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:
Apr. 14, 1981
Filed:
Oct. 04, 1979
William L Shepherd, West University, TX (US);
Hughes Tool Company, Houston, TX (US);
Abstract
A hydraulic mast digger has a kelly head with improved retaining and sealing features. The digger is of the type having a kelly with a bearing assembly mounted between the kelly and a bearing sleeve. The bearing sleeve is reciprocally carried in the hydraulic cylinder and moves in response to hydraulic fluid pressure. The bearing assembly allows rotation of the kelly with respect to the bearing sleeve. A cap is secured by threads to the bearing sleeve above the top of the kelly to define a piston. The cap has an upwardly facing shoulder located below the upper edge of the bearing sleeve. A retainer is rigidly secured to the cap and extends down into the space between the cap and bearing sleeve. A locking device locks the retainer to the bearing sleeve. Preferably the locking device includes a key that fits within slots formed on the retainer and bearing sleeve. A primary seal encircles the retainer.