The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 1992
Filed:
May. 31, 1991
Cary A Maurstad, Kingwood, TX (US);
James R Hall, Huffman, TX (US);
Hughes Tool Company, Houston, TX (US);
Abstract
An earth boring bit having a body, pressure compensating lubricating system and cantilevered bearing shaft with an annular seal surface and a radial seal surface. A cutter is rotatably secured to the bearing shaft, with an annular seal recess having radial and cylindrical seal surfaces to oppose the seal surfaces on the body and bearing shaft to define a seal gland. A resilient and annular packing ring is compressed between the cylindrical seal surfaces, but has a length less than the minimum length of the gland. A shroud extends inwardly near the outer backface a selected distance behind the packing ring to bias it inwardly. The shroud extends inwardly toward the bearing not more than about 30% of the cross-sectional thickness of the O-ring in the relaxed condition. The O-ring is compressed in a range of about 10 to 15 percent.