U.S. Pat. No. 4,241,949 issued to the inventor describes a novel development in rockable furniture in which the side frame pieces for rocking engagement with the ground are formed by a major smooth curved portion composed of at least three component arcs of curvature of increasing radius. The component arcs which form the continuous major curve of the side pieces are arranged with the curvature radius increasing from the base of the curved side pieces to the top. As a result of the increasing radius, the sharpness of the curvature decreases from the base to the top of the curved side pieces so that rocking motion is damped or slowed in the backward rocking direction. A feature and advantage of the rockable furniture invention described in U.S. Pat. No. 4,241,949 is that while a small shift in weight or center of gravity may produce rocking or rotation through a large angle, the motion in the backwards direction is safely slowed and in fact can be brought to a halt according to the selection of component arcs. As described in U.S. Pat. No. 4,241,949 rocking action through a total angle of rotation of 125.degree. is provided with a dramatic slowing to a halt at the back of the rock as a result of the decreasing curvature and increasing radius of the component arcs comprising the rocking curves.
A further control on the rocking action described in U.S. Pat. No. 4,241,949 is the provision of a slight or minor reverse curvature at the top of the curved side pieces forming an "ear" or back rocking stop which safely stops backward rocking motion beyond the reverse curved portion.
The present inventor has discovered that the rockable furniture invention described in U.S. Pat. No. 4,241,949 has valuable application in the medical field for orthopedic recliners and health related applications. The invention is also applicable in adult furniture generally. In these applications further control over the rocking action of the rockable furniture is desirable.
USPTO Backgrounds
USPTO Backgrounds