Patent attributes
Some embodiments include an outer tube, a pivot structure, an inner tube, a rotational element, and a central rod. The pivot structure perpendicularly intersects the outer tube at a midpoint of the outer tube. The inner tube is coaxially within the outer tube. A first portion of the inner tube is within the outer tube on one side of the pivot structure. A second portion of the inner tube is within the outer tube on another side of the pivot structure. The rotational element couples to the pivot structure, rotates about an axis of the pivot structure, and interfaces with the first and second portions of the inner tube to cause rotation of one portion of the inner tube in a first rotational direction to counter-rotate the other portion of the inner tube in a second rotational direction. The central rod is within the inner tube and translates axially.
