A device and method for treating a wound of a patient with negative pressure is provided. The device comprises a heat-assisted pump system. The pump system can be powered in part by heat derived from the patient. The pump system may be configured to be highly planar, light weight, and portable. The pump system may comprise a Stirling engine or a thermal acoustic engine.

Aspects of the present invention relate to a carriage assembly (3-n) for a swash plate engine (1) having a swash plate (7). The carriage assembly (3-n) has a carriage body (19) for reciprocating along a longitudinal axis (X-n). The carriage body (19) is configured to be connected to at least one piston (5-n). At least one bearing assembly (20-n) is disposed on the carriage body (19). The or each bearing assembly (20-n) includes a rolling bearing (21-n) configured to engage a rolling face of the swashplate (7); and a yoke (23-n) for supporting the rolling bearing (21-n). The yoke (23-n) is movable relative to the carriage body along the longitudinal axis. Aspects of the present invention also relate to a swash plate drive assembly (15); and a swash plate engine (1).

A weight training apparatus using hydraulics or pneumatics for applying positive and negative resistance closer to a user's maximum capacity throughout a lift is provided. The apparatus allows for weight training without weights. The apparatus may provide a more effective and safer mechanism for training than conventional techniques. An aerobic apparatus using hydraulics or pneumatics for a more realistic feel is also provided. Methods of using the devices are also provided.

A weight training apparatus using hydraulics or pneumatics for applying positive and negative resistance closer to a user's maximum capacity throughout a lift is provided. The apparatus allows for weight training without weights. The apparatus may provide a more effective and safer mechanism for training than conventional techniques. An aerobic apparatus using hydraulics or pneumatics for a more realistic feel is also provided. Methods of using the devices are also provided.

A hydraulic pump, in particular an adjustable axial piston pump, has at least one piston (22) movable in a reciprocating manner in a longitudinal direction within a pump housing during operation of the hydraulic pump. The piston (22) has a link head (24), a piston top (54) opposite the link head (24), and at least one hollow chamber (60) surrounded at least partially by a piston housing (62) that substantially or completely terminates each hollow chamber (60) towards the outside. A piston (22) for such hydraulic pump is also provided.

A variable displacement piston assembly including a plurality of cylinders, each cylinder having an axis substantially parallel to the axis of the other cylinders, a plurality of pistons, one piston in each cylinder, and each piston and corresponding cylinder having a displacement. The assembly also including a transition arm having a connector pin for each piston, each connector pin connecting each piston to said transition arm, a drive shaft connected to the transition arm and a control shaft rotatably coupled to the drive shaft, the control shaft being movable to adjust the displacement of the piston assembly.

A hydrostatic axial piston machine is disclosed, in the housing of which a drive shaft is rotatably mounted about an axis of rotation. The housing comprises a pot-like housing part having a first abutment and a cover-like housing part having a second abutment. The two abutments are clamped against one another in a sealing manner. A first fitting pin is inserted precisely into a first fitting recess of the first abutment on the one hand and into a second fitting recess of the second abutment on the other hand. A second fitting pin is provided on a side opposite the axis of rotation, which is inserted precisely into a third fitting recess of the first abutment on the one hand and into a fourth fitting recess of the second abutment on the other hand. The second fitting recess has a radial widening relative to the axis of rotation, whereby the second fitting recess is a slotted hole and/or a fitting groove.

An outer circumferential surface of a trunnion shaft includes a sliding contact region that has a circular arc shape as viewed along a slanting axis line and is substantially brought into contact with an inner circumferential surface of the bearing portion in a rotatably sliding manner, and at least one suction groove that forms a pocket portion between the suction groove and the inner surface of the bearing portion. The pocket portion is opened to an inner space of housing on at least one side in an axis line direction of the trunnion shaft.

A hand-operated piston pump includes a drive shaft and a rotor mounted in a housing case, the rotor having axial compression chambers, a piston biased by an elastic member sliding in each compression chamber and having a projecting end that engages a cam track; a fluid reservoir in the housing case; a valve plate downstream of the rotor having conduits for a pressurized fluid that communicate with conduits in walls of the compression chambers, the valve plate being non-rotatably mounted below the housing case and communicating with conduits that carry the pressurized fluid to and from a consuming unit through an interposed check valve inserted in a corresponding valve body, the valve body having an upper flange with fluid supply and return channels communicating with the fluid conduits of the valve plate. The valve plate floats relative to the upper flange and is separated therefrom by a separating member.

An axial piston pump has a swash-plate construction, in particular for hydraulic systems. A cylinder drum (3) can be rotationally driven about a rotational axis (7) in a pump housing (1). Pistons (9) are axially displaceable and support at their actuation ends a swash plate (15). The swash plate can be pivoted by an adjusting device (21) to the desired angles of inclination relative to the rotational axis (7) for adjusting the stroke of the pistons (9) and the fluid pressure generated. The adjusting device has an adjusting piston (35) in a hydraulically actuated adjusting cylinder (31). Their movement can be transmitted to the swash plate (15) by a driven connection having a pivot joint (37, 39; 29, 43). The pivot joint is formed by a ball joint (37, 39) arranged between the piston (35) and the piston rod (41) of the adjusting cylinder (31).