Abstract: Vibration testing apparatus comprises a vibration generator coupled to a horizontal slip plate by means of a driver bar, having limbs which embrace opposite sides of the slip plate. The lower limb of the driver bar is separable from the remainder of the driver bar so as to enable the vibration generator and the remainder of the driver bar to be pivoted away from the slip plate without lateral displacement of the slip plate along its horizontal axis.

Abstract: A seismic testing apparatus is provided in which linear motion or excitation of a horizontally disposed table is achieved simultaneously along three mutually orthogonal axes by means of independently operable hydraulic-actuator assemblies. Rotational or torsional motion of the table about the linear excitation axes is resisted by separate, mechanical rotation-inhibiting means each consisting of a torsionally rigid structure disposed parallel to the table and perpendicularly to their respective associated axes of excitation. The torsionally rigid structures are each connected to the table at two spaced-apart points, with all four points of connection lying in the same plane.

Abstract: A torsionally stiff flexure support for the slip plate in a vibration apparatus is provided permitting predetermined linear motion along the axis of vibration by longitudinal bending of the flexure, but by virtue of its torsional stiffness blocking pivoting movement about the center axis of the slip plate.

Abstract: A controlled motion apparatus capable of at least three degrees of freedom, such as apparatus for vibration testing of equipment, comprises a support suspended from a reaction mass by three anti-rotation, linear motion displacement actuator devices each extending and movable along one axis of an XYZ coordinate system. Each actuator may be independently activated to cause the support to undergo simultaneously controlled motion along the three axes.

Abstract: Apparatus for subjecting a test specimen to vibrational forces has a base, a first preselected massmounted for reciprocal movement relative to the base and a second preselected mass elastically coupled to the first mass to produce a resonant condition at a preselected frequency of reciprocal movement.

Abstract: The present invention provides a hydrostatic bearing type coupling for a vibrating machine. The coupling is interposed between a vibration table upon which a test specimen or the like is mounted and a vibrator in such a way that even when the vibration table is caused to vibrate three-dimensionally, there are free movements in the two directions.

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 mechanism is provided for oscillating a shake table or other member at high accelerations but over short distances. The mechanism includes a group of pad devices supporting the shake table on a base, with each pad device including upper and lower curved pads respectively received in sockets of the table and base and with the pads able to slide on one another. However, the centers of curvature of the two pads are spaced from one another, so that when a driver rotates the lower pad in its socket, causing the upper pad to rotate in its corresponding socket and slide on the lower pad, the upper pad is displaced vertically by a slight amount. Thus, an actuating device that applies a moderate force to the lower pad to rotate it, therefor applies a much greater vertical force to the table, to accelerate it at a high level. The pad devices also can support a large static loading on the table as where it lies in a centrifuge.

Abstract: Apparatus for obtaining tire dynamic characteristics in which a wheel and tire assembly is mounted on a shaft assembly of low mass. The tire tread is engageable with either a rotating or stationary supporting surface. Flexible connecting members having load-applying capabilities for urging the tire tread into loaded engagement with the tire supporting surface are located at each side of the tire and connected to the shaft assembly. The desired loading is measured by load cells on the connecting members. The tire may be vibrated at predetermined frequencies and amplitudes in predetermined directions by exciters and the resulting tire dynamic data selectively measured by one or more accelerometers.

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: A simple torque tube device which can be used in a shake table system to prevent rotation of the table about a predetermined axis without restricting the table in other degrees of freedom. A torque tube device which can prevent table rotation about a horizontal axis, includes a horizontal tube lying below the table, and a pair of largely vertical links having lower link ends pivotally connected to arms which lie at opposite ends of the tube and upper link ends pivotally connected to the table.

Abstract: A device for measuring the sensitivity of a patient to externally applied vibration. The device includes a pallometer head which supports a vibratable probe. The probe is caused to vibrate with a selected amplitude and at a selected frequency. The head is supported beneath a table with the probe extending through an opening in the table so that the probe can be engaged by a member of the patient as the member rests on the table. The head is supported on a beam which carries a counterweight so that the probe engages a member of the patient with a controlled pressure.

Abstract: A random vibration generator includes a hollow tabletop for supporting equipment to be subjected to vibration, and a sinusoidal reaction-type vibration machine connected to the tabletop to produce a sinusoidal vibration of adjustable frequency and amplitude. The hollow tabletop is horizontally divided into four sections, each containing a number of projectiles such as heavy balls which roll and bounce about within the compartments in the tabletop, impacting with the floor and ceiling of the compartment and with each other in a random fashion to produce random shocks over a wide band of frequency and amplitude, and subject the equipment to every possible vibration failure mode that might occur in nature.