A drilling casing, a drilling machine, and the extended method of a drilling casing

Title:

A drilling casing, a drilling machine, and the extended method of a drilling casing

Document Type and Number:

Japanese Patent JP6236970

Kind Code:

B2

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Inventors:

Tsutomu Kaneda
Nato wins
Masaaki Fukaya

Application Number:

JP2013162939A

Publication Date:

November 29, 2017

Filing Date:

August 06, 2013

Export Citation:

Assignee:

Obayashi Corporation

International Classes:

E21B7/20; E21B17/08

Domestic Patent References:

Foreign References:

EP0060549A1

Attorney, Agent or Firm:

Isshiki International Patent Service Corporation

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