The support 10 of the present invention resembles a conventional Acrow prop which may be used for temporarily supporting a load. In particular, the present invention is arranged to support a surface at a static position. For example, the surface may comprise a ceiling/beam/lintel within a structure wherein the usual permanent supports for the ceiling/beam/lintel are being replaced or deemed temporarily insufficient. However, the present invention can be used in numerous situations where a support 10 is required and for which the support 10 can be quickly and easily installed. The present invention provides (hydraulic) movement means to move the upper end relative to the lower end. In addition, the present invention provides retraction prevention means to prevent the upper end moving towards the lower end while supporting the load and prevents the inner core member 14 being forcibly retracted back into the outer sleeve member 12 due to the compressive force of the load. A hydraulic ram 22 has a maximum extension limit and the present invention uses an adjustable mounting/abutment mechanism which means that a relatively small hydraulic ram 22 can be installed in the outer sleeve member 12. This size of hydraulic ram 22 will then be suitable for all heights and the support is not limited to simply being moveable within a restricted range.

A chamber conveyor belt machine having a machine frame, a chamber cover with two or more columns and a lifting device for lifting the chamber cover. The lifting device may include a safety system that includes a latching rail that cooperates with a latching hook disposed on at least one of the two columns. The safety system may include one or more sensors for determining whether the lifting device is working correctly or is in a failure condition. The safety system may prevent the chamber conveyor belt machine from operating if a failure condition is sensed.

A chamber conveyor belt machine having a machine frame, a chamber cover with two or more columns and a lifting device for lifting the chamber cover. The lifting device may include a safety system that includes a latching rail that cooperates with a latching hook disposed on at least one of the two columns. The safety system may include one or more sensors for determining whether the lifting device is working correctly or is in a failure condition. The safety system may prevent the chamber conveyor belt machine from operating if a failure condition is sensed.

A hydraulic jack configured to be attached to a trailer and operable with a hydraulic power unit having an extend line and a retract line. The hydraulic jack may include a working cylinder and a valve body coupled to the working cylinder. The valve body may provide for a locking valve to be installed within the valve body and include a pilot port. The locking valve may be operable to allow substantially free hydraulic fluid flow in a first direction from the extend coupler to the working cylinder. The locking valve may be further operable, under control of the pilot port, to allow substantially free hydraulic fluid flow in a second direction from the working cylinder to the extend coupler when hydraulic pressure is present at the pilot port and to substantially prevent hydraulic fluid flow in the second direction from the working cylinder to the extend coupler when hydraulic pressure is not present at the pilot port.

A hydraulic jack configured to be attached to a trailer and operable with a hydraulic power unit having an extend line and a retract line. The hydraulic jack may include a working cylinder and a valve body coupled to the working cylinder. The valve body may provide for a locking valve to be installed within the valve body and include a pilot port. The locking valve may be operable to allow substantially free hydraulic fluid flow in a first direction from the extend coupler to the working cylinder. The locking valve may be further operable, under control of the pilot port, to allow substantially free hydraulic fluid flow in a second direction from the working cylinder to the extend coupler when hydraulic pressure is present at the pilot port and to substantially prevent hydraulic fluid flow in the second direction from the working cylinder to the extend coupler when hydraulic pressure is not present at the pilot port.

In order to secure a reached extension position of a piston rod (22, 22) of an in particular multi stage operating cylinder device (100) with at least one operating cylinder unit (50) not only through the operating pressure in the cylinder (1, 1) of the operating cylinder unit (50) but additionally mechanically, a mechanical safety through interlocking safety elements (4a, b) in the interior of the operating cylinder device (100) is provided which is activated exclusively by the operating pressure in the first pressure cavity and disengaged by a pressure in a second operating cavity.

A hydraulic jack for providing safety and 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 pressure of the hydraulic fluid stored in the hydraulic cylinder, thereby a heavyweight can be lifted by the piston. The piston has at least one drill hole on its body thereof that has a determined diameter and is perpendicular to the piston. A security piece is attachable on a top portion of the hydraulic cylinder. The security piece comprises a pair of through holes, which align with at least one drill hole of the piston.

A hydraulic jack for providing safety and 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 pressure of the hydraulic fluid stored in the hydraulic cylinder, thereby a heavyweight can be lifted by the piston. The piston has at least one drill hole on its body thereof that has a determined diameter and is perpendicular to the piston. A security piece is attachable on a top portion of the hydraulic cylinder. The security piece comprises a pair of through holes, which align with at least one drill hole of the piston.

The present invention, in one or more embodiments, provides a jack-positioning device of jack including a seating bottom and a loading table, where the jack-positioning device includes a base portion to support the seating bottom of the jack, an arm portion to connect the base portion, and a top portion to press against the loading table of the jack, and where the top portion along with the arm portion is to position the jack at a holding position, and the arm portion is rotatable relative to the base portion and the top portion. The jack-positioning device of the present invention may be employed to position the jack within a tight space in a relatively time efficient manner.

A latch assembly and telescoping mast having a plurality of telescoping tube sections including the same wherein the latch assembly includes a first latch member mounted to an associated first tube section, a second latch member mounted to an associated second tube section and configured to selectively engage the first latch member to interlock the first and second associated tubes when the associated first tube section is at least partially extended from the associated second tube section, and a trigger member mounted to an associated third tube section. The second latch member includes a latch housing having an opening configured to receive the trigger post when the second associated tube section is retracted into the third associated tube section.