PHILIP MARSHALL
Engineering in Lexington, MA

5083463, Jan 28, 1992

Feb 7, 1990

7/476175

Philip Marshall - Lexington MA
Paul Ford - Maynard MA

M/RAD Corporation - Woburn MA

G01N 2900, B06B 300

73663

A vibration test fixture assembly for releasably securing a test object to the top surface of a sliptable and for rotatably supporting the test object so that the test object can be repositioned between vibration tests without detaching the test object from the fixture. The assembly comprises a bottom plate, a top plate positioned on top of the bottom plate, and a plurality of spring-loaded bearing assemblies between the top and bottom plates for permitting the top plate to rotate relative to the bottom plate except when a downward force of sufficient magnitude to overcome the spring bias of the bearing assemblies is applied to the top plate. The assembly also comprises a plurality of clamps positioned adjacent the top plate for applying a downward force to the top plate sufficient to overcome the spring bias of the bearing assemblies and cause the top plate to engage the bottom plate. The test object is secured to the top plate and the bottom plate is secured to the top surface of a sliptable.

5199690, Apr 6, 1993

Jul 30, 1992

7/922650

Philip Marshall - Lexington MA

M/RAD Corporation - Woburn MA

F16F 922, F16F 943

267 6425

An active vibration isolation system which has three groups of airbag springs for supporting a load and isolating the load from vibration, together with a servo-valve system for admitting pressurized air to or exhausting pressurized air from each group of the airbag springs, and a damping system for damping movement of the load. The damping system comprises a plurality of pairs of shock absorbers which are mounted in parallel with and adjacent to the airbag springs. The shock absorbers are arranged so as to provide damping for each of the groups of airbag springs in three mutually-orthogonal directions.

5277066, Jan 11, 1994

Aug 28, 1992

7/937996

Philip Marshall - Lexington MA

M/RAD Corporation - Woburn MA

G01N 2900

73663

A vibration test apparatus for applying simultaneously three equal mutually-orthogonal vibration forces to each of at least two test objects so that each of said forces extends parallel to a corresponding respective one of mutually-orthogonal X, Y and Z axes of each test object. The apparatus comprises a fixture adapted for attachment to a conventional shaker table or a sliptable that has two or four object-supporting plates disposed in a selected angular relationship with the shaker table or sliptable. This angular relationship is selected so that the input vibration force generated by the shaker table is translated into the three equal forces, each of which extends parallel to a corresponding respective one of the three mutually-orthogonal axes of each test object secured to said fixture.

4069706, Jan 24, 1978

Nov 18, 1976

5/742872

Philip Marshall - Lexington MA
Albert Paul Laber - Revere MA
Ugo Cauteruccio - West Roxbury MA

MRAD Corporation - Woburn MA

G01N 332, B06B 110

73666

A mechanical complex vibration tester is provided which is capable of simultaneously applying a plurality of discrete frequencies to a workpiece positioned on a test surface of the device to simulate random vibration testing. The vibrations may be varied in amplitude and they may be applied in either the vertical or the horizontal direction. Means are provided for isolating the tester from its environment in order to simulate vibration testing in inertial space.

4848160, Jul 18, 1989

Oct 25, 1988

7/265310

Philip Marshall - Lexington MA
Jeffrey Marshall - Arlington MA
Paul Ford - Arlington MA
Darryl Huttunen - Malden MA

M/RAD Corporation - Woburn MA

G01M 700

73663

A vibration test fixture system for use with a conventional shaker table. The fixture system includes a cube fixture for supporting an object to be tested and a head expander for supporting the cube fixture and for providing a mechanical and vibration transmissive connection between the cube fixture and the shaker table. The fixture system also includes an index mechanism for automatically repositioning the cube fixture relative to the head expander so that the object may be vibration tested along mutually orthogonal axes of the object.

5156051, Oct 20, 1992

Jul 16, 1991

7/731372

Philip Marshall - Lexington MA

M/RAD Corporation - Woburn MA

G01N 2900

73663

A vibration test apparatus for applying simultaneously three equal vibration forces which extend along three mutually-orthogonal axes to a test object so that each of the forces extends parallel to a corresponding respective one of three mutually-orthogonal axes of the object. The apparatus comprises a fixture adapted for attachment to a conventional shaker table or a sliptable. The fixture supports the test object in selected angular relationship relative to the shaker table or sliptable. This angular relationship is selected so that the input vibration force generated by the shaker table is translated into the three equal forces, each of which extends parallel to a corresponding respective one of the three mutually-orthogonal axes of the test object.