Improvements in or relating to resolvers for producing electrical signals representative of the components in co-ordinate directions of a mechanical movement

摘要

848,506. Cathode-ray tube circuits. DECCA RECORD CO. Ltd. March 16, 1959 [March 28, 1958], No. 10082/58. Class 40(7). [Also in Group XXXVIII] A resolver for controlling the position of an electronic marker on a radar display screen comprises a ball freely mounted so as to be capable of unlimited movement about any axis, at least two wheels frictionally engaging the surface of the ball, and electrical signal generators, driven by the wheels to produce signals representative of the components in two co-ordinate directions of movements of the ball. As shown in plan in Fig. 1, a ball 15 of dense plastic material is supported on a horizontal base plate 10 by a castor assembly 13 and by wheels 16, 17, 18 which engage the ball at points in its horizontal diametral plane and which rotate about horizontal axes, the axes of wheels 16, 17 being mutually orthogonal. Wheels 16, 17, which have smaller diameters than that of the ball, drive potentiometers 19, 20, through reduction gearing; in addition, they may drive rods through rack and pinion gearing, the point of intersection of the rods indicating the position of the marker on the screen. Wheel 18 is an idler wheel and is urged against the ball by a spring 46. The wheels, including the castorwheel 14, are made of nylon and have grooved flat peripheries as at 21. To facilitate rapid movement of the potentiometers by spinning the ball, the friction wheels may be weighted, or separate flywheels may be provided on the friction wheel shafts. Instead of, or as well as, step down gearing between the friction wheels and the potentiometers, the differential output of two potentiometers, driven by wheels of slightly different diameters at opposite ends of a ball diameter, may be used for each co-ordinate signal.