A force feeder unit comprising a fixed body having two fluid orifices, mobile means mounted in said fixed body and defining a series of chambers of variable volume adapted to transfer a fluid along a cyclic path having a first region in which said chambers increase in volume and a second region in which said chambers decrease in volume, and a distribution means interposed in said fixed body between said orifices on the one hand and said chambers on the other, and comprising a first passage adapted to cause one of said orifices to communicate, at least in part, with the first region of said cyclic path and a second passage adapted to cause the other orifice to communicate, at least in part, with the second region of said cyclic path, said fixed body further comprising at least a third orifice, and said distribution means comprising at least a third passage adapted to cause said third orifice to communicate with at least the first region of the cyclic path of said chambers at which the chambers increase in volume, so that said unit has at least two input flows and one output flow.
A rotary fluid pressure device has a first oil passage with relatively high pressure fluid therein surrounding the gear set; a plurality of second oil passageways connecting the first oil passageway to the expanding and contracting oil chambers; and fluid non-return valves in each of the second oil passageways to permit the flow of oil therethrough only in a direction from the oil chambers to the first oil passageway.
