GB597941A - Improvements relating to the testing of the textile cords and the like - Google Patents

Abstract

597,941. Testing textile elements for fatigue. WINGFOOT CORPORATION. Feb. 28, 1945, No. 5049. Convention date, Sept. 19, 1944. [Class 106 (ii)] Textile elements, such as cords for vehicle tyres, are tested for fatigue by first embodying a number of such elements in a tubular member of flexible material, such as rubber, bending the member, inflating it and rotating it while in the bent condition. Each tubular test specimen is made from sheets of uncured rubber wrapped around a rod, two superposed sheets of rubber enclosing longitudinal tyre cords which adhere to the latter, additional sheets of rubber and a spirally-wound constraining cord, and further sheets of rubber to encase the constraining cord. The specimen is then vulcanized and cut into test pieces 6. The testing- apparatus comprises a frame 2 having a housing 7 in which a shaft 8, driven from a motor 12, is supported. A gear-wheel 9 on the shaft 8 drives a train of wheels 13 each mounted on a stub shaft 14 (not shown) projecting from each side of the housing 7. A specimen 6 is secured at one end, in a fluid-tight manner, to each end of each shaft 14, and at the other end is secured in a fluid-light manner to a tubular member 18 rotatably mounted in a bearing block 17. Each member 18 is connected to a source 30 of compressed air. The shaft 8 drives a counter-mechanism 47 through a belt 45, gearing 44 and shaft 46. In operation, the specimens 6 are rotated at constant speed for a definite number of cycles and the speed and air pressure inside the specimens is then increased in increments until failure of the specimens. Due to the constraining cords in the specimens, the air pressure produces only tensile stresses in the tyre cords.