An extension boom system for heavy equipment having, the extension boom system including a first actuator mounted on a base, and connecting a second stage, a second actuator mounted on the second stage and connecting the second stage to a third stage, a third actuator mounted on the third stage and connecting the third stage to an extendable portion, and a controller configured to control the first actuator, the second actuator, and the third actuator so as to selectively operate in a first operation mode and a second operation mode. In the first operation mode, the first actuator, the second actuator, and the third actuator are operated substantially simultaneously, and wherein in the second operation mode, two of the first actuator, the second actuator, and the third actuator are actuated substantially simultaneously, while another of the first actuator, the second actuator, and the third actuator is not actuated.

An oil pressure mobile device for a wood working machine is provided in a wood working machine, including a power mechanism and a lifting mechanism. The power mechanism is provided with an oil hydraulic cylinder having its inner wall annularly mounted with a piston fixed with a telescopic rod. The lifting mechanism is disposed with two wheel pressing plates at the underside of the wood working machine. The two wheel pressing plates are jointly provided with a connecting link connected with the telescopic rod, and respectively installed with a moving wheel. Thus, the telescopic rod is driven by the power mechanism to extend or retract and actuate the wheel pressing plates to produce angular variation to make the moving wheels stretch out of the housing of the wood working machine for facilitating shifting of the wood working machine with less labor.

An oil pressure mobile device for a wood working machine is provided in a wood working machine, including a power mechanism and a lifting mechanism. The power mechanism is provided with an oil hydraulic cylinder having its inner wall annularly mounted with a piston fixed with a telescopic rod. The lifting mechanism is disposed with two wheel pressing plates at the underside of the wood working machine. The two wheel pressing plates are jointly provided with a connecting link connected with the telescopic rod, and respectively installed with a moving wheel. Thus, the telescopic rod is driven by the power mechanism to extend or retract and actuate the wheel pressing plates to produce angular variation to make the moving wheels stretch out of the housing of the wood working machine for facilitating shifting of the wood working machine with less labor.

An aircraft store ejector systems and subsystems thereof. Embodiments can include a two-reservoir re-pressurization system wherein a remote reservoir is used to maintain desired pressure in a local ejector reservoir. The system can include a release valve having a vent valve and valve piston. The release valve can control release of pressurized gas to a pitch control valve. The pitch control valve can be configured to distribute the pressurized gas between two or more ejector piston assemblies. One or more of the ejector piston assemblies can include multiple concentric piston stages and piston chambers, the piston chambers configured to contain a volume of gas. The ejector piston assemblies can be configured to compress the volume of gas within the piston chambers as the piston stages are extended out from the aircraft. Such compression can provide a return force to the piston stages.

A two-stage, fully self-retracting, telescopic fluid actuator suitable for high speed ejection applications comprises a detent 38, 64, 26, which locks a cylinder 6 in an extended position for extension of a piston 3 therefrom. The detent is released by retraction of the piston into the cylinder again, e.g. unspring bias, so that the actuator is fully self-retracting. A locking ball 38 of the detent also serves to latch the piston and cylinder to each other for the first stage of the actuator extension. In an alternative embodiment, cam means (80, 117 FIGS. 10, 11 and 13) and plungers (90, FIGS. 10, 12, 13 and 15) perform the detent and latching functions.

A two-stage, fully self-retracting, telescopic fluid actuator suitable for high speed ejection applications comprises a detent 38, 64, 26, which locks a cylinder 6 in an extended position for extension of a piston 3 therefrom. The detent is released by retraction of the piston into the cylinder again, e.g. unspring bias, so that the actuator is fully self-retracting. A locking ball 38 of the detent also serves to latch the piston and cylinder to each other for the first stage of the actuator extension. In an alternative embodiment, cam means (80, 117 FIGS. 10, 11 and 13) and plungers (90, FIGS. 10, 12, 13 and 15) perform the detent and latching functions.

An aircraft store ejector systems and subsystems thereof. Embodiments can include a two-reservoir re-pressurization system wherein a remote reservoir is used to maintain desired pressure in a local ejector reservoir. The system can include a release valve having a vent valve and valve piston. The release valve can control release of pressurized gas to a pitch control valve. The pitch control valve can be configured to distribute the pressurized gas between two or more ejector piston assemblies. One or more of the ejector piston assemblies can include multiple concentric piston stages and piston chambers, the piston chambers configured to contain a volume of gas. The ejector piston assemblies can be configured to compress the volume of gas within the piston chambers as the piston stages are extended out from the aircraft. Such compression can provide a return force to the piston stages.

An electrohydraulic device includes an extender which is arranged to be actuated by hydraulic fluid, and a rotor of an electric motor, the rotor being arranged to rotate about a part of the extender. The rotor may have an annular body which encircles or surrounds part of the extender. There is also described a related method of use and a marine vessel or platform where the device may be applied.

The telescopic lift arm (1) for self-propelled operating machines (10), such a lifters, telehandlers and the like, comprises three tubular elements (21, 22, 23, 24, 25, 26), having a decreasing section and telescopically connected to one another to define a support structure which is able to move between a retracted configuration in which the tubular elements (21, 22, 23, 24, 25, 26) are inserted in one another, and an elongate configuration, in which two tubular elements are extracted.

The arm (1) comprises a hydraulic actuator (4), associated to the support structure (21, 22, 23, 24, 25, 26) and provided with three hydraulic elements (41, 42, 43) telescopically connected to one another, each of which is connected to a respective tubular element of the support structure.

A hydraulic strut assembly, for use in a semi-levered landing gear in an aircraft, comprising an actuator and a manifold associated with the actuator. The actuator comprises a housing, a first piston, a second piston, and a third piston. The first piston is positioned between outer and inner cylindrical structures of the housing. The outer and inner cylindrical structures and first piston form an outer chamber that receives a first fluid. The inner cylindrical structure, the first piston, and the second piston, which is nested within the first piston, form an inner chamber, which holds a second fluid comprising a gas. A volume of the inner chamber changes when at least one of the first and second pistons moves. The third piston is positioned between the outer cylindrical structure and the first piston. The first, second, and third pistons move in a direction parallel to an axis through the housing.