Patents by Inventor Charles W. Lehnert

Charles W. Lehnert 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).

  • Patent number: 5791109
    Abstract: Finishing systems and roof decks are provided which include a gypsum board having a set gypsum core faced with a fibrous mat. The gypsum core includes one or more additives which are effective in simultaneously improving the water and fire resistance of the board. In preferred embodiments, the board has sufficient water-resistant additive for absorbing less than about 10% water in an ASTM C-473 test.
    Type: Grant
    Filed: November 6, 1996
    Date of Patent: August 11, 1998
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 5704179
    Abstract: Finishing systems and roof decks are provided which include a gypsum board having a set gypsum core faced with a fibrous mat. The gypsum core includes one or more additives which are effective in simultaneously improving the water and fire resistance of the board. In preferred embodiments, the board has sufficient water-resistant additive for absorbing less than about 10% water in an ASTM C-473 test.
    Type: Grant
    Filed: January 26, 1994
    Date of Patent: January 6, 1998
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 5644880
    Abstract: Finishing systems and roof decks are provided which include a gypsum board having a set gypsum core faced with a fibrous mat. The gypsum core includes one or more additives which are effective in simultaneously improving the water and fire resistance of the board. In preferred embodiments, the board has sufficient water-resistant additive for absorbing less than about 10% water in an ASTM C-473 test.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: July 8, 1997
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 5371989
    Abstract: An exterior finishing system for a building, including particularly an exterior insulation system, which includes a fibrous mat-faced gypsum board, preferably a board in which the set gypsum core thereof is water resistant, and preferably one in which the set gypsum core is sandwiched between two sheets of porous glass mat, with the outer surface of at least one of said mats being substantially free of set gypsum, and means for preparing the board, including control of the viscosity of the aqueous gypsum slurry from which the set gypsum core of the board is formed. Also, the use of fibrous mat-faced gypsum board as the shaft liner panel in a shaft wall assembly.
    Type: Grant
    Filed: February 19, 1992
    Date of Patent: December 13, 1994
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 5319900
    Abstract: Finishing systems and roof decks are provided which include a gypsum board having a set gypsum core faced with a fibrous mat. The gypsum core includes one or more additives which are effective in simultaneously improving the water and fire resistance of the board. In preferred embodiments, the board has sufficient water-resistant additive for absorbing less than about 10% water in an ASTM C-473 test.
    Type: Grant
    Filed: May 6, 1993
    Date of Patent: June 14, 1994
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 5220762
    Abstract: Gypsum-containing boards, uses for these boards, and methods for making them are provided. The board includes a set gypsum core having a fibrous glass at disposed thereon. The core includes a water-resistant additive in at least a minimum amount sufficient to impart to the board an ASTM C-473 water absorption value of less than about 10%. This additive includes organohydrogenpolysiloxane resin added with a portion of the mixing water, or otherwise added in neat form to the process for preparing the slurry.
    Type: Grant
    Filed: June 27, 1991
    Date of Patent: June 22, 1993
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 5148645
    Abstract: Glass mat-faced gypsum boards having a set core containing gypsum dihydrate and at least a minimum amount of chopped fibers, as well as other optional fire-resistant additives, are provided. The resulting boards obtain superior fire resistance properties over conventional paper-faced boards of like thickness which include a similar amount of chopped glass fibers.
    Type: Grant
    Filed: August 6, 1991
    Date of Patent: September 22, 1992
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall, George F. Fowler, Jr., Ray W. Hinkel
  • Patent number: 4811538
    Abstract: A fire-resistant door comprises a core panel of mineral material, such as gypsum wallboard. A fiber mat, preferably comprising glass fibers, is at least partially embedded in each face of said core panel. An edge banding assembly disposed around the periphery of the core panel is centrally grooved to receive the panel edges. Facing sheets are affixed to the opposite sides of the edge banding assembly in spaced parallel relation to the core panel, and a spacer material at least partially fills the spaces between the facing sheets and the core panel.
