Thin wall shear resistant coupling and pipe assembly - made from fiber reinforced elastomer giving minimum indicated column expansibility and shear resistance

摘要

The conformable push-type shear-resistant pipe coupling when viewed in transverse cross-section, defines a closed, convexly rounded figure with a wall thickness in a range of about .006 D' to about .09 D, where D is the diameter in centimetres of the pipe for which the coupling is intended. The coupling has a column extensibility of at least about 1.12 x 10-3 centimetres per kilogram, and a sheer resistance providing about .12 centimetres of pipe deflection or less per centimetre of D under a sheer load of 26.787 D' kilograms. The couplings include a fibre-reinforced elastomer for providing the above indicated column extensibility and shear resistance. The composite includes fibres having a modulus of at least about 4.22 x 105 kilograms per square centimetre, oriented in an opposed balanced helical pattern or patterns at a helix angle in the range of about 45 to about 75 degrees measured from a reference line parallel to the longitudinal axis of the coupling. The angle is substantially uniform throughout the length of the coupling. An elastomer binder of substantially lower modulus than the fibres and has a modulus at 100% elongation of at least about 1.75 kilograms per sq. centimetre, a tensile strength of at least 21 kilograms per square centimetre, and a Shore A durometer hardness in the range of about 15 to about 90, mechanically interconnects the opposed fibres at the above indicated helix angle.