Abstract: An extensometer readout circuit conditions a strain information signal, representing strain of a specimen being tested, in such a way that yield point measurements and final elongation measurements of such specimen may be concurrently obtained. The strain information signal is provided by subjecting the specimen to a tensile or compression test by any conventional means known in the prior art. The strain information signal is first applied to a preamplifier. The preamplified strain information signal is then concurrently applied to both a high gain amplifier and a low gain amplifier. The signal obtained from the high gain amplifier is used for performing modulus calculations and for obtaining yield point measurements. The signal obtained from the low gain amplifier is used to obtain the total elongation measurement.

Abstract: A swivel joint which has two mating part spherical reaction surfaces carried on two loading members. One of the surfaces is defined in part on a piston which is urged under pressure toward the mating part to take up backlash between the mating surfaces. A sealed area may be defined between the mating surfaces and which contains a quantity of fluid under pressure to carry the loads between the two surfaces on a hydrostatic bearing. The swivel joint permits high loads from hydraulic actuators to be supported without encountering high friction forces while permitting swiveling of the joint across a substantial range of angles.