Patent GB-1047476-A (GB)
IPC: H04R17/08
Abstract: 1,047,476. Gramophone pick-ups. SONOTONE CORPORATION. July 5, 1963 [July 6, 1962], No. 26720/63. Heading H4J. A detachable stylus structure 60 (Fig. 8) for a gramophone pick-up comprises an elastomeric body 63 interposed between the front end of a seating member 67 and the rear end of a stylus drive member 61. A stereophonic pick-up comprises a casing 20 (Figs. 3, 4) in which two piezo-electric transducers 21 are held at their rear ends in compartments 52. Each movable front portion 27 of the two transducers 21 is coupled through a quadrangle type coupler 40 to the stylus drive member 61. The seating member 67 is shaped for detachable seating engagement with projections 81 (Figs. 6, 7) of casing 20. Each projection has a cylindrical seating 82 with a downwardly facing gate 83. The seating member 67 has two portions 68 for insertion through gates 83 into seats 82. For this purpose, portions 68 may be elastically deformed, or may have narrow segmental side surfaces which enable the stylus structure 60 to be removed on rotation through 90 degrees from an operative position (Fig. 9, not shown). The seating member 67 also has a front member 69 and a rear member 70 which fix the location of the stylus structure 60 relative to casing 20. Seating member 67 has a handle 72 with stops 74 adapted to engage stop surfaces of the casing 20 in accordance with whether stylus 12 or stylus 12-1 is in operative position. On turning the stylus structure 60 from one position to the other, handle arms 73 are first inwardly deformed on passing through bias surfaces 86 (Fig. 5). On further movement of handle 72, handle arms 73 are restored to their initial position until, towards the end of their travel, they are inwardly deformed on passing through further bias surfaces 86 which clamp the handle 72 in position. Stylus drive member 61 is of sheet aluminium alloy or magnesium alloy or sheet acetal-resin polymers and is of hollow conical, square, triangular or oval crosssection (Figs. 13, 13a, 13b, not shown). Into its rear end 64 and into front member 69 is cemented elastomer body 63 which provides a pivot for drive member 61. Elastomer body 63 may be of cylindrical, elliptical or polygonal cross-section, for example rectangular, square (Fig. 12, not shown) or cross-shaped (Fig. 12a, not shown), the recesses of rear end 64 and front member 69 being of complementary shape. Alternatively the end portions of elastomer body 63 may embrace the stylus drive member 61 and the seating member 67. In an alternative arrangement (Fig. 14, not shown) the stylus driving member 61 comprises a series of hollow cylindrical tubular sections of successively larger cross-section from the smallest cross-sectional area at the stylus end to the largest crosssectional area at the rear end. Alternatively, the elastomer body 63-9 (Fig. 15) has a keyed recess (e.g. of flat or cross-shaped cross-section) for holding coaxially fixed the rear flattened end 61-9 of stylus drive member 61-7. The front end of elastomer body 63-9 has affixed thereto a rigid enclosure 64-8 of metal or strong plastics which has a front wall 64-9 for holding in coaxial alignment the rear end of the stylus drive member 61-7. Stylus driven member 61-7 and enclosure 64-8 may be formed as a single structure. The transducer elements may be of other known types such as electromagnetic transducers. Reference has been directed by the Comptroller to Specification 747,406.