A portable hydraulic power unit includes a fluid tank supported on a frame, a first pump configured to draw hydraulic fluid from the tank and a second pump configured to draw hydraulic fluid from the tank. The portable hydraulic power unit further includes a two-way valve disposed on a high-flow line extending from an output of the second pump, the two-way valve movable between an open state and a closed state. The two-way valve is electrically-actuated and configured to shift to the open state based on a hydraulic fluid pressure in a combined flow line downstream of the first pump and the second pump exceeding a threshold pressure level. The two-way valve directs the output of the second pump back to the fluid tank when the two-way valve is in the open state.

A trigger guard for a pendant for controlling a hydraulic power unit includes a first prong extending from a front side of a handle of the pendant; a second prong extending from the front side of the handle; a groove disposed between the first prong and the second prong, the groove defined by the first prong, the second prong, and the handle; a first gap disposed between the first prong and a head of the pendant; and a second gap disposed between the second prong and the head. The trigger is disposed between the first prong and the second prong such that the trigger is accessible through the groove, the first gap, and the second gap.

A hydraulic system includes a pressure-driven actuator operable to provide a mechanical output in response to a pressure input, a single hydraulic circuit communicating with the pressure-driven actuator, a vibratory actuator in the single hydraulic circuit and operable to generate a first component of the mechanical output at a first frequency, and a hydraulic supply apparatus separate from the vibratory actuator, in the single hydraulic circuit, and operable to generate a second component of the mechanical output at a second frequency less than the first frequency.

To cope with a variety of flow rate balance required of two actuators flexibly in combined operations driving two actuators of high maximum demanded flow rates at the same time while suppressing the wasteful energy consumption caused by the throttle pressure loss in a pressure compensating valve, the arrangement is such that when the demanded flow rate of a boom cylinder 3a is lower than a prescribed flow rate, the boom cylinder 3a is driven only by hydraulic fluid delivered from a single flow type main pump 202 and when the demanded flow rate of the boom cylinder 3a is higher than the prescribed flow rate, the hydraulic fluid delivered from the single flow type main pump 202 and hydraulic fluid delivered from a first delivery port 102a of a split flow type main pump 102 are merged together and the boom cylinder 3a is driven by the merged fluids. Further, when the demanded flow rate of an arm cylinder 3b is lower than a prescribed flow rate, the arm cylinder 3b is driven only by hydraulic fluid delivered from a second delivery port 102b of the split flow type main pump 102 and when the demanded flow rate of the arm cylinder 3b is higher than the prescribed flow rate, hydraulic fluid delivered from the first delivery port 102a and hydraulic fluid delivered from the second delivery port 102b are merged together and the arm cylinder 3b is driven by the merged fluids.

A fluid storage reservoir that creates a regenerative loop inside the reservoir to maintain a pressurized main suction chamber of the hydraulic fluid reservoir is provided. This reservoir includes two separate chambers which are operably fluidly connected by one or more check valves. In the main suction chamber, the design arranges the return flow larger than suction flow in order to pressurize this chamber. This pressure can be adjusted by the check valve setting. This regenerative reservoir can provide sufficient pressure when large system flow occurs.

A hydraulic unit includes two pressure connections for supplying devices, in particular hydraulic rescue devices, including a first hydraulic circuit with a first pump arrangement and a first pressure connection and a second hydraulic circuit with a second pump arrangement and a second pressure connection, wherein the pump arrangements are driven at the same time by a common drive, and wherein by a first valve switch the first hydraulic circuit can be connected to the second hydraulic circuit and by a second valve switch the second hydraulic circuit can be connected to the first hydraulic circuit. The valve switches include a spring acting in the direction of an initial position and from the first hydraulic circuit or from the second hydraulic circuit a first control line runs to the first valve switch and from the second hydraulic circuit or from the first hydraulic circuit a second control line runs to the second valve switch.

A hydraulic system includes a pressure-driven actuator operable to provide a mechanical output in response to a pressure input, a single hydraulic circuit communicating with the pressure-driven actuator, a vibratory actuator in the single hydraulic circuit and operable to generate a first component of the mechanical output at a first frequency, and a hydraulic supply apparatus separate from the vibratory actuator, in the single hydraulic circuit, and operable to generate a second component of the mechanical output at a second frequency less than the first frequency.

A control system of a hybrid construction machine includes a regeneration passage switching valve having a normal position where flow of working fluid is blocked, and a regeneration position allowing for the working fluid to flow from main passages to a regeneration motor when a working fluid pressure of the main passages reaches a set pressure during operation of the actuators, and an assist switching valve having a normal position proportionally dividing the working fluid of an assist passage into a regeneration passages, a first switching position supplying more working fluid of the assist passage to one of the main passages when that the one has a higher working fluid pressure, and a second switching position supplying more working fluid of the assist passage to the other one of the main passages when that the other one has a higher working fluid pressure.

A hydraulic drive system for operating a hydraulic cylinder in first and second movement profiles. A hydraulic drive unit includes first and second hydraulic machines, each with first and second connections. In the first movement profile, a first cylinder chamber of the hydraulic cylinder is fluidly connected to a first fluid reservoir and a second cylinder chamber is fluidly connected to the second connection of the second hydraulic machine. In the second movement profile, the first connection of the first hydraulic machine is connected to the second connection of the second hydraulic machine.

A construction machine with a hydraulic system has a hydraulic control, which comprises a joystick, a hydraulic pressure source, and two hydraulic drives. Main control valves are controlled by a joystick. The construction machine comprises multiple components, and a hydraulic drive is assigned for moving these components. The hydraulic control comprises an electrically-actuatable priority proportional valve in the hydraulic connection of a drive. The priority valve is electrically connected to the electronic control unit and generates additional hydraulic resistance. The hydraulic control comprises sensors, on the components, for detection of the positions thereof. The detected sensor values are transferred to the control unit. At least one trajectory is stored in the control unit. A control mode can be activated, in which each priority valve is controlled using the current sensor values upon actuation of the joystick so that the stored trajectory is run by control of the drives.