Title:
BENDING METHOD OF PIPE MATERIAL AND CORE BAR FOR BENDING PIPE MATERIAL
Document Type and Number:
WIPO Patent Application WO/2008/093818
Kind Code:
A1
Abstract:
A bending method of pipe material which can positively prevent occurrence of
cracking or creasing at the bend, or the like. Core bars (5) each having a protrusion
of a quarter of sphere at the distal end are inserted into a pipe material (1) from
the opposite ends thereof and the planes of the protrusions are allowed to meet
each other. From that state, the core bars are moved relatively in the direction
perpendicular to the axis of the pipe while parallelism between them is sustained,
thus forming bends (1a, 1b) at two positions of the pipe material and a linear portion
(1c) at the middle thereof. In such a method for bending a pipe material, the pipe
material is bent while being pushed toward the bend (1a) by an amount of 81-97%
of the length of the linear portion (1c) at the middle.
Inventors:
MATSUNAGA HIDEAKI (JP)
FUJINO HITOSHI (JP)
ENDO ATSUSHI (JP)
FUJINO HITOSHI (JP)
ENDO ATSUSHI (JP)
Application Number:
PCT/JP2008/051614
Publication Date:
August 07, 2008
Filing Date:
January 25, 2008
Export Citation:
Assignee:
SANOH IND CO LTD (JP)
TOSHIDA INDUSTRY CO LTD (JP)
MATSUNAGA HIDEAKI (JP)
FUJINO HITOSHI (JP)
ENDO ATSUSHI (JP)
TOSHIDA INDUSTRY CO LTD (JP)
MATSUNAGA HIDEAKI (JP)
FUJINO HITOSHI (JP)
ENDO ATSUSHI (JP)
International Classes:
B21D7/06; B21D9/08
Foreign References:
| JP2000210722A | 2000-08-02 | |||
| JP2002239639A | 2002-08-27 |
Attorney, Agent or Firm:
IWANE, Masatoshi (1-1 Kandaawaji-ch, Chiyoda-ku Tokyo 63, JP)
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