Abstract: An adjustable axial piston machine in swashplate construction, preferably an axial piston pump, is provided in which the rocker body is supported with a semicylindrical surface by a friction bearing in a hollow semicylindrical surface and pressure pockets loaded with pressure medium are provided for hydrostatic relief of the bearing pressures in the bearing surfaces, in which case in a machine in which each of the two connections that can be loaded with feed pressure, a pressure pocket is provided on each side of the rocker body, where the pressure pocket that lies on the side on which the working pistons loaded with feed pressure also move is loaded with feed pressure.

Abstract: A rotating servomotor apparatus for use in rotating guide vanes in a hydraulic machine, wherein for the purpose of suppressing occurrence of flow-induced vibrations, there is provided a bearing to support wicket gates, a rotating servomotor which includes a movable spindle projecting in the axial direction and which has a plurality of movable partition members, a cylinder having a plurality of stationary partition members disposed around the spindle, and a plurality of compartments partitioned between the movable partition members and the stationary partition members; and a first distributing valve connected to one side of plural compartments within the cylinder of the rotating servomotor means, a second distributing valve connected to the other side of plural compartments within the cylinder of the rotating servomotor means, wherein the respective distributing valves have valve piston members sized and arrangeable with respect to fluid inlets and outlets to define a neutral position in which fluid is supplie

Abstract: A wobble plate compressor, which is adapted to vary the angularity of the wobble plate in response to the difference between the resultant reaction force exerted by the pistons on their compression strokes and the pressure in the crankcase, includes elastic means permanently biasing the wobble plate in the angularity-decreasing direction, and control valve means responsive to a signal indicative of at least one predetermined parameter to selectively connect the crankcase with a suction pressure space and a discharge pressure space for a rapid change in the pressure in the crankcase to thereby achieve control of the angularity of the wobble plate with high responsiveness.

Abstract: An adjustable axial piston machine of swash plate construction is provided in which the working pistons are supported against a swash plate that is formed on a rocker body 6, which in turn is supported with a semi-cylindrical support surface against a hollow-cylindrical bearing surface 4, in which case at least one pressure pocket recess 7, 57 is provided for generating a pressure cushion counteracting the bearing loads and it is connected with the high pressure line through channels in the servo piston that is capable of sliding in the operating cylinder loaded with high pressure.

Abstract: A mechanism for converting rotary motion in rectilinear to and fro comprising and hinged in the housing of a crosspiece by a prestressed rod and conical bearing. An even number of bearings stacked symmetrically on each side of the center and internal cages are fitted an intermediate bush with the interposition of spacing rings, the thicknesses of the rings being so determined that the pre-stressing force is distributed equally between the bearings and causes the complete take-up of play. The invention is particularly useful in multicylinder pump mechanisms distributed regularly around a shaft and with axial pistons.

Abstract: A hydraulic cylinder including a closed cylinder in which are mounted a rotor for rotation about the axis thereof and two pistons for linear movement, the pistons being respectively sleeved onto two ends of the rotor and bounding a first arcuate fluid tight chamber with the inner surface of the cylinder and the peripheral surface of the rotor. At least one vane member is provided on the rotor for operating with the fluid to produce a rotational output. At least one piston rod is connected to one end of the rotor and mounted to the closed end of the cylinder in fluid tight relationship. On both sides of the first fluid tight chamber are two second fluid tight chambers bounded respectively by two pistons associated with the inner surfaces of the cylinder and the closed ends.

Abstract: An axial piston, controlled displacement, wobble plate supercharger and control circuit for use with an internal combustion engine. A means for providing all torque loading along the drive shaft of such a supercharger is taught herein.

Abstract: An apparatus for moving a fluid medium comprising a positive displacement member movable to move the fluid medium and a drive mechanism adapted to be driven by a motor for driving the positive displacement member to move the fluid medium. The drive mechanism includes a wobble plate coupled to the positive displacement member for driving the positive displacement member. The drive mechanism is responsive to back pressure on the positive displacement member for adjusting the angle of the wobble plate to thereby change the volume of the fluid medium movable by the positive displacement member.

