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. 09, 1998
Filed:
Apr. 01, 1996
Hinrich Kattentidt, Darmstadt, DE;
Achim Kehrberger, Ostfildern, DE;
Winfried Scheid, Ebersbach, DE;
DELMAG Maschinenfabrik Reinhold Dornfeld GmbH & Co., Esslingen, DE;
Abstract
A boring tool with two driving heads which are used to sink a casing string and a borer string includes a controllable coupling mechanism fitted between the two driving heads. A mechanism is also provided for the lower driving head, such that the driving head is subjected to an additional downwards acting force. When both driving heads are coupled, the upper driving head is also subjected to an additional, downwards acting vertical force. In order to free the top end of the casing string, the coupling mechanism can be released so that the upper driving head can be fully raised, whilst the lower driving head remains in position adjacent to the ground.