A system for controlling extension and retraction of trailer landing gear of a trailer, with the landing gear including a shaft which is rotated to retract and extend the landing gear and the trailer further including a source of electricity. The system comprises: an electric motor having an output shaft disposed 90 degrees with respect to a longitudinal axis of the motor; a mounting plate affixable to the trailer landing gear, with the motor affixable to the mounting plate, the mounting plate sized and dimensioned to position the output shaft in axial alignment and adjacent to an end of the landing gear shaft, and to position the motor outboard of the trailer landing gear; and the motor connectable to the source of electricity to rotate and cause retraction or extension of the trailer landing gear.

A system for controlling extension and retraction of trailer landing gear of a trailer, with the landing gear including a shaft which is rotated to retract and extend the landing gear and the trailer further including a source of electricity. The system comprises: an electric motor having an output shaft disposed 90 degrees with respect to a longitudinal axis of the motor; a mounting plate affixable to the trailer landing gear, with the motor affixable to the mounting plate, the mounting plate sized and dimensioned to position the output shaft in axial alignment and adjacent to an end of the landing gear shaft, and to position the motor outboard of the trailer landing gear; and the motor connectable to the source of electricity to rotate and cause retraction or extension of the trailer landing gear.

A hand crank for a landing gear is described, the hand crank having a main body provided at a first end with a connecting element for fastening the hand crank to an input shaft of the landing gear and formed at an opposite, second end to rotate the hand crank. The hand crank only allows torque to be transmitted from the hand crank to the input shaft if the operator holds the hand crank with at least one hand. A clutch is arranged in the force flow between the first end of the main body and the connecting element, wherein the clutch is held in an open disconnected position and is moved into a force-locked connection position by operating an actuating element arranged at the second end.

A hand crank for a landing gear is described, the hand crank having a main body provided at a first end with a connecting element for fastening the hand crank to an input shaft of the landing gear and formed at an opposite, second end to rotate the hand crank. The hand crank only allows torque to be transmitted from the hand crank to the input shaft if the operator holds the hand crank with at least one hand. A clutch is arranged in the force flow between the first end of the main body and the connecting element, wherein the clutch is held in an open disconnected position and is moved into a force-locked connection position by operating an actuating element arranged at the second end.

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.

Vertical elongate support (2) for supporting a parked vehicle trailer (1), consisting of a top prop tube (21), an inner prop member (22) which can telescopically slide into the prop tube (21), and a threaded spindle (3) for moving the inner prop member (22) in relation to the prop tube (21), whereby the threaded spindle (3) meshes with a threaded bearing (31) that is secured to the upper end of the inner prop member (22). The upper end of the threaded spindle (3) is connected to a crown wheel (32), the upward-facing surface of which is part of a thrust bearing (33) or is designed to accommodate a thrust bearing (33). The thrust bearing (33) supports the vehicle trailer (1), either directly or via a cover (23) that is connected to the prop tube (21).

Vertical elongate support (2) for supporting a parked vehicle trailer (1), consisting of a top prop tube (21), an inner prop member (22) which can telescopically slide into the prop tube (21), and a threaded spindle (3) for moving the inner prop member (22) in relation to the prop tube (21), whereby the threaded spindle (3) meshes with a threaded bearing (31) that is secured to the upper end of the inner prop member (22). The upper end of the threaded spindle (3) is connected to a crown wheel (32), the upward-facing surface of which is part of a thrust bearing (33) or is designed to accommodate a thrust bearing (33). The thrust bearing (33) supports the vehicle trailer (1), either directly or via a cover (23) that is connected to the prop tube (21).

A support device, preferably for commercial vehicles such as semi-trailers, includes an inner support tube and an outer support tube moveable relative to one another along a longitudinal axis in a retraction and extension direction; a spindle rotated via a gear section and is arranged such that the spindle is stationary relative to the outer support tube; and a spindle nut which is mounted on the spindle, wherein the spindle nut is fixed on a mounting region of the inner support tube, and the mounting region is configured as a support edge facing the longitudinal axis.

A support device, preferably for commercial vehicles such as semi-trailers, includes an inner support tube and an outer support tube moveable relative to one another along a longitudinal axis in a retraction and extension direction; a spindle rotated via a gear section and is arranged such that the spindle is stationary relative to the outer support tube; and a spindle nut which is mounted on the spindle, wherein the spindle nut is fixed on a mounting region of the inner support tube, and the mounting region is configured as a support edge facing the longitudinal axis.

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%.