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:
Jun. 13, 1989
Filed:
Jan. 22, 1988
Applicant:
Inventors:
Sybil Pentith, Rotherham, GB;
Gerald R Pentith, Rotherham, GB;
Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21C / ;
U.S. Cl.
CPC ...
299 15 ; 299 73 ;
Abstract
A tunnel is constructed by progressively cutting away a predetermined depth of rock from a face using rotary diamond saws. Slots are cut into the face (12) at an acute angle to the face such that first slots intersect second slots to detach blocks from the face. In one embodiment, the cutter (29) is mounted on a slide which can traverse an elongate guide 26. The guide is carried on an arm (24) which can swivel about its own longitudinal axis. A series of angularly spaced slots are cut into the face through 360.degree. with alternate slots being cut at opposite acute angles to the face so that they intersect. A cylindrical tunnel is produced.