A pneumatic actuating element, an exhaust air system, a housing, and a pneumatic actuator, are provided, which are designed to provide a possibility to collect exhaust air that is discharged when the pneumatic actuating element is ventilated, which exhaust air typically includes contaminations, and to release the exhaust air in an area that is not visible during operation, in order to prevent irritation due to a contaminated housing on the one hand and, on the other hand, to protect components that might come into contact with the contaminated exhaust air.

A hydraulic circuit having a function of compensation and energy recovery comprises a distribution module, a three-way compensated regulator device, a variable flow rate or pressure feeding assembly, an energy recovery device connected to the three-way compensated regulator device. The distribution module comprises a spool including an inlet recess and a drain recess configured so that the flow rate of fluid inlet to the utility is equal to or less than the one outlet therefrom, possibly net of a correction factor. There is also a respective first driving channel and a second driving channel configured so that a pressure taken upstream of the drain recess acts on a first side of the regulator device, and so that a pressure taken downstream of the drain recess in the first channel acts on a second side of the regulator device, and an additional force.

A hydraulic system of a construction machine includes: a pump that supplies hydraulic oil to a hydraulic actuator; a control valve on a center bypass line extending from the pump to a tank, the control valve including a bypass passage; an unloading valve on the center bypass line downstream of the control valve; and a controller that controls the unloading valve. The control valve is configured such that an opening area of the bypass passage is greater than an opening area of the unloading valve while an operation signal outputted from an operation device increases from a predetermined value to a first setting value, and such that the opening area of the bypass passage is less than or equal to ¼ of a maximum opening area of the bypass passage when the operation signal is greater than or equal to a second setting value greater than the first setting value.

A hydraulic system may include a reservoir of hydraulic fluid, a hydraulic pump, a directional control valve, a hydraulic work loop, a bypass valve, and a hydraulic motor, as well as a plurality of hydraulic conduits interconnecting such components. When excessive hydraulic backpressures are encountered, the system may employ one or more bypass valves and one or more bypass conduits to automatically, and in an on-demand manner, return some or all of the hydraulic fluid from the hydraulic motor to the hydraulic reservoir without the hydraulic fluid passing through flow constrictions causing the excessive hydraulic backpressures.

A sub-system 200 for an aircraft hydraulic system 20 that includes a first inlet 202 for receiving fluid from a supply 22 of hydraulic fluid, a system valve 210 for controlling fluid flow from the sub-system 200 to a hydraulically-operable system 24 of the aircraft hydraulic system 20, a check valve 220 for permitting fluid flow from the sub-system 200 and preventing or hindering fluid flow into the sub-system 200, a second inlet 240 for receiving fluid from a second supply 28 of hydraulic fluid, and a selector 230. The selector 230 configured to place the system valve 210 in fluid communication with the first inlet 202 when the selector 230 is in a first state, and to place the system valve 210 in fluid communication with the check valve 220 and the second inlet 240 when the selector 230 is in a second state different from the first state.

A hydraulic circuit having a function of compensation and energy recovery comprises a distribution module, a three-way compensated regulator device, a variable flow rate or pressure feeding assembly, an energy recovery device connected to the three-way compensated regulator device. The distribution module comprises a spool including an inlet recess and a drain recess configured so that the flow rate of fluid inlet to the utility is equal to or less than the one outlet therefrom, possibly net of a correction factor. There is also a respective first driving channel and a second driving channel configured so that a pressure taken upstream of the drain recess acts on a first side of the regulator device, and so that a pressure taken downstream of the drain recess in the first channel acts on a second side of the regulator device, and an additional force.

A hydraulic system of a construction machine includes: a pump that supplies hydraulic oil to a hydraulic actuator; a control valve on a center bypass line extending from the pump to a tank, the control valve including a bypass passage; an unloading valve on the center bypass line downstream of the control valve; and a controller that controls the unloading valve. The control valve is configured such that an opening area of the bypass passage is greater than an opening area of the unloading valve while an operation signal outputted from an operation device increases from a predetermined value to a first setting value, and such that the opening area of the bypass passage is less than or equal to of a maximum opening area of the bypass passage when the operation signal is greater than or equal to a second setting value greater than the first setting value.

A hydraulic system includes first and second valve assemblies connected to a common pump. The first valve assembly includes a main valve housed inside a manifold. A pressure compensator valve maintains a constant pressure drop across a variable orifice of the main valve. A pressure limiter valve is in communication with the main valve and the pressure compensator valve, and allows an actuator connected to the first valve assembly to operate independently of the second valve assembly so that fluid flow to a work port of the first valve assembly is not interrupted by operation of the second valve assembly.

A power unit with manual override control for a hydraulic system having an initial state and at least one operational state is provided, comprising: a tank for storing hydraulic fluid that moves between a first chamber and a second chamber of a hydraulic cylinder; a pump that routes the hydraulic fluid in and out of the tank; a first relief valve; a first solenoid valve configured to shift between a plurality of positions based on the at least one operational state of the hydraulic system; a first check valve connected to the first solenoid valve; a manual override control unit comprising: a second check valve; and a second solenoid valve configured to shift between a plurality of positions based on activation of a manual override control, wherein the activation of the manual override control returns the hydraulic system from the at least one operational state to the initial state.

A hydraulic system may include a reservoir of hydraulic fluid, a hydraulic pump, a directional control valve, a hydraulic work loop, a bypass valve, and a hydraulic motor, as well as a plurality of hydraulic conduits interconnecting such components. When excessive hydraulic backpressures are encountered, the system may employ one or more bypass valves and one or more bypass conduits to automatically, and in an on-demand manner, return some or all of the hydraulic fluid from the hydraulic motor to the hydraulic reservoir without the hydraulic fluid passing through flow constrictions causing the excessive hydraulic backpressures.