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:
Apr. 14, 1992

Filed:

Jun. 26, 1990
Applicant:
Inventors:

Jan H Forsberg, Enebyberg, SE;

Carl S Hartwig, Taby, SE;

Nils M Astrand, Vallingby, SE;

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21D / ;
U.S. Cl.
CPC ...
405142 ; 405146 ; 405138 ; 299 53 ;
Abstract

Tunnel boring machine comprising a number of swingable arms (11,12,13,14) provided with boring tools (41,42,43,44) for the working of the tunnel wall outside its normal diameter. The arms may be swung outwardly into an active position or retracted into an inactive position. These tools may be independently actuated and facilitate the insertion of steel supporting arcs into the excavated area.


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