Abstract: Linear actuators driven by everted ball screw assemblies are described herein. In some examples, the everted ball screw assembly includes a hollow screw shaft with internal threads, a ball cylinder concentrically positioned therein and having external threads, and a plurality of balls sized to fit in a substantially contiguous series along a working pathway that is defined by the space between the internal and external threads. One or more limiters prevent the ball cylinder from rotating. A motor rotates the hollow screw shaft, thereby driving the balls along the pathway and imparting linear motion to the ball cylinder, which is coupled to a connecting rod for actuating a load. The ball cylinder in some examples includes an internal return path with scoop elements that are sized and shaped to guide the balls into the internal return path and then back onto the working pathway.

Abstract: Linear actuators are described herein. In particular embodiments, a linear actuator includes an everted ball screw assembly comprising a hollow screw shaft with internal threads, a ball cylinder concentrically positioned therein and having external threads, and a plurality of bearing balls sized to fit in a substantially contiguous series along a working pathway defined by the space between the internal and external threads. The linear actuator may include a support bearing for rotatably supporting the screw shaft in a housing. The ball cylinder in particular embodiments includes an internal return path along which the balls return to the working pathway. The everted ball screw assembly may include a lash reduction assembly and one or more scoop inserts that are sized and shaped to guide the balls into the internal return path and back onto the working pathway.

Abstract: Linear actuators are described herein, In particular embodiments, a linear actuator includes an everted ball screw assembly comprising a hollow screw shaft with internal threads, a ball cylinder concentrically positioned therein and having external threads, and a plurality of bearing balls sized to fit in a substantially contiguous series along a working pathway defined by the space between the internal and external threads. The linear actuator may include a support bearing for rotatably supporting the screw shaft in a housing. The ball cylinder in particular embodiments includes an internal return path along which the balls return to the working pathway. The everted ball screw assembly may include a lash reduction assembly and one or more scoop inserts that are sized and shaped to guide the balls into the internal return path and back onto the working pathway.

Abstract: Linear actuators driven by everted ball screw assemblies are described herein. In some examples, the everted ball screw assembly includes a hollow screw shaft with internal threads, a ball cylinder concentrically positioned therein and having external threads, and a plurality of balls sized to fit in a substantially contiguous series along a working pathway that is defined by the space between the internal and external threads. One or more limiters prevent the ball cylinder from rotating. A motor rotates the hollow screw shaft, thereby driving the balls along the pathway and imparting linear motion to the ball cylinder, which is coupled to a connecting rod for actuating a load. The ball cylinder in some examples includes an internal return path with scoop elements that are sized and shaped to guide the balls into the internal return path and then back onto the working pathway.

Abstract: A system and method for measuring flow resistance of a fluid in a conduit is provided. The system generally includes a reservoir for containing the fluid, a pump connected to the reservoir for distributing the fluid through a conduit having a straight measurement section, one or more pressure sensors connected to the conduit for measuring the pressure of the fluid in the conduit at one end of the straight measurement section and an opposite end of the straight measurement section.