Abstract: A swash plate assembly converts rotary motion to reciprocatory motion to reciprocate a diaphragm in a high frequency medical ventilator; the motor which drives the assembly is pivotally mounted for variation of the stroke of reciprocation thereby varying the tidal volume displaced by the diaphragm.

Abstract: An axial piston-type transmission in which a group of axially displaced pump pistons, that move in a cylinder block rotated by an input shaft, slidably engage one surface of a swash plate that rotates an output shaft. A group of axially displaced motor pistons, that move in a stationary cylinder block, slidably engage an opposite surface of the swash plate so that the plate is squeezed between the two groups of pistons. The swash plate is pivotally attached to the output shaft so that the angles between the two surfaces and the axis of rotation of the swash plate can be adjusted. The pump pistons and motor pistons are hydraulically connected in pairs. A rotary valve driven by the output shaft connects half the pump cylinders together hydraulically to form an output port and the other half together to form an input port.

Abstract: A wobble plate piston pump in which means for holding the slipper shoes in close proximity with the wobble plate comprises a first retainer member in the form of an annular plate, loosely fitted on the drive shaft and formed with a plurality of through bores circumferentially arranged in the vicinity of its outer periphery and loosely receiving therethrough trunk portions of the slipper shoes swivellingly engaging the pistons, the retainer member being movable in directions substantially parallel to the wobble plate as the slipper shoes slide on or in close proximity to the wobble plate, a second retainer member having a hollow tubular portion loosely fitted through the first retainer member and unremovably fitted in a central bore formed in the wobble plate and a flanged portion holding the first retainer member on flanged portions of the slipper shoes to keep the latter in close proximity with the wobble plate.

Abstract: A pair of bearing support members (48, 50) are located within opposite end portions (12, 14) of an elongated housing (10). Piston drive rings (58, 68) are mounted for rotation on oblique inner end portions of the bearing support members (48, 50). A cylinder block (44) is mounted for rotation within the housing (10) between the bearing support members (48, 50). The cylinder block (44) includes a plurality of axial bores (46). A pair of pistons (70, 72) reciprocate within each bore (46). Each piston (70, 72) is connected to the piston drive ring (58, 68) at its end of the housing (10) by means of a connector rod (74, 76). An inlet scroll (206 or 208) and an outlet scroll (206 or 208) communicate with center regions of the cylinder bores (46).

Abstract: A diaphragm pump having at least two working chambers communicating with inlet and outlet chambers via non-return valves, includes a reciprocal wobble plate affixed to a diaphragm in the working chambers. The wobble plate has a central guide shaft with a carrier at its free end, the carrier having resilient material, such as a rubber coating or rubber blocks, associated with it. A groove in a rotor connected to a drive shaft receives the carrier. The slope of the guide shaft with respect to the drive shaft is adjustable, and the resilient material holds the carrier in a preset eccentric position with respect to the drive shaft so that under overload conditions the carrier will press against the resilient material and reduce the eccentricity of the carrier with respect to the drive shaft. Once the overload conditions no longer exist, the guide shaft returns to its normal position and normal pumping continues.

Abstract: An elongate elastomeric seal member including a first portion to be partially received in an elongate groove of a selected element where the groove has opposite sides and a base connecting the sides and a second portion extending outwardly from the opposite edges of the groove to sealably engage a sealing surface adjacent the element where fluid pressure is selectively applied to at least one side of the seal and where the seal, in cross section, includes a central body with first and second spaced feet extending outwardly therefrom to be received in the groove and engage the sides and base of the groove and third and fourth feet extending outwardly from the central element to slidably engage the sealing surface wherein fluid can be applied to at least one of the third and fourth feet to urge one of said third and fourth feet to sealing relation with said sealing surface.

