A linear jack includes an outer tube, a high speed assembly comprising a first rotating member threadedly coupled to a first translating member, a low speed assembly comprising a second rotating member threadedly coupled to a second translating member, wherein the low speed assembly is coupled to and translates with the first translating member. At least a portion of the high speed assembly is slidable in the outer tube between a first position, wherein the high speed assembly is engaged with a shaft, and a second position, wherein the high speed assembly is disengaged from the shaft. A thread pitch of the high speed assembly is greater than a thread pitch of the low speed assembly.

A linear jack includes an outer tube, a high speed assembly comprising a first rotating member threadedly coupled to a first translating member, a low speed assembly comprising a second rotating member threadedly coupled to a second translating member, wherein the low speed assembly is coupled to and translates with the first translating member. At least a portion of the high speed assembly is slidable in the outer tube between a first position, wherein the high speed assembly is engaged with a shaft, and a second position, wherein the high speed assembly is disengaged from the shaft. A thread pitch of the high speed assembly is greater than a thread pitch of the low speed assembly.

A lifting device includes a drive, a speed change gear device arranged above the drive and configured to be rotatable by means of the drive, a transmission device connected to the speed change gear device and a lifting mechanism fixed in the transmission device, and the speed change gear device is fixed to a side wall of the transmission device. Under an action of the drive and a speed change of speed change gear device, a gravity of a weight suspended on the lifting device is converted, so that the weight is lifted under a small force. The lifting device can also be driven via an electric hand tool. In addition, a first transmission device and a second transmission device are provided with a safety device to lock the lifting device when reaching a top, so as to prevent the lifting device from slipping to cause injuries.

A lifting device includes a drive, a speed change gear device arranged above the drive and configured to be rotatable by means of the drive, a transmission device connected to the speed change gear device and a lifting mechanism fixed in the transmission device, and the speed change gear device is fixed to a side wall of the transmission device. Under an action of the drive and a speed change of speed change gear device, a gravity of a weight suspended on the lifting device is converted, so that the weight is lifted under a small force. The lifting device can also be driven via an electric hand tool. In addition, a first transmission device and a second transmission device are provided with a safety device to lock the lifting device when reaching a top, so as to prevent the lifting device from slipping to cause injuries.

A method for monitoring the health of an actuator that includes a permanent magnet motor, a rotor and a stator. The method includes: providing a flux linkage reference map comprising a) nominal flux linkage map, having a plurality of nominal flux linkage curves of said motor, each of said nominal flux linkage curves being defined as defining a healthy condition of said actuator, and b) upper and lower tolerance limits of each of said nominal flux linkage curves, the range between said upper and lower limits being defined as a healthy condition of said actuator, and said method of monitoring the health of the actuator further comprising generating a first flux linkage curve of said motor that is to be monitored and determining whether or not said generated first flux linkage curve to be monitored is between the defined upper and lower limits of said flux linkage reference map.

Maneuverable ergonomic trailer stands are disclosed. An example portable trailer stand includes a frame having an upper ledge; an extendible leg coupled to the frame, the upper ledge being vertically movable to selectively engage and disengage an underside of a trailer parked on a driveway based on movement of the extendible leg relative to the frame; a wheel connected to the frame, the wheel to remain at a substantially fixed distance from the upper ledge as the upper ledge is vertically moved

Maneuverable ergonomic trailer stands are disclosed. An example portable trailer stand includes a frame having an upper ledge; an extendible leg coupled to the frame, the upper ledge being vertically movable to selectively engage and disengage an underside of a trailer parked on a driveway based on movement of the extendible leg relative to the frame; a wheel connected to the frame, the wheel to remain at a substantially fixed distance from the upper ledge as the upper ledge is vertically moved

Maneuverable ergonomic trailer stands are disclosed. An example portable trailer stand includes: a frame having an upper ledge, a post, and a lower subframe, the lower subframe connected to the upper ledge via the post; an extendible leg coupled to the post independent of the lower subframe, the upper ledge being vertically movable based on movement of the extendible leg relative to the upper ledge, the post, and the lower subframe of the frame; and a wheel connected to the frame via the lower subframe such that the wheel is to move with the upper ledge as the upper ledge is vertically moved.

Maneuverable ergonomic trailer stands are disclosed. An example portable trailer stand includes: a frame having an upper ledge, a post, and a lower subframe, the lower subframe connected to the upper ledge via the post; an extendible leg coupled to the post independent of the lower subframe, the upper ledge being vertically movable based on movement of the extendible leg relative to the upper ledge, the post, and the lower subframe of the frame; and a wheel connected to the frame via the lower subframe such that the wheel is to move with the upper ledge as the upper ledge is vertically moved.

A leveling and stabilizing jack includes an intermediate member joining first and second lifting sections. Each lifting section includes a cross beam, a leg, a brace, a foot, a motor and a drive screw. The motor powers the drive screw, which is operably associated with the leg, to cause the leg to extend away from or retract toward the cross beam depending on the motor's direction of rotation. A motor control can control the motor of each of the lifting sections independently in a manner that results in leveling of the jack when deployed.