GB348575A - Improvements in and relating to electric pick-ups - Google Patents

Abstract

348,575. Gramophone pick-ups. ASPDEN, R. L., 6, Southport Road, Chorley, Lancashire. Feb. 12, 1930, No. 4794. [Class 40 (iv).] The magnet or magnets of a gramophone pick-up are adapted to constitute the pick-up arm or a portion thereof. As shown, a horseshoe magnet A is mounted on pivots i on a rotatable support l, the pivots passing through slots k in the magnet to provide for adjustment of the effective length of the arm. The pole ends d, e are bent or otherwise shaped to provide for a suitable tracking of the needle and are provided with polepieces g, h which are sloped as shown to give the correct needle angle with the record. Alternative forms of magnet may comprise (i) two separate magnets magnetically connected at one end, (ii) magnets arranged one within the other, (iii) a magnet concealed in the pick-up arm or (iv) an electromagnet, in which case a variable resistance may be connected in the windings to enable the output from the pick-up to be adjusted. The polepieces g, h are slotted at o to form opposing projections m, m<1> and n, n<1> with gaps p, q. A rigid T-shaped armature, Fig. 2, has the body portion r gripped with the interposition of a rubber sheath in the gap p, the stem t projecting through a coil in the slot o and vibrating in the gap q by virtue of the rubber sheath. The needle is secured by a screw s. Specification 339,949, [Class 40 (iv), Telephones &c.], is referred'to.