Patent GB-680799-A (GB)
Title: Improvements in or relating to automatic gramophone-record changing apparatus
IPC: G11B3/08
Filed: 1948-07-16
Abstract: 680,799. Automatic magazine gramophones; turntables. FITCH, C. K. July 18, 1949 [July 16, 1948; Nov. 19, 1948], Nos. 19203/48 and 18834/49. Divided out of 680,795. Class 40 (ii). In automatic record changing run-out movement of the pickup at the end of a record effects engagement of a follower with a traversing groove or thread on a continuously driven rotating part which through the follower operates mechanism for loading a new record on the turntable, then after a predetermined rotation automatically disengages the follower. Figs. 1-5 are the same as Figs. 1, 3, 4, 8, 9 respectively of Specification 680,795 but a further embodiment is described using two oppositely handed spiral grooves on the underside of the turntable as the automatic initiation and timing mechanism. On the pick-up reaching the quick-pitch groove of a record a sensing arm 116 frictionally mounted on the pick-up shatt 66 has a pin 117 thereon gathered in by a cam surface mounted on the boss of the turntable, so that the cam top edge lies underneath an abutment 119 on the arm 116 and its shape tilts the arm. The latter actuates through a pallet 113, two pegs 107, 110 mounted in bosses in a traversing arm 109 pivoted at P, which pegs respectively engage the innermost groove under the turntable and one of two holes 122, 123 in a link 124 connecting with the record stack mechanism. The arm 109 then makes an inward traverse with the peg 107 riding on top of a guide plate 128, a further peg 153 on the arm operating through a lever 150 to raise a push rod 39 tilting the record off the turntable. Near the innermost position of arm 109 a further peg 108 with head sliding on an upwardly bent leaf spring 126 comes to a gap in the guide plate 128 so that it is forced up into engagement with the oppositely handed spiral groove and rides on top of the bar. For a short time both pegs 107, 108 engage parallel portions of the spirals, then peg 107 falls through a gap in the plate 128 back on to the pallet 113, and the arm 109 makes an outward traverse. Record stack mechanism. The records are stacked between rails 10 and a ledge 13 on an opposite pillar 14. The link 124 moves through a universal joint enclosed nose-pieces 17 pivoted at 154 so that projections 18 move the lowermost record over the upturned ends 16 of the rails into the opening of a deep recess 20 between the projection 18 and a lower projection 19. After the inclined portions 8 have pushed all the records on to rounded projection 9 except the lowermost which is stopped by a shoulder on the projection 9, the lowest record is free to slide into the recess 20 so as to be supported between the lowest pillar ledge 131 and lower projections 19, finally on return motion of the latter falling on to the turntable. The rails 10 and link peg hole (122 or 123) are adjustable for different size records. Pick-up operating mechanism. Upward motion of the sensing arm 116 also tilts upwardly, about a transverse axis at the pick-up mounting 65, the pick-up and an arm 92 with friction pad 94 engaging underneath the rim of the turntable so that the pick-up and arm 92 are swung clear of the table and are secured by a catch 136, 137 between the arm 92 and a pivoted bracket 138. On a fresh record being deposited on the turntable a spring-loaded peg 156 Fig. 8 (not shown), is depressed to engage a lever 145, 147 which operates through a cam slot 148 to raise the bracket and release the catch and at the same time engage a friction roller 141 with the turntable. This operates to drive a leadscrew 139 engaging the lower edge of an extension 143 of the arm 92 and thus inwardly traversing the pick-up and arm 92 until a recess 144 in the extension is reached whereupon the pick-up is lowered and if a large size record is present the stylus prevents the bottom of the recess 144 reaching the leadscrew. If not, the extension 144 is further traversed inwardly until first the side of the recess is engaged raising the pick-up, then a part beyond the recess, finally the end of the leadscrew lowering the pickup on to the smaller record. The bracket 138 is held upwardly against spring action by torque applied to the roller 141, but a gap in the rim of the turntable finally removes drive from the roller, lowering the bracket so that the drive of the leadscrew ceases. A spring 8 between the arm 92 and sensing arm 116 draws the latter outwardly out of reach of the turntable cam. Specification 680,810 also is referred to.