A safety system has a valve block (10) to which at least one gas safety valve (12, 14) is connected in a detachable manner. At least one controllable valve (50, 52, 58) is in or at the valve block (10). At least one pressure accumulator (42) holds a gaseous pressure medium and is connected to the valve block (10) in a detachable manner. A gas-conveying connection routed at least partially within the valve block (10) between the connected pressure accumulator (42) and the connected gas safety valves (12, 14) can be opened or blocked by the valve (50, 52, 58).

A method of controlling a hydraulic valve includes putting a first control chamber under pressure and putting a second control chamber to return so as to cause a slide to move into one of two end positions, putting a second control chamber under pressure and putting the first control chamber to return, thereby causing the slide to move into the other one of the two end positions. An intermediate step of applying pressure to the one of the first or second control chamber that was connected to return can be provided so that both control chambers are maintained simultaneously under pressure for a determined length of time.

A control system for construction machinery, includes a hydraulic pump, at least one control valve installed in a center bypass line connected to the hydraulic pump and configured to control a flow direction of a working oil discharged from the hydraulic pump to selectively supply the working oil to an actuator, a bypass control valve installed downstream from the control valve in the center bypass line to variably control an amount of the working oil draining to a drain tank through the center bypass line, and a controller configured to control operations of the hydraulic pump and the bypass control valve according to a manipulation signal of an operator and to open the bypass control valve according to pump peak occurrence to reduce a pump peak.

Provided is a hydraulic drive apparatus of a work machine capable of reducing a surge pressure. The hydraulic drive apparatus includes a control valve interposed between the hydraulic pump and a hydraulic actuator, an operation device moving the control valve in response to an actuator operation, an unload valve, an unload operation valve changing a pilot pressure of the unload valve in response to an input of an unload operation command, a target pressure calculation part, and an unload operation command part. The target pressure calculation part calculates a target pressure that increases with an increase in the holding pressure of the hydraulic actuator. The unload operation command part inputs an unload operation command to the unload operation valve to make the pump pressure of the hydraulic pump follow the target pressure.

A diaphragm accumulator provided with a flexible diaphragm inside an accumulator housing has a stress relaxing member having a contact surface which the diaphragm deformed by a pressure fluctuation inside the accumulator housing contacts and regulating the deformed attitude of the diaphragm by the contact surface on the inner surface. When the diaphragm is deformed by the pressure fluctuation inside the accumulator housing, the stress relaxing member regulates the deformed attitude of the diaphragm to reduce a stress generated in the diaphragm.

A hydraulic system for a working machine includes a hydraulic pump to output an operation fluid, a hydraulic device to be operated by the operation fluid, an operation member to be operated, a first operation valve to regulate a pressure of the operation fluid in accordance with operation of the operation member, and a pressure supplying portion to supply a first counteracting pressure of the operation fluid against a first operation pressure, the first operation pressure being a pressure of the operation fluid regulated by the first operation valve.

A method and control system operable to control movement of a work implement of a work vehicle. The control system includes a reservoir that retains fluid, a pump in fluid communication with the reservoir, and an actuator in fluid communication with the pump. The actuator has a first side and a second side. A control valve is fluidly positioned between the pump and the actuator, a first proportional relief valve is fluidly positioned between the pump and the first side of the actuator, and a second proportional relief valve is fluidly positioned between the pump and the second side of the actuator. The first proportional relief valve is configured to permit flow of fluid from the first side of the actuator to the reservoir when a pressure at the first side of the actuator exceeds a pressure set point.

Example aspects of an over-pressure protection system and a method for operating an over-pressure protection system are disclosed. The over-pressure protection system can comprise a main body housing defining a main body chamber; a fluid received in the main body chamber, the fluid defining a fluid pressure; a pressure sensor configured to measure the fluid pressure of the fluid, the pressure sensor configurable in an activated mode and a deactivated mode; and a control system configured to place the pressure sensor in the deactivated mode when the fluid pressure is equal to or above a pre-determined threshold pressure.

Example aspects of an over-pressure protection system and a method for using an over-pressure protection system are disclosed. The over-pressure protection system can comprise a main body comprising a main body housing, the main body housing defining a main body chamber; an incompressible fluid received in the main body chamber, the fluid defining a fluid pressure; a pressure sensor for measuring the fluid pressure of the incompressible fluid, the pressure sensor configurable an activated mode and a deactivated mode; a first barrier movable between a first position and a second position; wherein the over-pressure protection system is configurable an under-pressure configuration, wherein the pressure of the incompressible fluid is below a threshold pressure, and an over-pressure configuration, wherein the pressure of the incompressible fluid is equal to or above the threshold pressure; and a control system configuring the pressure sensor in the deactivated mode in the over-pressure configuration

A time-based power boost control system. A fluid source supplies fluid. A relief device relieves pressure of the fluid supplied by the fluid source when the pressure of the fluid exceeds a relief pressure level. A control device controls the relief device. When a boost mode in which at least a first level of pressure and a second level of pressure, higher than the first level of pressure, are allowed to be selectively used as the relief pressure level is active, a length of a boost-on time in which the second level of pressure is used as the relief pressure level is shorter than a preset maximum boost-on time limit, and a length of a succeeding boost-off time succeeding the boost-on time in which the first level of pressure is used as the relief pressure level is equal to or longer than a preset minimum boost-off time limit.