    Type: Grant
    Filed: October 20, 1987
    Date of Patent: March 14, 1989
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, George F. Fowler, Jr.
  • Patent number: 4810569
    Abstract: An exterior finishing system for a building. including particularly an exterior insulation system, which includes a fibrous mat-faced gypsum board, preferably a board in which the set gypsum core thereof is water resistant, and preferably one in which the set gypsum core is sandwiched between two sheets of porous glass mat, with the outer surface of at least one of said mats being substantially free of set gypsum, and means for preparing the board, including control of the viscosity of the aqueous gypsum slurry from which the set gypsum core of the board is formed. Also, the use of fibrous mat-faced gypsum board as the shaft liner panel in a shaft wall assembly.
    Type: Grant
    Filed: March 2, 1987
    Date of Patent: March 7, 1989
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 4748771
    Abstract: A fire door comprising a core and edge banding, the principal ingredients of the core being expanded perlite, gypsum and cement, the edge banding comprising a strip of natural wood, a strip of a cast mixture of which the principal ingredient is gypsum and an intervening strip of plastic laminate.
    Type: Grant
    Filed: July 30, 1985
    Date of Patent: June 7, 1988
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, James R. Van Dyke, Ray W. Hinkel
  • Patent number: 4722866
    Abstract: A composition useful as the core of fire resistant gypsum board and comprising a major amount of set calcined gypsum and minor amounts of whisker fibers, glass fibers and clay.
    Type: Grant
    Filed: May 4, 1987
    Date of Patent: February 2, 1988
    Assignee: Georgia-Pacific Corporation
    Inventors: Glenn E. Wilson, Charles W. Lehnert
  • Patent number: 4695494
    Abstract: A fire-resistant article, for example, a fire door core comprising a major amount of expanded perlite in compressed form, an adhesive material, the major portion of which is starch, and preferably glass fibers, and a method for making the article by dry-mixing the ingredients substantially completely before water is added for the purpose of developing the adhesive characteristics of the starch.
    Type: Grant
    Filed: November 25, 1986
    Date of Patent: September 22, 1987
    Assignee: Georgia-Pacific Corporation
    Inventors: George F. Fowler, Jr., Charles W. Lehnert
  • Patent number: 4664707
    Abstract: A composition useful as the core of fire resistant gypsum board and comprising a major amount of set calcined gypsum and minor amounts of whisker fibers, glass fibers and clay.
    Type: Grant
    Filed: April 9, 1985
    Date of Patent: May 12, 1987
    Assignee: Georgia-Pacific Corporation
    Inventors: Glenn E. Wilson, Charles W. Lehnert
  • Patent number: 4647496
    Abstract: An exterior finishing system for a building, including particularly an exterior insulation system, which includes a fibrous mat-faced gypsum board, preferably a board in which the set gypsum core thereof is water resistant, and preferably one in which the set gypsum core is sandwiched between two sheets of porous glass mat, with the outer surface of at least one of said mats being substantially free of set gypsum, and means for preparing the board, including control of the viscosity of the aqueous gypsum slurry from which the set gypsum core of the board is formed. Also, the use of fibrous mat-faced gypsum board as the shaft liner panel in a shaft wall assembly.
    Type: Grant
    Filed: February 27, 1984
    Date of Patent: March 3, 1987
    Assignee: Georgia-Pacific Corporation
    Inventors: Charles W. Lehnert, Brian G. Randall
  • Patent number: 4343127
    Abstract: A fire door comprising a core and edge banding, the principal ingredients of the core being expanded perlite, gypsum and cement, and including, as minor ingredients, an organic binder, and having a density not greater than about 35 lbs./cu. ft. The banding comprises composite stiles and rails, each formed of a strip of wood and a strip of a cast mixture of which the principal ingredient is gypsum and including a binder and preferably also including fibers, unexpanded vermiculite and clay.
    Type: Grant
    Filed: January 15, 1981
    Date of Patent: August 10, 1982
    Assignee: Georgia-Pacific Corporation
    Inventors: Dale R. Greve, Charles W. Lehnert