HYDRAULIC MACHINE TENSILE TEST OF TUBES Russian patent published in 2000 - IPC

FIELD: testing equipment. SUBSTANCE: preferable application field of invention is testing stands for investigation of strength characteristics of tubes tested for tension. Hydraulic machine is made of hydraulic loading and control system, loading gear composed of base carrying two hydraulic cylinders whose pistons are continuation of columns anchored in cross-piece, grippers for anchoring of tested tube mounted uniaxially on base and cross-piece which include strapping embracing end of tested tube over external diameter, device gripping end of tube and embracing it over internal surface which includes segment collet with mechanism of its expansion. Device gripping end of tested tube has double action hydraulic cylinder mounted on cross-piece ( upper gripper ) and base ( lower gripper ) whose rod end is made in the form of truncated pyramid which faces are movably coupled to surfaces of segments of collet placed uniaxially with strapping and resting upon plate-disc. Spaces of double action hydraulic cylinder communicate with hydraulic system of machine. Operational area of grip of double action hydraulic cylinder exceeds operational summary area of hydraulic cylinders. Segments of collet are joined by means of elastically pliable members. EFFECT: structure provides for automatization of clamping and unclamping of tested tube and for more uniform and reliable gripping of its ends. 2 cl, 2 dwg