Reference frame and hold-down support system for remote supported axial torsional extensometer

For use in connection with a test frame comprising a base and means for loading a test specimen along a specimen loading axis, said base extending generally perpendicular to said loading axis and having an upper surface on a side thereof adjacent to said specimen that is substantially perpendicular to said axis, and wherein said base includes means for loading said specimen in direction along said axis and also in torsion about the axis, the improvement comprising an extensometer support for supporting an extensometer relative to a test frame base independently of the specimen including a support plate, said support plate having a plane and generally parallel to the upper surface of said base, a plurality of flexure support spools comprising stand-off members spacing the plate from the upper surface of such base, means to load the plate in compression against first ends of the support spools and when second ends of the flexure support spools are forced against the upper surface of such base to permit flexing movement of such base relative to the support plate when the support plate is supported thereon, said support plate having an extension portion extending laterally from the specimen loading axis of a test frame on which it is mounted, a rigid tubular upright column mounted on said extension portion of said support plate and having a central axis generally parallel to such test specimen axis and extending in a direction away from a base on which the support plate is mounted, clamp means on said column for adjustable movement along and about the axis of said column, a second support plate, means to adjustably support the second support plate on said clamp means for movement in a direction perpendicular to the axis of said column, said second support plate having a plane that is generally parallel the axis of the column, and generally spans the distance between the column and a test specimen mounted on a test frame on which the first mentioned support plate is mounted, a block mounted on said second support plate and adjustable about an axis generally perpendicular to the plane of the second support plate, a pair of arms mounted on said block for pivotal movement individually about axes perpendicular to the plane of the second support plate and parallel to the axis of adjustment of said block, said arms extending outwardly from their pivotal mounting in a direction generally toward the test specimen loading axis, but being laterally offset therefrom, said arms including flat spring means prebent to urge the outer ends of said arms in a direction toward the axis of a test specimen being tested in a test frame on which the arms are mounted, said flat spring means being substantially planar when the arms are supporting an extensometer assembly against a specimen located centrally on such a test specimen axis.

An extensometer support for use in combination with a test frame having a base, and having means for loading a test specimen along a specimen loading axis generally perpendicular to the base, and for loading said specimen for rotation about its specimen axis, the improvement comprising a support plate, an upright column fixed to said support plate and laterally offset from a specimen when the plate is installed on a base for a test frame holding a test specimen, a plurality of flexure standoff members for mounting the support plate relative to the base in a position spaced from said base and connected to the base only through said standoff members, means at the upper end of said column for supporting an extensometer in engagement with a specimen to be tested, including a pair of arms pivotally mounted at first ends thereof about an axis perpendicular to the axis of the column and spaced apart in the direction of the longitudinal axis of the column, the arm axes being positioned adjacent the column, a pair of elongated rods having first ends for engaging a specimen and second ends, means for pivotally mounting second ends of the elongated rods to the respective arms at second ends of the arms when the elongated rods are engaging a specimen to be tested, said standoff members providing a flexible connection to the base which will not substantially deflect extensometer members supported relative to and operatively engaging a specimen as the base deflects during loading of the specimen, said plate and column being sufficiently stiff to prevent the line defined by the pivot points of the second ends of the elongated rods from becoming substantially displaced from a plane passing through one of the pivot points of the second ends of the arms and the axis of a specimen to be tested.