Mechanical structure of articulated sheath

Abstract

A sheath apparatus includes, a plurality of node rings configured to be tilted with respect to each other, each node ring defining a substantially cylindrical wall and having at least one hole passing through said cylindrical wall, the plurality of node rings being arranged next to each other along a linear axis such that consecutive node rings contact each other at a contact plane; a manipulating wire going through the holes in said stacked node rings; and a position restoring component configured to restore said stacked node rings from a tilted position to an original position, wherein said position restoring component is located inside or outside of the stacked node rings.

1 .- 11 . (canceled) 
     
     
         12 . A mechanical structure of articulated sheath comprising:
 comprising:   a series of stacked node rings disposed adjacent to each other and possible to be tilted with respect to each other;   a manipulating wire going through said stacked node rings;   a position restoring component configured to restore said stacked node rings from a tilted position to a original position,   wherein said position restoring component is located inside said stacked node rings, and   wherein said position component includes a bendable spring with a plurality of links disposed at a pitch equal to a length of each stacked node ring.   
     
     
         13 . An endoscopic apparatus comprising the mechanical structure of articulated sheath according to  claim 12 , and further comprising a surgical assisting tool within the sheath. 
     
     
         14 . The mechanical structure according to  claim 12 ,
 wherein the position restoring component includes a plurality of cylindrical units connected to each other by a bendable elastic link,   wherein stiffness of the bendable elastic link is smaller than stiffness of each cylindrical unit, and   wherein the contact plane of said stacked node rings is located at a substantially same location along the linear axis as a bending point of said elastic bendable link in the position restoring component.