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:
Jun. 22, 2004
Filed:
Dec. 10, 2002
Applicant:
Inventors:
Hirokazu Karasawa, Tsukuba, JP;
Tetsuji Ohno, Tsukuba, JP;
Akinori Ota, Chiyoda-ku, JP;
Tsutomu Kaneko, Yoshii-machi, JP;
Naoto Yamada, Isumi-gun, JP;
Tetsuomi Miyamoto, Isumi-gun, JP;
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B25D 1/722 ;
U.S. Cl.
CPC ...
B25D 1/722 ;
Abstract
Provided is a downhole percussion drill, which is installed at an end portion of a drillstring and performs drilling by giving impact blows to a drill bit at the bottomhole, which includes a hydraulic hammering mechanism which uses oil having high lubricating ability as a driving medium, a hydraulic pump which pressurizes the oil, and a downhole motor which drives the hydraulic pump