Patent GB-568663-A (GB)
Title: Improvements in automatic record changers for gramophones
IPC: G11B17/02
Filed: 1942-07-23
Abstract: 568,663. Magazine gramophones. AGABALTIC AKTIEBOLAG. July 23, 1942, No. 10307. Convention date, July 24, 1941. [Class 40 (ii)] Relates to automatic record-changers for gramophones of the kind in which the records, piled above the turntable, are supported at their centre by a shoulder on a central inclined stem and at least at one point at their edge, and consists mainly in so arranging the stem and associated parts that when a record is released and drops on the turntable the travel of the centre of the record in a radial direction is at least equal to the difference between the radii of large and small records, this enabling the machine to operate with a pile of records of both sizes mixed indiscriminately. Magazine.-The records are stacked on a shoulder 13, Fig. 1, on a central stem 12 and their edges rest on a side table 24 to which an arm 16 is hinged at 15; the end of this arm has a hole 17 to engage the end of the stem 12 over the records stacked thereon ; a spring 18 is provided on the arm to grip a groove 19 in the end of the stem 12 ; and a weighted lever 22 is hinged to the arm 16 at 21 to press the edges of the records down on the table 24. The records are dropped one at a time by the reciprocation of a slide 26 in a slot of the table 24, first outwards then inwards. The slide has two shoulders 32, 33. If the lowest record is one of small diameter its edge is engaged by the shoulder 33 during the inward return movement of the slide. If the lowest record is one of large diameter its edge is engaged by the other shoulder 32. In either case, the record is pushed under a shoulder 14 on the stem 12 and over the shoulder 13 and drops down the inclined part of the stem 12 on to the turntable 10. The length and inclination of the stem 12 is such that the edge of the record will drop off the table 24 whether the record is small or large. The table 24 is provided with a spring- urged seat 65, Fig. 4, which yields to its spring when the last record has been dropped to cause the driving motor to be switched off as described below. The slide 26 is provided with a spring plunger 148 which is differentially positioned according to the diameter of the lowest record as it is dropped and controls the repositioning of the pick-up on this record in accordance with its diameter as described below. Initiation of record-changing operation.- During the playing of a record an arm 118, Figs. 3 and 5, follows the inward movement of the pick-up arm 99 and at the end of the record a side flange on the arm 118 comes against a finger 136 of a lever 134 pivoted at 135, and causes this lever to be turned anticlockwise. The lever 134 is connected by a link 133 to a lever 131 pivoted at 132 and formed with a tooth 130, which normally engages a shallow notch 129 in the cam-shaped end of a lever 126 pivoted at 127. When the lever 134 is turned anticlockwise the tooth 130 is moved away from the notch 129 and thus unlocks the lever 126. The other end of this lever has a pin 124 normally in engagement with a shallow notch 137, Fig. 7, in the cam face 123 of a lever 120, Fig. 2, above the lever 126, whereby the lever 120 is normally locked. When the lever 126 is unlocked a spring 138 turns the lever 120 counterclockwise about its pivot 122, forcing the pin away from the notch 137 and wedging it away by the cam 123 so that the lever 126 is turned clockwise against its spring 128. The turning of the lever 120 counterclockwise causes a face 140 thereof to bear obliquely against a pin 72 on a cam-disc 42 thereby turning the disc slightly round clockwise in the direction of the arrow 49. Normally the cam-disc is at rest with a recess 152 in its rim opposite a rubber roller 41 on the turntable spindle 11, which roller is then not in contact with the cam-disc. The slight turning of the cam-disc by the lever 120 causes the rim of the cam-disc to be gripped by the roller 41 and to be driven thereby to make one revolution to produce the recordchanging operations. These operations may also be initiated at any time by an inward push of a knob 156, Fig. 2, at the end 157, Fig. 3, of a rod 158 connected at its inner end with the lever 134. Record changing and pick-uy operating mechanism.