Patent GB-647416-A (GB)
Title: An automatic gramophone to play 12 inch and 10 inch records on both sides, on one side only, and to repeat playing on one side, as required
IPC: G11B17/16
Filed: 1948-02-06
Abstract: 647,416. Automatic gramophones. BURNS, L. F. Feb. 6, 1948, Nos. 3494 and 13379. [Class 40 (ii)] In an automatic gramophone, two turntables, facing each other on a common vertical axis, are driven in opposite directions by peripheral engagement with a roller and counter roller driven by a single motor driven shaft, records being held against the upper turntable by a projection 10 on the centre shaft for the playing of the underside of the records, each record being released from the projection 10 by a trip lever 11, Fig. 5, or 11a, Fig. 6 (not shown), to fall on to the lower turntable for playing the upper side of the records. The pick-up has oppositely directed styli and is resiliently mounted on an arm 24 pivotally supported at a point 25 on a rotatable sleeve 23. The arm 24 is extended below the point 25 to form two tracks 26, 27 which encircle the sleeve 23 and are engaged alternately by a roller 28 driven counterclockwise, as viewed in Fig. 3, by gearing 30, shaft 31 and worm 32, Fig. 15. During the playing of a 12-inch record the roller 28 engages the outer part B of the tracks 26, 27 and during a 10 inch record the inner part A. Prior to the playing of the underside of the lowermost record on the upper turntable a switch lever 42 is moved counterclockwise, as viewed in Fig. 3, by contact with an arm b so that the part D, Fig. 4, of track 27 is pressed into contact with the roller 28 by the spring 40. The arm 24 and the pick-up are thus pressed towards the upper record and are moved inwardly towards the edge of the record. When the gap 35 reaches the roller 28 the pickup moves up to and engages the groove of the record. At the end of the playing of the upper record the roller 28 engages the next part of the track 27, thus withdrawing the stylus from the record and swinging the pick-up arm 24 across the record to the other side. Near the end of the travel of the arm 24 a striker on the collar 23 comes into contact with a lever 39 coupled to a lever 39A which releases, by means of a bell-crank 14, Fig. 15, the record just played on to the lower turntable ready to be played on its upper side. At the end of the travel of the arm 24, switch lever 42 is tripped by an arm a, and the pick-up arm 24 tilts by gravity so that the roller 28 rests in the gap 37 in track 26. Almost immediately, however, the roller 28 is brought into contact with part C of the track 26 under the influence of a spring 39B connected to lever 39 which presses against the striker which caused the release of the record. As the roller 28 rides under the part C of track 26 and into the gap 36 the pickup is fed in over the groove of the record on the lower turntable and lowered thereon. At the end of the playing of this record the roller 28 engages the next part of the track 26 so that the pick-up arm 24 is lifted and swung across the record to the position prior to playing the record on the upper turntable, when the switch lever 42 strikes the arm b and a fresh cycle of operations is commenced. The roller 28 is set to the inner or outer position, according to the diameter of the record, before the beginning of the playing of the underside of a record, by means of a lever 58, Fig. 8, rod 59, and a lever 60 (controlled by a dead-centre spring), which are set to one of two positions by a lever 54 on the end of a shaft 52 having a feeler 53 which rests in the position shown in Fig. 9, when the upper record to be played is a 10 inch one, but is held by a 12 inch record in the dotted position 53B, whereby the lever 58 is pushed back to the position 58A, Fig. 8, when the pick-up 24 is swung out after playing the lower record. A fresh setting therefore does not take place again normally until both sides of a record have been played. A record on the upper turntable may be repeated by moving the arm a to the position b<SP>1</SP> so that switch lever 42 is tripped before gap 36 reaches the vicinity of roller 28, and the pick-up arm is returned to the start of the same record, Similarly, a record on the lower turntable may be repeated by moving arm b to position b<SP>1</SP>, arm a being also moved to position a<SP>1</SP> in order to suspend record changing. If the arm a, however, is left in position a, records will be released from the upper turntable and played only on the lower turntable. Similarly, if arm a is set to position b<SP>1</SP> and the arm b set to position b<SP>2</SP> records will be successively played on the upper turntable only. The gramophone may be adapted for records applied manually to the lower turntable by removing the upper section 6 of the centre shaft.