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:
Mar. 31, 2015
Filed:
Jan. 31, 2008
Ward D. Morrison, Claremont, NH (US);
Ward D. Morrison, Claremont, NH (US);
J.H. Fletcher & Co., Huntington, WV (US);
Abstract
In a valveless percussive drill of the hydraulic type and incorporating a hammer assembly, an 'intermediate' shoulder between the head portion and cushion portion of a reciprocating piston engages the end face of a distributor or liner, rather than an interior bearing structure for the piston. This end face can be made harder than the ulterior bearing structure, which may include a surface made of a different material than the piston. Collectively, the result is a percussive drill with the hammer assembly incorporating the piston substantially less susceptible to failure due to galling as the result of contamination in the working fluid.