Patent GB-526715-A (GB)
Title: Improvements relating to automatic record changing mechanism for gramophones or like talking machines
Filed: 1939-03-25
Abstract: 526,715. Magazine gramophones. SLADE, H. V., and GARRARD ENGINEERING & MANUFACTURING CO., Ltd. March 25, 1939, No. 9404. [Class 40 (ii)] Relates to automatic record changing mechanism of the kind in which the records are supported by an off-set or shouldered central spindle 3, 4, Fig. 1, and are released therefrom one at a time by means acting on the edge of the lowermost record. According to the invention, a laterally movable platform 13 Fig. 3, is provided with an abutment such as a pawl 21 which can move transversely but not longitudinally with respect to the path of movement of the platform, and the arrangement is such that during a first inward movement of the platform the pawl passes with the platform underneath the record, whereas during an outward return movement of the platform the pawl rises as soon as it is uncovered by the edge of the record, so that during the next reciprocation of the platform the record is pushed by the pawl and dropped on the turntable, the point at which the pawl rises depending on the diameter of the record and this serving to position the pick-up on the record. Preferably, the central spindle 3 is inclined or curved as described in Specification 450,966. The records are pressed down on the shoulder of the spindle by a forked arm 7 pivoted at 8, Fig. 5, on a side column 6 and controlled by a toggle spring 11. The platform 13 is pivoted at 16 to a lever 14 and at 19 to a pair of links 18 connected to a bell-crank lever 17. Both levers 14 and 17 are pivoted at 15. The bottom end of the lever 14 is connected by a link 28 to an intermediate point on a lever 29, Fig. 2, which is pivoted at 30 and provided at its end with a stud 31 co-operating with a twotrack rotary cam 32. The bottom end of the lever 17 is connected by a link 33 to an intermediate point of a lever 34 which is pivoted at 35 and provided at its end with a stud 36 cooperating with a rotary one-track cam 37, Fig. 1. The upper part of the lever 14 bears against the end of a link 48 connected to one end of a lever 47 and slidably mounted by means of a slot 48a on fixed pin 48b. A spring 49 attached to the link 48 serves to urge this link and the platform 13 outwards. The other end of the lever 47 is connected by a pin and slot joint to a lever 44 carrying a bell-crank 45 biassed by a spring 46. This bell-crank co-operates with a member 42 which is provided with a stud 41 co-operating with a two-track cam 43 and is pivoted at one end of a lever 40 and biassed by a spring 42a. The other end of the lever 40 is connected to the pick-up arm 39. The operation is as follows : at the end of the playing of a record, a clutch sets the cams in rotation. The cam track 37 acting on the lever 34 holds the inner edge of the platform depressed, while the cam 32 acting on the lever 29 causes the platform to move in under the bottom record. Then cam track 37 causes the platform to swing up against lower face of record and this depresses the pawl 21. Next the cam 32 causes an outward return movement of the platform during which the pawl 21 rises as soon as it is uncovered by the edge of the record. If the record is a ten-inch record, the tail 24 of the pawl abuts against a fixed stop 25, the outward movement of the platform is stopped, and the stud 31 travels in the left track of cam 32, which causes a second reciprocation of the platform during which the pawl 21 bearing on the edge of the record delivers the record to the turntable. If the record is a twelve-inch record, the tail 24 of the pawl passes over the stop 25, the platform moves further outward and the stud 31 travels in the right track of the cam 32, which causes the delivery of the record in the same way by a second reciprocation of the platform. The two outward positions of the platform 13 determined by the pawl 21 according to the size of the record determines the outward position of the link 48; and this determines which track of cam 43 comes into operation and thus positions the pick-up according to the size of the record. Specification 516,421 is referred to for a somewhat similar record feeding device.