Patent GB-962810-A (GB)
Title: Improvements in or relating to stereophonic pick-ups
IPC: H04R17/08
Filed: 1960-07-20
Abstract: 962,810. Stereophonic pick-ups. M. DE VRIES. July 20, 1960 [April 22, 1960], No. 25336/60. Heading H4J. A stereophonic pick-up comprises plate or strip form transducer elements 1, 2 (Fig. 1), e.g. piezo-electric elements, the.major face of one element being perpendicular to the major face of the other element and each element 1, 2 having a corner 10, 13 free to vibrate in a direction normal to the plane of its major face, the corners 10, 13 being closely adjacent one another and a rigid part of a stylus holder 11 being disposed to lie opposite to and to cause a pressure to be exerted upon a main face region of each of said corners 10, 13 so as to be capable of transmitting vibrations in a direction perpendicular to either main face plane while being capable of movement relative to either element 1, 2 in a direction parallel to either of said main face planes. The pressure is exerted through a block 17 comprising a synthetic, resilient, non-metallic material having high internal damping (e.g. polyvinylchloride). The other corners 5, 6, 7 of both elements 1, 2 are clamped in the pick-up casing (not shown) by blocks 8, 9 of synthetic, non-metallic, resilient material having high internal damping. The stylus holder 11 is provided with plates 14, 15 between which is inserted a bearing plate 16 of resilient material having a slot 16<1> wide enough to permit passage therethrough of the stylus holder 11. The end of slot 16<1> is of complementary form to the square-sectioned shank of the stylus holder 11. Alternative arrangements.-The stylus holder 18 (Fig. 2) drives the transducer elements from the underside. It comprises two upwardly and outwardly extending lips 19, 20 located at an angle of about 90 degrees to each other. The lips are rigid and are lined with layers 21, 22, e.g. of polyvinylchloride. An enlarged rear portion 23 of the stylus holder 18 is clamped to the pick-up casing (not shown). The forward ends of transducer elements 26, 27 (Fig. 3) extend into apertures 29, 30 in a double sleeve 28 of material such as polyvinylchloride. Stylus holder 34 is fitted into a block-like eye portion 33 which is united with the rest of sleeve 28 only by way of junction regions of reduced cross-section. The block-like eye portion 33 functions in the same way as block 17 of Fig. 1. Projections 31, 32 are secured to the casing (not shown). Two piezo-electric elements 35, 36 (Figs. 4, 5) are clamped in slots 39, 40 in a P.V.C. block 37 held in a casing 38. A contact block 41 of synthetic material has projections 42, 43 fitting into openings 44, 45 of block 37. Connecting strips 50, 51, 52, 53 for the piezoelectric elements 35, 36 pass through openings 46, 47, 48, 49 in block 41 into which fit contact pins 54, 55, 56, 57 mounted on an insulating plate 58. Ridges 59 anchor the plate 58 to casing 38. Corners 60, 61 of the piezo-electric elements 35, 36 are secured in slots 63, 64 in a bridge-piece 62 whose ends 65, 66 are clamped in the casing 38. A stylus holder 70 is inserted in a bearing element 72 made of P.V.C. A spherical enlargement 73 of the bearing element 72 forms a pressure transmitting block. Two enlargements 74, 75 of the bearing element 72 are spaced apart and a plate 76 having prongs 77, 78 is slid between them. Plate 76 is carried by casing 38. End portion 67 of the slot complements the square section portion 79 of bearing element 72, to prevent rotation of the bearing element and stylus holder 70.