Abstract: An oscillatory fluid powered motor includes a cylindrical body closed at its opposite ends by head members to define a chamber. Each head member has a central opening in aligned relationship with the longitudinal axis of the cylindrical body for receiving the opposite ends of a shaft. At least one vane is structurally associated with the shaft for rotation therewith, and extends radially of the cylindrical housing from the shaft. At least one stationary stator is attached to the interior wall of the cylindrical housing and extends radially of the housing. The cylinder heads include a bearing surface surrounding the central openings, and a ring seal concentrically disposed with and radially spaced from the central openings. The vane has a peripheral seal which sealingly contacts the bearing surface of each cylinder head, the interior wall surface of the cylindrical body and a portion of each ring seal.

Abstract: A variable displacement, rocker cam type, axial piston pump in which the rocker cam is driven by a stroking piston and the stroking piston is connected to the rocker cam by a pair of flexible connectors and tension in the first flexible connector is raised and tension in the second flexible connector is lowered when the stroking piston is moved in one direction to pivot the rocker cam toward a position of maximum fluid displacement and tension in the second flexible connector is raised and tension in the first flexible connector is lowered when the stroking piston is moved in the other direction to pivot the rocker cam toward a position of minimum fluid displacement.

Abstract: A drive for a variable-stroke swash plate machine, comprising a rotatably journalled shaft and a swash plate mounted so that the plate cannot rotate with respect to the shaft during operation. The plate is journalled on the shaft so that it is rotatable about an axis of rotation which intersects the shaft axis at an acute angle. A first conical gear on the plate engages a second conical gear on a sleeve arranged coaxially around the shaft. Control means rotate the sleeve and second conical gear with respect to the shaft.

Abstract: A variable displacement axial piston pump having a rocker cam and a rocker cradle in which a complement of recirculating rollers is mounted at each side of the rocker cam to support the cam in the cradle and a holddown plate engages the rollers opposite the bearing surfaces between the rocker cam and cradle.

Abstract: The invention relates to wabbler plate engine mechanisms. One such mechanism has a wabbler plate rotatably mounted on a wabbler carrier which is in turn inclinably mounted on a crankshaft in a crankcase. The wabbler plate has a plurality of arms which are coupled to pistons slidably mounted in cylinders arranged around the axis of the crankshaft. As the crankshaft rotates, each arm oscillates laterally relative to its respective piston and a stabilizer mechanism comprising ball races on the wabbler plate and a ball carrier on the crankcase, is included to prevent the oscillations from unbalancing the mechanism. This construction is quite satisfactory but is not readily adaptable to provide for variable displacement. Attempts have been made to incorporate this facility, but a successful solution has not yet been found.

Abstract: A motor and especially a thermal motor has a connecting rod assembly comprising two radial rolling surfaces constituted by pairs of cones, one cone of each pair being fixed while the other is carried by a rotatable inclined seat.With this arrangement the position of the pistons of the motor at the end of their strokes is rigidly controlled and centered.

Abstract: A hydraulic servomechanism permitting a wrist like universal motion of an extending member through a generally hemispherical operating range in which a sphere or sphere-like drive member is mounted for movement in a spherical or sphere-like cavity and driven by fluid pressure in intersecting circumferential channels mounted either in the drive member or the support means. The circumferential channels are sealed by curved metal bands with gaskets along the edge. Hydraulic fluid enters the channels through ports in the sealing bands themselves so as to facilitate easier movement of the drive member.

Abstract: A drive comprising a rotatably journalled shaft on which a plate is mounted so that the plate cannot rotate with respect to the shaft during operation. The plate can, however, be adjusted around a pin which extends transverse to the rotatably journalled shaft, so that the angle enclosed by the plate and the shaft can be varied. The pin is journalled in a bearing block which is adjustable in the shaft direction. Each of the pistons has a piston rod with a piston rod head whose side which faces the plate is provided with a spherical surface which cooperates with a sliding body which bears against the contact surface of the plate. The side of the plate which is remote from the piston rod comprises a spherical cam which has the same center of curvature as the spherical surface of the drive rod head. The cam is supported by a surface which forms part of a structural member which is rigidly coupled to the shaft.

