Patents by Inventor John B. Campbell

John B. Campbell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • DYNAMIC HEATING OF A DIFFERENTIAL MOBILITY SPECTROMETER CELL
    Publication number: 20240085373
    Abstract: A method of operating a differential mobility spectrometer (DMS) includes providing a heater disposed proximate a ceramic body of a DMS cell. A first control voltage is applied to the heater. A first threshold is detected by a first sensor disposed within a curtain plate that substantially surrounds the DMS cell. A second control voltage is applied to the heater based at least in part on the detected first threshold. During application of the second control voltage, a mass spectrometry analysis of a gas within the DMS cell is performed.
    Type: Application
    Filed: February 23, 2022
    Publication date: March 14, 2024
    Applicant: DH Technologies Development Pte. Ltd.
    Inventors: John L. CAMPBELL, Bradley B. SCHNEIDER, Thomas R. COVEY
  • Asymmetrical column assembly for high-cycle fatigue test machines
    Patent number: 6813960
    Abstract: A column assembly for use in conjunction with a test machine, for inducing high-cycle fatigue (at kilohertz vibration rates) in a specimen of a material under test. The column assembly has isolation masses, a specimen grip, and two actuators, the latter for imparting dynamic forces to the test specimen. The actuators are arranged on the column assembly asymmetrically relative to the test specimen.
    Type: Grant
    Filed: August 19, 2002
    Date of Patent: November 9, 2004
    Assignee: Southwest Research Institute
    Inventors: Thomas E. Owen, David L. Davidson, John B. Campbell, Andrew Nagy
  • Fretting fixture for high-cycle fatigue test machines
    Patent number: 6601456
    Abstract: A fretting fixture accessory for a_test machine (10) that induces high-cycle fatigue (at kilohertz vibration rates) in a specimen of a material under test. The fretting fixture (20) is clamped to the test specimen (21), for the purpose of testing for fretting damage. The fixture (20) is designed to provide both the normal and shearing forces that result in fretting damage.
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: August 5, 2003
    Assignee: Southwest Research Institute
    Inventors: David L. Davidson, Thomas E. Owen, John B. Campbell
  • Dehydrohalogenation of 3,4-dichloro-1-butene
    Patent number: 3981937
    Abstract: Dichlorobutene is treated with aqueous inorganic alkali in the presence of a catalytic amount of a quaternary ammonium compound catalyst to dehydrochlorinate the dichlorobutene and directly form chloroprene.
    Type: Grant
    Filed: February 13, 1970
    Date of Patent: September 21, 1976
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: John B. Campbell, Robert Edward Tarney
  • Powered air inflator
    Patent number: D402997
    Type: Grant
    Filed: August 5, 1997
    Date of Patent: December 22, 1998
    Assignee: Campbell Hausfeld/ Scott Fetzer Company
    Inventors: John B. Campbell, Kurt W. Kamka, Randy A. Smith