Patent ID: 8287598
Filing Date: 2012-10-16
Classification: A61F

Abstract:
1. A device for providing at least one and up to three rotational degrees of freedom and at least one and up to three linear degrees of freedom comprising: a superior plate having a cranial end defined by a superior surface and a caudal end, wherein the caudal end comprises a planar socket cavity with a planar surface therein; a piston element comprising, a piston head having a cranial end, forming a piston planar surface, a caudal end and a lip portion therebetween, where the piston head is movably disposed within the planar socket cavity, such that the piston planar surface can slide against the planar surface and the lip portion is entirely retained within the planar socket cavity; a planar retainer having a cranial end having an upper surface around a slider surface, a caudal end forming a lower surface, and a retainer hole therebetween having a diameter that is smaller than a diameter of the piston head lip portion, wherein the upper surface engages with the planar socket cavity, so that the slider surface surrounds the neck of the piston element, retaining the piston head within the planar socket cavity; a cylinder having a cylinder wall, a cylinder planar surface, a cylinder inferior surface, a cylinder opening within the cylinder planar surface, wherein the cylinder wall has an exterior cylindrical surface with at least one bearing raceway formed therein that is orthogonal to the cylinder inferior surface and the cylinder planar surface, wherein the bearing raceway is blocked by a first bearing interlock located at or near the cylinder inferior surface, and wherein the piston shoulder is fixedly disposed within the cylinder opening; a ball having an outer spherical surface, an interior cylindrical surface that defines a ball cavity open to a cranial end of the ball, and at least one bearing raceway formed within the interior cylindrical surface, where the cranial end of the bearing raceway is blocked by a second bearing interlock, such that the cylinder body can be disposed within the ball with the at least one hearing raceway in the exterior cylindrical surface aligned with the at least one bearing raceway in the interior cylindrical surface, such that the cylinder body can piston within the ball cavity and is prevented from exiting the cranial end of the ball cavity by interference of the first bearing interlock with the second bearing interlock; a ball retainer with a cranial end and a caudal end having therebetween an inner spherical surface, which defines a central orifice, wherein the inner spherical surface has the same center of curvature as the outer spherical surface of the ball and an interior edge that has the same radius as the outer spherical surface of the ball, and a recess around the caudal end of the inner spherical surface, such that when the central orifice is placed over the cranial end of the ball, the interior edge abuts the outer spherical surface of the ball wherein the radii are the same, preventing the ball retainer from moving past the radius of the ball; a ball platform having a superior surface on a cranial end and an underneath planar surface on a caudal end, a spherical segment extending from the underneath planar surface, and a peripheral spherical edge between the superior surface and the underneath planar surface, such that the caudal end of the ball and the caudal end of the cylinder body can contact the superior surface, and wherein the outer spherical surface of the ball forms a contiguous spherical surface with the spherical edge of the ball platform; and an inferior plate having a caudal end defined by an inferior surface, an inferior cavity therein, opening at a cranial end, which has an interior spherical surface with a radius and center of curvature that are compatible with the contiguous outer spherical surface of the ball and the spherical edge of the ball platform, a lower recess around the cranial end of the inferior cavity, and a socket cavity positioned within the inferior cavity, such that when the ball platform, with the ball thereon, is placed within the inferior plate, the spherical segment of the ball platform can movably contact the socket cavity, the lower recess can be fixedly attached to the recess on the ball retainer, causing the interior spherical surface of the inferior plate to be contiguous with the spherical edge of the ball retainer, forming a slidable surface for the contiguous outer spherical surface of the ball and the ball platform, so that the device when assembled forms a kinematic chain characterized by inseparably connected, articulating components.