Method of manufacturing a two-layer multistrand metal cord

Abstract

In a method of manufacturing a two-layer multistrand metal cord, N wires constituting an outer strand layer are wound in a helix around two wires constituting an inner strand layer, so as to form a strand. L>1 previously formed strands, which are incorporated as outer strands of an unsaturated outer cord layer of the cord, are wound in a helix around K>1 previously formed strands, which are incorporated as inner strands of an inner cord layer of the cord, to form a wound cord. The wound cord is overtwisted, the overtwisted cord is balanced so as to obtain zero residual torque in the overtwisted cord, and the balanced overtwisted cord is untwisted.

1 - 30 . (canceled) 
     
     
         31 . A method of manufacturing a two-layer multistrand metal cord, the method comprising steps of:
 obtaining a plurality of strands, each strand being formed of an outer layer including N wires and an inner layer including two wires, with the N wires of the outer layer being wound in a helix around the two wires of the inner layer;   winding L>1 of the strands, which are incorporated as outer strands of an unsaturated outer cord layer of the cord, in a helix around K>1 of the strands, which are incorporated as inner strands of an inner cord layer of the cord, to produce a wound cord;   overtwisting the wound cord, to produce an overtwisted cord;   balancing the overtwisted cord so as to obtain zero residual torque in the cord, to produce a balanced overtwisted cord; and   untwisting the balanced overtwisted cord.   
     
     
         32 . The method according to  claim 31 , wherein the K inner strands are wound in a helix. 
     
     
         33 . The method according to  claim 31 , wherein:
 (a) each of the inner strands and the outer strands is obtained;   (b) after (a), the K inner strands are wound in a helix; and   (c) after (b), the L outer strands are wound in a helix around the helix formed of the K inner strands.   
     
     
         34 . The method according to  claim 32 , wherein:
 (a) each of the inner strands and the outer strands is obtained;   (b) after (a), the K inner strands are wound in a helix; and   (c) after (b), the L outer strands are wound in a helix around the helix formed of the K inner strands.   
     
     
         35 . The method according to  claim 31 , wherein the outer layer of each strand is unsaturated. 
     
     
         36 . The method according to  claim 31 , wherein a structural elongation (As) of the cord is greater than or equal to 1%. 
     
     
         37 . The method according to  claim 31 , wherein a structural elongation (As) of the cord is greater than or equal to 1.5%. 
     
     
         38 . The method according to  claim 31 , wherein a structural elongation (As) of the cord is greater than or equal to 2%. 
     
     
         39 . The method according to  claim 31 , wherein a total elongation at break (At) of the cord is greater than or equal to 4.5%. 
     
     
         40 . The method according to  claim 31 , wherein a total elongation at break (At) of the cord is greater than or equal to 5%. 
     
     
         41 . The method according to  claim 31 , wherein a total elongation at break (At) of the cord is greater than or equal to 5.5%. 
     
     
         42 . The method according to  claim 31 , wherein K=3 or K=4. 
     
     
         43 . The method according to  claim 31 , wherein L=8 or L=9. 
     
     
         44 . The method according to  claim 31 , wherein N=2 or N=3 or N=4. 
     
     
         45 . A method of manufacturing a two-layer multistrand metal cord, the method comprising steps of:
 forming a plurality of strands, each strand including N wires, which constitute an outer layer, wound in a helix around two wires, which constitute an inner layer;   winding L>1 of the strands, which are incorporated as outer strands of an unsaturated outer cord layer of the cord, in a helix around K>1 of the strands, which are incorporated as inner strands of an inner cord layer of the cord, to produce a wound cord;   overtwisting the wound cord, to produce an overtwisted cord;   balancing the overtwisted cord so as to obtain zero residual torque in the cord, to produce a balanced overtwisted cord; and   untwisting the balanced overtwisted cord.