A double action hydraulic jack has a primary hydraulic pump in fluidic communication with the hydraulic fluid reservoir and with the lift cylinder. The hydraulic jack has an auxiliary hydraulic pump also in fluidic communication with the hydraulic fluid reservoir and the lift cylinder. The auxiliary hydraulic pump operates at light-load conditions to drive the jack ram upwards at a rate at least three times faster than at heavy lift-load conditions with only the primary hydraulic pump in operation.

A double action hydraulic jack has a primary hydraulic pump in fluidic communication with the hydraulic fluid reservoir and with the lift cylinder. The hydraulic jack has an auxiliary hydraulic pump also in fluidic communication with the hydraulic fluid reservoir and the lift cylinder. The auxiliary hydraulic pump operates at light-load conditions to drive the jack ram upwards at a rate at least three times faster than at heavy lift-load conditions with only the primary hydraulic pump in operation.

A hydraulic jack for providing safety security is disclosed. The hydraulic jack comprises a hydraulic cylinder storing hydraulic fluid inside, and a piston installed in the hydraulic cylinder that is raised up from the hydraulic cylinder by a pressure of the hydraulic fluid stored in the hydraulic cylinder, thereby a heavyweight can be lifted by the piston. The piston has a drill hole on a body thereof that has a determined diameter and is perpendicular to the piston. When the piston is raised up, a safety pin is penetrable through the drill hole to secure the piston in place.

A hydraulic jack for providing safety security is disclosed. The hydraulic jack comprises a hydraulic cylinder storing hydraulic fluid inside, and a piston installed in the hydraulic cylinder that is raised up from the hydraulic cylinder by a pressure of the hydraulic fluid stored in the hydraulic cylinder, thereby a heavyweight can be lifted by the piston. The piston has a drill hole on a body thereof that has a determined diameter and is perpendicular to the piston. When the piston is raised up, a safety pin is penetrable through the drill hole to secure the piston in place.

A lifting device with a head cavity in the lifting member shaped to accept a removable lifting head. The head cavity in the lifting devicee.g., the piston of a bottle jackmay be provided with threads, or may have the threads removed. A yoke fitted on the lifting head provides registration, horizontal restraint, or both against a lifted object, component, or surface to prevent sliding off the lifting head while in use. In a smooth-walled-shaft embodiment, a set of risers (spacers, adjusters, trims, or shims) serves to adjust an extension height of the shaft, elevating the lifting head with respect to the piston prior to beginning to lift the hydraulic piston.

A mobile lifting device, which preferably has a mobile frame with a plurality of castors. The lifting device has a closed fluid circuit, in particular a hydraulic circuit. It has a cylinder with an elevating work chamber. The elevating work chamber is fluidically connected to a fluid reservoir via a first fluid conduit and a second fluid conduit. In the first fluid conduit, a main pump is arranged which can be driven by means of a rotatably drivable hand tool to supply fluid from the fluid reservoir into the elevating work chamber, thereby extending a piston rod of the fluid cylinder, for example, to lift a load. In the second fluid conduit, a flow control arrangement is arranged which can be switched between a blocking state and a release state by means of a lowering operating element. When the piston rod is extended, the flow control arrangement is in the blocking state. To retract the piston rod, it is switched to the release state, allowing fluid to flow out of the elevating work chamber through the second fluid conduit.

A portable and foldable lift can be attached to a surface such as a tailgate of a truck. The lift can be slid off the gate and used to lift heavy objects from the ground to the bed of the truck. The portable and foldable lift is returned in a folded position to the tailgate for easy storage. The portable and foldable lift can also be attached to a work bench, either on top or underneath, and can be folded up and stored out of the way.

A portable and foldable lift can be attached to a surface such as a tailgate of a truck. The lift can be slid off the gate and used to lift heavy objects from the ground to the bed of the truck. The portable and foldable lift is returned in a folded position to the tailgate for easy storage. The portable and foldable lift can also be attached to a work bench, either on top or underneath, and can be folded up and stored out of the way.

An airplane jack apparatus for lifting a flat main spring landing gear includes a base that supports a hydraulic jack and an upright member, to which a lift arm is pivotably attached. The lift arm has a rotatable cross member that engages a piston that raises out of the hydraulic jack, and the lift arm has a horizontal lifting portion that engages the ground-facing end of a landing gear. The base of the airplane jack apparatus has wheels to allow the jack to move as the angle of a landing gear changes while being lifted.

An airplane jack apparatus for lifting a flat main spring landing gear includes a base that supports a hydraulic jack and an upright member, to which a lift arm is pivotably attached. The lift arm has a rotatable cross member that engages a piston that raises out of the hydraulic jack, and the lift arm has a horizontal lifting portion that engages the ground-facing end of a landing gear. The base of the airplane jack apparatus has wheels to allow the jack to move as the angle of a landing gear changes while being lifted.