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:
Feb. 10, 1981
Filed:
May. 09, 1979
Applicant:
Inventor:
Paul Schmidt, 5940 Lennestadt-Saalhausen, DE;
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ; E21B / ;
U.S. Cl.
CPC ...
175 53 ; 175 19 ; 175 62 ; 405184 ;
Abstract
A method of boring holes in the ground, which holes are open at both ends, includes forming an open-ended pilot bore by means of a first self-propelled displacement hammer of smaller diameter. Next a cable is introduced through the pilot bore and then the diameter of the pilot bore is increased to form the hole by means of a second displacement hammer of greater diameter. The second displacement hammer is guided through the pilot bore by pulling it with the cable which for this purpose is attached to the leading end of the second hammer.