Abstract: Vibration equipment bases which are isolated from the floor by air bags are made self-leveling by interposing a valve between each of the air bags and a pressurized air supply and each of the air bags and the atmosphere, the valve being sensitive to height of the base in air flow controlling relation to and from the bags to adjust their inflation and thus the height of the base.

Abstract: Hydrostatic bearing vibration test apparatus in which the pillow block housing is opertively coupled to the workpiece by an oil film while the carriage blocks are fixed to the workpiece and the bearing shaft, the housing being supported on flexible bolts permitting two degrees of freedom in the bearing appartus.

Abstract: A driver bar assembly for coupling together a shaker head 12 and a slip plate 34 carrying a test piece 60 to be vibration tested, the assembly comprising a driver bar 14 having a laterally extended locus of intersection (L-L, P-P) with the slip plate in the slip plate plane of test movement, and fastener means comprising a rigid pin 50 extending laterally within the locus of intersection in slip plate and bar interconnecting relation for transmission of shaker head vibration to the slip plate through the pin.

Abstract: Vibration fixture apparatus and method of use for high volume testing of circuit boards and the like is provided comprising a frame peripherially surrounding the board and a shimming structure which is hydraulically actuated to bind against the board and frame selectively for faithful transmission of vibration energy from a vibration source through the frame to the board to be tested.

Abstract: Driver bar assembly for vibration test apparatus, comprising a bar element and a retainer element separably connected thereto; the bar element having a normally vertically disposed base attachable to a pivotally mounted shaker head and a normally horizontally disposed flange adapted to lie in a common plane with and spaced from a slip plate to be driven by the shaker head; the retainer element having a first bracket in which the bar element flange is bracketable, and a second bracket in which the slip plate is bracketable opposite the bar element flange, whereby the flange and slip plate spacing is bridged in vibration transmitting relation between the shaker head and the slip plate; the retainer element being separable from the slip plate and the bar element flange without relative movement of the slip plate and shaker head, the bar element and shaker head being freely angularly movable relative to the slip plate in the separated condition of the retainer element and the bar element.

Abstract: A vibration test, bearing table apparatus comprising a support block having a surface slideably supporting a test piece-carrying slip plate intended to oscillate along a single predetermined axis at a desired test frequency responsive to shaker head driving of the slip plate is provided, with an improvement comprising means within the locus of sliding engagement including a cooperating shaft and bearing assembly distributively coupling the slip plate and support block together in a manner maintaining the test piece on a single degree of freedom path coincident with the test axis, whereby tendencies of the driving force to impart spurious cross-axis pitch, yaw and roll test piece motion relative to the intended test axis are blocked.

Abstract: Hydrostatic bearing apparatus adapted to mount a shaker-coupled, dimensionally temperature dependent test piece for vibratory oscillation along a predetermined test axis. The apparatus comprises a support block having a compliant section defining a bore, a shaft axially journaled in the bore and defining therewith a bearing locus paraxial with the test axis. Bracket means is provided securing the test piece to the shaft beyond the locus for bearing-guided test axis oscillation, the bearing locus being test axis paraxially bodily displaceable responsive to displacement of the compliant section in test piece dimensional change accommodating relation.

Abstract: A slip plate assembly is provided for shaker-head generated vibration testing of a test piece being exposed to thermal cycling between preselected test temperature extremes in a closed environment. The assembly comprises a pair of opposed plate elements, a first plate element being beyond the closed environment and a second plate element exposed to test temperatures within the closed environment. Pin means is provided defining a singular locus of vibration transmitting connection between the first plate and the second plate in dimensionally temperature-responsive relation.