Abstract: Apparatus of preferred embodiments of my invention is a training device aimed at developing correct and efficient movement of the body during striking or throwing action. It could be applied to any activity in which striking or throwing motion is required—tennis, golf, baseball, boxing etc. The training device of my invention is designed to compel the user to perform and repeat the correct lower body movement in isolation. The movement produced during this exercise is the cornerstone of all efficient throwing or striking actions. Sufficiently strengthened and correctly applied, this movement provides all the necessary force to propel the throwing arm or striking implements such as a tennis racquet, a golf club or a baseball bat. The method of my invention is directed to objectives similar to those of the apparatus, but the apparatus and method are mutually independent.

Abstract: A crossmember defines guide surfaces to receive a leg tip. Preferably a screw, cam or lever applies nonimpulse force to wedge the tip against the surfaces. The tip is preferably unthreaded, exclusively noncircular in at least external cross-section, and very generally aligned with the leg axis. Preferably the screw or the like pulls the tip length-wise into the crossmember without rotating or threading the tip into the surfaces, and also retains the tip wedged in place. Also preferably a notch or analogous traction feature is formed in the leg or crossmember, and the screw (distinct from the tip) threaded to the other. The screw engages the notch to force the tip into the crossmember.

Abstract: A connective joint comprises the following seven elements:(a) Four quarter spheres arranged in adjacent quadrant relationship to form a substantially spherical element or "ball". The quarter spheres are provided with grooved edges that form two substantially perpendicular grooves extending around the spherical element;(b) Two hinge elements, each having a ring shaped portion that is inserted in an individual one of the two grooves;(c) A device for applying a force between two diametrically opposing ones of the quarter spheres in the spherical element.

Abstract: This mechanical joint allows relative rotation of two articles (one may be a stationary fixture), on an arbitrary axis. The joint has as much angular-rotation range as a hinge, but as many degrees of freedom as a ball-and-socket or universal joint. It allows transmission, between the objects, of force or flux (e.g., of electricity, gas, or liquid), or both. It can be used as an applied-force or motion sensor, varying electrical contacts or conductivity in response to relative motion or force applied between the articles. In one form the invention is simply a mechanical joint formed of two closely interlocked toroids. The minor cross-section of each toroid is sized to just fit through the central aperture of the other; there is a connection point on each toroid for attachment of one article. By adjusting closeness of fit, a designer can impart to the device a wide range of desirable frictional properties.

Abstract: These joints are particularly useful for transmitting a flux (electrical, optical, liquid or gaseous) either entirely across the joint, or from one side of the joint to devices mounted on the joint itself that use such a flux. Such devices can, for example, be motors to drive the joint itself. The interlocking bodies are typically but not necessarily circular rings, mounted to a common internal structure that permits each body to rotate about its own axis. The resulting joints can rotate in all directions with a very high angular range--in most cases limited only by the angle subtended by connecting stems used to mount the joint to a base or to mount objects to the joint for motion. Some of these joints have hollow central enclosures for passing flexible wires or tubing to carry the flux, so that the flux can be transmitted across or into the joint with the same high degree of freedom, and yet without slip rings, brushes, or other expensive motionaccommodating components subject to wear.

Abstract: This fluid-current-transmitting mechanical joint allows relative rotation of two articles (one may be a stationary fixture), on an arbitrary axis. The joint has as much angular-rotation range as a hinge, but as many degrees of freedom as a ball-and-socket or universal joint. The invention has a dual outer structure consisting of two interlocked bodies, each generally arched and generally surrounding an aperture, with a connection point on each body for attachment of one of the articles; and a dual inner structure of two mutually fixed, interlocked rings or the like. The two bodies of the outer structure can be generally ring-shaped and if desired can take the form of two closely interlocked toroids, the minor cross-section of each toroid being sized to just fit through the central aperture of the other. These outer-structure bodies ride on the inner structure.

Abstract: This mechanical joint allows relative rotation of two articles (one may be a stationary fixture), on an arbitrary axis. The joint has as much angular-rotation range as a hinge, but as many degrees of freedom as a ball-and-socket or universal joint. It allows transmission, between the objects, of force or flux (e.g., of electricity, gas, or liquid), or both. In can be used as an applied-force or motion sensor, varying electrical contacts or conductivity in response to relative motion or force applied between the articles. In one form the invention is simply a mechanical joint formed of two closely interlocked toroids. The minor cross-section of each toroid is sized to just fit through the central aperture of the other; there is a connection point on each toroid for attachment of one article. By adjusting closeness of fit, a designer can impart to the device a wide range of desirable frictional properties.