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. 17, 1994

Filed:

Jul. 08, 1992
Applicant:
Inventors:

Tatemi Masaki, Urayasu, JP;

Tetsuo Kawahito, Chiba, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
166 77 ; 166 98 ; 226162 ;
Abstract

An apparatus is provided for automatically extracting a grout injection pipe through which grout is injected into fragile ground for improving the same. An extractor for an injection pipe has an extracting main body including a chucking element for chucking the periphery of the injection pipe through a chucking member, a piston cylinder having a rod to which the chucking element is secured, and a rod position detector opposite to the rod of the piston cylinder for detecting movement of the rod. A control device is included for providing an injection pipe chucking and releasing signal to the chucking actuating valve and for providing rod ascending and descending signals to a rod ascending and descending valve. The extracting main body and the control are separately located.


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