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:
Sep. 14, 1982

Filed:

Dec. 11, 1980
Applicant:
Inventors:

Ernst Braun, Essen-Heisingen, DE;

Gert Braun, Essen-Heisingen, DE;

Karlheinz Wetzchewald, Essen-Kettwig, DE;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21C / ;
U.S. Cl.
CPC ...
299 92 ; 3714 / ; 407115 ;
Abstract

A trench hewing tool assembly comprises a cutting blade holder having a shank receiving opening and at least one retaining recess, a cutting blade having a shank disposed in the shank receiving opening, the shank having an inclined wall recess on one side thereof, and a cutting edge member connected to the cutting blade facing a hewing direction. A tapered clamping bolt is connected to the holder and spring loaded toward the blade shank to engage an inclined wall of the inclined wall recess to retain the blade in the holder. A projection is provided on the holder which is spaced from the cutting blade and a guard member has lateral legs which straddle the projection. The guard member includes at least one claw which is engaged on the retaining recess of the holder and has a locking groove in which is received the blade. The guard is held between the blade and the holder. The guard includes projections on either side of the blade receiving groove for guarding the holder and also for widening a cut made by the tool assembly in a lateral direction to prevent jamming of the holder.


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