Patent GB-680795-A (GB)
Title: Improvements in or relating to automatic gramophone-record changing apparatus
IPC: G11B3/08
Filed: 1947-11-21
Abstract: 680,795. Magazine gramophones; turntables and mandrels. FITCH, C. K. Nov. 19, 1948 [Nov. 21, 1947], No. 30972/47. Class 40 (ii). In automatic record changing apparatus records are stacked face to face in inclined position between spaced supports 11 for their lower edges and an abutment 13 overhanging the opposite side of turntable. On the pick-up arm reaching the quick pitch groove of the record means are engaged to raise and return the pick-up clear of the turntable, to raise the existing record at one side from the turntable so that motion of the latter slides the record into a receptacle (not shown) and to operate mechanism 17 releasing the lowest record to tall by gravity on to the table and preparing the next stack record for release. Automatic initiation and timing mechanism. Inward traverse of the pick-up arm 63, Fig. 1, operates through lost motion linkage 77, 80, 82, 57 to cause inward movement finally of a spring mounted pin 99 (Fig. 4) towards a crescent shaped cam surface 89 on the turntable spindle 49 within which it is finally trapped so that the arm 57 with depending lug 56 is drawn inwards and inserts a follower 50 into engagement with a leadscrew 48 on the spindle. The follower 50 (Fig. 1), is mounted in a slotted guide 60 and connected to cams 42, 26 connected by a spring 25. On reaching its lowest position, after operating the cams 42, 26, the follower 50 is disengaged by a projection from the leadscrew and returns by action of spring 25 with the cams to initial position. Movement of the pin 84 into the path of the cam by an amount corresponding to the pitch of a recordgroove results in the pin and its mounting member being correspondingly permanently displaced by the leading edge of the cam surface but the quick-pitch groove traps the pin. Pick-up positioning and return and record removing action. The cam 42 has pins 69, 73 engaging slots in a bar 67 having an abutment 91 adapted to engage an arm 92 on the pick-up shafts terminating in a friction pad 94 projecting through a slot in the deck of the gramophone. The slots are such that the bar 67 is first moved laterally to the right to tilt the pick-up shaft about a transverse axis at mounting 65 and thus raise the pick-up and arm 92 so that the pad 94 contacts a friction surface on the underside of the turntable and the pick-up arm thus swing free outside the edge of the record, at the same time a further arm 75 on the pick-up shaft running upon a ramp 76 to engage a retaining recess 96. On a new record being deposited on the turntable a spring-loaded peg on the turntable is depressed and operates one arm of a bell-crank lever the other arm of which engages the friction pad 94 so that the arm 75 is forced out of the recess. By this time the pin 73 has reached a portion of its slot in which the bar 67 which is spring-loaded moves to the left and lowers the pick-up arm slowly along the ramp 76 on to the new record. The pin 73 has a chamfer along one side so that on return movement of the cam 42 it rides under the bar 67 to its initial position without moving the latter. The cam 42 also operates near its upper limit a spring-loaded plunger 46 which raises the record off its central peg, rotation of the turntable sliding the record into a laterally located magazine. The base of the plunger 46 is chamfered to permit the return of the cam. Hand control means may move the plunger aside when a record repeat is wanted. Record supporting and depositing means. The cam 26 operates through linkage to lower arms 17 pivoted on each of the two record supports 11, each arm having a nose formed of two projections 18, 19, with an intermediate notch 20 for the lowermost record. The latter tilts about the notches just above the level of the turntable so that its far edge falls from the abutment 13 on to the turntable, the main stack of records being still held by the support edges 16. As the record tilts its near edge rises and rebounds from the inside edge of an upstanding peg so located between the two supports that in conjunction with suitable location of the notches the record centre engages a tapered and spring-mounted extension of the turntable spindle. The same arrangement is suitable for different sizes of record as smaller records are given a greater rebound by the peg. On the arms 17 rising the projections 18 engage between the two lowermost stack records so that the lower one slides into the notches 20 preparatory to release. The return movement of the cam 26 is slowed up by a detent lever 35 pivoted to the linkage biased against a cam 90 on the turntable spindle by a spring 33. The turntable is rotated from the rim by a friction drive. Switches in parallel are associated with the arm 75 and cam 26 respectively opened when the pick-up arm is located in its rest and when the cam 26 has returned to its initial upper position, so that the gramophone is switched off when the final record has been played. Specification 680,799 is referred to. According to the Provisional Specification the means starting the sequence actuating mechanism may be a star wheel carrying a cam swung through linkage by the pick-up cam into engagement with a peg on the underside of a disc secured to the turntable so that the star wheel and cam are both rotated to engage the mechanism.