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.

Date of Patent:
May. 29, 2001

Filed:

Mar. 30, 1999
Applicant:
Inventors:

Franz-Josef Püttmann, Lennestadt, DE;

Andreas Riekes, Schmallenberg, DE;

Frank Prutti, Lennestadt, DE;

Bernhard Kaufmann, Lennestadt, DE;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21B 1/704 ;
U.S. Cl.
CPC ...
E21B 1/704 ;
Abstract

In an apparatus for drilling in earth, a push-pull linkage, especially a ladder-type linkage consisting of individual sections connected together in each case by a plug-in coupling, is connected to a push-pull drive, and a stationary locking pawl and a thrust pawl which is moveable in the longitudinal direction of the linkage and is connected to the drive, with two mutually opposite directions of action, can each be brought into active connection with the linkage in order to move the linkage forward stepwise and lock it temporarily after each movement step.


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