Improvements in mechanism for the reproduction of sound

Abstract

Abstract 337,811. Lanchester, F. W. Aug. 7, 1929. Magnetic instruments; gramophone pick-ups.- An electromagnetic pick-up has a holder for the needle, or armature carrying a needle, consisting of a sleeve of rubber or similar material, which may be open or closed at its upper end, and is so formed that the needle or armature is adapted to roll in an oscillatory manner within the holder in conformity with the vibrations impressed upon it. In Fig. 9, the needle 4 is supported by two rubber blocks 17, 18 and the reaction of the record on the tip of the needle. A force in the direction of the arrow at the tip of the needle causes a rolling motion. This effect is obtained in the pick-up by the needle being loosely held by the sleeve so that in operation it bears on two edges only; or the sleeve 14c may be almond shaped, Fig. 10, to accommodate the armature 5. The rubber sleeve, Figs. 7, 8, is held in position by the spool 6, Fig. 1, mounted between the four laminated pole pieces of a magnet 1. A bar 2 of insulating material carries terminals 8, and clamping washers 8a holding leads 7a, 7b to the coil 7 and 9a, 9b to the amplifier. The pick-up may be mounted as described in Specification 321,967. When the needle serves as an armature, it may be inserted in the rubber sleeve from above or below. The needle may otherwise be connected to the armature 5, Fig. 11, by a clamping nut 15 and screw 16, the armature having a V-shaped or cylindrical slot along its length to accommodate the needle 4. According to the second Provisional Specification, the needle when serving as an armature may be of soft iron and may have its point hardened by the electrodeposition of iron; or the needle may be in two parts, an outer cylinder of soft iron and a core of hardened steel capable of renewal by simple insertion.

Inventors

No inventors recorded.

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