Patents by Inventor David Andrew Gilchrist

David Andrew Gilchrist 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: 5853053
    Abstract: The invention relates to stabilisation devices for down-hole drill motors and provides such a device comprising a tubular motor body portion (18) adapted for rotational movement on a selective basis to provide a steering capability, a motor shaft (16) passing through the body portion (18). A lower end portion of the shaft provides an end surface (20) for attachment of a tool (32) by a bit attachment means (28, 30) provided within a lower end of the shaft. The lower end of the shaft (16) has an external diameter less than the internal diameter of the motor body portion so as to be either completely or partially received within the body portion to enable the overhang distance between the operating faces of the bit and the stabiliser on the bearing housing to be as short as possible. Alternatively the end face (20) of the shaft may project slightly (.ltoreq.5 cm) from the end face (22) of the motor body portion (18).
    Type: Grant
    Filed: September 19, 1996
    Date of Patent: December 29, 1998
    Assignee: Neyrfor-Weir Limited
    Inventors: David Andrew Gilchrist, Andrew McPherson Downie