An example apparatus includes: a plate configured to move along an underlying surface via a layer of fluid disposed in a gap between the plate and the underlying surface, where pressurized fluid forms the layer of fluid in the gap; a first rack gear coupled to the plate and meshing with a first gear; and a second rack gear coupled to a second gear. The second rack gear is fixed, and the second gear is coupled to the first gear. The pressurized fluid in the gap repels the plate away from the underlying surface, thereby causing (i) the first rack gear to move linearly and the first gear to rotate, (ii) the second gear to rotate and move along the second rack gear, and (iii) the plate to move along the underlying surface.

An example apparatus includes: a plate configured to move along an underlying surface via a layer of fluid disposed in a gap between the plate and the underlying surface, where pressurized fluid forms the layer of fluid in the gap; a first rack gear coupled to the plate and meshing with a first gear; and a second rack gear coupled to a second gear. The second rack gear is fixed, and the second gear is coupled to the first gear. The pressurized fluid in the gap repels the plate away from the underlying surface, thereby causing (i) the first rack gear to move linearly and the first gear to rotate, (ii) the second gear to rotate and move along the second rack gear, and (iii) the plate to move along the underlying surface.

A single-rod hydrostatic actuator or pump-controlled actuator, comprises a hydrostatic pump connected in a closed circuit to a single-rod hydraulic cylinder where the cylinder velocity is directly controlled by the pump flow, without the need of intermediary valves. Due to the absence of throttling losses, the efficiency of hydrostatic actuators is considerably superior to the efficiency of conventional valve-controlled circuits. However, because of the differential areas at the cap and rod sides of the cylinder, the flows coming into and out of the cylinder do not match. Several attempts have been made to this date to produce a stable, robust and reliable circuit that can be used in everyday applications but no circuit has ever been conceived to reach the high standards of reliability and robustness required by industry. The current invention solves the problem of the differential flows with a design that is reliable, oscillation-free and robust. The present conception is based on the correction of a misstated theory concerning the modus operandi of hydrostatic actuators. The resulting design can be translated into different embodiments using electronic or hydraulic technologies and uses only logical combinations of the pressure readings at the cap and rod-sides of the circuit.

A work vehicle includes a bypass passage formed in an operational valve of a dump cylinder and configured to feed pressure oil from a hydraulic pump to a power steering device when the operational valve is under a neutral state and an oil feeding passage equipped with an orifice, the orifice-equipped oil feeding passage being configured to feed the pressure oil from the hydraulic pump to a rod side oil chamber of the dump cylinder when the operational valve is under the neutral state.

A dual action hydraulic clutch system. The system includes a master cylinder having an outer piston therein, wherein the outer piston includes a channel therethrough that can receive an inner piston therein. A gap is formed between the outer and inner pistons, such that activation of the outer piston activates the inner piston once the outer piston has traveled a length of the gap. The outer piston forces hydraulic fluid through an outer outlet connected to a hydraulic clutch, and the inner piston forces hydraulic fluid through an inner outlet connected to a rear brake, allowing a user to simultaneously disengage the clutch and engage the rear brake. A lever is connected to the outer piston, such that the lever can move the outer piston between a resting position, a clutch position, and a brake position. The master cylinder can secure to a support surface via a mounting bracket thereon.

A crane, in particular a mobile crane, having a closed hydraulic circuit in which a hydraulic pump is hydraulically connected to at least one hydraulic motor via a feed and a discharge, and in which the feed is hydraulically connected to the discharge via at least one bypass which bypasses the at least one hydraulic motor, wherein the at least one bypass includes a continuously adjustable valve for variably controlling the fluid flow bypassing the at least one hydraulic motor. In addition, a corresponding control device and a corresponding crane control program for actuating a closed hydraulic circuit of a crane are provided.

A linear actuator system includes a linear actuator and at least one proportional control valve and at least one pump connected to the linear actuator to provide fluid to operate the linear actuator. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The linear actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of a flow and a pressure in the linear actuator system to an operational set point.

A piezohydraulic actuator system includes four chambers: a first chamber defined by a drive bellows filled with a hydraulic fluid and movable by a piezo actuator, a second chamber defined by a hydraulic cylinder filled with the hydraulic fluid, which defines a first output; a third chamber defined by an output bellows filled with the hydraulic fluid, which defines a second output; and a fourth chamber defining a reservoir of the hydraulic fluid. The drive bellows is hydraulically connected via a first check valve to the second chamber. A hydraulic piston in the hydraulic cylinder is coupled mechanically to the output bellows. The drive bellows is hydraulically connected via a second check valve to the fourth chamber. The hydraulic fluid reservoir is hydraulically connected via a third check valve to the output bellows, and the hydraulic cylinder is hydraulically connected via a fourth check valve to the output bellows.

The invention relates to a spring (1, 23) comprising at least one tensile body (2, 17, 71, 76) that can be subjected to tensile stress and/or at least one compressive body (37) that can be subjected to compressive stress, the spring also comprising a force-displacement conversion unit (3, 18, 24) for converting the force-displacement of the spring force F, said force-displacement conversion unit (3, 18, 24) having a moveable input control element (6, 19, 29), to which the spring force can be applied and a moveable output control element (7, 20, 30, 54, 60, 68, 72) which is operatively connected to the tensile body (2, 17, 71, 76) or to the compressive body (37) in such a way that the spring force F produces a tensile stress in the tensile body (2, 17, 71, 76) or a compressive stress in the compressive body (37) in a specific force-displacement conversion ratio.

The invention relates to a spring (1, 23) comprising at least one tensile body (2, 17, 71, 76) that can be subjected to tensile stress and/or at least one compressive body (37) that can be subjected to compressive stress, the spring also comprising a force-displacement conversion unit (3, 18, 24) for converting the force-displacement of the spring force F, said force-displacement conversion unit (3, 18, 24) having a moveable input control element (6, 19, 29), to which the spring force can be applied and a moveable output control element (7, 20, 30, 54, 60, 68, 72) which is operatively connected to the tensile body (2, 17, 71, 76) or to the compressive body (37) in such a way that the spring force F produces a tensile stress in the tensile body (2, 17, 71, 76) or a compressive stress in the compressive body (37) in a specific force-displacement conversion ratio.