Patents by Inventor Bruce A. Wittrup

Bruce A. Wittrup 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).

  • Press cycle reduction for wet pressed hardboard
    Patent number: 4411738
    Abstract: The production of hardboard by the wet press process is speeded up by the incorporation of finely divided fibers in an aqueous slurry of otherwise fast draining wood fibers and a thermosetting binder so that a barrier of said fine fibers is formed during hot pressing of the mat and steam pressure is built up in the mat. The high pressure permits a curing temperature of from about 300.degree. F. to about 350.degree. F. in the core of the mat and a concomitant acceleration of the cure of the binder.
    Type: Grant
    Filed: April 30, 1982
    Date of Patent: October 25, 1983
    Assignee: United States Gypsum Company
    Inventors: Bruce A. Wittrup, Kendall D. White, Jr.
  • Paper-backed acoustical tile
    Patent number: 4016234
    Abstract: An acoustical tile comprising a relatively thin, flat body of acoustical composition including fibrous material and a binder, and a paper backing affixed thereto having a fire-retardant material dispersed therein, the outer facing surface of the tile being either planar or slightly convex.
    Type: Grant
    Filed: June 20, 1975
    Date of Patent: April 5, 1977
    Assignee: United States Gypsum Company
    Inventors: Herbert L. Warren, Bruce A. Wittrup
  • Paper-backed acoustical tile
    Patent number: 4010817
    Abstract: An acoustical tile comprising a relatively thin, flat body of acoustical composition including fibrous material and a binder, and a paper backing affixed thereto having a fire-retardant material dispersed therein, the outer facing surface of the tile being either planar or slightly convex.
    Type: Grant
    Filed: May 20, 1974
    Date of Patent: March 8, 1977
    Assignee: United States Gypsum Company
    Inventors: Herbert L. Warren, Bruce A. Wittrup