Kelvin B Scribner

US Patent:

59201738, Jul 6, 1999

Filed:

Nov 15, 1995

Appl. No.:

8/559518

Inventors:

Mathieu Mercadal - Fontenay aux Roses, FR
Kelvin B. Scribner - Hood River OR
Andreas H. von Flotow - Hood River OR

Assignee:

Applied Power Inc. - Butler WI

International Classification:

B64C 1706

US Classification:

318649

Abstract:

An apparatus has a mass suspended between two mounting plates by a separate springs to form a resonant structure that absorbs vibration in a structural member to which the mounting plates are attached. Permanent magnets are fixed to opposite sides of the mass. A sensor produces a signal indicating the frequency of the vibration. A feedback circuit receives the signal from the sensor and produces an output signal having first component frequency which corresponds to a harmonic of the frequency of the vibration. The output signal is applied to a separate voice coil adjacent to each permanent magnet. The magnetic fields produced by the output signal flowing through the voice coils interact with the magnetic fields from the permanent magnets to generate forces that act on the mass in a manner that increases the impedance of the absorber to the vibration in the structural member.

US Patent:

57107149, Jan 20, 1998

Filed:

Nov 15, 1995

Appl. No.:

8/559519

Inventors:

Mathieu Mercadal - Fontenay aux Roses, FR
Kelvin B. Scribner - Hood River OR
Andreas H. von Flotow - Hood River OR

Assignee:

Applied Power Inc. - Butler WI

International Classification:

F16F 1300

US Classification:

364508

Abstract:

An apparatus for absorbing vibrations in a structural member has a mass suspended between two mounting plates by a separate springs. The mass has two sections and a mechanism for adjusting the spacing between the sections to alter the spring stiffness. Two sensors produce first and second signals representing the vibration of the structural member and the mass. The mechanism is operated by a controller that includes separate filters for the first and second signals in which each filter has a center frequency that is tuned by a clock signal. The phase comparator produces a phase output signal indicating a phase relationship between signals from the two filters and the control signal for the mechanism is produce in response to the phase output signal. A phase locked loop produces the clock signal for tuning the filters in response to a comparison between one of the first and second signals and a signal from one of the filters.

US Patent:

58735593, Feb 23, 1999

Filed:

Apr 17, 1997

Appl. No.:

8/839275

Inventors:

Andreas H. von Flotow - Hood River OR
Mathieu Mercadal - Hood River OR
Kelvin B. Scribner - The Dalles OR
Timothy Mixon - Hood River OR
Corydon Roeseler - Hood River OR

Assignee:

Applied Power Inc. - Butler WI

International Classification:

F16M 1300
G01M 700

US Classification:

248557

Abstract:

An aircraft engine is attached to the fuselage by a mounting structure that has a vibration absorbing system which includes first and second sensors to produce signals indicating vibration along two orthogonal axes. A third sensor, such as an accelerometer, is coupled to the mounting structure for sensing vibration of the engine. A tachometer circuit, connected to the third sensor, produces first and second speed signals that indicate the speeds of two rotating spools in the engine. Four vibration absorbers are attached to the engine mounting structure and controllers are provided to dynamically tune the resonant frequency of each vibration absorber in response to a unique combination of one of the two vibration signals and one of the two speed signals. Thus the vibration absorbers reduce the engine spool vibrations that are transmitted through the mounting structure along the two orthogonal axes. The resonant frequency of each absorber is altered to track variation of the vibrations due to changes in engine speed.