JPH0781666B2 - Pipe positioning tool - Google Patents

Abstract

PURPOSE:To decrease dispersion further with high welding strength obtained by protruding a protrusion unit, formed of material harder than a pipe or a joint, to the inner in internal peripheral surfaces of a pipe holding part or a joint holding part. CONSTITUTION:A pipe positioning tool is provided with a joint holding part 5 for holding one end part peripheral edge of a welding joint A and a pipe holding part 6 which is integrally formed in an outer side edge of the joint holding part 5 to hold the peripheral surface of a pipe P1. The joint holding part 5 and the pipe holding part 6 are provided in a manner wherein the respective shaft centers thereof are positioned in the same straight line. A protrusion unit 9 of triangular section is formed in internal peripheral surfaces of the vertically divided pipe holding part 6 and joint holding part 5. In this way, at the time of welding the joint to the pipe, uniform welding can be applied over the total periphery of a connection part. In such a way as mentioned, dispersion is decreased further with high welding strength obtainable.

Description

Description: TECHNICAL FIELD The present invention relates to a pipe positioning device, for example, a welding joint and two thermoplastic resin pipes inserted at both ends of the joint.
It is used for positioning and fixing so that the respective shaft cores are located on the same straight line.

(Prior Art) When connecting thermoplastic resin pipes to each other, a thermoplastic resin welding joint in which a heating wire as a heating element is embedded in the inner peripheral surface of the receiving portion is used, and the joint of the pipe is connected to the receiving portion of this joint. There is known a technique in which the heating wire is energized to generate heat when the end portion is inserted, and thereby the inner peripheral surface of the receiving portion and the outer peripheral surface of the pipe end are melted to connect the both pipes.

By the way, in such a connecting method, the pipe and the joint are connected to each other until the constant welding strength is generated after the energization so that uniform welding is performed on the entire peripheral surface of the connecting portion. It is necessary to firmly position and fix it against thermal stress and thermal deformation so that the core is not displaced.

For this reason, conventionally, a pipe positioning device as disclosed in, for example, Japanese Patent Laid-Open No. 62-62074 has been proposed.

The above-mentioned device is composed of at least one bar, and a support plate that has a fan-shaped notch portion having a different curvature corresponding to a pipe diameter at an edge portion and is slidable on the bar.
The tube applied to the fan-shaped notch is fixed to the support plate by a belt.

(Problems to be Solved by the Invention) However, the above-mentioned pipe positioning device merely aims at positioning and fixing the pipe, and does not attempt to position and fix even the joint. However, the joint and the pipe cannot be positioned and fixed so that their mutual axial centers coincide with each other. Therefore, there is a problem that uniform welding is not performed over the entire circumference of the pipe. If such uniform welding is not performed, the pipe may oscillate around the receiving part of the joint when an external force is applied to the pipe after welding, which causes the welded part. There was a problem that a crack was generated in the pipe and the gas or fluid flowing in the pipe leaked from the crack.

At the same time, there is a problem that handling of the tube is extremely troublesome because the tube is fixed by a belt.

The present invention has been made in view of the above problems, and a joint and two pipes inserted at both ends of the joint are arranged such that their respective axial cores are located on the same straight line before and after welding. An object of the present invention is to provide a pipe positioning tool that can be positioned and fixed.

(Means for Solving the Problems) A pipe positioning device of the present invention is a pipe positioning device that holds a welding joint and a pipe inserted in the welding joint so that their respective axial cores are aligned with each other. Each of the half-divided members, each half-divided member holding a joint holding portion for holding an outer peripheral edge of the end portion of the welding joint, and a pipe holding portion formed integrally with the joint holding portion for holding the outer peripheral surface of the pipe. And the joint holding portion and the pipe holding portion are arranged such that their respective axial cores coincide with each other, and at least the inner peripheral surface of the pipe holding portion or the joint holding portion is made of a material harder than the pipe or the joint. The projection body is formed so as to project inward.

(Operation) For example, in the case of connecting two pipes, the pipes are respectively inserted from the opening portions at both ends of the joint, and in this state, the joint and the pipe are held by the pipe positioning tool.

