Title:
リング状先端金物
Document Type and Number:
Japanese Patent JP6847899
Kind Code:
B2
Abstract:
To provide a ring-shaped front end fitting that uses a down-the-hole hammer which has an established reputation for an ability to excavate hard ground or rocks incapable of being excavated by an earth auger method when driving piles into such hard ground or rocks while there is a need to reliably install foundation piles in hard ground such as rock layers, that enables driven piles to keep sufficient support force, and that can configure a tip close mechanism while maintaining the clearance between the down-the-hole hammer and the ring-shaped front end fitting.SOLUTION: The ring-shaped front end fitting is used for an inner excavation pile construction method to excavate by setting a down-the-hole hammer 6 in an inner excavation manner in a steel pipe 1, and has a struck surface 14 provided on a tip of the steel pipe 1. The inner side of the ring-shaped front end fitting is provided with shear keys 13 protruding an axial center perpendicular direction and used as slip preventive fittings. The struck surface 14 is formed on one of the shear keys 13 and protrudes more than other shear keys 13 in the axial center perpendicular direction.SELECTED DRAWING: Figure 1
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Inventors:
Kosuke Yokoyama
Masahiro Inoue
Yuki Kusaka
Atsushi Kato
Masahiro Inoue
Yuki Kusaka
Atsushi Kato
Application Number:
JP2018153428A
Publication Date:
March 24, 2021
Filing Date:
August 17, 2018
Export Citation:
Assignee:
Yokoyama foundation work
Nippon Steel Corporation
Nippon Steel Corporation
International Classes:
E02D7/00; E02D5/28; E21B6/00
Domestic Patent References:
| JP2018091028A | ||||
| JP2006207320A | ||||
| JP11107665A | ||||
| JP2017193930A | ||||
| JP8105045A | ||||
| JP6212871A | ||||
| JP2504657A |
Foreign References:
| US4860835 |
Attorney, Agent or Firm:
Tsukasa Kubo