Patent GB-395009-A (GB)
Title: Improvements relating to gramophones or like sound-reproducing instruments
IPC: G11B17/28
Filed: 1931-11-09
Abstract: 395,009. Magazine gramophones. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.-(Grand Rapids Trust Co.; 77, Monroe Avenue, N.W., Baxter, H. M.; 266, Orchard Hill, S. E., and Automatic Musical Instrument Co. ; 1500, Union Avenue, S.E., all in Grand Rapids, Michigan, U.S.A.) Nov. 9, 1931, No. 31010. [Class 40 (ii).] A gramophone comprises a turntable 5, a plurality of cam elements mounted for rotation about a vertical axis concentric with the turn-table, and mechanical connections actuated in timed relation by the cam elements for operating means for transferring a record between the turntable and a record rack, and for moving a tone-arm into and out of operative engagement with a record on the turntable. The whole of the operating mechanism, apart from the driving motor, is carried by a platform 3, Fig. 1, which is rotatable on rollers 4 above a circular opening 7 in the frame 2. The various cam elements, which are pinned together so as to be rotatable on a hollow post 99 mounted on the platform 3 and encircling the turntable spindle 17, comprise the following : (1) Cams 98, 106 for operating the mechanism for transferring the record to and from the magazine ; (2) a cam 162 for returning and positioning the tone-arm ; and (3) a cam 171 for raising and lowering the tone-arm. During the first part of one revolution of the cams, a record is transferred to the turntable, and after an inoperative interval a record is played, and the revolution is completed to effect return of the record and tone-arm. The platform 3 is adapted to be rotated alternately in opposite directions so as to bring the record-transferring member thereon into correct position opposite the selected record in the record rack 6 which is provided with the records vertically arranged adjacent the platform. The platform is rotated by means comprising a member 24, Fig. 1, arcuate-shaped in plan and provided on the upper, lower and end faces with teeth engaged by a gear 40 on a shaft 23 which passes through an opening in a member 27 depending from the platform. A plate 28 at the opposite end of the shaft 23 is connected by pins 30 with a gear 31, and is spaced therefrom by springs. The gear 31 is driven from the main shaft 10 by gearing 32 34, 35 and a clutch 36, 37. The record-selecting mechanism comprises a plurality of discs 44, Fig. 7, separated by discs 45 and arranged on a shaft 43 which is driven by gearing from the gear 31. Each of the discs 45 corresponds to one side of a record disc Where, for example, there are ten records in the magazine, the first ten discs 44 correspond in succession to the sides of the records facing in one direction in the rack and the next ten discs represent in succession the opposite sides of the records. Therefore, according as to the direction of movement of the platform, i.e., as to which surface of the rack 23 is engaged by the gear 40, will depend which side of a record is to be withdrawn from the rack. Each disc 44 has a projecting lug 47 uniformly spaced angularly as indicated in Fig. 7 for co-operation with a pivoted trigger 48 movable vertically against a spring on a horizontal bar 50. Each trigger 48 is connected by a link 55, as shown in Fig. 31, with the armature levers 54 of a pair of electro-magnets 53, 531 so that when the switch 57 in the circuit of any pair of electro-magnets 53, 53<1> is closed, the corresponding trigger 48 is moved so that, in due course, it will be engaged by a lug 47 to operate a lever 64, Fig. 1, which causes a lever 72 to be raised from engagement with a projection 74 on a horizontally-sliding bar 75. A spring 78 then slides the bar 75 into position to effect disengagement of the clutch members 36, 37 by means of a catch 80 and lever 82, and thereby stops rotation of the platform. The gear ratio between the means for rotating the platform and the means for rotating the discs 44 is such that the platform is stopped with the transferring member opposite the selected record in the rack. The movement of the lever 82 also moves a lever 87 from supporting engagement with a pin 89 on a vertically-movable bar 90 which then falls so as to engage clutch members 92, 93 and cause the main shaft 10 to drive the cams on the hollow post 99 by means of a gear 95, shaft 96, and gearing 97, 98. The cams then cause the record to be transferred to the turntable, and the tone-arm to be positioned on the record. Record-gripping means. The platform carries an upstanding member 105, as shown in Figs. 1 11 and 15, having a horizontally-pivoted hollow member 119 provided with a gear 122 which meshes with a toothed rack 115 mounted on a post 116 carried by a bar 110 adapted to slide radially of the platform under the action of the cam 106 and roller 107. The hollow member 119 is provided with a transversely-disposed and rotatably-mounted hollow member 127 carrying spaced arms 124 provided with pivoted