Specifically, the joint holding portion holds the outer peripheral surface of one end of the joint, and the pipe holding portion holds the outer peripheral surface of the inserted pipe. At this time, since the projections provided on the inner peripheral surfaces of the joint holding portion and the pipe holding portion are harder than the joint and the pipe, the outer peripheral surfaces of the joint and the pipe are difficult to fit into, and thus the joint and the pipe are connected to the joint holding portion and the pipe. It is held by the pipe holder. By being held in this way, the elastic core of the thermoplastic resin of the pipe is positioned so that its axis coincides with the axis of the pipe holding portion, and the joint is also made of thermoplastic resin. Due to the action of the elastic repulsive force possessed, the shaft center is positioned so as to coincide with the shaft center of the joint holding portion. Therefore, the joint and the pipe respectively positioned on the pipe holding portion and the joint holding portion located on the same straight line are positioned (centered) on the same straight line, and as a result, the inner peripheral surface of the joint is The clearance between the pipe and the outer peripheral surface is constant over the entire circumference.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, in describing the pipe positioning tool of the present invention, the welding joint will be briefly described.

As shown in FIG. 3, the welding joint A includes a joint body 1 formed in a cylindrical shape, and a pair of bosses 2, 2 projecting from outer peripheral surfaces of both end portions of the joint body 1. The thermoplastic resin such as polyethylene resin is used as a material and is formed by, for example, injection molding. The boss 2 may be integrally molded at the same time as the joint body 1, or may be separately molded in advance and fixed and integrated when the joint body 1 is molded.

A protrusion 13 for regulating the insertion of the thermoplastic resin pipes (hereinafter, simply referred to as pipes) P1 and P2 inserted from the open end at a predetermined position is provided in the axially substantially central portion of the inner peripheral portion of the joint body 1. Has been formed. The protrusion 13 may be formed on the entire circumference, or may be formed on a part of the entire circumference.

In addition, a heating wire 3 such as a nichrome wire, which serves as a heating element, is embedded in the inner peripheral portion of the joint body 1 in a spiral shape around the axis of the joint body 1. The heating wire 3 is divided into a first group 31 which is welded to the one pipe P1 and a second group 32 which is welded to the other thermoplastic resin pipe P2 with the projection 13 as a boundary. They are arranged separately.

The heating element may be, for example, a heating resistance wire in which a large number of thin long heating wires (carbon fiber, nichrome wire, etc.) are bundled, or a nichrome wire having a length of 10 to 200 mm or A sheet made of electrothermal fiber such as carbon fiber may be used.

Next, a pipe positioning tool according to the present invention will be described with reference to FIGS. 1 to 3.

The pipe positioning tool holds the welding joint A and the pipe P1 inserted from the one end opening of the welding joint A in a state of being positioned on the same straight line, and holds the outer peripheral edge of the one end of the welding joint A. And a pipe holding portion 6 formed integrally with the outer edge of the joint holding portion 5 for holding the outer peripheral surface of the pipe P1.

The joint holding portion 5 and the pipe holding portion 6 are provided so that their respective axial centers are located on the same straight line, and the joint holding portion 5 and the pipe holding portion 6 constitute a positioning portion 7.

The positioning part 7 is divided into an upper positioning part 7a and a half member of a lower positioning part 7b.
A hinge 71 is used to open and close the lower positioning portion 7b. Therefore, the upper positioning portion 7a and the lower positioning portion 7b can have a closed position for holding the welding joint A and the pipe P1 and an open position for opening this holding.

The upper positioning part 7a and the lower positioning part 7b are manufactured by casting aluminum.

Also, the upper positioning portion 7a located on the opposite side of the hinge 71
A clamp 75 is provided on the mating surface between the lower positioning portion 7b and the lower positioning portion 7b. The clamp 75 includes a spring-shaped locking member 76 provided on the upper positioning portion 7a side, and a locked member provided on the lower positioning portion 7b side and locked with the tip end portion of the locking member 76.
77, the upper positioning portion 7a and the lower positioning portion 7a by locking the locking member 76 to the locked member 77.
7b and 7b can be held in a closed state.

Further, a projection 9 having a triangular cross section is formed on the inner peripheral surface of the pipe holding portion 6 and the inner peripheral surface of the joint holding portion 5 which are divided into upper and lower parts. The projections 9 are annularly provided in the circumferential direction of the inner peripheral surface of the pipe holding portion 6 and the inner peripheral surface of the joint holding portion 5, and the plurality of projections 9 ... It is provided continuously.

Next, a procedure for welding the welding joint A and the pipe by using the pipe positioning tool of the present invention will be described.

First, connect the pipes P1 and P2 to the pipes P1 and P2 through the openings on both ends of the joint body 1.
Insert until the end of touches the protrusion 13. Then, in this state, the pipes P1 and P1 inserted into both ends of the welding joint A and the welding joint A by the two left and right pipe positioning tools.
Hold 2 Hereinafter, the case where the pipe positioning tool is attached to the one end side of the welding joint A will be described, and the attachment to the other end side of the welding joint A is the same, so the description thereof will be omitted.

