Abstract: A hydrostatic piston machine having a housing comprising two shells of a part-cylindrical form, the shells connectable together along a parting-plane in which the central axes of the drive-shaft and cylinder-barrel lie. Each housing element is provided with a number of semi-circular formations and recesses which form pockets or apertures when the housing shells are connected together to provide support surfaces for the working elements of the machine. A cylinder-barrel mounted within a chamber formed between the shells and is provided with a number of cylinders each containing a piston. Fluid-passageways are provided in the housing to receive and supply fluid to the pistons of the machine.

Abstract: A radial piston hydrostatic machine contained within a housing and comprising a cylinder-barrel mounted to rotate on a pintle-valve fixed to said housing. Two hydraulic-rams operatively acting on a track-ring to provide eccentric displacement relative to the pintle-valve to change the rate of fluid output from the machine. The hydraulic-rams being of unequal size and subjected to the same level of machine discharge pressure during periods when the level of discharge pressure is insufficient to cause an internally disposed pressure relief-valve to "open". A throttle-valve disposed in a fluid channel linking the cylinders of said hydraulic-rams and arranged to introduce a pressure differential across two said two cylinders during periods when the machine discharge pressure is sufficiently high to cause said pressure-relief-valve to "open".

Abstract: A transaxle driving apparatus for a self-propelled vehicle such as a grass-mowing lawn tractor, the transaxle comprising a two-piece housing structure forming an internal chamber for encapsulation of a hydrostatic machine and associated reduction gearing. The hydrostatic machine may comprise in one form a single hydrostatic pump driven by an input shaft rotatably supported in the housing, and fluidly coupled to two hydrostatic motors. In a modified form, the hydrostatic machine may comprise two hydrostatic motors fluidly coupled to a pumping source remotely mounted outside the transaxle.

Abstract: A hydrostatic machine includes a casing (10) containing a rotary member (12) having radial cylinders (24) each with a piston (25) engaging a track ring (27). The member (20) is coupled to an external shaft (13) via reduction gearing (43,44) which also acts as a gear pump. This can be used to supply external power take-off fluid circuits, or an attached oil filter (64) or internal bearings (47,57) or make-up fluid for the machine via valve (42).