Patents by Inventor Robert L. Cragg

Robert L. Cragg 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: 8590086
    Abstract: A wear resisting span lock system for bascule bridges includes a normally-inactive hydraulic lockbar shoe expander operable to minimize sliding engagement of the lockbar with its guiding and receiving shoes only during bridge opening and closing operations.
    Type: Grant
    Filed: April 11, 2013
    Date of Patent: November 26, 2013
    Assignee: Steward Machine Co., Inc.
    Inventor: Robert L. Cragg
  • Patent number: 7020924
    Abstract: An adjustable static stabilizer used to ameliorate shock loading. The static stabilizer has a housing forming a chamber and an upwardly-open cylindrical carrier moveably mounted in the chamber. A plurality of spring washers are mounted in the carrier, and a shoe cap extends transverse to the carrier for engaging the spring washers therein. A tie rod interconnects the shoe cap and the carrier for displacement of the shoe cap relative to the housing, and a threaded means is disposed between the housing and the carrier for rotatably mounting the carrier in the housing which is operable upon rotation of the shoe cap relative to the housing to enable the overall height of the stabilizer to be adjusted.
    Type: Grant
    Filed: March 29, 2004
    Date of Patent: April 4, 2006
    Assignee: Steward Machine Co., Inc.
    Inventor: Robert L. Cragg
  • Patent number: 6588041
    Abstract: A drawbridge span lock system in which a locking bar longitudinally slides between wear shoes in each of guide and socket assemblies. The wear shoes are pre-loaded to a selected level by springs within the assemblies to maintain continuous contact of the shoes with the locking bar under no-load operating conditions of the bridge. Threaded adjusting carriers externally accessible in each assembly enable the springs to be precisely pre-loaded to any level within a design range.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: July 8, 2003
    Assignee: Steward Machine Co., Inc.
    Inventors: Robert L. Cragg, James F. Alison, III
  • Patent number: 5327605
    Abstract: An energy absorbing span lock system for drawbridges, such as a double-leaf bascule leaf span. A retractable and extendible connector mounted on one leaf of the span engages a receiver on the other leaf. Resilient energy absorbing shoes in the receiver accept the connector and allow relative deflection between the leaf ends caused by vehicular traffic.
    Type: Grant
    Filed: March 31, 1993
    Date of Patent: July 12, 1994
    Assignee: Steward Machine Co., Inc.
    Inventor: Robert L. Cragg