re-engage the parts 101, 103a; the repeated engagement of the projections 100<a> and balls 100 thus fails to raise the wheel 98. When the tone-arm ceases to move at the end of a reproduction, the detent 101 is not re-engaged with the pin 103a, so that the next engagement of the projections 100a and balls 100 lifts the plate 98 so that the teeth thereon strike the tooth 97. The finger 64 is thus released from the projection 67 to engage the clutch teeth 61, and the sleeve 42 rotates to actuate the record-changing and tone-arm repositioning mechanisms.