Patents by Inventor Kjell L. Dahl

Kjell L. Dahl 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: 6679024
    Abstract: A high strength grouted pipe coupler by which either a pair of spaced, axially aligned steel reinforcement bars (i.e. rebars) are reliably spliced to one another or a single reinforcement bar is spliced to a flat steel plate to form a T-headed bar configuration. The reinforcement bars are surrounded by a spiral reinforcing spring within a hollow cylindrical sleeve or tube. The coupler tube is filled with an epoxy or cement based grout within which the reinforcement bars and the reinforcing spring are embedded. Set screws are moved through the coupler tube to maintain the position of the reinforcement bars prior to the coupler tube being filled with epoxy or cement. The pipe coupler herein disclosed has application for connecting together contiguous columns, walls, beams and similar structures to enable buildings, parking garages, bridges, subways and airports to be better able to survive a seismic event.
    Type: Grant
    Filed: February 26, 2002
    Date of Patent: January 20, 2004
    Inventor: Kjell L. Dahl
  • Publication number: 20030159395
    Abstract: A high strength grouted pipe coupler by which either a pair of spaced, axially aligned steel reinforcement bars (i.e. rebars) are reliably spliced to one another or a single reinforcement bar is spliced to a flat steel plate to form a T-headed bar configuration. The reinforcement bars are surrounded by a spiral reinforcing spring within a hollow cylindrical sleeve or tube. The coupler tube is filled with an epoxy or cement based grout within which the reinforcement bars and the reinforcing spring are embedded. Set screws are moved through the coupler tube to maintain the position of the reinforcement bars prior to the coupler tube being filled with epoxy or cement. The pipe coupler herein disclosed has application for connecting together contiguous columns, walls, beams and similar structures to enable buildings, parking garages, bridges, subways and airports to be better able to survive a seismic event.
    Type: Application
    Filed: February 26, 2002
    Publication date: August 28, 2003
    Inventor: Kjell L. Dahl
  • Patent number: 6192647
    Abstract: A high strength grouted pipe coupler by which pairs of spaced axially aligned steel reinforcement bars (i.e. rebars) are reliably spliced to one another for the purpose of connecting together and providing continuous support for contiguous columns, walls, beams, and similar structures to enable buildings, parking structures, bridges, subways, and airports, to be better able to survive a seismic event. The coupler includes a hollow steel pipe to receive opposing ends of the pair of reinforcement bars. A first of the reinforcement bars is upset to include a relatively wide head, and a relatively rigid spiral wire surrounds the upset head of the first reinforcement bar at the interior of the hollow pipe. The hollow pipe is filled with a cement grout which engulfs the upset head of the first reinforcement bar and the spiral wire extending therearound.
    Type: Grant
    Filed: April 15, 1999
    Date of Patent: February 27, 2001
    Inventor: Kjell L. Dahl
  • Patent number: 5729952
    Abstract: Methods and apparatus for making and assembling reliable mechanical rebar couplers so that a short upstand of rebar that protrudes from an existing concrete structure can be connected to a new rebar at a retrofit work site out in the field so as to provide a connection between a new and the existing structure. According to a first embodiment, one end of the protruding upstand is upset, and a threaded male coupling member surrounds the protruding upstand behind the upset end thereof. The threaded male coupling member is mated to a threaded female coupling member that is affixed to the new rebar such that the upset end of the upstand is retained between the male and female coupling members. According to a second embodiment, one end of each of the protruding upstand and the new rebar is upset, and a threaded male coupling member surrounds the protruding upstand and the new rebar behind the respective upset ends thereof.
    Type: Grant
    Filed: December 11, 1995
    Date of Patent: March 24, 1998
    Inventor: Kjell L. Dahl
  • Patent number: 5669196
    Abstract: A relatively low cost, easy to install reinforcement coupler to be interconnected between a pair of opposing reinforcement steel bars that are either embedded in and protrude outwardly from adjacent precast concrete structures or form part of the reinforcement of a prefabricated reinforcement element or cast in place concrete member. An eyelet is welded to the protruding end of each reinforcement steel bar. A pair of steel coupler plates having bolt holes formed through each end thereof extends between opposite sides of the reinforcement steel bars so that the eyelets of the reinforcement steel bars are sandwiched between the coupler plates and the bolt holes at the ends of the coupler plates are axially aligned with respective ones of the eyelets. A threaded bolt is then inserted through the bolt holes in each of the ends of each of the pair of coupler plates as well as the eyelets disposed therebetween.
    Type: Grant
    Filed: February 13, 1996
    Date of Patent: September 23, 1997
    Inventor: Kjell L. Dahl