Abstract: A dampener for a clapper valve wherein a rotor member having radially outwardly extending vanes which subdivide each of two fluid cavities defined in a housing into first and second fluid volumes is characterized by radially extending, first and second passages axially spaced within the rotor which respectively communicate each of the first volumes and the corresponding second volume. The increase in pressure within either of the volumes generated by the motion of the vanes (which move with the clapper) is accommodated by the fluid in one passage venting to the other passage through an axially movable valve. The valve piston presents equal surface areas to each passage, to thereby fluid balance the damper in both the opening and closing directions of the clapper. A bypass channel is provided through which one of the fluid volumes in the first cavity with one of the volumes in the second cavity.

Abstract: A hydraulic aircraft nose landing gear steering actuator includes a coaxial stator and rotor ring assembly mounted on the fixed outer cylinder of a nose landing gear shock absorber strut. Hydraulic vanes protruding radially inwardly and outwardly from the rotor and stator, respectively, form semi-annular pressure chambers between the stator and rotor rings which may be selectively hydraulically pressurized. A torsion link connects the steering actuator to the landing gear wheels. The steering actuator is capable of providing a constant steering torque to the landing wheels over a total steering displacement angle of approximately 150.degree..

Abstract: A rotary piston machine is shown that is operable with a compressible fluid; such as a rotary pump, compressor or engine construction. There is a housing having an inner and an outer ring member that are rotatably mounted on a common axis. The outer ring has at least two diametrically opposed inwardly directed segmental pistons. The inner ring has at least two diametrically opposed outwardly directed segmental pistons so as to define working chambers therebetween. An oscillating coupling means is positioned within the inner ring and flexibly joined to both ring members as well as rotating around a fixed offset crankpin to cause the inner and outer pistons to change position with relation to each other as the two ring members revolve around their common axis so as to create compression and expansion strokes.

Abstract: Apparatus for handling fluid is provided. The apparatus can serve to pump fluid and increase its pressure when power is applied to a shaft, or the apparatus can drive the shaft when fluid under pressure is supplied. The apparatus includes a housing having a plurality of chambers formed therein in a circular pattern. Each of the chambers includes two generally triangularly-shaped cavities communicating at apexes and positioned symmetrically with respect to a center line extending through the apexes. The chamber also is of a generally bow-tie shaped configuration. Each of the chambers has a piston therein which is oscillated about an axis at the center line of the chambers. The piston is generally of the same shape as the chamber but narrower. Each cavity has intake lines and outlet lines through which fluid flows as the piston oscillates therein. The pistons have arms extending outside the chambers and driven to oscillate the pistons.

Abstract: An engine internal-combustion engine having cylinders secured symmetrically spaced on a wheel rotor equipped with a main shaft and with their piston rods extending outwardly against a substantially saddle-shaped cam. The operation of the engine will make the reciprocating piston rods confront the undulating top surface of the cam and therefore revolve the internal-combustion cylinders themselves together with the wheel rotor along the undulating surface. The invention also includes an oil pressure cam receiver to cushion the cam confronting the piston rods and push the pistons to their maximum inward position in the cylinder to achieve a desired compression ratio of the fuel-air mixture in the combustion chamber of the cylinder.

Abstract: A hydrostatically driven road roller having a swash plate pump controlling the supply of pressurized fluid to a drive motor, a dead man's handle or the like controlling pressurization of the fluid in the fluid system, a manual speed control lever connected to the swash plate pump, and a disconnectible device positioned in the connection between the control lever and the pump. The disconnectible device comprises a piston fixed to a swash plate control shaft, a cylinder movable on and lockable with the piston, and means for moving the cylinder into and out of locking engagement with the piston. Centralizing means are also provided to move automatically the swash plate into a neutral position.

