Patent GB-605201-A (GB)
Title: Record changer control mechanism
IPC: G11B17/16
Filed: 1945-09-24
Abstract: 605,201. Magazine gramophones. TRIGGS, W. W. (Farnsworth Television & Radio Corporation). Sept. 24, 1945, No. 24735. [Class 40 (ii)] In a magazine gramophone of the type provided with change-cycle control means for moving the pick-up arm after a record has been played and for moving the lowest record of a stack from the record stack-supporting means to the turntable, a pivoted member forming part of the control means when in a certain position prevents the pick-up arm being moved in towards the turntable when no records are left in the stack. The pivoted member is moved into its operative position by a control member controlled by the record-supporting means by means of a pivoted lever having a projection which rotates the control member when all the records have been removed from the stack. As shown, the turntable 14 is driven by the friction wheel 19 which engages the inner surface of the turntable flange. The supporting means for the record stack comprises a peripheral support and a centring spindle. The 'support includes a pedestal 36 carrying a bracket 37 which is rotatable on the shaft 40 so that one of the record-supporting shelves 37A, 37B may co-operate with small or large records respectively. A pair of bosses 46 on the flange 42 of shaft 40 are urged into engagement with the notches 47 on the shoulder 43 of the pedestal 36 by a spring 49, Fig. 4, thus locking the bracket 37 in the position to which it is manually set. The centring spindle 56 is provided at its upper end with a notch 58 and shoulder 59, co-operating with a slotted guiding member 61 which cams the records towards the bracket 37 so that the shoulder and the shelf jointly support the lowest record. Record changing. Automatic tripping mechanism is provided to initiate the recordchanging cycle. In moving towards the centre of a record during reproduction, the pick-up arm 25 rotates the shaft 26 which carries a clutch 95, Figs. 1 and 2, comprising a flanged sleeve 96 fixed to the shaft, and a friction washer 97 adjacent the upper surface of the arm 82. The annular end of a lever 99 is fitted between the sleeve and the washer, so that while the record is being played, the lever 99 tends to move in a counter-clockwise direction, Fig. 3. This lever has an enlarged portion 102 which engages one end of a starting lever 106 pivotally mounted intermediate its ends on a pin 107 attached to the cam gear 76, and rotates it in a clockwise direction, so that its lower end moves into the path of a pin 108 on the turntable shaft 12 which is rotating with the turntable. During playing this pin strikes the face of the lever 106 and pushes it back out of its path, so that the lever 99 is moved in a clockwise direction and tripping is prevented. However, when the stylus enters the customary tripping groove at the centre of the record, the increased speed of movement of the pick-up arm results in the lower end of lever 106 being fully engaged by the pin 108, which moves it and the cam gear 71 so that the gear meshes with the pinion 70 on the turntable shaft 12, and is driven through a complete revolution, during which the pin 94 strikes the turned-. down ear 101 on the lever 99, Fig. 3, and disengages the lever from starting lever 106 to prevent a second revolution being initiated. The cam gear 71 carries a cam surface 75 over which rides one end 79 of a lever 77, the other end of which is coupled to the pin 30 so that as the end 79 moves downward over the cam surface the pin 30 rises vertically in the shaft 26 and tilts the pick-up arm 25, thus raising the stylus from the record. A second cam surface 91 on the cam gear 71 engages the heel 90 of an L-shaped lever 86, Fig. 3, and moves the lever in a counter-clockwise direction about its pivot 87, so that the right-hand wall of the aperture 84 drives the pin 83 on the lever 82 in a clockwise direction. The lever 82 is clamped to the shaft 26 which is therefore rotated so that the pick-up arm is traversed towards the outside of the turntable. The shape of the cam surface 91 is such that the pick-up arm reaches a position beyond the edge of the record on the turntable before being stopped. The pin 94, Fig. 2, extending above the cam gear 71 then engages the left-hand end of the lever 55, Fig. 3, and turns it in a clockwise direction, thus moving the lower end of the lever 53 outwards. Lever 53 pivots about the pin 54, Fig. 2, and moves the recordmoving member 39 in the bracket 37 towards the centre of the turntable, thus pushing the lowest record of the stack off the shoulder 59 and the shelf 37A (or 37B) so that it drops to the turntable. The pin 94 immediately engages the right-hand end of lever 55 and returns it and the member 39 to their normal positions. The lever 86 now begins to ride down the cam 91 and to rotate clockwise, the pick-up arm thus being moved in until the stylus is over the initial groove of the newly-dropped record. As cam 75 now resumes the position shown in Fig. 2, the end 79 of the lever 77 moves upward, and the stylus is lowered on to the record. Setting for large or small records. When the bracket 37 is rotated to the position for supporting large records, the tapered portion of the shaft 40 moves a pin 50 downwards so that it intersects the path of movement of an arm 109 provided on the lever 86 and prevents further clockwise rotation of lever 86, whereby the pick-up arm is positioned for engaging the initial groove of a large record. In the other position of the bracket 37, the spring 51 retains the pin 50 in the position shown in Fig. 2 and lever 86 is allowed to move far enough clockwise, under control of cam 91, to bring the pick-up arm over the initial groove of a small record. Control of pick-up arm during changing of records. While one or more records are resting upon the shoulder 59, the lever 63 is depressed to the full-line position, Fig. 1, so that its righthand end engages an ear 119 of the control member 118 pivoted on the underside of the cam gear 71, Figs. 1 and 3, and moves it into the position shown in Fig. 3, so that, on further rotation of the cam gear, ear 119 engages the right-hand end of lever 110, which is mounted on plate 64, and moves it into the full-line position, Fig. 2, in which its left-hand end is raised above the path of the projection 114 on the lever 86, Fig. 3. Immediately thereafter, the lever 86 is rotated clockwise under control of cam 91 and the pick-up arm assumes its usual position over the initial groove of the record. The left-hand end of lever 110 then rests upon the projection 114 until the lever 86 moves back, when it returns to the dottedline position, Fig. 2. When the last record is moved off the shoulder 59, the spring 66 raises the lever 63 to the dotted-line position, Fig. 1, in which it engages the other ear 120 of the member 118 and rotates it in a counter-clockwise direction, Fig. 3, until the finger 121 engages the cam surface 75. Ear 119 cannot now engage the lever 110, so the spring 92 moves the lever 86 clockwise until the projection 114 engages the left-hand end of the lever 110, whereupon the pick-up arm is stopped in a position outside the edge of the records on the turntable. Immediately thereafter, the ear 120 actuates the switch lever 122, Fig. 3, and the mechanism is stopped.