Title:
ELECTRIC-FUSION TYPE BRANCH PIPE JOINT
Document Type and Number:
Japanese Patent JP3164775
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent a heating wire from short-circuiting itself on the outer peripheral side by providing a branch pipe protrusively at the upper face of a synthetic resin saddle, embedding the heating wire in the back face of the saddle spirally with specified spaces to constitute an electric fusion type branch pipe joint, and making the spaces of the heating wire larger on the outer peripheral side than the inner peripheral side.
SOLUTION: A joint body 1 is injectingly molded out of synthetic resin. A branch pipe 12 is integrally protruded from the upper face of a saddle 11, and a heating wire is embedded in the back face of the saddle 11 spirally with specified spaces. In this case, the spaces of the spirally wound heating wire 2 are so set as to be larger on the outer peripheral side than the inner peripheral side. At the time of fusion-joining a branch pipe joint to a main pipe 3, when current is applied to the heating wire 2 through a terminal pin 21, thermal expansion is larger toward to the outer peripheral side of spiral shape, but since the spaces of the heating wire 2 are made larger toward the outer peripheral side from the inner peripheral side, the heating wire 2 in prevented from short-circuiting itself by coming in contact with each other at the time of thermal-expansion. The spaces of the heating wire 2 can also be enlarged from the third or fourth round on the inner peripheral side.
Inventors:
Masayoshi Sekiyama
Application Number:
JP11061497A
Publication Date:
May 08, 2001
Filing Date:
April 28, 1997
Export Citation:
Assignee:
Mitsubishi Plastics Co., Ltd.
International Classes:
F16L47/02; H05B3/36; (IPC1-7): F16L47/02; H05B3/36
Domestic Patent References:
| JP861582A | ||||
| JP642689A | ||||
| JP842775A | ||||
| JP7253186A | ||||
| JP7151287A | ||||
| JP8240294A | ||||
| JP7174282A | ||||
| JP835595A | ||||
| JP60198224A |