Variable stiffness flexure

Abstract

An intrauterine device includes a central support member, first and second internal flexures and first and second external flexures. The first and second internal flexures each include a first section having a first stiffness, a second section having a second stiffness, and third section having a third stiffness, wherein the second stiffness is more flexible than the first and third stiffness and wherein the first section of each internal flexure is coupled to the central support member. The first and second external flexures are coupled to the central support member and coupled to the third sections of the first and second internal flexures, the first and second external flexures in combination with the first and second internal flexures being configured to extend from a collapsed position parallel to the central support member to a deployed position flexing away from the central support member.

What is claimed is: 
     
         1 . A intrauterine device, comprising:
 a central support member;   first and second internal flexures each including a first section having a first stiffness, a second section having a second stiffness, and third section having a third stiffness, wherein the second stiffness is more flexible than the first and third stiffness and wherein the first section of each internal flexure is coupled to the central support member; and   first and second external flexures each coupled to the central support member and each coupled to the third section of the respective first and second internal flexures, and the first and second external flexures in combination with the first and second internal flexures being configured to extend from a collapsed position parallel to the central support member to a deployed position flexing away from the central support member.   
     
     
         2 . The intrauterine device of  claim 1 , wherein the first and second internal flexures further include a fourth section having a fourth stiffness and a fifth section having a fifth stiffness,
 wherein the fourth section is positioned between the inner section and the second section and the fifth section is positioned between the second section and the third section, and   wherein the fourth and fifth stiffnesses are more flexible than the first and third stiffnesses and less flexible than the second stiffness.   
     
     
         3 . The intrauterine device of  claim 2 , wherein the fourth and fifth stiffnesses taper, decreasing in stiffness toward the second section. 
     
     
         4 . The intrauterine device of  claim 1 , further comprising arms coupled to the central support member and configured to support a mesh array. 
     
     
         5 . The intrauterine device of  claim 4 , wherein the arms are configured to extend parallel to the central support member in the first position and to at least partially flex away from the central support member and in a longitudinal direction parallel to the central support member in the second position. 
     
     
         6 . The intrauterine device of  claim 5 , further comprising a central bridge coupled to a middle portion of each arm and configured to extend parallel to the central support member in the first position, and to at least partially flex away from and back toward and beyond the distal end of the central support member in the second position. 
     
     
         7 . The intrauterine device of  claim 1 , further comprising a mesh array surrounding the first and second external flexures, the first and second internal flexures and the central support member. 
     
     
         8 . The intrauterine device of  claim 1 , wherein first internal flexure is coupled to the central support member so that it forms part of the central support member. 
     
     
         9 . The intrauterine device of  claim 1 , wherein the central support member and the first internal flexure form a V-shape in the deployed position. 
     
     
         10 . The intrauterine device of  claim 1 , wherein the first internal flexure includes an aperture. 
     
     
         11 . The intrauterine device of  claim 1 , wherein the first section has a first thickness and the second section has a second thickness, and wherein second thickness is less than the first thickness. 
     
     
         12 . The intrauterine device of  claim 11 , wherein the third section has a third thickness, and wherein second thickness is less than the third thickness. 
     
     
         13 . An intrauterine device, comprising:
 a central support member having a center line;   first and second internal flexures each including first and second sections, wherein the first section of each of the first and second internal flexures includes a middle portion that has a C-shape, wherein the middle portion curves inward toward a center line and curves outward toward the second section; and   first and second external flexures each coupled to the central support member and each coupled near a distal end of the respective first and second internal flexures, the first and second external flexures in combination with the first and second internal flexures being configured to extend from a collapsed position parallel to the central support member to a deployed position flexing away from the central support member.   
     
     
         14 . The intrauterine device of  claim 13 , further comprising a sheath configured to enclose the central support member, the first and second internal flexures and the first and second external flexures when in the collapsed position. 
     
     
         15 . The intrauterine device of  claim 13 , further comprising a mesh array about the first and second external flexures, the first and second internal flexures and the central support member. 
     
     
         16 . The intrauterine device of  claim 13 , further comprising arms coupled to the central support member and configured to support a mesh array. 
     
     
         17 . The intrauterine device of  claim 16 , wherein the arms are configured to extend parallel to the central support member in the first position and to at least partially flex away from the central support member and in a longitudinal direction parallel to the central support member in the second position. 
     
     
         18 . The intrauterine device of  claim 17 , further comprising a central bridge coupled to a middle portion of each arm and configured to extend parallel to the central support member in the first position, and to at least partially flex away from and back toward and beyond the distal end of the central support member in the second position. 
     
     
         19 . The intrauterine device of  claim 13 , wherein the first internal flexure includes an aperture.