Abstract: An extensometer measures strain on a test specimen subjected to tensile, compression or fatigue tests. The extensometer has a pair of members that are connected together preferably with at least two spaced-apart flexible plates. The members are coupled to move with the specimen when the specimen is subjected to the foregoing tests. A measuring device measures a change in distance of the members relative to each other in order to measure elongation or compression of the test specimen.

Abstract: An extensometer for measuring strain in a test specimen is disclosed. The extensometer includes a frame and a flexible support structure, preferably, a loop, mounted to the frame. A measuring device is mounted to the flexible support loop at a position spaced apart from the frame and engages a surface of the specimen with a selected amount of contact force. The measuring device provides an output signal proportional to the measured strain.

Abstract: A high temperature extensometer system carries specimen contact rods of substantial length which pass through openings in a furnace to engage a specimen in such furnace. The rods are supported at the exterior of the furnace on a paralleogram linkage support frame made to provide an output indicating specimen strain as the contact rods separate and also made with parallel beams which shift so the rods can move differentially in longitudinally axial direction. The rods shift axially when the specimen and test loading grips shift in position, for example when the grips and specimen are initially heated.