Patents by Inventor Dennis M. Lettkeman

Dennis M. Lettkeman 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: 10260241
    Abstract: An improved resilient wallboard channel constructed and arranged for attachment to a surface of a framing member and accommodating standard fasteners. Included on the present channel is a first, generally planar surface having an elongate edge, an inclined web disposed along the elongate edge and projecting at an oblique angle relative to the first surface, a web edge of the inclined web opposite the first surface is shared with a second, generally planar surface, a stop flange, which is shorter than the inclined web, projects from a stop flange edge of the second surface opposite the inclined web, and the first surface and the web edge are separated by at least ¾-inch measured normally from the framing member surface.
    Type: Grant
    Filed: September 14, 2017
    Date of Patent: April 16, 2019
    Assignee: UNITED STATES GYPSUM COMPANY
    Inventors: Raymond A. Kaligian, II, Dennis M. Lettkeman, Peter A. MacDonald, Brett Fleury, Randy Mullet
  • Publication number: 20190078335
    Abstract: An improved resilient wallboard channel constructed and arranged for attachment to a surface of a framing member and accommodating standard fasteners. Included on the present channel is a first, generally planar surface having an elongate edge, an inclined web disposed along the elongate edge and projecting at an oblique angle relative to the first surface, a web edge of the inclined web opposite the first surface is shared with a second, generally planar surface, a stop flange, which is shorter than the inclined web, projects from a stop flange edge of the second surface opposite the inclined web, and the first surface and the web edge are separated by at least ¾-inch measured normally from the framing member surface.
    Type: Application
    Filed: September 14, 2017
    Publication date: March 14, 2019
    Inventors: Raymond A. KALIGIAN, II, Dennis M. LETTKEMAN, Peter A. MACDONALD, Brett FLEURY, Randy MULLET
  • Patent number: 8343273
    Abstract: A method for preparing a modified beta-stucco from calcined natural rock gypsum that includes preparing a solution of liquid diethylene-triamine-pentaacetic acid in water, applying the solution onto beta-stucco while hot from the calciner, forming a wetted beta-stucco, and allowing the wetted stucco to dry and heal, forming the modified beta-stucco.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: January 1, 2013
    Assignee: United States Gypsum Company
    Inventors: Dennis M. Lettkeman, Raymond A. Kaligian, II, Michael L. Cloud, John W. Wilson
  • Patent number: 7932308
    Abstract: An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.
    Type: Grant
    Filed: July 30, 2009
    Date of Patent: April 26, 2011
    Assignee: United States Gypsum Company
    Inventors: Dennis M. Lettkeman, Michael P. Shake, Qingxia Liu, John W. Wilson, Brian Randall, David R. Blackburn
  • Patent number: 7776462
    Abstract: A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.
    Type: Grant
    Filed: November 10, 2009
    Date of Patent: August 17, 2010
    Assignee: United States Gypsum Company
    Inventors: Qingxia Liu, Michael P. Shake, David R. Blackburn, John W. Wilson, Brian Randall, Dennis M. Lettkeman
  • Patent number: 7767019
    Abstract: A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.
    Type: Grant
    Filed: June 9, 2006
    Date of Patent: August 3, 2010
    Assignee: United States Gypsum Company
    Inventors: Qingxia Liu, Michael P. Shake, David R. Blackburn, John W. Wilson, Brian Randall, Dennis M. Lettkeman
  • Publication number: 20100056655
    Abstract: A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.
    Type: Application
    Filed: November 10, 2009
    Publication date: March 4, 2010
    Inventors: Qingxia Liu, Michael P. Shake, David R. Blackburn, John W. Wilson, Brian Randall, Dennis M. Lettkeman
  • Publication number: 20090292045
    Abstract: An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.
    Type: Application
    Filed: July 30, 2009
    Publication date: November 26, 2009
    Inventors: Dennis M. Lettkeman, Michael P. Shake, Qingxia Liu, John W. Wilson, Brian Randall, David R. Blackburn
  • Patent number: 7608347
    Abstract: An improved gypsum slurry that includes water, calcium sulfate hemihydrate, a polycarboxylate dispersant and a modifier. The modifier is chemically configured to improve the efficacy of the polycarboxylate dispersant. Preferred modifiers include cement, lime, slaked lime, soda ash, carbonates, silicates and phosphates.
    Type: Grant
    Filed: June 9, 2006
    Date of Patent: October 27, 2009
    Assignee: United States Gypsum Company
    Inventors: Dennis M. Lettkeman, Michael P. Shake, Qingxia Liu, John W. Wilson, Brian Randall, David R. Blackburn
  • Patent number: 7572329
    Abstract: In a method of making a gypsum slurry, a polycarboxylate dispersant, a modifier and a hydraulic material comprising stucco are selected for use in the slurry. These components are then combined with water to form a slurry, where the modifier is added to the slurry prior to formation of a slurry phase by the water, the stucco and the dispersant. The modifier has been shown to be less effective when added after the dispersant and stucco have been contacted in an aqueous slurry. In a preferred embodiment, an amount of stucco is obtained and the modifier and dispersant are selected. A predissolved solution of a dispersant and modifier is prepared in water to form a solution prior to the addition of the stucco. After mixing the solution, the stucco is added to form the slurry. Optionally, the slurry is then shaped into a product and allowed to set.
    Type: Grant
    Filed: June 9, 2006
    Date of Patent: August 11, 2009
    Assignee: United States Gypsum Company
    Inventors: Qingxia Liu, David R. Blackburn, Michael P. Shake, Brian Randall, John W. Wilson, Dennis M. Lettkeman
  • Patent number: 7572328
    Abstract: A slurry is made including water, at least 50% by weight calcium sulfate hemihydrate, and a specific polycarboxylate dispersant prepared using at least three repeating units. A first repeating unit is a vinyl ether-type repeating unit. A second repeating unit includes a maleic acid-type repeating unit. A third repeating unit includes an acrylic acid-type repeating unit. The polymer dispersant has a molecular weight of from about 20,000 to about 80,000 Daltons. The slurry made from this composition can be made at reduced water levels to speed drying and reduce drying costs.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: August 11, 2009
    Assignee: United States Gypsum Company
    Inventors: Dennis M. Lettkeman, Qingxia Liu, John W. Wilson, Brian S. Randall, David R. Blackburn, Michael P. Shake
  • Patent number: 7504165
    Abstract: A composition is disclosed for a mixture to be used in conjunction with water for preparing a slurry that hydrates to form a high strength flooring compound. The mixture includes from about 50% to about 98% by weight calcium sulfate hemihydrate. A three repeating unit polycarboxylate dispersant is included in the mixture in amounts from about 0.2% to about 10% by weight. The repeating units include a polyether repeating unit, an acrylic acid-type repeating unit and a maleic acid-type repeating unit. A modifier that enhances the efficacy of the dispersant is also a component of the mixture. When combined with recommended amounts of water, a slurry is formed that is useful as a flooring composition.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: March 17, 2009
    Assignee: United States Gypsum Company
    Inventors: Dennis M. Lettkeman, John W. Wilson, William K. Bedwell
  • Publication number: 20060278127
    Abstract: A gypsum slurry includes water, a hydraulic component including stucco and a polycarboxylate dispersant. The dispersant has two repeating units wherein the first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt, and the second repeating unit is a vinyl or allyl group bound to a polyether by an ether linkage. The slurry can be made into a gypsum panel.
    Type: Application
    Filed: June 14, 2005
    Publication date: December 14, 2006
    Inventors: Qingxia Liu, Michael P. Shake, David R. Blackburn, John W. Wilson, Brian Randall, Dennis M. Lettkeman