Patents by Inventor Lawrence R. Barrett

Lawrence R. Barrett 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).

  • Evacuation pump control for a centrifuge instrument
    Patent number: 4857811
    Abstract: A centrifuge instrument has a vacuum pump responsive to a rotor recognition arrangement. The pump is operative to provide a predetermined pressure level in the chamber compatible with which one of a plurality of rotors is mounted within the chamber. The requested angular velocity can also be used to control the pressure level in the chamber.
    Type: Grant
    Filed: March 31, 1988
    Date of Patent: August 15, 1989
    Assignee: E. I. Du Pont De Nemours and Company
    Inventors: Lawrence R. Barrett, Ronald C. Robertson, Mark A. Sullivan
  • Misalignment system for a microtome
    Patent number: 4395075
    Abstract: A misalignment pivot system for permitting pivotal movement of a main pivot socket in a direction along an axis Q-Q' connecting a pair of main pivot balls includes a pair of misalignment pivot balls one of which is captured between a fixed socket and a V-groove. The misalignment pivot system permits pivotal movement of the main pivot socket without the imposition of a restoring force.
    Type: Grant
    Filed: March 24, 1982
    Date of Patent: July 26, 1983
    Assignee: E. I. Du Pont de Nemours & Co.
    Inventors: Lawrence R. Barrett, Allan J. Weiner
  • Method and apparatus for automatically positioning centrifuge tubes
    Patent number: 3951334
    Abstract: A locking ring having castellations is provided for a swinging bucket-type centrifuge. The locking ring is constructed such that the castellations can be angularly positioned relative to the rotor to either block or permit the buckets to swing outwardly during operation. The angular positioning of the castellations relative to the buckets is accomplished by relative angular acceleration and deceleration between the rotor and the locking ring.
    Type: Grant
    Filed: July 7, 1975
    Date of Patent: April 20, 1976
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: John A. Fleming, Lawrence R. Barrett