Patents by Inventor Duncan R. Stewart

Duncan R. Stewart 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: 7307271
    Abstract: A nano-colonnade structure-and methods of fabrication and interconnection thereof utilize a nanowire column grown nearly vertically from a (111) horizontal surface of a semiconductor layer to another horizontal surface of another layer to connect the layers. The nano-colonnade structure includes a first layer having the (111) horizontal surface; a second layer having the other horizontal surface; an insulator support between the first layer and the second layer that separates the first layer from the second layer. A portion of the second layer overhangs the insulator support, such that the horizontal surface of the overhanging portion is spaced from and faces the (111) horizontal surface of the first layer. The structure further includes a nanowire column extending nearly vertically from the (111) horizontal surface to the facing horizontal surface, such that the nanowire column connects the first layer to the second layer.
    Type: Grant
    Filed: November 5, 2004
    Date of Patent: December 11, 2007
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: M. Saif Islam, Philip J. Kuekes, Shih-Yuan Wang, Duncan R. Stewart, Shashank Sharma
  • Patent number: 7227379
    Abstract: One embodiment of the present invention is an array of nanoscale latches interconnected by a nanowire bus to form a latch array. Each nanoscale latch in the nanoscale-latch array serves as a nanoscale register, and is driven by a nanoscale control line. Primitive operations for the latch array can be defined as sequences of one or more inputs to one or more of the nanowire data bus and nanoscale control lines. In various latch-array embodiments of the present invention, information can be transferred from one nanoscale latch to another nanoscale latch in a controlled fashion, and sequences of information-transfer operations can be devised to implement arbitrary Boolean logic operations and operators, including NOT, AND, OR, XOR, NOR, NAND, and other such Boolean logic operators and operations, as well as input and output functions.
    Type: Grant
    Filed: July 27, 2005
    Date of Patent: June 5, 2007
    Assignee: Hewlett-Packard Develoment Company, L.P.
    Inventors: Gregory S. Snider, Philip J. Kuekes, Duncan R. Stewart
  • Patent number: 5357847
    Abstract: A fluid-pressure operated actuator has a body and an end cap which when telescoped in the body provides confronting grooves which receive a circlip in the form of a flexible length of wire spring. The end cap carries an O-ring seal axially only outwards of the circlip. Relative rotation between the body and end cap draws the circlip into position. A threaded plug, which may be secured to the outer end of the circlip, sealingly connects the body and end cap and may permit relative axial and angular movement.
    Type: Grant
    Filed: April 17, 1991
    Date of Patent: October 25, 1994
    Assignee: Hytork Actuators Limited
    Inventor: Duncan R. Stewart
  • Patent number: 4716815
    Abstract: A fluid-pressure-operated actuator is arranged to have three set positions and preferably a fail-safe characteristic in one of the three positions. In one embodiment an H-section piston moves in an actuator body and is set in its two extreme positions by fluid pressure introduced behind the web of the piston through one or other of spindles having heads and bores. To set the intermediate position, annular pistons can be moved along the spindles by pressure introduced at inlet pipes in the body until those pistons contact the heads of the spindles. The spindles are adjustable in the body to set the intermediate position of the piston and adjusting bolts set the extreme positions of the piston. For a fail-safe situation, a reservoir and control valve are introduced. As an alternative to annular pistons springs acting through top-hat shaped buffers can be used giving a fail-safe situation in the intermediate position of the piston.
    Type: Grant
    Filed: April 18, 1984
    Date of Patent: January 5, 1988
    Assignee: Hytork Actuators Limited
    Inventor: Duncan R. Stewart
  • Patent number: 4651627
    Abstract: A fluid-pressure operated actuator comprises a housing, at least one piston reciprocable in the housing, a rotatable output shaft having a portion thereof within the housing, means operatively connecting the piston and the output shaft, and stop means mounted on the housing and engageable with the shaft portion for limiting rotary movement of the shaft.
    Type: Grant
    Filed: February 10, 1986
    Date of Patent: March 24, 1987
    Assignee: Hytork Actuators Limited
    Inventor: Duncan R. Stewart
  • Patent number: 4496071
    Abstract: A pressure vessel 11 has a hollow member 10, an end closure 19 in telescope relationship with the hollow member, a flexible continuous element 26 extending around the end closure and operatively connecting the closure and the hollow member, a passage 14 for insertion and withdrawal of the continuous element, a removable plug 18 closing said passage for resisting removal of the continuous element, and annular seals 24, 25 between the hollow member and the end closure on both sides of the continuous element. The continuous element may be a length of wire spring.
    Type: Grant
    Filed: July 15, 1983
    Date of Patent: January 29, 1985
    Assignee: Valve Conversions Limited
    Inventor: Duncan R. Stewart