First, the one end of the welded joint and the pipe P1 are arranged in the positioning part 7 opened vertically, and the upper positioning part 7a and the lower positioning part 7b are arranged.
After closing and, the clamp 75
Hold in a closed state. As a result, the joint holding portion 5 holds the outer peripheral surface of one end of the welded joint A, and the pipe holding portion 6 holds the outer peripheral surface of the pipe P1. At this time, the joint holding portion 5
Since the projections 9 provided on the inner peripheral surface of the pipe holding portion 6 are harder than the welding joint A and the pipe P1, the outer peripheral surfaces of the welding joint A and the pipe P1 are pushed into the welding joint A and the pipe P1. It is held by the joint holding portion 5 and the pipe holding portion 6. By being held in this way, the pipe P1 is positioned so that its axis coincides with the axis of the pipe holding portion 6 due to the action of the elastic repulsive force of the thermoplastic resin, and the welding joint A also has the same shape. By the action of the elastic repulsive force of the thermoplastic resin, it is positioned so that its axis coincides with the axis of the joint holder 5. Therefore, the welding joint A and the pipe P1 respectively positioned on the pipe holding portion 6 and the joint holding portion 5 located on the same straight line are positioned on the same straight line. The gap generated between the peripheral surface and the outer peripheral surface of the pipe P1 is constant over the entire circumference.

After the thermoplastic resin pipes P1 and P2 and the joint body 1 are held by the pipe positioning tool in this way, a connector is connected to the terminals 4 and 4 and a constant voltage is applied to heat the heating wire 3. And
This heat heats and melts the inner peripheral portion of the joint body 1 and the outer peripheral portions of the pipes P1 and P2, so that the joint body 1 and the pipes P1 and P2 are welded.

Therefore, since the joint body 1 and the pipes P1, P2 are welded in the centered state as described above, the gap between the inner peripheral surface of the joint body 1 and the outer peripheral surfaces of the pipes P1, P2 is constant. It is welded in the state of being secured. As a result, the joint body 1 and the outer peripheral surfaces of the pipes P1 and P2 are uniformly melted over the entire circumference, and at the same time, a uniform molten resin pressure is always applied in the circumferential direction, so that the welding is performed in an appropriate state without uneven welding. be able to. Also, the welding joint A
It is also possible to prevent the problem that the pipes P1 and P2 are joined in an inclined state.

The projection 9 is not limited to the one shown in this example, and, for example, as shown in FIG. 4, a granular projection 91 is provided at the intersection of the bases, or shown in FIG. In this way, the projections 92 formed in a ring shape in the circumferential direction are arranged at appropriate intervals in the axial direction, and the projections 93 formed continuously or discontinuously in the axial direction as shown in FIG. It may be arranged at appropriate intervals in the circumferential direction.

Further, the pipe positioning tool is shown in this example as being configured to be separately attached to both ends of the welding joint A by using two pipe positioning tools, but two pipe positioning tools to be attached to both ends of the welding joint A are shown. The upper positioning portions 7a of the pipe positioning tool and the lower positioning portions 7b of the pipe positioning tool may be arranged in series and may be simultaneously attached to both ends of the welding joint.

(Effects of the Invention) As described above, according to the pipe positioning tool of the present invention, the joint and the pipe inserted into the joint are positioned and fixed so that their respective axial cores are located on the same straight line. You can Accordingly, when the joint and the pipe are welded, uniform welding can be performed over the entire circumference of the joint portion, and it is possible to obtain high welding strength with little variation. Moreover, the structure is simple, and the joint and the pipe can be easily attached at the time of joining.

[Brief description of drawings]

FIG. 1 is a side view showing a pipe positioning device according to the present invention in a partial cross section, FIG. 2 is a front view thereof, and FIG. 3 is a sectional view showing a state in which a pipe and a welding joint are positioned and held by the pipe positioning device, 4 to 6 are perspective views showing another embodiment of the protrusion. P1, P2 ... Pipe A ... Welding joint 5 ... Joint holding part 6 ... Pipe holding part 9 ... Projection body

Claims (1)

[Claims] 1. A pipe positioning tool for holding a welded joint and a pipe inserted in the welded joint so that their respective axial cores coincide with each other. The pipe positioner comprises a pair of half-split members, each half-split member. Has a joint holding portion that holds the outer peripheral edge of the end of the welded joint, and a pipe holding portion that is integrally formed with the joint holding portion and holds the outer peripheral surface of the pipe, and the joint holding portion and the pipe holding portion. And the projections made of a material that is harder than the pipe or the joint are projected inward on at least the inner peripheral surface of the pipe holding portion or the joint holding portion. Pipe positioning tool characterized by.