Endless power transmission belt construction, cord therefor and methods of making the same

In a method of making a p-aramid fiber cord, said cord comprising five plies twisted together in one direction at a rate to approximately equal a first certain twist multiplier with each said ply comprising three yarns of a plurality of p-aramid fiber filaments having a certain denier and being twisted together in a direction opposite to said one direction at a rate to approximately equal a second certain twist multiplier, each said twist multiplier being equal to the quotient of the product of the turns per linear inch of twisted material multiplied by the square root of the product of said certain denier of said fiber filaments multiplied by the total number of said yarns being twisted at that time divided by seventy-three, the improvement comprising the step of twisting said yarns and said plies respectively on a 2 for 1 twister means so as to cause the longitudinal axes of said fiber filaments to be disposed generally in the longitudinal direction of said cord with said certain denier being approximately 1500, said first certain twist multiplier being 3.6986 as the five plies are being twisted together by said twister means at a rate of approximately 1.8 turns per linear inch of said cord, said second certain twist multiplier being 3.5838 as the three yarns for each said ply are being twisted together by said twister means at a rate of approximately 3.9 turns per linear inch of that said ply, and said p-aramid comprising co-poly (paraphenylene/3,4'oxydiphenylene terephthalamide).

In a construction comprising a section having a p-aramid fiber cord therein, said cord comprising five plies twisted together in one direction at a rate to approximately equal a first certain twist multiplier with each said ply comprising three yarns of a plurality of p-aramid fiber filaments having a certain denier and being twisted together in a direction opposite to said one direction at a rate to approximately equal a second certain twist multiplier, each said twist multiplier being equal to the quotient of the product of the turns per linear inch of twisted material multiplied by the square root of the product of said certain denier of said fiber filaments multiplied by the total number of said yarns being twisted at that time divided by seventy-three, the improvement wherein said yarns and said plies are respectively twisted on a 2 for 1 twister means so as to cause the longitudinal axes of said fiber filaments to be disposed generally in the longitudinal direction of said cord with said certain denier being approximately 1500, said first certain twist multiplier being 3.6986 as the five plies are twisted together at a rate of approximately 1.8 turns per linear inch of said cord, said second certain twist multiplier being 3.5838 as the three yarns for each said ply are twisted together at a rate of approximately 3.9 turns per linear inch of that said ply, and said p-aramid comprising co-poly (paraphenylene/3, 4'oxydiphenylene terephthalamide).

In a method of making a construction comprising a section having a p-aramid fiber cord therein, said cord comprising five plies twisted together in one direction at a rate to approximately equal a first certain twist multiplier with each said ply comprising three yarns of a plurality of p-aramid fiber filaments having a certain denier and being twisted together in a direction opposite to said one direction at a rate to approximately equal a second certain twist multiplier, each said twist multiplier being equal to the quotient of the product of the turns per linear inch of twisted material multiplied by the square root of the product of said certain denier of said fiber filaments multiplied by the total number of said yarns being twisted at that time divided by seventy-three, the improvement comprising the step of twisting said yarns and said plies respectively on a 2 for 1 twister means so as to cause the longitudinal axes of said fiber filaments to be disposed generally in the longitudinal direction of said cord with said certain denier being approximately 1500, said first certain twist multi-plier being 3.6986 as the five plies are twisted together by said twister means at a rate of approximately 1.8 turns per linear inch of said cord, said second certain twist multiplier being 3.5838 as the two yarns for each said ply are twisted together by said twister means at a rate of approximately 3.9 turns per linear inch of that said ply, and said p-aramid comprising co-poly (paraphenylene/3,4'oxydiphenylene terephthalamide).