A gas cylinder includes supply passages for supplying, to an accommodation chamber, a part of gas supplied to a second port. When the pressure in a first pressure chamber is equal to or lower than a prescribed pressure, a valve element closes a discharge flow passage by the biasing force of a spring member and the pressure in the accommodation chamber. When the pressure in the first pressure chamber exceeds the prescribed pressure, the valve element is moved by the pressure in the first pressure chamber, against the biasing force and the pressure in the accommodation chamber, to thereby open the discharge flow passage.

The invention relates to a hydraulic cylinder, for example for use with a hydraulic tool, which hydraulic tool is provided with a frame and an element which is movable with respect to the frame by means of the hydraulic cylinder.

A hydraulic tool which is operated by means of a hydraulic cylinder as described above is known from, for example, European patent no. 0641618. This patent discloses a frame which is coupleable to a jib of an excavator or the like and to which an assembly of two jaws can be coupled. One of the jaws is pivotable with respect to the other jaw by means of a hydraulic adjusting cylinder (a double-acting piston/cylinder combination).

A hydraulic cylinder (1) which acts as a cylinder hollow rod in an outer hydraulic cylinder (10) is disclosed comprising an inner rod (4) with a piston (2) and piston-gland (3) wherein the cylinder hollow rod (1) is held longitudinally displaceably in the cylinder housing (10). The system additionally has a cylinder base (5) and a fibre cover (14) on the outer casing of hydraulic cylinder (10). The system also has ports for fluid (11, 12 and 13) corresponding to four chambers, (67, 8 and 9 respectively). According to the invention, when pressure is applied to chamber (7), the internal rod (4) extends into the chamber (6), displacing its mass and dramatically increases the pressure in Chamber (6). This displacement is effectively an internal pump which can be activated multiple times within a given stroke of rod (1).

A milking robot for automated milking of milking animals, comprising a cylinder supporting movement of at least one movable component. The cylinder has a wall with a ventilation opening and a cylinder rod which can move in and out of the cylinder. The cylinder wall surrounds at least one variable volume part for movement of the cylinder rod. The opening configures the cylinder to remain in virtual pressure equilibrium with an environment. A gas capture device is connected which has a variable volume and which together with the variable volume part, forms an air-tight gas volume. Thus the variable volume part is kept at almost ambient pressure, so that no unnecessary counter-pressure occurs in the cylinder, during extension and retraction of the cylinder rod. Also less to no exchange of gas and dirt with the environment can take place for longer life and better reliability of the cylinder.

Proposed is a CFRP surface coating method and a hydraulic cylinder including a component coated by the method. The CFRP surface coating method can prevent damage to a CFRP surface due to thermal spray coating and increase the bonding strength between a CFRP surface and a metal coating layer formed by the thermal spray coating. To this end, the method includes: forming a mesh layer on a CFRP surface; fixing the mesh layer on the CFRP surface by impregnating a heat-resistant resin therein; and forming a metal coating layer by thermal spray coating on the fixed mesh layer in which the heat-resistant resin is impregnated.

A lift arm lifting and lowering mechanism cylinder case provided with a cylinder portion into which oil is fed, a piston slidable inside the cylinder portion to define a hydraulic chamber and receiving hydraulic pressure of the hydraulic chamber on a front surface, a safety valve provided to the piston to discharge the oil inside the hydraulic chamber to the outside when the hydraulic pressure of the hydraulic chamber becomes greater than or equal to a predetermined value, and a lift arm supported by the cylinder case and rotatable in conjunction with movement of the piston, in which the piston includes an oil passage allowing communication between a rear surface of the piston and the front surface, and the oil passage includes a containing portion provided to open on the axially front surface side and capable of containing the safety valve, and a non-containing portion provided on the axially rear surface side relative to the containing portion and incapable of containing the safety valve.

A hydraulic system for operating a hydraulic fall-back support of a work machine including at least one hydraulic fall-back support cylinder for tracking and limiting movements of a boom of the work machine and a hydraulic pump by means of which the fall-back support cylinder and at least one further hydraulic consumer can be supplied with hydraulic fluid. A stop valve having a blocking position and a passage position is connected between the hydraulic pump and the fall-back support cylinder, by means of which the stop valve and a load-bearing cylinder space of the fall-back support cylinder is blockable and a hydraulic store connected to the load-bearing cylinder space is provided between the stop valve and the fall-back support cylinder.

A fluid leakage detection device includes: an annular member attached to a cylinder head, the annular member being configured such that a piston rod is inserted through the annular member; a passage formed in the annular member, the passage being configured such that a working fluid is guided to the passage from a gap between an outer circumference of the piston rod and an inner circumference of the cylinder head; and a detector configured to detect the working fluid guided through the passage, wherein the annular member includes a press-fitted portion, the press-fitted portion being configured to be press-fitted to an annular groove formed in the cylinder head.

A hydraulic cylinder comprising a cylinder, a piston element movably guided in the cylinder in a working direction and comprising an active surface, and a first opening for feeding a fluid into a cylinder chamber by the active surface. A working pressure of the fluid acting on the active surface drives the piston element in the working direction. The active surface includes a first partial surface and at least one second partial surface, the cylinder chamber being divided into a first sub chamber with the first opening by the first active surface and a second partial surface with a second opening by the second partial surface, and the partial surfaces are hydraulically separated from each other at least in a selectable operating mode.

A hydraulic apparatus is disclosed, which includes a hydraulic cylinder body, a piston, a push assembly, and a first sealing component; the hydraulic cylinder body is of a hollow cylinder shape, provided with a first opening and a second opening respectively at two ends; the piston is disposed in the hydraulic cylinder body and is located at the first opening; the first sealing component covers the second opening; the hydraulic cylinder body, the piston, and the first sealing component are configured to form a hydraulic chamber; the hydraulic cylinder body is provided with a liquid flow opening which is located between the first sealing component and the piston; and the piston is configured to be enabled to move in the hydraulic cylinder body, driven by the push assembly.