Abstract: An hydraulic power generating pack 1 comprises a primary pump 23 of the multi-cylinder, reciprocating ram type with a reciprocable piston 27 located in each cylinder 28 and displaceable by a crank shaft 20 rotatable by a prime mover 2 to provide a primary hydraulic fluid output 32 at a predetermined constant pressure and constant volume, and a power take off 14 to drive a secondary pump 36 of the pressure compensated variable delivery type, the output 40 of which drives a pressure intensifier 42 serving to intensify, to the required secondary pressure and volume, hydraulic fluid supplied to the intensifier 42 at a first pressure and volume.

Abstract: A transmission coupling 1 for location between an electric motor 2 and a gearbox 3, comprises a rigid housing 4, an input shaft 5 rotatably supported within the housing 4, an output shaft 6 also rotatably supported within the housing 4 and connectable to the input shaft 5 by operation of a hydraulically actuated, multi-plate clutch 11, the output shaft 6 also carrying some elements of a multi-plate brake 22, other elements being carried by the housing 4, the brake 22 being spring loaded into operative position and hydraulically displaceable into a non-operative position, a constant pressure pump 31 to provide hydraulic pressure fluid to effect operation of the clutch 11 and brake 22, in accordance with the fluid volume demanded by clutch and brake operation, the pump volume output automatically being adjusted in response to such demand, and at least one control valve 35 to control the flow of the hydraulic fluid to the working circuit 39.

Abstract: A reciprocable piston hydraulic pump is provided with a piston periphery sealing means 24 comprising, at the pressure side, a seal 25 of flexible material and adapted to surround the piston periphery, a ring 27 separating the seal 25 from a moulded pressure seal, with a reservoir 28 defined between the seal 25 and the pressure seal, and spring means 29 operable on the seal 25 to urge the latter towards the pressure seal 26.