Patent GB-757379-A (GB)
Title: Improvements relating to phonograph record changing apparatus
IPC: G11B17/16
Filed: 1951-09-10
Abstract: 757,379. Automatic gramophones. HANSEN, H. C. Sept. 10, 1951, No. 23450/53. Divided out of 757,303. Class 40(2) [Also in Group XXIV] In an automatic gramophoneemploying a stack of records of different sizes, the tone arm is provided with an abutment which engages the edge of the lowermost record of the stack, and thereby determines the subsequent setting down position of the stylus on the record. The records, are supported on a stepped centre post 190a, Fig. 10, and are pressed against a withdrawable forked support 233a by a steadying arm 114a. During the inward movement of the pick-up arm 112a under the influence of a. cam-disc 144a, Figs. 3 and 9, a member 270a, Fig. 2, on the pickup arm 112a, projecting above the forked support 233a, comes into contact with the edge of the lowermost record of the stack. If the lowermost record is the smaller of two particular sizes, a cam follower 252a follows a track 280a in cam-disc 144a, but if of the larger size, a light wire spring 284a is forced aside so that the follower 252a enters a track 282a Both of the tracks 280a and 282a run spirally inward and serve to cause the lowermost record to be unseated from the post 190a. Continued movement of the disc 144a brings the follower 252a into one of the tracks 289a, Fig. 9, so that the stylus is brought over the start of the record, after which it is lowered under the control of a follower 258a, Fig. 7, mounted on a lever 256a and following a cam surface 287a. The forked support 233a, which is mounted on pillars 231a on a plate 228a, is withdrawn during record changing, by means of a cam track 232a, Fig. 8, in the upper face of the camdisc 144a which engages a follower 230a on the plate 228a. During playing of a record, the cam-disc 144a is stationary, a jockey pulley 164a, coupled to the turntable, idling in a notch 322a, Fig. 8, in the cam-disc 144a. The automatic cycle is initiated by means of a tap-tap lever 306a, Fig. 8, frictionally coupled to another lever 302a, which is moved by the cam follower arm 250a. When the run-off groove of the record is reached, lever 306a is moved counterclockwise about the pin 304a so that a lug 310a on lever 306a is pressed against a projection 312a of a central cam on cam-disc 144a to give it a small initial rotation whereby the jockey pulley 164a engages the cam-disc 144a and continues its rotation. The earlier part of the rotation forces a light spring 320a on lever 306a out of a notch 314a in the central cam so that the lever 306a is clear of the projection 308a on the turntable spindle 152a. The turntable is driven by a belt 624a, Fig. 2, connected to a pulley driven by the spindle of a motor 130a. The apparatus may alternatively be provided with means for driving the turntable at different speeds in which the shaft of the motor 619, Fig. 11, has three different driving diameters 612, 614, 616 for engagement with a pulley 620 splined by pins 626 on a shaft 618 carried by a bracket 630 rotatable about a shaft 634. The pulley 620 is moved up and down the shaft 618 by means of an arm 650 under the control of knob 664 which rotates a cam sleeve 632, Fig. 11a, against which a projection 660 on the arm 650 is pressed by a spring 666. Clockwise rotation of the knob 664 moves the pulley 620 down the steps of the shaft 610, whilst counterclockwise rotation moves the pulley up the steps, the actual direction of rotation of knob 664 serving to move the pulley away from motor shaft against the tension of the driving belt 624 and thereby enabling the pulley to pass up over each step. The motor is switched on in the first instance by the rotation of the steadying arm 114a into the operative position by means of a notch 198a in a disc 196a mounted on the end of a shaft 180a carrying the steadying arm 114a. The notch 198a engages a projection 209a on a rightangled switch arm 234a pivoted at 211a. When the last record has been released on to the turntable the steadying arm 114a is lowered sufficiently for a step 181a on its shaft 180a, Fig. 3, to press a lever 238a downwardly about a hinge 250a on the plate 228a. During the last automatic cycle when the plate 228a next moves outwardly the lever 238a drops behind a turned up lug 137a on the switch arm 234a, so that on the return of the plate 228a, the switch arm 234a is moved to the " off " position, and the jockey pulley 164a moved out of contact with the turntable shaft by means of a rod 172a coupled to the switch arm 234a. Means are provided to reject a record being played, consisting of a push button 330a coupled by a cord 332a to a spring 334a, one end of which is secured below the base plate, while the other is pressed against a projecting portion 337a on the tap-tap lever 306a, whereby the mechanism may be tripped in a similar manner as by the run-off groove of a record. Specification 757,378 is referred to.