Title: Boring apparatus provided with drill bits freely rotatable around their own axis

Abstract: A boring apparatus in which a plurality of drill bits are supported in a casing fixed to a boring pipe in such a manner that these bits are axially substantially parallel with the axis of the boring pipe and are freely rotatable around their own axis independently of the rotation of the boring pipe.

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Inventors: Ikeda, Nobuhisa (Yokohama, JA)

Application Number: 512067
Filing Date: 1974-10-04
Publication_date: 1976-03-23
Assignee: Tone Boring Company Limited (Tokyo, JA)
Primary Class(es): 175/319
Other Classes:
US Patent Ref:

1140673	May, 1915	Giggey	175/319.
1417363	May, 1922	Wadsworth	175/319.
1551783	Sep, 1925	Baptie	175/319.
2563913	Aug, 1951	Binney	175/319.
3285351	Nov, 1966	Caro	175/319.
R25470	Nov, 1963	Allimann	175/319.

Other Refs: 68,288122,464170,358

, 1942	NO
, 1962	SU
, 1951	OE

Primary Examiner: Leppink, James A.
Assistant Examiner:
Attorney: Spensley, Horn and Lubitz