Patent GB-801174-A (GB)
Title: Improvements in record changing phonographs
IPC: G11B3/08
Filed: 1955-02-28
Abstract: 801,174. Automatic gramophones. HANSEN, H. C. Feb. 2S, 1955 [Feb. 27, 1954; Feb. 27, 1954], No. 5886/55. Class 40 (2). In a record-changing phonograph a single-revolution cam-disc, having a plurality of cam tracks to control the horizontal movements of the tone arm and a recess for a follower to move freely in during the playing of a record, is also provided with a landing track to guide the tone arm after a record size has been tested and means whereby the approach path is governed by the size of the record, the approach path being by way of a ramp up which the follower rides. The embodiment described is provided with means for lifting and lowering the pick-up arm as described in Specification 757,303, and the pick-up arm is provided with a high-friction member 142, Fig. 1, and a low-friction member 140, on which records of the stack normally rest, Fig. 6. While a record is being played the camdisc 26, Fig. 4, is stationary and the downwardly spring-loaded follower 164 traverses freely in track 146. When an automatic cycle is initiated the follower 164 enters the extension 146a of track 146 and from thence into track 174. If the lowest record of the stack is the smallest of three different sizes, the low-friction member 140 slips from beneath the edge of the lowermost record at an early stage, and the resistance to further outward movement of the follower 164 produced by high-friction member 142 causes the follower 164 to ride up a ramp-like inclined entry 180a of the track 180 corresponding to the pick-up arm control for the smaller-size records. If a medium-size record is in the lowermost position in the stack, the follower 164 passes the end of track 180 but enters the ramp-like entry 178a of track 178 corresponding to medium-size records, and if the lowermost record is of the largest size the follower 164 passes freely into the outer track on the cam-disc. At the conclusion of the playing of the last record a fresh cycle of the camdisc 26 is started but is stopped almost immediately in the position shown in Fig. 3. In this position, the pick-up has been lifted from the record and the follower 164 rests on undulations 168 on the cam-disc 26 so that the pick-up arm can be moved manually across the record, and in particular into a position in which it can act as a partial support for records placed on the stepped centre post 16. At the end of a record the automatic cycle is initiated by a tap-tap lever 110 which is permitted limited longitudinal movement against a spring 114 along a lever 104 frictionally pivoted about a pin 100. When the stylus reaches the run-off groove of the record, the tap-tap lever 110 is given an endwise thrust whereby a tongue 111 thereon pushes against a pin 120 on the cam disc 26 to initiate a fresh cycle by causing a jockey pulley 32 to ride up out of a notch in the cam-disc 26 and establish a drive with a shaft 34 carrying the turntable. When the last record of the stack falls to the turntable during an automatic cycle a steadying arm 22, resting on the record and mounted on a shaft 62, Fig. 9, drops on to the end of a rod 64 having a foot 66 which tilts a control bar 38 so that a tongue 39 thereon lays in the path of a pin 92 on the cam-disc 26. At the end of the cycle the pin 92 comes to rest short of the tongue 39, but when the said last record has been played and the next automatic cycle initiated, the pin 92 moves the bar 38 until another tongue 77 thereon moves a switch lever 78 to a stop position shown in Fig. 3. When the machine has been reloaded with records and the arm 22 lifted and swung into position over the records, a plate 84 on the shaft 62 engages a tongue 86 on the control bar 38, which is now in the non-tilted position, and draws it endwise so that the switch lever 78 is operated by a tongue 76 on the bar 38 and the machine is started. Alternatively, the machine could be started by the movement of a handlever 88 to a position I, Fig. 4. If it is desired to initiate a record change during the playing of a record, the lever 88 may be moved to a position II in which a spring pawl 94 engages a notch 96 in the cam-disc 26 and gives it the initial rotation to start and automatic cycle. If, however, the lever 88 is pushed to the position III a hook 89 on the lever 88 also tilts the control bar 38 so that the pin 92 engages the tongue 39 and stops the machine in the manner previously described. Specifications 770,544, 801,175 and 801,176 also are referred to.