Abstract: A base structure defining a generally hemispherical seat and a generally spherically shaped body mounted in seating engagement with the seat. The base defines a pair of diametrically opposed guide channels each of which receives a portion of a different one of a pair of trunnions, another portion of each trunnion being received in a first circumferentially extending channel in the body. The body has a second circumferentially extending channel at right angles to the first circumferentially extending channel for sliding and rotating reception of a portion of each of a pair of second trunnions that have other portions each journaled in the base between respective ends of the guide channels and in diametrically opposed relationship.

Abstract: A pneumatic apparatus for the rotation of a valve rod having a box-design body with a cylindrical seat, on the inner wall of which there is disposed a static resilient gasket, shaped so as to convert the said cylindrical seat to an almost 8-shaped configuration. In this manner, the cylindrical seat is divided into two half-chambers communicating with each other and each of them communicating with the inside, through cross tubular lines.

Abstract: An axially oriented variable displacemnt pistoned device adaptable for use as motor and having a pivoted swash plate angularly positionable for establishing displacement of the device is fitted with externally mounted low pressure hydraulic actuators operably connected with the swash plate for operation thereof. Adjustable stops are provided in the device body to limit travel of the swash plate under urging of the low pressure hydraulic actuators.

Abstract: A spring compensation mechanism for a swashplate drive having a variable swashplate angle, particularly suited for use with ahot gas engine. A compensating rod has one end connected for movement in one direction in response to tilting of the swashplate while the other end is connected to move in a perpendicular direction against the force of a spring.

Abstract: A fluid operated engine having a pair of spaced apart disc-like plate members respectively fixedly secured to a pair of drive shaft sections having adjacent ends interconnected by a universal joint, a plurality of pressurized fluid actuated axially expansile and retractile devices extending between and being connected to corresponding circumferentially spaced points of said members, a valve mechanism for sequentially controlling the flow of actuating fluid to and from said devices, said shaft sections being rotatably supported in tiltable bearing supports selectively adjustable to vary the angular relation of the interconnected shaft sections and selectively position the connected plate members respectively in different angular nutating relationships to cause shaft rotations in opposite directions at varied speeds, and in a parallel non-nutating relationship in which the shaft remains stationary.

Abstract: A wobble plate compressor including a three-part housing in the form of a front shell-like section, defining a wobble plate mechanism cavity, an intermediate cylinder block section and a rear head section, all of the parts being connected in series such as by elongated cap screws. A blind bore in the first section end cover receives a piston to define an expansible chamber actuator. Passage means are formed in the housing for conducting hydraulic fluid from the housing sump to the inlet of pump means. Hydraulic liquid outlet passage means, providing a flow passage between the front and rear heads, are formed in the housing such that control valve means in the rear head can affect the flow of the liquid or oil from the sump to the expansible chamber, causing the modulating piston to vary the angle of the wobble plate mechanism and thus the pumping capacity of the compressor.

Abstract: A multiple cylinder sinusoidal engine comprising a plurality of piston/cylinder arrangements lying parallel to, and around, a shaft cylinder is disclosed. Mounted in the shaft cylinder is a sine shaft, i.e., a cylindrical shaft having formed in its periphery at least one closed, double wave, continuous, sinusoidal groove. Coupling mechanisms couple the pistons to the sinusoidal groove or grooves of the sine shaft such that reciprocating motion of the pistons causes rotary motion of the shaft. Various air/fuel, exhaust and ignition passageways are provided through the sine shaft (or through the engine block in some embodiments) to allow air and fuel to enter the piston cylinders and exhaust gases to be emitted therefrom, and to allow ignition energy to be applied to air/fuel mixtures, as necessary. In one form, a single igniter is provided. The single igniter is coupled, sequentially, to each piston/cylinder arrangement as the sine shaft revolves.

