Method of manufacturing a merged cord

Abstract

A pneumatic tire for use on aircraft has a tread, a crown reinforcement, and a radial carcass reinforcement having at least one axially inner ply of textile cords wound around a pair of bead cores, at least one axially inner ply being wound around the bead core in each bead from inside to the outside forming outside turn-ups and at least one axially outer ply of textile cords extending from bead to bead along the turn-ups of the at least one axially inner ply. The at least one axially inner ply or at least one axially outer ply has merged cords having a percent elongation at break of 12% to less than 20% and a break strength greater than 1050 N with a linear density of greater than 9,000 dtex. Merged cord reinforcement is preferably used in the ply layers or strips of the crown reinforcement as well.

1 . A method of manufacturing a merged cord comprising the steps of:
 constructing a merged cord of two plies of aromatic polyamide and one ply of aliphatic polyamide having a greige low elongation capability in the range of 6% to 15% and a dipped high elongation at least 20% higher than the value of the greige merged cord.   
     
     
         2 . The method of  claim 6  wherein the greige merged cord has a percent elongation of 10% to 15%. 
     
     
         3 . A method of manufacturing a merged cord comprising the steps of:
 constructing a merged cord of at least one yarn of aromatic polyamide and at least one yarn of aliphatic polyamide wherein merged cords having greige cord properties of a percent elongation at break of 14% to less than 16% and a break strength greater than 1050 N with a linear density of greater than 9,500 dtex.   
     
     
         4 . The method of manufacturing a merged cord of  claim 3  wherein the merged cords are constructed by helically twisting together at least one aromatic polyamide yarn and at least one nylon yarn. 
     
     
         5 . The method of manufacturing a merged cord of  claim 4  wherein the at least one aromatic polyamide yarn is two 3300 dtex aromatic polyamide yarns. 
     
     
         6 . The method of manufacturing a merged cord of  claim 5  wherein the at least one nylon yarn is a single 1880 dtex nylon yarn. 
     
     
         7 . The method of manufacturing a merged cord of  claim 6  wherein the twist of each aromatic polyamide yarn is 6.7 turns per inch (TPI), the twist of the nylon yarn is 4.5 TPI, and the cord twist is 6.7 TPI.