Abstract: An X-Y position indicator control for manual movement over any surface to move a cursor over a display on a cathode ray tube, the indicator control generating signals indicating its position to cause a cursor to be displayed on the tube at the corresponding position. The indicator control mechanism contains X-Y position wheels mounted with their axes in perpendicular planes, which rotate according to the X and Y movements of the mechanism. Each position wheel is mounted on a flexible shaft. Each position wheel is resiliently urged into contact with the surface by the flexible shaft.

Abstract: The sub-assembly includes a telescopically arranged rotatable driving shaft and rotatable driven shaft. Both shafts are substantially triangular in cross-section. A spring provides a pre-determined spring force having a magnitude to permit one shaft to slide within the other shaft. The complementary triangular shapes of the shafts causes the torque from the driving shaft to be transmitted to the driven shaft without rotational lash.