Abstract: A hydrostatic transmission drive pump swash plate control including a control arm and a cam which are mounted on axes perpendicular to one another. The control arm is connected to the swash plate to effect simultaneous movement of the control arm and swash plate. Cushioned link means operatively interconnect the cam and a manual control member. The cam includes a cylindrical portion with a cam slot which is shaped similar to the first 90.degree. of a sine wave between full speed reverse and neutral and similar to the first 90.degree. of another sine wave from neutral to full forward speed. A resilient cam roller on the control arm absorbs fluctuating stroking forces of the pump and cooperatively engages the cam slot to produce a low rate of ground speed change near the neutral condition of the hydrostatic transmission and also near maximum forward and maximum reverse ground travel speed.

Abstract: A wobble plate compressor in which the output of the compressor is modulated in response to refrigeration requirements by varying the compressor piston displacement to match the cooling requirement. An expansible chamber power unit including a sleeve surrounds the drive shaft in sealing relation therewith for axial movement with said sleeve including a wobble plate connected thereto for pivotal movement relative to the shaft. The wobble plate angle is varied during the axial movement of the sleeve by means of a drive lug on the drive shaft having a cam track therein connected in rotary driving relation to cam follower means on the wobble plate. The cam track opposite ends define respectively, maximum and minimum stroke lengths for each of the pistons whereby under controlled pressure conditions the force system results in the pistons tending to go to their full stroke positions.

Abstract: A multi-directional positioner for moving one element relative to another element wherein a socket in a housing receives a ball with a rotating fit with a portion of the ball projecting outwardly of the socket and being connected to one element and the housing being connected to the other element. An arcuate groove in the socket extends in a plane passing generally through the center of the ball and receives a piston which is pivotally connected to the adjacent side of the ball. An arcuate groove in the outer surface of the ball extends in a plane passing generally through the center of the ball and perpendicular to the groove in the socket and receives a piston which is pivotally connected to the adjacent portion of the housing. Fluid is introduced under pressure selectively into the arcuate grooves in the ball and the arcuate groove in the socket to impart relative movement between the ball and the housing.

Abstract: A device comprising at least three reciprocable piston-shaped bodies, each of which is provided with a drive rod which cooperates, via a drive rod head accommodating sliding bodies, with a plate which is mounted on a rotatable shaft and which can be tilted about a tilting axis which is transverse to the center line of the shaft. The means for tilting the plate are formed by piston-shaped bodies which can rotate with the shaft and which can be adjusted in the direction of the shaft, the first of the said bodies being coupled to the plate on the one side of the tilting axis, the other body being coupled to the plate on the other side of the tilting axis. Each of the said piston-shaped bodies bounds a space whereto pressurized liquid can be applied, the masses of the said piston-shaped bodies also serving for balancing the unbalancing forces occurring during operation.

Abstract: A pump or motor having a cylindrical housing member and a shaft member extending coaxially therethrough. The shaft member carries shaft vanes which project radially from the shaft member into close proximity with an inner cylindrical surface of the cylindrical housing member while the cylindrical housing member carries cylinder vanes which are fixed to the cylinder housing member and project therefrom radially toward and into close proximity with the shaft member. The ends of the shaft vanes are fixed with a pair of circular flanges which have outer peripheral edges next to the inner surface of the cylindrical member, these flanges extending across the opposed ends of the cylinder vanes. Axially extending sealing members extend along the outer edges of the shaft vanes between the latter and the inner surface of the cylinder member while annular sealing members extend along the peripheral edges of the flanges engaging the latter and the inner surface of the cylinder member.

Abstract: An axial piston machine with a variable or adjustable stroke comprises a rotatable cylinder drum provided with annularly spaced cylinder bores each of which receives a piston reciprocal in its bore parallel to the axis of rotation of the drum and with a stroke determined by the extent of tilt of a guide surface about an axis perpendicular to the axis of rotation of the drum. The piston stroke is controlled by a rocker carrying the control surface and hydraulically displaceable in the machine housing by application of hydraulic fluid pressure directly to the rocker.

