Patent ID: 6865954
Filing Date: 2005-03-15
Classification: A61F,G01N

Abstract:
1. An apparatus for testing components of a joint in articulation relative to one another under a load, comprising: a support structure for a first component of the joint and a second component of the joint against the first component, the second component having a semispherical surface and an engagement surface, the first component having a semispherical pocket closely accommodating the semispherical surface of the second component for articulation thereagainst about a center of rotation at a center of a sphere defined by the semispherical surface; an adapter coupled to the engagement surface of the second component and having a semispherical surface concentric with the center of rotation; a load assembly configured in load applying relation to the semispherical surface of the adapter; and a drive assembly configured in articulating driving relation with the adapter; wherein a driving of the drive assembly effects an articulation of the adapter about the center of rotation under a loading of the load assembly, which in turn effects an articulation of the second component in the semispherical pocket of the first component about the center of rotation under at least a portion of the loading of the load assembly; wherein the drive assembly comprises a first drive shaft and a second drive shaft mechanically coupled in angular offset relation to the first drive shaft, which second drive shaft is fixed to the adapter, wherein a driving of the first drive shaft effects the articulation of the adapter about the center of rotation in an articulation pattern determined by the angular offset relationship; wherein the first drive shaft is fixed to a central region of a wheel, and a distal portion of the second drive shaft is longitudinally translatably and longitudinally rotatably coupled to an outer region of the wheel, and a proximal portion of the second drive shaft is fixed to the adapter, and wherein the driving of the first drive shaft comprises rotating the first drive shaft about a longitudinal axis of the first drive shaft such that the outer region of the wheel travels in a circular path around the longitudinal axis of the first drive shaft; wherein the articulation pattern comprises angulation about the center of rotation in a first plane, during angulation about the center of rotation in a second plane, during rotation about a longitudinal axis of the second component; wherein the first plane and the second plane are perpendicular to one another and intersect one another and a third plane at a line of intersection that is perpendicular to the longitudinal axis of the first drive shaft, such that the first plane is disposed at a convergent angle to the third plane, and wherein the angulation about the center of rotation in the first plane sweeps an angulation angle that is equal to the cosine of the convergent angle multiplied by twice a magnitude of the angular offset relationship, and wherein the rotation about the longitudinal axis of the second component sweeps a rotation angle that is double magnitude of the angular offset relationship.