Abstract: A flexure structure for mounting an element such as a mirror in an optical device to a frame such as a telescope support structure includes a flexure blade defining a fork having three coplanar tines. A first mounting pad is located on the center tine for attaching the flexure blade to the mirror. A pair of mounting feet are located on the outside tines for attaching the flexure blade to the frame. The relative sizes of the tines being such that zero moment is applied to the mirror by the flexure structure when the mirror is displaced relative to the frame.

Abstract: A novel method for determining a coefficient of moisture expansion of a single, identified workpiece or coupon. The method includes the steps of positioning the workpiece in a chamber having known environmental parameters; determining a workpiece length change .DELTA.L caused by a chamber induced change in the workpiece moisture content .DELTA.M, by positioning first and second transformers to opposite ends of the single workpiece; and, measuring a chamber induced change in the workpiece moisture content .DELTA.M, by weighing the workpiece.

Abstract: An assembly for determining a coefficient of moisture expansion of a single, identified workpiece or coupon. The assembly includes means for positioning the workpiece in a chamber having known environmental parameters; means for determining a workpiece length change, .DELTA.L caused by a chamber induced change in the workpiece's moisture content .DELTA.M; and, means for measuring a chamber-induced change in the workpiece's moisture content .DELTA.M.

Abstract: An improved dilatometer suitable for testing the coefficient of thermal expansion (CTE) of a workpiece. The workpiece having a CTE in the range of -0.2.times.10.sup.-6 inch/inch .degree.F. to 0.2.times.10.sup.-6 inch/inch/.degree.F. The improvement includes a reference structure means for positioning and isolating the workpiece, and for maintaining an independent reference temperature, uninfluenced by a required workpiece temperature differential. The temperature independent reference structure means helps assure that measurements of expansions/contractions of the workpiece, as a function of temperature, are uniquely that of the workpiece, and not that of the reference structure means, or any other ambient temperature determinant. The improved dilatometer is particularly useful for determining the CTE of a workpiece having a relatively low value, e.g., a CTE less than 0.1.times.10.sup.-6 inch/inch .degree.F.

Abstract: An assembly and method suitable for determining the coefficient of thermal expansion (CTE) of a workpiece. The assembly includes a dual channel laser interferometer system placed in operative association with the workpiece, and a vacuum, heating and cooling chamber surrounding the workpiece. The assembly is particularly useful for determining the CTE of a workpiece having a relatively low value, e.g., a CTE less than 0.1.times.10.sup.-6 inch/inch .degree.F. It is therefore advantageously employed for determining the CTE of a workpiece comprising a composite, like a graphite/epoxy composite, that may have a CTE in the range of .+-.0.2.times.10.sup.-6 inch/inch .degree.F.

Abstract: A reversible snap-action switch including a drive member and a switch-actuating driven member connected by a lost motion coupling. The relative position between the drive and driven members is shifted by substantially the lost motion distance as the drive member moves the driven member through a switching zone and then reverses its direction to return to its original position. In each direction of movement a bidirectional accelerating means imparts a snap-action motion to the drive member. This motion is coordinated with the position of the driven member so that switching occurs during the snap-action motion in each direction of movement, thereby inhibiting any hesitation in making or breaking the switch contacts. The invention also includes a cement-free mounting for the switch contacts.