Title:
SWIVEL FOR DOUBLE-PIPE EXCAVATOR
Document Type and Number:
Japanese Patent JP3635229
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To eliminate inconveniences of damping of a striking force at the tip of a bored hole and damage of an inner rod, the inconveniences being caused by mutual interference and resonance of shock waves generated by a strike of an air hammer per se and shock waves generated by a strike of a top hammer.
SOLUTION: A cylinder chamber is arranged at a shaft center portion of an upper rotary core of a swivel. The cylinder chamber has a reciprocating inner pipe inserted thereinto, and pressure oil is injected into a portion on an upper side of a piston of the reciprocating inner pipe. As a result, a striking force of the top hammer of a drill applied to a head of the swivel is cushioned by the pressure oil in the cylinder chamber as an oil damper, whereby the inner pipe connected to the reciprocating inner pipe and the air hammer are protected from application of the striking force. As a result, damping of the striking force and damage of the inner pipe can be prevented.
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Inventors:
Koichi Suga
Yuji Kawashima
Yuji Kawashima
Application Number:
JP2000211317A
Publication Date:
April 06, 2005
Filing Date:
July 12, 2000
Export Citation:
Assignee:
Nittoku Construction Co., Ltd.
Rui Engineering Co., Ltd.
Rui Engineering Co., Ltd.
International Classes:
E21B10/38; E21B6/00; E21B17/05; (IPC1-7): E21B17/05; E21B6/00
Domestic Patent References:
| JP7020387U | ||||
| JP3072993U | ||||
| JP56059284U | ||||
| JP60178089U | ||||
| JP2000179271A | ||||
| JP116384A |
Attorney, Agent or Firm:
Minoru Fujii