GB1514921A - Record-playing apparatus - Google Patents

Abstract

1514921 Record player S A J KANJI 2 April 1974 [2 Jan 1974 27 Feb 1974] 00082/74 and 8765/74 Heading G5R In a record player for playing gramophone records carrying a series of tracks separated by non-recorded annular bands a control system, including a photo-electric arrangement for detecting the bands, is provided for automatically traversing the pick-up arm and lowering it to bring its stylus into engagement with the band in advance of a selected track whereby a series of tracks may be selected and played in sequence. Alternatively selected length portions only of each selected band are played back. Each pick-up head includes in addition to its pick-up cartridge a light source 51 and lenses 53, 54 for directing light from the source on to a record and a light dependant resistor 57 on which light reflected from the record is directed via lens 58. The resistor 57 is connected in a circuit which produces an output signal when a band is detected irrespective of whether the head is same distance above the record during traversing or close to the record during play back. The movements of the pick-up arm are controlled by the mechanism shown in Fig. 2A which includes a cycling cam gear 5 driven through one complete revolution during each control sequence from a DC motor 1. The pick-up arm is provided with a drive sector plate 13 which can be engaged for traversing the pick-up arm by a drive shoe 12 mounted on a line 11 driven by the cam 5. The shoe is moved into engagement with the sector plate by spring 23 when cam 5 rotates and moves links 11 leftwards moving the shoe out of engagement with rest lever 17. The shoe is disengaged from the sector plate by operation of latch member 15 by solenoid 16. The pick-up arm is raised via link 21 by lever 6 when this is engaged and pivoted anticlockwise by stud 18 rotating with the cam gear. The lever is turned clockwise to lower the pick-up arm when operation of solenoid 9 moves a gear 4 on the solenoid armature into engagement with cam gear 5 whereby cam 8 secured to the gear 4 rotates to pivot lever 7 into drive engagement with a nut on a rod connected to the lever 7. After initial energization motor 1 is maintained energized via switch S6 closed by switch lever 10 during one revolution of the cam gear. The photo-electric detector circuit and numerous switches operated by movement of the mechanical elements are connected in a logic circuit with a record track selecting arrangement, a counter for counting the bands detected by the photo-electric detector, indicators for indicating the track being traversed or played back and timing elements for selecting the duration of the portions of the track played back. The logic circuit controls the step by step operation of the system. Figs. 8-10 (not shown) indicate how a standard record player can be modified to include the system.