The present disclosure provides an electric jack with a current limiting protector, which relates to the technical field of mechanical equipment. The electric jack with the current limiting protector includes: a current limiting protector, a four-pin double-reset switch, a control motor, and a supporting leg main body. The current limiting protector is connected in parallel to the control motor through the four-pin double-reset switch. The current limiting protector, the four-pin double-reset switch, and the control motor are detachably mounted on the supporting leg main body. A first wiring terminal, a second wiring terminal, a third wiring terminal, a fourth wiring terminal, a fifth wiring terminal, and a current limiting protection circuit are distributed on the current limiting protector.

The present disclosure provides an electric jack with a current limiting protector, which relates to the technical field of mechanical equipment. The electric jack with the current limiting protector includes: a current limiting protector, a four-pin double-reset switch, a control motor, and a supporting leg main body. The current limiting protector is connected in parallel to the control motor through the four-pin double-reset switch. The current limiting protector, the four-pin double-reset switch, and the control motor are detachably mounted on the supporting leg main body. A first wiring terminal, a second wiring terminal, a third wiring terminal, a fourth wiring terminal, a fifth wiring terminal, and a current limiting protection circuit are distributed on the current limiting protector.

A portable semi-trailer landing-gear motor system and method for use in raising and lowering landing gear on a variety of different semi-trailers by motorized turning of the various-sized drive shafts of the landing gears in appropriate opposing directions, providing motorized performance of an otherwise physically difficult procedure, providing transportability and easy storage within a tractor or truck for use on a variety of semi-trailers in various locations and under various conditions.

A device for adjusting the height of a first part relative to a second part includes a first hollow profiled element, a second hollow profiled element which is displaceable along its longitudinal axis relative to the first hollow profiled element, a drive unit for displacement of the second hollow profiled element relative to the first hollow profiled element and a support unit which, in relation to the longitudinal axis, is arranged between the first hollow profiled element and the second hollow profiled element for the purpose of supporting the first hollow profiled element against the second hollow profiled element.

A device for adjusting the height of a first part relative to a second part includes a first hollow profiled element, a second hollow profiled element which is displaceable along its longitudinal axis relative to the first hollow profiled element, a drive unit for displacement of the second hollow profiled element relative to the first hollow profiled element and a support unit which, in relation to the longitudinal axis, is arranged between the first hollow profiled element and the second hollow profiled element for the purpose of supporting the first hollow profiled element against the second hollow profiled element.

A linear lifting device including a lifting column, a synchronous adjusting mechanism, a first motion element and a second motion element is provided. The lifting column has a fixed end and a movable end. The synchronous adjusting mechanism, disposed on the movable end, has a first force-bearing end and a second force-bearing end, which are respectively separated from the center of the synchronous adjusting mechanism by a rotating radius and remain at a synchronous state. The first and second elements respectively connect the first and second force-bearing ends for generating a first force to push the first force-bearing end to move in a first force direction and generating a second force to push the second force-bearing end to move in a second force direction, such that the movable end can move with respect to the fixed end in a resultant force direction of the first and second force directions.

A linear lifting device including a lifting column, a synchronous adjusting mechanism, a first motion element and a second motion element is provided. The lifting column has a fixed end and a movable end. The synchronous adjusting mechanism, disposed on the movable end, has a first force-bearing end and a second force-bearing end, which are respectively separated from the center of the synchronous adjusting mechanism by a rotating radius and remain at a synchronous state. The first and second elements respectively connect the first and second force-bearing ends for generating a first force to push the first force-bearing end to move in a first force direction and generating a second force to push the second force-bearing end to move in a second force direction, such that the movable end can move with respect to the fixed end in a resultant force direction of the first and second force directions.

An improved device and method of lubrication for a tongue jack, 5th wheel jack, or other jack or other threaded positioning device. Ports are provided in the inner and outer tubes of the jack. The aligned ports provide access to a lubrication cavity in the jacknut. The lubrication cavity may include a grease fitting such as a zerk fitting. When the ports are in alignment, a grease gun can be inserted easily to the zerk fitting to apply grease to the interior structure of the nut as well as to the threads of the jackscrew. The lubricant may be introduced directly at a region of contact between a screw and the load bearing element. Applicant's test results show that this improved lubrication can increase the life cycle of the jack by more than 100%.

An improved device and method of lubrication for a tongue jack, 5th wheel jack, or other jack or other threaded positioning device. Ports are provided in the inner and outer tubes of the jack. The aligned ports provide access to a lubrication cavity in the jacknut. The lubrication cavity may include a grease fitting such as a zerk fitting. When the ports are in alignment, a grease gun can be inserted easily to the zerk fitting to apply grease to the interior structure of the nut as well as to the threads of the jackscrew. The lubricant may be introduced directly at a region of contact between a screw and the load bearing element. Applicant's test results show that this improved lubrication can increase the life cycle of the jack by more than 100%.

A lifting column includes a component having an internal thread, as well as a hollow shaft having an external thread, which is in engagement with the internal thread of the component. A threaded spindle is disposed inside the hollow shaft and has an external thread, which is in engagement with an internal thread of the hollow shaft. Furthermore, the lifting column includes a drive device configured to rotate the hollow shaft relative to the threaded spindle and the component. When the hollow shaft rotates, the component and the hollow shaft move in the same axial direction so that the height of the lifting column is changeable.