Patent GB-392173-A (GB)
Title: Improvements in or relating to gramophones
IPC: G11B17/04
Filed: 1931-11-10
Abstract: 392,173. Automatic gramophones. ANDREWS, E. F., St. Clair Hotel, Chicago, U.S.A. Nov. 10, 1931, No. 31182. Convention date, Nov. 10, 1930. [Class 40 (ii).] An automatic gramophone has the records stacked on the turntable and after the top record has been played the turntable pin is depressed from above so that the played record can be displaced laterally by means which engages the central aperture in the record and moves it until it rocks on the edge of the pile and falls into a receptacle. The records 26 are placed on a hollow round topped and vented pin 27 movable vertically under the control of a spring plunger 54 in the hollow turntable spindle 31 which is driven by a motor, preferably a synchronous motor, geared directly with a gear 196 fixed to the turntable 19. The turntable is rotated by hand up to the necessary speed for starting. After playing the top record, the pick-up arm 17 is moved by the engagement of the stylus 25 in the terminal groove to effect a drive connection from the turntable shaft 31 to a shaft 63, which is thereby driven for one revolution and actuates mechanism for lifting the pick-up, moving the pick-up arm to displace the top record into a receptacle and reposition the arm for playing the next record according to its size. For this purpose, the turntable spindle 31 is connected by gears 59, 58, 61 with a gear 62 which together with a notched wheel 68 are fixed to a sleeve freely mounted on the shaft 63. This shaft has fixed thereto cams 75, 77 and a disc 74 which carries a pivoted spring-pressed pawl 72 adapted for engagement with the notched wheel 68 when the shaft 63 is to be driven after playing a record. The pick-up arm 17 is mounted on a pivot 34 with counterbalancing spring 120 on a projection 35 from a hollow vertical pivot 36 housed in the mounting 21 on the mptor board 22, and a rod 45 pivoted to the arm 17 extends through the hollow pivot 36 and rests on a bell-crank lever 42 pivoted at its upper corner and connected to a forked link 101 embracing the shaft 63 and carrying a bowl 99 contacting the cam 77. A quadrant arm 37 fixed to the pivot 36 so as to move with the pick-up arm has a substantially circumferential slot which in conjunction with a pivoted pawl 92 controls the movement of a spring retracted sliding bar 82 by which the engagement of the pawl 72 with the wheel 68 to drive the shaft 63 is controlled. The pick-up 24, Fig. 7, carries a .pivoted stirrup 49 having a projection 53, and a brush 52 normally bearing on the record. If at the end of playing the stylus passes 'into a steep inward spiral, the quadrant arm 37 is carried clear of the pivoted pawl 92 and the pin 89 on the sliding bar 82 ; if, however, the stylus passes into an eccentric groove, the reverse movement of the quadrant rocks the pawl 92 out of its normal relation with the quadrant arm and the pin 89 on the bar is at this stage in an enlarged part of the slot in the quadrant : in either case, the spring 88 can now pull the bar and permit the pawl 72 to engage the wheel 68, whereby the shaft 63 is driven. The cam 77 now acts through link 101 and rod 45 to lift the arm 17, which is then turned about its pivot 36 by the engagement with the quadrant 37 of a pin 121 on a ring 111 freely mounted on the mounting 21 and pulled by a spring 114 and flexible band 117. This turning movement of the arm is controlled by the cam 75 which acts on a bowl on a link 106 pivoted to the ring 111, to position the pick-up over the turntable pin 27 with projection 53 on the stirrup, now hanging vertically, directly over the pin. The cam 77 now allows the pick-up to fall, whereby the projection depresses the pin and enters the hole in the record, and the cam 75 then permits a further swing of the arm 17, to carry the played record clear so that it falls into a receptacle, and to move the arm to its extreme position in which it is resiliently arrested. by a pin 132 on the quadrant engaging spring arms 135. Further, rotation of the cam 75 acts through the link 106 to turn the ring 111 in the reverse direction, thereby re-energizing the spring 114 and also, by the engagement of a notch 138 therein with a pivoted pawl 136 on the quadrant 37, returning the pick-up arm, which is arrested at starting position for playing the next record by a pin 143 on a fixed ring 145 tripping the pawl 136 clear of the notch 138. In this movement, the circumferential slot in the quadrant operates the sliding bar 82 so that a pin thereon is in position to disengage the pawl 72 from the wheel 68, whereby the shaft 63 comes to rest when the pawl is carried against the pin, and the cam 77 permits the pick-up arm to descend, the stirrup being swung forward by contact with the record. To enable records of different sizes to be played, the ring 145 is adjustable by a thumb-screw 152 and slot 153 to vary the trip of the pawl 136 and consequently the inward travel of the pick-up arm to starting position. In a modification, the pick-up arm is actuated positively by the cam 75 in removing a record after playing and is returned to starting position by a spring, and provision is made for automatically cutting out a resistance in the motor circuit during record removal whereby increased driving power is attained.