Patent ID: 6860668

Claim:
A flexible arm linkage apparatus provided with a tensioning cable, comprising: a first link forming a first contact surface composed of a first contact material and approximating a partial convex surface supporting said tensioning cable passing through said first contact surface; a second link forming a second contact surface composed of a second contact material and approximating a partial concave surface supporting said tensioning cable passing through said second contact surface; and a high friction coupling between said first link and said second link is created by said first contact surface contacting said second contact surface when induced by said tensioning cable; wherein said first contact material is distinct from said second contact material; wherein each of said first contact material and said second contact material is primarily composed of a respective metallic compound; wherein said first contact surface composed of said first contact material contacting said second contact surface composed of said second contact material has a friction coefficient greater than each member of the collection comprising: a friction coefficient value of 0.3; said first contact surface composed of said first contact material contacting said second contact surface composed of said first contact material; and said first contact surface composed of said second contact material contacting said second contact surface composed of said second contact material, wherein said first link further forms a third contact surface composed of a third contact material and approximating a second partial concave surface supporting said tensioning cable passing through said third contact surface; wherein said apparatus is further comprised of a third link forming a fourth contact surface composed of a fourth contact material and approximating a second partial convex surface supporting said tensioning cable passing through said fourth contact surface; and a second high friction coupling between said first link and said third link is created by said third contact surface contacting said fourth contact surface when induced by said tensioning cable; wherein each of said third and said fourth contact material is primarily composed of a respective metallic compound.