Patents by Inventor Nicolaas J. H. Strydom

Nicolaas J. H. Strydom 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: 4912877
    Abstract: A security door comprises an outer frame for closing off a doorway and door hinge means connected to the outer frame for hingedly mounting the outer frame in the doorway. An opening is provided through the outer frame and a plurality of security bars are mounted on the outer frame and extend across the opening. A closure member for closing off the opening is provided, closure member hinge means being connected to the closure member whereby the closure member is pivotally mounted on the outer frame. An insert is provided by the closure member, which insert projects into the opening in the outer frame and occupies said opening when the closure member is in its closed condition, the insert having a plurality of recesses in the form of elongate grooves for respectively receiving the security bars when the closure member is in its closed condition with the bars at least partially enclosed and concealed therein.
    Type: Grant
    Filed: February 17, 1989
    Date of Patent: April 3, 1990
    Inventor: Nicolaas J. H. Strydom