Abstract: A rotary hydraulic motor valve operator having a rotor shaft with diametrically opposite vanes operating between diametrically opposite stops forming two pairs of fluid chambers, one chamber of each pair being connected through the top plate of the motor housing with a conduit which alternates as a supply or an exhaust conduit. Annular cross-over grooves at different levels in the top plate around the rotor shaft are connected one to the opposite chambers of each pair.

Abstract: A control for an axial piston type variable displacement fluid energy translating device has an auxiliary control device which connects to a manual control and provides a variety of operating functions for the fluid energy translating device.

Abstract: Hydraulic and pneumatic motors having expansion chambers arranged between two supporting means, at least one of which is rotatable, said chambers formed at least in part of material that is elastically deformable by the pressure medium used, are provided. The invention also provides a control system for introducing the pressure medium into the chambers sequentially and expelling it sequentially after each chamber has attained maximum volume.

Abstract: An orbiting, floating mechanism which reciprocates while rotating and is capable of varying, stopping, or reversing a flow of fluid therethrough at any one revolution or any combination of revolutions or any part thereof.

Abstract: A two-speed control for dual hydrostatic motors, especially for self-propelled, skid-steered loaders having hydrostatic transmissions. Each motor has a rotating piston group and a swash plate inclinable in either of two positions of piston displacement for low or high speed output. A shift lever connects the swash plate control arms of the motors with a manual selector lever biased by an over-center spring mechanism to either the high or low speed position. The shift lever has a slide and guide connection with one swash plate control arm and pivotally connects to the other in an arrangement which automatically locks the swash plates in the proper attitude in either shifted position of the slide and guide connection corresponding to the low or high speed range.Two variable displacement hydrostatic pumps, one associated with each motor, are independently controlled by a pair of control levers operable to vary the pump displacement within both the high and low speed ranges of the motors.

Abstract: A variable displacement axial piston pump has a rocker cam for controlling the output of the pump. The rocker cam is driven by a fluid motor member. A valve with a follow-up device regulates pressure fluid flow to the fluid motor member to move the rocker cam. Both the fluid motor member and a part of the follow-up device are rigidly secured to and movable with the rocker cam to provide precise positioning of the rocker cam.

Abstract: A two-speed control for dual hydrostatic motors, especially for self-propelled, skid-steered loaders having hydrostatic transmissions. Each motor has a rotating piston group and a swash plate inclinable in either of two positions of piston displacement for low or high speed output. A shift lever connects the swash plate control arms of the motors with a manual selector lever biased by an over-center spring mechanism to either the high or low speed position. The shift lever has a slide and guide connection with one swash plate control arm and pivotally connects to the other in an arrangement which automatically locks the swash plates in the proper attitude in either shifted position of the slide and guide connection corresponding to the low or high speed range.Two variable displacement hydrostatic pumps, one associated with each motor, are independently controlled by a pair of control levers operable to vary the pump displacement within both the high and low speed ranges of the motors.

Abstract: A hydraulic pumping apparatus including a cylindrical housing member having an open upper end closed by a cover held in place by a snap ring. A rotor is rotatably supported in the housing and in turn supports a plurality of pistons which are parallel to the axis of rotation of the rotor. The novelty resides in the swash plate assembly which includes an off-the-shelf bearing comprising two parallel plates with all bearings sandwiched therebetween with one of the plates engaging the pistons. An integral plastic ring member is disposed within the annular opening of the upper thrust plate of the bearing assembly and includes trunnions extending laterally in opposite directions for disposition in grooves in the cover member for changing the angle of inclination of the bearing assembly. An adjustment member extends through the cover for engaging the upper thrust plate of the bearing assembly to change the angle of the inclination thereof.

Abstract: A variable displacement cylindrical pump is provided having a sectional housing and a cam plate having trunnions and trunnion bearings. A first generally annular pump housing section is provided having oppositely disposed recesses formed in its inner periphery that have semi-circular portions at one end for axially receiving the cam plate trunnions and trunnion bearings. The trunnion bearings are secured in their recesses by the assembly of a second adjoining pump section housing and by biasing springs disposed between the trunnion bearings and the second housing section.