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. 12, 1981

Filed:

Jul. 21, 1977
Applicant:
Inventors:

Thomas J Retka, Lakeville, MN (US);

Donald W Schoen, St. Paul, MN (US);

Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
E21C / ;
U.S. Cl.
CPC ...
299 87 ; 175394 ; 299 90 ; 173D / ;
Abstract

An auger construction is provided which reduces the surface noise radiated by the auger and serves to at least partially isolate the auger from the remainder of the machine. The auger construction comprises an inner shaft and outer concentric shafts, the latter carrying the helical cutting blade and generally corresponding to the shaft of a conventional auger. An elongated annulus of noise and vibration dampening material is disposed between the inner and outer shafts. Preferably, the outer shaft is isolated from the machine by further noise dampening material disposed between the mounting flange and the proximate end of that shaft and between the free end of the inner shaft and the end of the hose in the outer shaft. A bore in the inner shaft is also filled with noise dampening material. A number of arrangements are disclosed for fixing the two shafts together so as to prevent rotational slippage therebetween.


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