record-gripping jaws 125. A rod 128 is slidable in the hollow member 127 into or out of engagement with the inner ends of the jaws 125 so as to cause the latter to grip or release a record. The cam 106 rotates the hollow member 119 through the medium of the rack 115 and thereby turns the jaws 125 so that they straddle the selected record. A rod 133 is then caused by a lever 142 associated with the periphery of the cam 106 to slide the rod 128 so that the jaws 125 grip the record. The rack 115 then swings the jaws and record towards the turntable, and during this operation the hollow member 127 is rotated so as to bring the correct side of the record uppermost by means of a gear on the hollow member 127 engaging one of a pair of toothed sectors 146, 147, Fig. 14, on a slidable member 150 according to the direction of rotation of the platform. A stop 151, 152 is arranged at each of the extreme positions of movement of the platform and according to the direction of movement of the platform the corresponding stop is adapted to actuate a pivoted catch 154 which slides the sector member to produce the desired rotation of the record. The cam 98 operates a bar 103 carrying springs 285<1>, 287, Fig. 11, which are adapted to be compressed during the outward and inward movement respectively of the bar 105 so as-to assist the latter in its return to medial position. The tone-arm 158 is provided with an arm 161, Figs. 1 and 11, connected by a link 174 with a lever 165 which is pivoted on the platform and carries a roller engaging a cam groove in the cam 162. The inner end of the lever 165 engages the cam 171 in order to raise and lower the tone-arm. For records having a diameter of 10 inches, the lever 165 and link 174 swing together in the positioning of the tone-arm relatively to a record, but larger records, whch overhang the turntable, contact with a post 179 which releases the lever 165 and allows it to be swung without swinging the link 174 until a projection 187 on the lever 165 strikes the link 174. The tone-arm is then moved the necessary distance to co-operate with the record. While the record is being transferred to the turntable, a cam 221 on the periphery of the cam disc 162, Fig. 11, engages the arm 222 of a belt-crank lever 223 mounted, as shown in Fig. 31, in a block 219 on the platform 3 so as to move a member 217 on the other arm of this lever downwardly until a hole 216 in the member 217 is aligned with the end of a long rod 206 which extends through an opening 214 of a vertical rod 215. When at the time the tone-arm is positioned correctly for playing a record on the turntable, the arm 222 passes off the cam 221, a spring 232 raises the member 217 and the end of the rod 206 so as to lift the rod 215 and disengage the clutch members 92, 93 to stop rotation of the cams while the record is being played. At the end of playing a record, one of a pair of bell-crank levers 202, 211, Fig. 31, is moved so that its arm 203, 212 engages a stop 204 on the long rod 206 and slides the opposite end of the latter out of engagement with the hole 214 in the rod 215. The latter then falls and effects engagement of the clutch members 92, 93 in order to drive the cams for returning the tone-arm and transferring the record to the rack. The bell-crank levers 202, 211 are operated according as to whether the control groove at the end of a record is of concentric or eccentric form ; in the first case a depending member 199 on a member 193, Fig. 11, movable with the tonearm being adapted to engage a screw 200 mounted on the lever 202, and in the second case a tongue 196 mounted on an arm 195 on the member 193 engages ratchet teeth on a' member disposed on the lever 211. The rod 206 is re-engaged with the holes 214, 216 by a spring 213 acting on the levers 202, 211. When the record has been returned to the rack the lower end of a vertical rod 238, Fig. 1, is disengaged from a notch in a sliding bar 77 by the action of a cam disposed on the underside of the cam 98. A spring 247 then moves the bar 77 to the right so that the catch 80 engages the lever 82 and a shoulder 73 on the lever 72 engages the projection 74 of bar 75. An arm on a shaft 242, which is driven by gearing from the cam 98, then slides the bar 77 so as to cause the lever 82 to engage the clutch members 36, 37 and to disengage the clutch members 92, 93. The playing of a record may be stopped at any time by closing a switch 250, Fig. 31, in the circuit of an electro-magnet 252 so as to cause the rod 206 to effect disengagement of the clutch members 92, 93. Should a number of records be selected at the same time by closing the switches in circuit with the electro-magnets 53, the records thus selected will be played in the order in which the lugs 47 corresponding thereto engage the corresponding triggers 48. When an armature lever 54 is turned inwardly to engage a lug 47, it causes a horizontal lever to act on a lever 276 and arm 273, Fig. 1, and close a mercury switch 278 which is in circuit with the driving motor. When the