Patent GB-1412302-A (GB)
Title: Automatic record changers
IPC: G11B17/00
Filed: 1972-12-19
Abstract: 1412302 Automatic record changer GENERAL ELECTRIC CO 19 Dec 1972 [28 Dec 1971] 58541/72 Heading G5R  In an automatic record changer including a record balance arm 122, an operational mode control lever 126 is coupled to a slide member 212 which can be releasably held in each operational position. Automatic change initiation.-The automatic change cycle is controlled by a cycle gear 150 which is normally stationary with a toothless portion of its periphery opposite a pinion 270 rotating with the turntable, the cycle gear is rotated into engagement with the pinion by a pawl 266 mounted on the cycle gear which can be pivoted into engagement with a striker member 274 also rotating with the turntable. The pawl is pivoted either by lug 278 on slide member 212 when the operational mode control lever 126 is manually moved to the reject position or automatically, when the tone arm stylus enters a record run out groove, by a velocity trip mechanism including an arm 282 which is pivoted about pin 283 and frictionally coupled to arms 284 which are movable about pin 283 by rod 286 connected to tone arm plate 164. During the one revolution of the cycle gear a pin 154 eccentrically mounted thereon and engaged in a slot 153 in a main slide member 152 drives the slide member in a single reciprocation. Automatic change operation.-During the initial movement of the reciprocation a detent 240 on the main slide moves away from tone arm lift pin 168 and thus is driven into lifting engagement with the tone arm. At this time spring 170 forces tone arm plate 164 into frictional engagement with flange 162 fixed to the base-plate 111  to restrain tone arm movement. Tab 242 carried by slide 241, which is resiliently secured to the main slide, now engages pin 244 carried by the tone arm plate to pivot the tone arm to its outward position. When the main slide reaches the end of its first movement a tab 156 thereon engages the spring loaded knife member 157 of the turntable centre spindle 120 whereby the next record to be played is dropped on to the turntable. The tone arm is moved inwardly by positioning plate 246 which is pivoted about its support pin 204 and against the action of spring 249 by cam 256 which rotates with the cycle gear 150. A tab 248 on the plate engages a pin 252 carried by the tone arm plate 164 to move the tone arm inwards until one of the steps 264 on function cam 200 intercepts the tab movement. The position of the function cam which determines which of the steps 264 engages the tab is determined by set down cam 262 controlled by the record size selector 130. The pick up arm is then lowered when the main slide resumes its original position and detent 240 is re-entered by the lift pin 168. At this time spring 170 releases the tone arm for free tracking of the record. Automatic shut off.-Automatic shut off of the gramophone when the last record has been played is controlled by record balance arm 122 and the function cam 200. During an early part of each change cycle the cam is moved through a single oscillation about its support pin 201 by a pin 150a which rotates with the cycle gear, the movement being against the action of spring 210. A part of the cam normally resides in a slot 192 in a tube member which receives the support shaft 124 of the balance arm. The shaft includes a cut away part which when there are records supported on the turntable spindle is opposite the slot so that the part of the cam member can move out of the slot and return thereto after the oscillation of the cam. However in the change sequence following the playing of the last record the shaft falls when the cam part moves out of the slot and a complete part of the shaft now in the slot prevents return of the cam to its initial position. In this position of the function cam a tab on plate 220 is presented to a tab on a release member which is oscillated by pin 150a on the cycle gear once each change cycle, the plate 220 is pivoted so that a pin thereon is moved out of a detent on function slide 212 and this is moved to the right to release the motor switch 138. In addition in this position the function cam 200 stops the inward movement of the tone arm when this is above its rest post 121.  - Operational mode control.-Mode selector handle 126 has four positions "off"; "normal play"; "automatic play"; and "reject" and is coupled by rod 127 and bell crank lever 211 to slide member 212 which it moves to corresponding positions defined by the engagement of a restraining pin 220 with teeth 218 formed on the slide. The pin is mounted on a catch plate 222 which is urged by spring 210 towards the slide 212. In the "off" position the slide member is furthest to the right in Fig. 12 so that tab 212a on the slide engages and operates switch 138 to its "off" position. For "manual play" the tab 288 on the slide is in a position to prevent arm 282 of the velocity trip mechanism from engaging a tab 276 on pawl 266. In the "reject" position as previously described an automatic change is initiated by the engagement of the pawl 266 by a lug 278 on the slide member. Cueing.-Movement of cueing lever to position A, Fig. 7, raises platform 180, along guide 174 into engagement with tone arm lift pin 168 and spring 170. During raising of the tone arm the spring moves the tone arm plate 164 into frictional engagement with flange 160 on base-plate 111 to restrain lateral movement of the arm.