GB1298225A - Phonograph record player apparatus - Google Patents

Abstract

1298225 Auto-change; radial arm gramophone E G NORRIS 9 Dec 1969 [20 Dec 1968] 60077/69 Heading G5R In an automatic record change gramophone having a pick-up unit 15 slidably mounted on an arm 17A which during play extends parallel to the radius of a record on the gramophone turn table and on initiation of an automatic cycle at the end of record play, the pick-up unit is pivoted about arm 17A to raise stylus 16 from the record, the unit is then moved along arm 17A to a position adjacent arm housing 18 and the arm turned to its out of play position clear of the turn table; thereafter when the next record has been released and the height of its top surface is sensed and the pick-up arm height set accordingly, the arm is swung back to its fixed position parallel to the record radius and the pick-up unit pivoted to lower the stylus to the record start groove. As the pick-up stylus enters a record run out groove the unit 15 engages a turned out end 28 of a shaft extending through arm 17A and the other end 29 of this shaft moves a rod 73 towards the turn table centre where it pushes a lever into contact with a pin rotating with the turn table. This rotates the usual cam disc a few degrees to bring it into mesh with a pinion also rotating with the turn table and this drives the disc through 360 degrees until it again enters on the usual cut out portion in the cam disc periphery. Cam followers 79, 84 move control plates 85, 120 outwardly and inwardly during a change cycle. As plate 120 is driven outwardly elbow actuator 132 rotates about its pivot 133 under spring control due to disengagement between wing 138 of the actuator and detent 129 on the plate. This action allows elbow 155 to partially collapse lowering head control rod 147 so that arm 17B of pick-up arm 17 rotates about arm 17A and engages a portion of the pick-up unit to rotate this and move stylus 16 out of engagement with the record. In its outward movement arm 120 also carries with it rod 180, as cam follower 188 enters a cutaway portion of the rod, spring 183 forces a rack end portion 81 of the rod into engagement with a drive pinion 152 of the head control rod 147 so that as the rod moves outwardly rod 147 is rotated and rotates a pulley 170 carrying an endless cord 30 which extends through arms 17A, 17B. The arm 17B is slotted and the portion of the pick-up unit engaged by arm 17B extends through the slot to frictionally engage the cord so that as the pulley is rotated the unit is moved along the arm 17 to a position adjacent housing 18. Pin 117 on arm 120 is connected to lower clutch plate 115 which is rotatable with upper clutch plate 110 on the pick-up arm shaft. On further outward movement of plate 120, pin 117 engages a surface 169 of a shaft collar 163 which rotates shaft 144, pick-up arm 17 and its housing 18 to a position clear of the turn table. During this movement a pin 165 of the collar engages a lift cam 166 whereby the shaft, tone arm, &c., are lifted to remove the load on a tone arm elevation wedge. Secondary control plate 85 moving outwardly moves a swinging weight 234 into a position in which it is engaged by catch 237 and also acts via socket 209 on spindle tongue member 204 whereby a new record 10 is lowered on to the turn table. Thereafter push rod 211 pushes lower end 217 of a rod 213 off its perch support 218 and this drops until finger 214 of the rod engages the upper surface of record 10. The downward . movement of the rod 213 encountering cam surface 224 forces height linkage 220 to the right forcing an elevation wedge (not shown) beneath a surface of the shaft collar 163. At the end of the outward movement of plate 120 cam 188 engages cam surface 194 on rod 180 whereby the rack surface 180 is moved out of engagement with pinion 152. As the plate starts to move inwardly it produces a clockwise rotation of lower clutch plate 145 so that actuator 111 depending from upper clutch plate 110 engages arm 168 on the shaft collar and rotates the pick-up arm to its playing position over the record. During this movement the collar, shaft 144 and the pick-up assembly are lowered by the lift cam to a position defined by the elevation wedge in which the tone arm lies parallel to the surface of the new record. Pin 226 on plate 120 now engages repositioning arm 225 to reposition the left hand portion 221 of height linkage 220 which also repositions rod 213 on its perch 218. Swinging weight 234 is now moved out of its clip position by arm 240 to lie against a second repositioning arm 228 associated with the right hand end 222 of linkage 220. This restores the linkage to the left when next the weight of the tone arm &c. is moved from the tone arm elevation wedge. Detent 129 in plate 120 now engages wing 138 of elbow actuator 132 and its movement causes straightening of the elbow to rotate tone arm 17B about tone arm 17A so that the pick-up stylus is lowered on to the record. When the absence of a record is sensed during the change process by spindle tongue 204, apparatus (not shown) is actuated to move stop element 108 into the path of the upper clutch plate to prohibit further inward movement of the pick-up arm after the playing cycle is completed. On switch on the turn table drive motor is energized, the stop element 108 is moved to a rotated position and the rod 73 is moved towards the turn table centre to start a change sequence. This latter action can be initiated during course of play by operating a reject control.