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Title:
TAPER TAP FOR PIPE OF MATERIAL OF HIGH HARDNESS
Document Type and Number:
WIPO Patent Application WO/2000/023219
Kind Code:
A1
Abstract:
A taper tap for pipes of materials of high hardness, having a high durability and capable of forming a pipe taper female thread even of a material of a hardness of substantially more than 50 HRC. The sum $g(S)r of edge thickness angles is around 130°, and each edge thickness is large enough to obtain high strength and rigidity. The rake angle $g(a) of a cutting edge (6) is about -20°, so that the tool angle ($g(b)) formed by the rake face (8) and the outer circumferential flank (9) is over 90°, improving the strength of the cutting edge (6). The bottom taper of a groove (4) is 1/16 which is nearly equal to that of a thread portion (2). Hence all of the rake angles $g(a) of the cutting edges from the small end to the large end of the thread portion (2) are the same, enabling all the cutting edges (6) to carry out the same cutting. The radius Df of the groove bottom of a front end portion (1a) is around 60 % of the outer diameter D of the small end of the thread portion (2), and therefore this taper tap is thicker than an ordinary tap, so that the pipe taper tap has a high strength, a high rigidity and a high abrasion resistance owing to such a structure.

Inventors:
Kato, Kazumi (3-22, Honnogahara Toyokawa-City Aich-pref, 442-0005, JP)
Application Number:
PCT/JP1998/004741
Publication Date:
April 27, 2000
Filing Date:
October 19, 1998
Export Citation:
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Assignee:
OSG CORPORATION (3-22, Honnogahara Toyokawa-City Aich-pref, 442-0005, JP)
Kato, Kazumi (3-22, Honnogahara Toyokawa-City Aich-pref, 442-0005, JP)
International Classes:
B23G5/06; (IPC1-7): B23G5/06
Domestic Patent References:
WO1994017946A1
Foreign References:
JPH035740U
JPH035741U
JPH04111714A
JPH0760546A
Other References:
See also references of EP 1036625A1
Attorney, Agent or Firm:
Kaneko, Naohisa (Sugita Building 2nd Floor 101, Sinhonmachi Toyohasi-City Aichi-Pref, 440-0892, JP)
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