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Patent Searching and Data

Document Type and Number:
Japanese Patent JP3222973
Kind Code:

PURPOSE: To widen an enlarging blade so that enlargement and excavation can be made by a pile end, confirm such a state from the ground and surely withdraw the enlarging blade to an original state.
CONSTITUTION: An excavating blade 12 is provided to a cylindrical shaft 11, and both upper and lower bits 1a and 1b divided into two parts so as to cross an excavation bit 1 forming an excavating blade 13, a connection joint 6 inserted to the insides of cylinders of the upper bit and lower bit, a guide shaft 7 freely inserted into a slot 115 formed in the cylindrical shaft 11 of the lower bit and fixed to the connection joint 6, an enlarging blade 3 mounted to the lower bit 1b and a link mechanism 4' connecting the guide shaft 7 and the enlarging blade 3 are provided to the lower end of the excavating blade 12. When the upper bit 1a is forwarded, both upper and lower bits maintain the shape of the excavating blade in a state prior to the division, and while the link mechanism 4' stores forcedly the enlarging blade 3 in the excavating blade, when the upper bit 1a is reversed, the enlarging blade 3 is projected outward of the excavating blade 12, and the guide shaft 7 is interlocked with the other end of the slot 115 in order to maintain a projection state.

Hayashi, Takahiro
Mori, Yoshiharu
Application Number:
Publication Date:
October 29, 2001
Filing Date:
February 21, 1993
Export Citation:
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International Classes:
E21B10/44; E21B7/28; E21B7/30; (IPC1-7): E21B10/44; E21B7/28; E21B7/30
Attorney, Agent or Firm:
小林 宜延