GB1233791A - - Google Patents

Abstract

1,233,791. Stereophonic pickups. NIPPON COLUMBIA K.K. 19 June, 1968, No. 29246/68. Heading H4J. A stereophonic pickup comprises a plate 3 (Figs. 1, 2) magnetized in the direction of its thickness. A cantilever 1 has one end fixed in the plate 3 and projects from a major surface of the plate 3. Its other end supports a stylus 2. A pair of cores 4L, 4R are adjacent to and separate from the plate 3. Signals are inducable in windings 5L, 5R on the cores 4L, 4R when the plate 3 vibrates relative to the cores 4L, 4R. The longitudinal axis of the cantilever 1 passes through the centre of gravity of the plate 3. The cantilever 1 is anchored to the support 7 to constrain its longitudinal movement when vibrated. Preferably the cantilever 1 is anchored to the support 7 by fine wire 6. A damper 8 between the plate 3 and support 7 provides a resilient mounting. The wire 6 secures the cantilever against longitudinal movement and ensures that the centre of vibration of the vibration system including stylus 2, cantilever 1 and plate 3 lies substantially at the centre of gravity of the plate. The cores 4L, 4R may be E-shaped or U-shaped. Where they are E-shaped there may be a single winding on the centre limb or windings on the outer limbs. The outer limbs may be bent inwardly (Fig. 9, not shown). Alternatively, pot-shaped cores having an E- shaped cross-section may be used. The cores may be above or below the plate 3 or there may be four cores, two above and two below plate 3 (Fig. 8, not shown). The plate 3 may be square, circular, cross-shaped or octagonal (Fig. 11, not shown). A plurality of cylindrical members I 1 , I 2 . . . &c. may be mounted about the cantilever 1 to prevent undesired cantilever vibration. The pickup support 7 (Fig. 12) may have a rod R inserted in a hole H in a base-plate S. Base-plate S has a groove corresponding to the shape of support 7. This arrangement facilitates stylus replacement. Reference has been directed by the Comptroller to Specification 897,323.