Patents Assigned to David A. White
  • Patent number: 5324482
    Abstract: A pipette tip storage and dispensing system has a series of pipette tip holder cards each of which has a plurality of openings for holding a set of pipette tips extending partway through the openings in an upright orientation. The openings in each card match those in the other cards, and cards loaded with pipette tips can be stacked vertically with the pipette tips in one card extending into the open upper ends of the tips in the next adjacent card of the stack, to minimize storage space. An alignment device is arranged to hold the pipette tips in a card in a vertical orientation as the card is removed from the top of the stack and transferred to a pipette tip holder tray so that the pipette tips can be lowered into aligned openings in the holder tray with the card resting on the top wall of the tray.
    Type: Grant
    Filed: August 27, 1992
    Date of Patent: June 28, 1994
    Assignee: David A. White
    Inventors: Larry G. Scaramella, Jeffrey F. Boone, Robert W. Arnold, Charles O. Peinado, David A. White
  • Patent number: 5208438
    Abstract: A fixture for use in adjusting a laser type leveling instrument has a cradle mounted on a base and operative to support the instrument with its normally vertical axis disposed horizontally. A pentaprism is mounted on a rotable platform on the base to reflect a laser beam, emitted by an instrument in the cradle and impinging on the pentaprism, in a horizontal path. The rotatable platform for the pentaprism permits movement of the pentaprism from a first position in which the beam is directed forwardly and a second position in which the beam is reversed and reflected rearwardly.
    Type: Grant
    Filed: June 17, 1991
    Date of Patent: May 4, 1993
    Assignee: David White, Inc.
    Inventor: Robert L. Underberg
  • Patent number: 4993161
    Abstract: The laser beam level instrument includes a laser diode mounted on a pendulous platform suspended from a frame by gold plated Mylar strips which also serve as conductors for supplying power to the diode. The strips are mounted with a 180 degree twist to overcome resistance to flexing/bending so that the platform moves freely under the influence of gravity to provide automatic self-leveling. The diode operates on low d.c. voltage but if d.c. is applied to the strips the magnetic field around the Mylar strips will have sufficient force relative to the geomagnetic field to interfere with free pendulation. So 4.5 volts d.c. is stepped up and inverted to about 20 volts a.c. to avoid interference with the geomagnetic field and to reduce power loss across the gold plated strips. The a.c. voltage is then stepped down and converted back to d.c. voltage (2-3 volts) on the platform to power the diode.
    Type: Grant
    Filed: January 4, 1990
    Date of Patent: February 19, 1991
    Assignee: David White, Inc.
    Inventor: Henry S. Borkovitz
  • Patent number: D440506
    Type: Grant
    Filed: February 18, 2000
    Date of Patent: April 17, 2001
    Assignee: David White, L.L.C.
    Inventors: Torsten J. R. Blaetter, Alan D. Bengtson, Casey A. Ketterhagen
  • Patent number: D469369
    Type: Grant
    Filed: January 8, 2002
    Date of Patent: January 28, 2003
    Assignee: David White Instruments, LLC
    Inventor: William L. Durkin