Abstract: A constant velocity coupling which rotatably connects an input shaft to an output shaft via a control mechanism which includes a gimbal arrangement with an inner yoke rotatably connected to an outer yoke. The control mechanism includes a control yoke to constrain at least portions of the coupling to lie on or in association with a homokinetic plane of the coupling. The control mechanism operates symmetrically about a supplementary angle bisector. In another arrangement the coupling includes a double constant velocity joint in which the control mechanism is located in a control tube connecting the two joints. In another arrangement the angle between the input shaft and the output shaft is controlled so as to vary the volumetric capacity of a swash plate hydraulic displacement device.

Abstract: A constant velocity coupling which rotabably connects an input shaft to an output shaft by means of a control mechanism or control system which, in particular forms, includes a gimbal arrangement comprised of an inner yoke rotatably connected to an outer yoke. The control mechanism including control yoke constrains at least portions of the coupling to lie on or in association with a homokinetic plane of the coupling. In particular forms the control mechanism operates symmetrically about supplementary angle bisector.

Abstract: A constant velocity coupling 10, 305 which rotabably connects an input shaft 11 to an output shaft 12 by means of a control mechanism or control system 21, 309 which, in particular forms, includes a gimbal arrangement comprised of an inner yoke 22 rotatably connected to an outer yoke 16.

Abstract: A thermal engine including a positive displacement compressor (A) having at least one rotatable vane partly defining at least one of the variable chambers within the compressor (A) having at least one rotatable vane partly defining at least one of the variable volume chambers within the compressor, a thermal chamber (D) in fluid communication with the outlet of the compressor (A), the thermal chamber (D) having heat transfer means for transferring heat from a heat source to the working fluid; and a positive displacement motor (B) having at least one rotatable vane partly defining at least one of the variable volume chambers within the motor and drive means for driving the compressor and an external load wherein, in use the flow of working fluid through the thermal chamber is substantially continuous.