Unipat Ag

Unipat Aktiengessellschaft

Arthur Atholl Blair

Christian Helmut Thoma

George Duncan Arnold

Hydraulic radial piston machines

A radial piston hydrostatic machine having an outer housing structure comprising at least two housing elements connectable together along a parting-plane arranged perpendicular to the rotational axis of said drive-shaft to define an internal chamber, a drive-shaft supported in the housing to drive the cylinder-barrel, the cylinder-barrel having a number of radial cylinders, each cylinder containing a piston such that the pistons can bear on the track-ring, fixed abutment means in the housing and disposed radially adjacent the track-ring for resisting the action of the pistons on the track-ring and suppressing vibration emanating from the track-ring.

Hydrostatic piston machines

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'.

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.

Variable speed transaxle

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).

Growing community of inventors

Jersey, United Kingdom

Arthur Atholl Blair