Patents by Inventor James Gray Stevenson

James Gray Stevenson 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).

  • Mine roof supports
    Patent number: 4002036
    Abstract: A mine roof support of the type having a canopy supported from a base structure by hydraulically extensible legs and a cantilever roof-engaging member pivotally attached to the forward end of the canopy, is provided with a selectively positionable laterally extending cantilever member by means of which the effective roof-engaging surface of the canopy can be extended, the lateral cantilever member being optionally provided with a forwardly projecting cantilever member by means of which the effective width of the roof-engaging member can also be extended.
    Type: Grant
    Filed: May 9, 1975
    Date of Patent: January 11, 1977
    Assignee: Gullick Dobson Limited
    Inventors: Ian Campbell Jeffrey, James Gray Stevenson