Gary P Thomas

US Patent:

6422089, Jul 23, 2002

Filed:

Apr 26, 2001

Appl. No.:

09/842564

Inventors:

Richard Madden - Groton MA
Daniel Joseph McCarthy - Cambridge MA
Gary L. Thomas - Hingham MA

Assignee:

BBNT Solutions LLC - Cambridge MA

International Classification:

G01B 500

US Classification:

73779, 73780

Abstract:

A variable reluctance load cell for measuring the static or slowly fluctuating load, or tension, on devices is contained in a support tube. A sensor in the tube utilizes opposing C and I shaped magnetic cores attached to opposing ends of the support tube. A magnetic circuit is formed having an inductance defined by the size of the gap between the magnetic cores with the reluctance dominated by the gap. The sensor inductance is coupled with a fixed, predetermined capacitance in a resonant LC circuit, and the resonant frequency is a function of the gap. The sensor is in a cavity within the tube, and the cavity is sealed in a manner that prevents water or other damaging agents from entering the sensor. In this manner, mounting the sensor and tube to a static device and measuring the AC voltage at the sensor, the amount of load, or stress can be determined.

US Patent:

6437510, Aug 20, 2002

Filed:

Dec 6, 1999

Appl. No.:

09/455886

Inventors:

Gary E. Thomas - Wenham MA
James D. Deveau - Wenham MA

Assignee:

Communications Power Industries, Inc. - Beverly MA

International Classification:

H01J 2542

US Classification:

315 393, 333252, 333 99 MP

Abstract:

A crossed-field device such as a crossed-field amplifier or magnetron has a cathode body portion and an anode which cooperates with a crossed magnetic field to maintain emitted electrons on cycloidal paths and amplify an input signal or develop a microwave or millimeter wave output signal in an interaction space. The device is switched to shut down between working cycles, and delayed and secondary emissions are reduced to allow low noise operation and reduce multipactor for dependable operation at lower magnetic field strengths. Ceramic windows cover the output transformer (and input transformer in an amplifier device), and at least one window is grooved to reduce its secondary electron yield while maintaining its rf aperture. In addition, one or more walls within the device are physically structured or chemically treated or arranged to further address multipactor, allowing operation at reduced magnetic field strengths. A thin layer of molybdenum oxide may be coated on the anode, and/or a source of molybdenum may be provided in the cathode to form or sustain such a layer in operation.

US Patent:

6752029, Jun 22, 2004

Filed:

May 3, 2002

Appl. No.:

10/138272

Inventors:

Richard Madden - Groton MA
Daniel Joseph McCarthy - Cambridge MA
Gary L. Thomas - Hingham MA

Assignee:

BBNT Solutions LLC - Cambridge MA

International Classification:

G01L 112

US Classification:

7386269

Abstract:

A variable reluctance load cell for measuring the static or slowly fluctuating load, or tension, on devices is contained in a support tube. A sensor in the tube utilizes opposing C and I shaped magnetic cores attached to opposing ends of the support tube. A magnetic circuit is formed having an inductance defined by the size of the gap between the magnetic cores with the reluctance dominated by the gap. The sensor inductance is coupled with a fixed, predetermined capacitance in a resonant LC circuit, and the resonant frequency is a function of the gap. The sensor is in a cavity within the tube, and the cavity is sealed in a manner that prevents water or other damaging agents from entering the sensor. In this manner, mounting the sensor and tube to a static device and measuring the AC voltage at the sensor, the amount of load, or stress can be determined.

US Patent:

7493827, Feb 24, 2009

Filed:

Sep 30, 2005

Appl. No.:

11/240683

Inventors:

Richard Madden - Groton MA, US
Daniel Joseph McCarthy - Cambridge MA, US
Gary L. Thomas - Hingham MA, US

Assignee:

Oil States Industries, Inc. - Arlington TX

International Classification:

G01B 5/00

US Classification:

73779

Abstract:

A variable reluctance load cell for measuring the static or slowly fluctuating load, or tension, on devices is contained in a support tube. A sensor in the tube utilizes opposing C and I shaped magnetic cores attached to opposing ends of the support tube. A magnetic circuit is formed having an inductance defined by the size of the gap between the magnetic cores with the reluctance dominated by the gap. The sensor inductance is coupled with a fixed, predetermined capacitance in a resonant LC circuit, and the resonant frequency is a function of the gap. The sensor is in a cavity within the tube, and the cavity is sealed in a manner that prevents water or other damaging agents from entering the sensor. In this manner, mounting the sensor and tube to a static device and measuring the AC voltage at the sensor, the amount of load, or stress can be determined.

US Patent:

20050028606, Feb 10, 2005

Filed:

May 17, 2004

Appl. No.:

10/848525

Inventors:

Richard Madden - Groton MA, US
Daniel McCarthy - Cambridge MA, US
Gary Thomas - Hingham MA, US

Assignee:

BBNT SOLUTIONS LLC - Cambridge MA

International Classification:

G01L001/00

US Classification:

073779000

Abstract:

A variable reluctance load cell for measuring the static or slowly fluctuating load, or tension, on devices is contained in a support tube. A sensor in the tube utilizes opposing C and I shaped magnetic cores attached to opposing ends of the support tube. A magnetic circuit is formed having an inductance defined by the size of the gap between the magnetic cores with the reluctance dominated by the gap. The sensor inductance is coupled with a fixed, predetermined capacitance in a resonant LC circuit, and the resonant frequency is a function of the gap. The sensor is in a cavity within the tube, and the cavity is sealed in a manner that prevents water or other damaging agents from entering the sensor. In this manner, mounting the sensor and tube to a static device and measuring the AC voltage at the sensor, the amount of load, or stress can be determined.