Magnetischer Tonabnehmerkopf mit kompensierender Polstueckanordnung

摘要

1,061,740. Stereophonic pick-ups. PICKERING & CO. Inc. June 29, 1964, No. 26865/64. Heading H4J. In a stereophonic pickup an elongate magnetic member carrying a stylus is embraced by four polepieces 401, 411, 421, 431(Fig 15), the spacings 741, 751 between the adjacent lateral edges of the polepieces 401, 421 and of the polepieces 411, 431 being greater than the spacings 761, 771 between the adjacent lateral edges of the polepieces 401, 431 and of the polepieces 411, 421. Cross-talk is thereby reduced. In addition, the polepieces 401, 411, 421, 431 may have the included angles at 761 and 771 greater than the included angles at 741 and 751. The pick-up includes coils (25), (26) (Figs. 7, 10, not shown) for one channel and coils (27), (28) for the other channel. The coils of each pair are connected in series aiding relationship for the generated signals. The polepieces (40), (41) (Fig. 11, not shown) of one channel are opposite and parallel, as are the polepieces (42), (43) of the other channel. The polepieces flare outwardly and extend through the centres of the respective coils, forming cores (44), (45), (46), (47) (see Fig. 10). At the rear ends the cores (44), (45) are connected by members of magnetic material, as are cores (46), (47). Overlapping portions of the members are separated by non-magnetic material (50) (Fig. 12, not shown). The fixed parts of the pick-up, including the coils, polepieces, cores and terminals (32 ... 35) (see Fig. 7) are embedded in polystyrene or polyester (54), (55). The assembly is encased in a shielding casing (56). The ends of the polepieces are insulated from the casing (56) by a washer (57). A removable stylus assembly includes a non- magnetic tube (60) (see Fig. 7) connected to a plastics or resin handle (61). The moving system includes the stylus (62), an aluminium tube (64) and a permanent magnet (63) (Fig. 8, not shown). The tube (60) fits with the ends of the magnet (63) disposed between the polepieces (40-43). The tube (60) is a sliding fit with the washer (57). The forward end of the tube (60). flares outwardly and is embedded in the handle (61). A resilient bushing (65) (see Fig. 8) serves as a fulcrum for the magnet (63) and dampens oscillations. A tie wire (66) (see Fig. 8) extends between a slit (67) of the tube (60) and the tube (64). In use the coils, polepieces and moving system are at an angle to the record surface to minimize the mass of the moving system. Because of this the direction of movement of magnet (63) is along lines (72), (73) and crosstalk compensation is required. Reference has been directed by the Comptroller to Specifications 847,138, 897,323 and 943,873.