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:
May. 16, 1978
Filed:
Apr. 07, 1975
Applicant:
Inventor:
George A Hibbard, Claremont, NH (US);
Assignee:
Joy Manufacturing Company, Pittsburgh, PA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21C / ; E21C / ;
U.S. Cl.
CPC ...
173133 ; 173132 ; 173134 ; 173139 ; 173-1 ;
Abstract
A hammer and more particularly a fluid operable hammer wherein alternating impetus provided by pressurized liquid and gas means actuates a reciprocable hammer piston to generate repetitive impact loads. A work member is provided to receive blows from the hammer and includes an enlarged portion located in a sealed, variable volume cushion chamber. Means are provided to provide fluid above atmospheric pressure in the chamber. The chamber is sealed before hammer operation to provide a variable gas pressure cushioning chamber for the work member.