Patents by Inventor David W. Walker

David W. Walker 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: 6186528
    Abstract: A wheelchair and trailer system comprising a trailer which has a planar support in a generally rectangular configuration. The trailer has a front edge, a rear edge and two side edges. Also provided is a forwardly extending rod with an aperture therethrough for positioning over the hole of the wheelchair. It also has an associated pin to selective effect the coupling between the trailer and the wheelchair. Two rear wheels are provided for rotation about a common horizontal axis coupled to the trailer adjacent to the rear edge. A front wheel is provided for rotation about a horizontal axis coupled to the trailer adjacent to the front edge. The front wheel is secured to the forwardly extending rod to allow rotation of the front wheel about a vertical axis for steering purposes.
    Type: Grant
    Filed: August 13, 1998
    Date of Patent: February 13, 2001
    Inventors: David W. Walker, Sr., Janice Walker
  • Patent number: 5616299
    Abstract: An apparatus for dispensing reagent spheres from a vial includes a housing with an inlet through which the reagent spheres are received from the vial. Within the housing is a dispensing tube which forms a passageway for the reagent spheres and which has a first relatively large section in communication with the inlet and a funnel section in which the passageway reduces in cross section to a narrower linearizing section. The cross sectional area of the linearizing section is only slightly larger than one of the reagent spheres being dispensed. A metering shaft extends across and blocks the linearizing section of the passageway. The metering shaft has a depression for conveying one reagent sphere at a time between portions of linearizing section when the metering shaft is rotated 180 degrees. A gear on the metering shaft meshes with teeth on a plunger which is slidably mounted to the housing.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: April 1, 1997
    Assignee: Pharmacia Biotech, Inc.
    Inventors: David W. Walker, Brent A. Burdick, James F. Jolly, Daniel D. Zender
  • Patent number: 5609270
    Abstract: A dispenser include a housing with an inlet through which reagent pills are received from a vial. Within the housing is a dispensing tube that forms a pill passageway which has a first portion of relatively large cross section adjacent the inlet and a funnel portion in which the passageway reduces in cross section to a narrower linearizing portion. The dispensing tube has a series of ridges on an exterior surface. A metering shaft extends across the linearizing portion and has a depression for conveying one reagent pill at a time between sections of the linearizing portion when the metering shaft is rotated. A gear on the metering shaft is meshes with teeth on a plunger which is slidably mounted in the housing. The plunger also has a member projecting therefrom and against dispensing tube. A user pressing the plunger causes the metering shaft to rotate transferring a reagent pill to a portion of the passageway connected to the outlet of the housing and thereby ejects that reagent pill from the housing.
    Type: Grant
    Filed: November 27, 1995
    Date of Patent: March 11, 1997
    Assignee: Pharmacia Biotech, Inc.
    Inventor: David W. Walker
  • Patent number: 5603899
    Abstract: An apparatus, for simultaneously separating multiple samples into their constituents, includes a column manifold which has a plate with a plurality of apertures therethrough. A plurality of support tubes extend from the plate and each support tube has a passage in communication with one of the apertures. The column manifold also includes a fitting to which a vacuum source can the connected, thus enabling the apparatus to be used with both a centrifuge and a vacuum source. A separate separation column is removably received in each support tube and projects through the associated aperture. A collection plate has a plurality of wells arranged so that each well is aligned with a different support tube when the column manifold is placed against the collection plate. This alignment enables each well to receive material expelled from the separation column received in the corresponding support tube.
    Type: Grant
    Filed: April 12, 1995
    Date of Patent: February 18, 1997
    Assignee: Pharmacia Biotech, Inc.
    Inventors: Phillip P. Franciskovich, David W. Walker, Cynthia A. Mielke, David R. Boyer
  • Patent number: 5565318
    Abstract: A reagent semi-sphere is disclosed comprising at least one biological reagent and a glass forming filler material in a concentration sufficient to facilitate formation of a glassy, porous composition, wherein the reagent semi-sphere is room temperature stable, water soluble, and has a T.sub.g above room temperature.
    Type: Grant
    Filed: September 2, 1994
    Date of Patent: October 15, 1996
    Assignee: Pharmacia Biotech, Inc.
    Inventors: David W. Walker, Robert A. DiFrancesco, Jean A. Heaster, James F. Jolly, Chris R. Lively, Suzanne B. Treml
  • Patent number: 5434328
    Abstract: This invention relates to a process for restructuring an olefinic feedstock rich in linear olefins into a product olefin of narrower composition which is richer in branched olefins than the starting feedstock. Such restructuring is achieved by contacting the feedstock with an unmodified or partially modified tectometallosilicate of the Theta-1 type at relatively low temperatures. The product olefins are valuable as petrochemical feedstock for producing polyolefins, alcohols, ethers and other oxygenates, surfactants, alkyl aromatics and oligomers useful as gasoline blending components.
    Type: Grant
    Filed: April 30, 1987
    Date of Patent: July 18, 1995
    Assignee: The British Petroleum Company p.l.c.
    Inventors: Sami A. I. Barri, Rabaab Tahir, David W. Walker
  • Patent number: D377669
    Type: Grant
    Filed: August 21, 1995
    Date of Patent: January 28, 1997
    Inventor: David W. Walker