Adjustable chair

Claim 1

A positionable chair comprising: a base having transverse support structure and curved, downwardly convex, longitudinally disposed support tracks; a top section having transverse support structure and having an upwardly concave top surface whereby parts of the body resting thereon may be higher than other points, the top section parts being in fixed relation to each other from end to end; means for movably supporting the top section upon the curved tracks so that the top section as a whole can move in a curved path relative to the base alternately to raise the foot or head portions of the chair; a power assembly comprising a motor and an extensible drive means connected together as a unit, the extensible drive means having a first portion operatively connected to and united with the motor and a second portion associated with the first portion and moved toward and away from the first portion upon operation of the motor; connecting means to pivotally connect one portion of the power assembly to the base transverse structure at a first point thereon; and other connecting means to pivotally connect the other portion of the power assembly to the top section transverse structure at a second point longitudinally separate from the first point, so that the power assembly can move the top section in the curved path relative to the base and the power assembly can pivot relative to the top section and to the base between the transverse support structure of the base and the top section during the curved movement; and said connecting means for the base and top section confining movement of the extensible means between the pivotal connections of the base and top section; the base section comprising side rails and the base transverse structure comprising transverse braces at intervals along the base side rails holding the side rails together; the top section being likewise formed of side rails and the top section transverse structure comprising transverse braces at intervals along the top section side rails holding those side rails together; the braces of the top section between the two points being above the bottom of the top section, and the braces of the base section being below the top thereof, to provide an open space in the sections between the first and second points; the motor portion of the power assembly being pivotally mounted on the underside of a brace of its section within said space and projecting therefrom toward the other section, and the second portion of the extensible drive means being pivotally connected to the upper side of a brace of the other section in the said space and projecting therefrom toward the first section, so that the power assembly can be extended and contracted, to move the top section in its curved path, without interference with the transverse braces; the connections on the base section being at least substantially wholly below the upper limits of the base section at the connections, and the connections on the top section being below the top thereof and depending below the top section, to dispose the extensible drive means at least largely below the top section.