A hydraulic cylinder includes a cylinder having axially spaced-apart first and second bores, and a piston having a piston rod and arranged in the cylinder for movement between two end positions and dividing the cylinder into a piston side and a piston-rod side. A hydraulic pump pumps hydraulic oil into the piston side to move the piston from one end position toward the other end position while hydraulic fluid is discharged from the piston-rod side via the first bore and a first outlet line. A throttling device is operably connected to the cylinder to throttle a flow of the hydraulic fluid as the piston moves past and seals the first bore so that hydraulic fluid is discharged via the second bore, thereby reducing a delivery amount of the hydraulic oil and thereby braking and damping a movement of the piston toward the other one of the end positions.

An actuator comprising: a piezo actuator; a drive having a drive chamber and a drive piston element driven by the piezo actuator; a first output having an output chamber and a piston element; and a second output having an output chamber and a piston element. At least part of the hydraulic fluid is conveyed out of the drive chamber by movement of the drive piston element and into the first output chamber. At least part of the hydraulic fluid is conveyed out of the drive chamber and into the second output chamber. The second output piston element has a hydraulically active second output face which is different in size from the first output face. There may be a coupling device mechanically coupling the first output piston element to the second output piston element.

A valve system for use with a cylinder having an extensible rod, includes a first valve assembly including a first inlet/outlet port, a check valve biased toward a closed state, the check valve having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the first inlet/outlet port and the check valve, and a first pilot port selectively communicable with a pressurized gas for opening the check valve. The valve system further includes a second valve assembly including a second inlet/outlet port, a second pilot port through which the pressurized gas must flow before being introduced to the first pilot port, and a valve body at least partially receivable within a second port of the cylinder, wherein the second inlet/outlet port and the second pilot port are integrally formed as a portion of the valve body.

A regulator valve has a check valve manifold for use in subsea control circuits. For example, the regulator valve having the check valve manifold can be used in a circuit between a directional control valve and an actuator for a gate valve. The check valve manifold can have a flange that attaches to the regulator valve to communicate with the supply-side and outlet-side of the regulator valve. Internal communication inside the manifold includes a check valve. If the pressure in the circuit downstream of the regulator valve needs to be vented, the check valve can open to allow the pressure to bleed from the outlet-side back to the supply-side without needing to pass through the internal pressure control valve of the regulator.

The present invention pertains to an air cylinder (10) in which flow rate controllers (24, 24A) are built into a head cover (14) and a rod cover (16), said flow rate controllers (24, 24A) being provided with a first flow rate adjustment part (28) connected between a port (14a, 16a) and a cylinder chamber (12c), a second flow rate adjustment part (32) provided adjacent to the first flow rate adjustment part (28), and a pilot check valve (38) connected in series to the second flow rate adjustment part (32). In response to the pressure of pilot air, the pilot check valve (38) switches between a state in which the passage of exhaust air from the cylinder chamber (12c) is permitted and a state in which the passage of exhaust air is prevented.

Disclosed is a tower lifting device for a rotary blasthole drill, comprising a hydraulic cylinder (5), an extending oil path (7), a retracting oil path (6), a speed control oil path (14) and a proximity switch (3), wherein the extending oil path (7) is connected to a non-rod-end chamber of the hydraulic cylinder (5), and an extension control unit is provided on the extending oil path (7); the retracting oil path (6) is connected to a rod-end chamber of the hydraulic cylinder (5), and a retraction control unit is provided on the retracting oil path (6); the speed control oil path (14) is connected to the retracting oil path (6), the speed control oil path (14) is connected to a speed control valve block (15) in series and the tail end thereof is connected to an oil tank (16); the proximity switch (3) is arranged on a tower supporting frame (2) for controlling the switching on and off of the speed control valve block (15), and when the tower (4) is approximately in a horizontal state, the speed control valve block (15) is on. By using such a tower lifting device in the present invention, the speed at which the tower is laid down to a horizontal state can be conveniently controlled.

A flow rate controller and a drive device are provided with a cylinder flow passage connected to an air cylinder; a main flow passage for supplying air to and discharging air from the air cylinder; an auxiliary flow passage that has a first throttle valve and through which exhaust air discharged from the air cylinder passes with a smaller flow rate than that of the main flow passage; a switch valve that switches between a first position in which the cylinder flow passage communicates with the main flow passage and a second position in which the cylinder flow passage communicates with the auxiliary flow passage; and a pilot air adjustment part that guides a portion of the exhaust air from the air cylinder as pilot air to the switch valve.

A gas-powered drive system has a drive which includes a first chamber and a second chamber which are separated from one another by a piston. One of the chambers is connected to a gas source to drive the work element and the other chamber is connected via an exhaust air throttle to a gas sink by means of a reversing valve to movement of the piston. A control valve is assigned to the driving chamber through which the driving chamber can be filled with gas from the gas source. The opening cross-section of the control valve is set as a function of a control pressure.

An example valve includes a piston configured to block fluid flow from a first port of the valve to a second port of the valve when the valve is in a closed position; a relief mode spring applying a first biasing force on the piston in a distal direction; a reverse flow spring applying a second biasing force on the piston in a proximal direction, wherein the reverse flow spring is weaker than the relief mode spring; and a pressure setting spring applying a third biasing force on a check element in the distal direction, causing the check element to be seated when the valve is in the closed position.

A speed controller capable of controlling an action speed of an external cylinder in one stroke in a step-wise manner. The speed controller includes a first flow path and a second flow path that allow a first port and a second port to be in communication with each other. The first flow path is provided with a first check valve for allowing flow from the first port to the second port. The second flow path is provided with a first needle valve, and an opening hole of the first check valve is constituted as a part of a flow path. The first needle valve adjusts the flow rate by changing an opening area of the opening hole with a tip portion fixed on a piston in the cylinder chamber. The speed controller further includes a third flow path allowing the first port and the cylinder chamber to be in communication with each other. The third flow path is provided with a second check valve for allowing flow from the first port to the cylinder chamber.