JPH0512557Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a thermoplastic synthetic resin branched saddle joint (hereinafter referred to as "saddle joint").

(Prior art) In a so-called saddle joint in which a saddle is provided at the bottom of a cylindrical body, when the saddle joint is molded by injection molding or the like, a circular spiral shape is formed on the bottom surface of the saddle part. A thermoplastic synthetic resin sheet embedded with electrically heated metal wires is welded using the insert molding method, and when using this saddle joint, the saddle part is brought into contact with the main pipe and the electrically heated metal wires are energized and welded. Saddle joints designed to be joined are well known, and joints with this structure are said to be easy to join because they can be welded by simply applying electricity to the heating metal wire when joining to the main pipe. There are advantages.

(Problem to be solved by the invention) However, in the above-mentioned conventional technology, during insert molding, a relatively soft sheet incorporating a highly rigid electric heating metal wire is used on the saddle bottom molding surface of the core mold. Since the wires are set along a certain curved surface, unreasonable tension is applied to the heated metal wires, making it difficult to obtain wires embedded at a uniform depth in the sheet, which results in uneven injection molding. The saddle joint, which is a standard product, has a problem in that it is impossible to uniformly fuse the saddle joint with the main pipe.

(Means for Solving the Problems) The saddle joint of the present invention was made to solve the problems of the prior art, and is a branched saddle joint in which a saddle portion is provided at the bottom of a cylindrical body. ,
A thermoplastic synthetic resin sheet having a substantially elliptical spiral metal wire attached to the bottom surface of the saddle portion is integrally formed with the substantially elliptical long axis facing the circumferential direction and the short axis facing the axial direction. The gist of the saddle joint is that it is welded.

In the present invention, the metal wire may be any metal wire that generates heat when energized, such as stainless steel wire, nickel wire, nichrome wire, etc., and may be coated with thermoplastic synthetic resin. Insulated ones are preferred.

In this invention, thermoplastic synthetic resins include polyethylene, polyvinyl chloride, polyacetal,
Polypropylene, polyvinylidene fluoride, etc. are preferably used.

(Function) The saddle joint of the present invention has a thermoplastic synthetic resin sheet on which a substantially elliptical metal wire is attached to the bottom of the saddle, with the long axis of the substantially elliptical shape extending in the circumferential direction of the saddle and the short diameter being the axis. Since the metal wires are welded together in the direction, the tensile strain of the metal wires that occurs when the sheet is written on the core mold can be reduced.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of the saddle joint of the present invention, in which the bottom surface of the saddle part 2 provided at the bottom of the cylindrical body 1 has a substantially elliptical spiral groove 31 provided on the top surface. A thermoplastic synthetic resin sheet 3 having a metal wire 4 attached thereto is integrally welded to the substantially elliptical shape with its major axis oriented in the circumferential direction of the saddle and its minor axis oriented in the axial direction. A cylindrical connection port 21 is protruded from the top of the saddle portion 2 on both sides of the cylindrical body 1 in the axial direction, and a terminal pin 5 is provided upright within the opening.

FIG. 2 shows the thermoplastic synthetic resin sheet 3 used in the saddle joint, in which both ends 33, 33 of the approximately elliptical spiral groove 31 on the upper surface are located on the short axis of the approximately ellipse. A small disk-shaped spacing holder 32 made of thermoplastic synthetic resin is fused on the short axis of the inner end, and the head of the spacing holder 32 has an inner The metal wire 4 on the end side is fused. Terminal pins 5, 5 are attached to both ends of the metal wire 4.

To manufacture the saddle joint of the present invention, first, a thermoplastic synthetic resin sheet 3 having an approximately elliptical spiral groove 31 on one side is molded by injection molding, and a center portion having the same diameter as the inner diameter of the cylindrical body 1 is formed. A circular hole 6 is bored. Next, a thermoplastic synthetic resin-coated metal wire 4 is spirally attached to the groove 31, and radially pressed with a heater so that the metal wire 4 does not come off. Then, the synthetic resin of the sheet or metal wire melts as if the thermoplastic synthetic resin pieces 34 were suspended like a bridge, and the metal wire 4 can be prevented from coming off from the groove 31. Next, a small disk-shaped spacing holder 32 made of thermoplastic synthetic resin was fused on the short axis of the inner end, and the metal wire 4 on the inner end was fused to the head of the spacing holder 32. After that, terminal pins 5 are attached to both ends of the metal wire 4. Next, as shown in FIG. 3, the sheet 3 is attached to the upper surface of the approximately semi-cylindrical core mold 7 in the radiation molding machine by temporarily attaching it with adhesive or the like, and from above, After fitting the core mold 8 of the cylindrical body 1 into the core mold 7, the terminal pin 5 is inserted into the connecting port 21 and the core mold 9 for molding.
Fixed to. Next, the core mold 7 is inserted into an injection molding machine, the mold is closed, and a thermoplastic synthetic resin is injected into the mold cavity.

In addition, in the present invention, the small disc-shaped thermoplastic synthetic resin spacer is integrally molded on the outside of the periphery of the thermoplastic synthetic resin sheet during injection molding, and then separated. Bye.

(Effect of the invention) The saddle joint of the present invention has a substantially elliptical spiral groove on the top surface on the bottom surface of the saddle part, and a thermoplastic synthetic resin sheet with a metal wire attached to the groove. Since the long axis of the approximately elliptical shape is oriented in the circumferential direction of the saddle and the short axis is oriented in the axial direction, welded together, the tensile strain of the metal wire that occurs when attaching the seat to the core mold can be reduced. Since the sheet can be brought into close contact with the core mold, the bottom surface of the saddle joint can be formed into a predetermined curved surface, and the saddle and the main pipe can be uniformly fused together.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing one embodiment of the saddle joint of the present invention, Fig. 2 is a perspective view showing a thermoplastic synthetic resin sheet used in the same, and Fig. 3 is a perspective view showing the sheet made of a core metal. FIG. 3 is a perspective view showing a state in which the cylindrical body is placed on a mold and the core mold of the cylindrical body is fitted. 1... Cylindrical body, 2... Saddle portion, 3... Thermoplastic synthetic resin sheet, 4... Metal wire.

Claims (1)

[Scope of utility model registration request] This is a branched saddle joint in which a saddle portion is provided at the bottom of a cylindrical body, and a thermoplastic synthetic resin sheet having a substantially elliptical spiral metal wire attached to the bottom surface of the saddle portion is attached to the bottom surface of the saddle portion. A thermoplastic synthetic resin branched saddle joint characterized by being welded together with the long diameter facing the circumferential direction of the saddle and the short diameter facing the axial direction.