In one embodiment, an actuator has a roller, a helical track, and at least one track follower. The roller has a cylindrical body that has a first end, a second end that is offset from the first end along a central axis, and a cylindrical outer surface that extends from the first end to the second end. The helical track is disposed around the cylindrical outer surface in a helical pattern. The at least one track follower can be attached to a load, and rides along the helical track when the roller is rotated about the central axis so as to translate the load along an axial direction that is substantially parallel to the central axis. In some embodiments, the roller has an internal motor that is disposed within the cylindrical body.

The multiple small pitch helical drives in linear and rotary actuators uses a plurality of small pitch helical screws in place of a single large pitch lead screw to provide increased power or force in a linear actuator or increased torque in a rotary actuator. The multiple small pitch helical drive includes a plurality of screws disposed between a base panel and a rear panel in a rigid skeleton, the screws having a single degree of freedom, i.e., they are free to rotate, but cannot move axially. A piston head having spaced disks includes floating nuts disposed in sockets on the disks for each of the screws, the piston head being free to travel on the screws between the base panel and the rear panel as the screws are rotated. The helical pitch reduction provided results in increased force output and increased torque for linear and rotary actuators.

A bearing screw transfer device which converts a rotational motion of a screw shaft into a linear motion by the medium of a bearing is disclosed. The bearing screw transfer device has a first driving bearing and a second bearing which run along a screw groove of a rotating screw shaft, thereby converting a rotational force of the screw shaft into a translational force of an operating plate disposed on an upper portion of the screw shaft, wherein a two-surface screw groove is formed on the screw shaft, and an outer ring of the first driving bearing runs in contact with one surface of the two-surface screw groove, and an outer ring of the second driving bearing runs in contact with the other surface of the screw groove.

The present invention relates to a linear module. The linear module according to an example of the present invention comprises a base plate; a screw disposed on the base plate and arranged in the longitudinal direction of the base plate; a carrier block including a hollow part surrounding a portion of the screw; a carrier block rail disposed on one side of the carrier block and arranged in the longitudinal direction of the base plate; a long rail disposed on the base plate and arranged in the longitudinal direction of the base plate; and a roller guide disposed between the carrier block rail and the long rail and to reduce the frictional force between the carrier block rail and the long rail when the carrier block moves in the longitudinal direction of the base plate.

A variable pitch lead screw assembly and actuator assembly therewith is provided. The lead screw assembly includes a lead screw having a groove extending helically along a length of the lead screw. The groove is formed having a varying pitch. A drive nut is provided having a body with a through bore configured for receipt of the lead screw therethrough. The drive nut has teeth extending radially inwardly into the through bore for receipt in the groove of the lead screw. The teeth are pivotal in multiple directions relative to the body to allow the teeth to pivot in multiple directions within the groove.

There is disclosed a linear actuator comprising: a screw shaft comprising a screw thread and having a longitudinal axis A; a nut movable along the screw shaft from a retracted position to an extended position; and a plurality of rollers movable with the nut, each comprising a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft; wherein the screw thread comprises one or more detents (e.g., grooves) configured to lock the nut in one or more axial positions.