Abstract: The exercise device of the present invention has an elongated member that extends from a user's head to the user's upper back for providing back support during abdominal crunches. The member is curved to conform to the user's cervical lordosis and kyphotic curve formed by the user's thoracic vertebrae and has a tapered lower portion to provide freedom of movement.

Abstract: A prestressed structural member is described in which there is provided in combination a pair of longitudinal elements, a plurality of strut elements, a plurality of diagonal members and a plurality of joint connector means for rigidly interconnecting the strut elements and diagonal elements together and the same to the longitudinal elements. The longitudinal elements are spaced apart and prestressed in compression. The strut elements are also spaced apart and each strut element extends between the longitudinal elements, and is disposed orthogonally of a line equidistant from each longitudinal element. The strut elements are also prestressed in compression. The diagonal members are oriented diagonally in pairs in box sections or bays delimited by the longitudinal and strut elements and with the strut elements form a lattice structure. The diagonal members are prestressed in tension.

Abstract: A heavy duty hydraulic shock absorber having an inner tube in which is slidably mounted an impact receiving piston assembly. Upon application of an impact force on the piston assembly, the piston assembly is moved inwardly of the inner tube and fluid from the inner tube is metered through a plurality of exponentially disposed metering orifices into an accumulator chamber formed between the inner tube and an outer tube which encloses the inner tube. An adjustable, slidable metering spool is operatively mounted in the accumulator chamber, over the metering orifices, for regulating the flow of fluid through the metering orifices into the accumulator chamber.

Abstract: An adjustable hydraulic shock absorber of the dashpot type which includes an elongated outer tube and an inner tube fixed in said outer tube. A piston is movably mounted in the inner tube and has a piston rod extended outwardly of the outer tube for receiving reciprocating actuating loads. A double action, flexible, tubular diaphragm is positioned in the outer tube, with its inner end secured to the outer tube in a position surrounding one end of the inner tube, and with its outer end secured to the piston rod, so as to form an expandable fluid reservoir. The reservoir is connected by passageway means to the inner tube. The reservoir, passageway means and inner tube are normally filled with fluid under pressure so as to normally move the piston to an initial load receiving position.