The present disclosure relates to a compressor control system that detects the pressure (or flow rate) at the rear end of a compressor and performs proportional control in mechanical manner to uniformly control the pressure (or flow rate) of the compressor while preventing a compressor suction valve from being fully closed. To this end, the present disclosure includes a cylinder including a first piston and a second piston therein, a pressure control valve which supplies fluid to operate the second piston to an area above the second piston, a control valve which supplies fluid to operate the first piston to an area above the first piston, and supplies fluid to the pressure control valve, a fluid condition transmission unit which detects fluid condition (pressure or flow rate) at a rear end of a compressor, and converts the detected fluid condition value to an electrical signal and outputs it.

A battery-powered log splitting machine can include a frame structure, a first hydraulic actuator supported by the frame structure and including a first piston rod assembly movable between extended and retracted positions, a splitter wedge connected to the piston rod assembly, a second hydraulic actuator in fluid communication with the first hydraulic actuator in a series arrangement, a linear electric actuator operably coupled to the first hydraulic actuator, a battery pack for powering the linear electric actuator, and an operator input controlling operation of the linear electric actuator. When the operator input is displaced in a first direction, the electric motor is energized to result in the first piston rod assembly moving towards the extended position. When the operator input is displaced in a second direction, the electric motor is energized to result in the first piston rod assembly moving towards the retracted position.

Provided is an outboard motor raising and lowering apparatus that is capable of automatically changing the speed of raising/lowering an outboard motor according to a status of the outboard motor. The outboard motor raising and lowering apparatus (1) includes: a first fluid passage that connects a pump (42), a second chamber(s) of one or more tilt cylinders (14), and a second chamber(s) of one or more trim cylinders (12); a second fluid passage that is connected to the first chamber of at least one of the one or more trim cylinders; a switching valve (60) provided at the second fluid passage; and a control section (100) configured to control the switching valve with reference to a watercraft status signal.

A sanitary valve system (10) comprising an actuator arrangement (20) in an actuator housing (32) comprising a first piston chamber (30I) with a first piston (32I) separating the first piston chamber in a first upper cavity (341U) and a first lower cavity (341L) and having a first piston shaft (36I) configured to operate outside of the actuator housing. The valve system is configured to operate in multiple states. The operation of each state and transitions amongst states including identical states are controlled by regulating the liquid pressure or flow in each respective first and second upper and lower cavities. The regulation of liquid may be via a common distribution plate arrangement (90). The distribution arrangement may be with least one common distribution plate (92) with a set of canals (94) configured to connect at least one set of upper and lower regulation lines (82IU, 82IL,82IIU, 82IIL) with the respective first and second upper and communication lines (50IU, 50IL, 50IIU, 50I IL). A sanitary valve kit and a method of retrofitting an existing valve arrangement are also disclosed.

The invention relates to a mobile hydraulic tool with a drive piston hydraulically adjustable between a start position and an end position, a hydraulic tool housing having a cylindrical section guiding the drive piston, and a tractive tool unit or pressing tool unit releasably connectable to the drive piston and the hydraulic tool housing. In order to provide a mobile hydraulic tool in which the movement provided by the drive piston can be used to optionally drive a tractive tool unit and a pressing tool unit, the hydraulic tool housing is designed on one side for arranging the tractive tool unit connectable to the drive piston, and on the other side for arranging the pressing tool unit connectable to the drive piston.

A variable compression ratio apparatus may include: a connecting rod having an end connected with a crank pin of a crank shaft; a plunger housing formed at the other end of the connecting rod, the plunger housing having a space to which a plunger is inserted. In particular, the plunger moves upwardly and downwardly, and an outer circumference surface of the plunger contacts an inner circumference surface of the plunger housing. The apparatus further includes a protrusion protruded from the plunger to the plunger housing and connected with a piston, and a hydraulic pressure control valve for supplying hydraulic pressure to the space and moving the plunger by supplying hydraulic pressure.

The present disclosure relates to a compressor control system that detects the pressure (or flow rate) at the rear end of a compressor and performs proportional control in mechanical manner to uniformly control the pressure (or flow rate) of the compressor while preventing a compressor suction valve from being fully closed. To this end, the present disclosure includes a cylinder including a first piston and a second piston therein, a pressure control valve which supplies fluid to operate the second piston to an area above the second piston, a control valve which supplies fluid to operate the first piston to an area above the first piston, and supplies fluid to the pressure control valve, a fluid condition transmission unit which detects fluid condition (pressure or flow rate) at a rear end of a compressor, and converts the detected fluid condition value to an electrical signal and outputs it.

A piston body (11) of an advancing-retracting first piston (10) and a force-multiplying second piston (15) are arranged in series in a vertical direction in a housing (1). Force acting on the second piston (15) due to pressurized oil in a lock chamber (16) is multiplied and converted into multiplied upward force via engaging balls (32) of a force multiplier (30). Then, the multiplied upward force is transmitted to an output rod (12) of the first piston (10). At an intermediate part of a first air detection passage (38) for use in detection formed in the housing (1), a first detection valve (40) is provided. When the engaging balls (32) move inward in a radial direction, the first detection valve (40) is closed.

A variable displacement hydraulic device comprising: a housing having an inlet for receiving hydraulic fluid and an outlet for outputting the hydraulic fluid, the housing having a reciprocation axis; a first cylinder positioned in the housing along the reciprocation axis, the first cylinder having a first input for receiving the hydraulic fluid on a first intake stroke and a first output for ejecting the hydraulic fluid on a first exhaust stroke; a first piston positioned for a first reciprocal motion within the first cylinder, the first piston having a first main end exposed to the hydraulic fluid and a second main end coupled to an actuator, the actuator for driving the second main end when coupled to the actuator for causing the first reciprocal motion to induce a first portion of said outputting of the hydraulic fluid; a second cylinder positioned in the first piston along the reciprocation axis, the second cylinder having a second input for receiving the hydraulic fluid on a second intake stroke and a second output for ejecting the hydraulic fluid on a second exhaust stroke; a second piston positioned for a second reciprocal motion within the second cylinder, the second piston having a first secondary end exposed to the hydraulic fluid and a second secondary end coupled to the actuator, the actuator for driving the second secondary end when coupled to the actuator for causing the second reciprocal motion to induce a second portion of said outputting of the hydraulic fluid; and a locking mechanism for inhibiting the first reciprocal motion of the first piston; wherein when engaged the locking mechanism inhibits the first portion of said outputting of the hydraulic fluid by decoupling the first piston from the actuator while continued operation of the actuator provides the second portion of said outputting of the hydraulic fluid by the second piston.

A plurality of detection valves (12 and 13) are provided to a housing (1), and at least one air passage (14 and 15), which communicatively connects the detection valves (12 and 13) to each other in series, are provided to the housing (1). One or some of the detection valves (12 and 13) are each configured as a throttle detection valve (13) including a throttle passage (56a).