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:
Nov. 03, 1981
Filed:
Jun. 12, 1980
Applicant:
Inventor:
Wilfried Krabbe, Dreieich-Buchschlag, DE;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21D / ;
U.S. Cl.
CPC ...
299 33 ; 299 58 ; 299 90 ;
Abstract
A tunnelling apparatus has an annular tunnelling element subdivided into a leading and a trailing chamber. The front end of the leading chamber is open to the material-removing face. A material-removing cutting device is lodged in an opening formed in the transverse wall to remove material from the working face. It can be axially withdrawn from the opening into and if necessary rearwardly beyond the trailing chamber, so as to expose the opening and permit access of an operator to the working face through the opening.