-The cam disc 42 has a groove 48, 50, 51 in its upper face, Fig. 2, and a multiple groove 103, 104, 105, 106 in its lower face shown in Fig. 3 as viewed from above. In both Figures, the parts are shown in the normal rest position. The cam disc when started as described above makes one revolution counterclockwise to perform the record-changing operations in the following sequence. A pin 86, Fig. 2, on a lever 85 is moved by the inclined cam slot 51, and the lever is thereby turned counterclockwise about a pivot 87. The other end of the lever 85 is below the motor-board 40 and is connected by a link 89, Figs. 3 and 5, to one arm of a bell-crank 90 pivoted at 92. The other arm of the bell-crank is connected by a pin-and-slot joint 93, 94 to a vertical rod 96 bearing at its upper end underneath a plate 102 attached to the pick-up arm 99, which is mounted on a horizontal pivot 101 on a lug 100 on a vertical bush 97 rotatable in a socket 98. The rod 96 extends through the bush 97. When the cam groove 51 turns the lever 85 counterclockwise as described above, the pickup arm is lifted by the rod 96. After this, the pin 86 rides in the concentric cam groove 48 while other operations are proceeding. Another pin 113, Fig. 3, on a lever 114 normally lies in the wide cam groove 104 ; and this lever is connected by a link 116 to the arm 118 attached to the bush 97. After the pick-up has been lifted, the pin 113 is guided by the inner face face of the cam groove 104 into the concentric cam groove 103, this causing the pick-up arm to be swung to its outward position. Another pin 47 normally in the concentric cam groove 48 is then reached and moved by curved cam groove 50. The pin 47 is on a lever 45 which is then turned clockwise and by means of a connecting link 31 turns a lever 28, Fig. 1, counterclockwise about its pivot 30. The lever 28 is connected to the slide 26 and pulls that slide to the left allowing the edge of the lowest record to fall in front of the shoulder 32 or 33 according to the diameter of the record. Immediately after this, the pin 47 and the several parts connected thereto are driven back by the oppositely directed cam groove 51 ; this causes the lowest record to be pushed by the slide 26 and to drop on the turntable. The pin 113, Fig. 3, which has meanwhile been travelling in the concentric cam groove 103 has now reached the inwardly directed cam grooves 105, 106 and is guided into one of them according to the diameter of the record as will be described below. The lever 114 is thereby moved counterclockwise and brings the pick-up arm in over the edge of the fresh record. Then the pin 86, Fig. 2, is moved by the inclined cam groove 50 back to its original position shown, and the lever 85 is thereby turned clockwise, causing the pick-up arm to be lowered to place the needle in the starting groove of the fresh record. When the pick-up arm is moved from its inward to its outward position, a flange on the arm 118 bears on the finger 136 and deflects the lever 134 clockwise, causing the tooth 130 on the lever 131 to be pressed against the camshaped end of the lever 126 ; and, when near the end of the rotation of the cam disc 42, the pin 72 thereon engages the oblique face 121 of the lever 120 and turns that lever back clockwise against its spring 138 and thereby allows the lever 126 to be turned back counterclockwise by its spring 128, the tooth 130 re-engages the notch 129 and these parts are again looked in the normal rest position. The recess 152 in the rim of the cam disc is then back opposite the roller 11 and the rotation of the cam disc stops, the record-changing operation being completed. Control of pick-up by diameter of record.- When a record rests on the slide 26, Fig. 1, the spring plunger 148 in the slide is depressed by the record. When the slide is moved outwards during the record-changing cycle, the plunger 148 remains depressed if the lowest record is a large one, but springs up outside the edge of the lowest record if this is a small one. When the plunger is not depressed, a lug 38 thereon is out of reach of a lever 39; but when the plunger is depressed, the lug 38 engages and turns the lever 39 clockwise when the slide 26 returns forward to cause the lowest record to be dropped on the turntable. The notched end 52 of the lever 39 then engages and turns a lever 53, Fig. 3, clockwise. The lever 53 is pivoted at 54 and connected by a pivot joint 55 to a link 56 provided at its other end with a pin 57 guided in a slot 58 in the motor board 40. A lever 59, Fig. 2, is jointed at one end to the pin 57 and has a pin 60 at its other end guided in a slot 61 in a fixed bar 62. When the lowest record in the pile is a small one and the plunger 148 therefore undepressed at the operative inward stroke of the slide 26, the lever 39 is not operated and the pin 60 lies at the inner end of the slot 61 as shown. When the lowest record is a large one, the lever 39 is operated and shifts the pin 60 to the end of the slot 61 away from the centre of the cam disc 42. The pin 60 when in this outward position is adapted to co-operate with a lever 110 on the cam disc. The lever 110 is attached to the pivot 109, Fig. 3, of a point lever 108 at the junction of the cam grooves 105, 106 with the cam groove 103. In the early part of the rotation of the cam disc, the lever 110 passes a fixed pin 111 which turns the lever inwards if it is not already inward. The point lever 108 is then in such a position that it leads from the groove 103 to the inner groove 105 corresponding to a record of small diameter. If the record deposited on the turntable during the rotation of cam disc is a small one, the pin 60 is inward and the lever 110 is not shifted from the position g