JPH11348123A - Resin pipe fusing jig - Google Patents

Abstract

(57) [Summary] [Problem] Even if a pipe has a large ratio of SDR, which is the ratio of the pipe diameter to the wall thickness, it can be fused with a sufficient resin pressure without leaving a core inside and can be corrected to a perfect circle. Another object of the present invention is to obtain a jig for welding a resin tube which can be easily performed. SOLUTION: An outer surface 4a is a parallel surface and an inner surface 4c is one end 4b.
A divided cylindrical body 4... 4 divided into a plurality of equal parts in the circumferential direction, and one end 4 b of the divided piece of the divided cylindrical body 4 are respectively formed in a radial direction. A base 5 which is supported so as to be able to move in parallel to a truncated cone; a truncated cone-shaped member 6 which is concentrically arranged in a space 7 surrounded by the divided piece 4 of the cylindrical body so that the outer periphery thereof is along the inclined surface; A driving member 8 forcibly moving the member 6 toward the base 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for welding a resin pipe, and more particularly to a jig for welding a resin pipe which is suitably used for heat-sealing a polyolefin pipe.

[0002]

2. Description of the Related Art A plastic tube made of a polyolefin resin or the like is difficult to bond with an adhesive, and even when connected with a pull-out prevention joint, a so-called cold flow phenomenon occurs due to the elasticity of the material and plastic deformation of the holding portion. There is a problem that the secure connection becomes difficult. Therefore, plastic pipes made of these polyolefin resins are generally connected by heat fusion using a color joint.

[0003] When connecting tubes by this heat fusion, FIG.
As shown in (1), the collar joint 1 is externally fitted to the plastic tube 2, and the contact surface between the outer surface of the plastic tube 2 and the inner surface of the collar joint 1 is heated by the heater 3 to be melted and integrated. In the figure, reference numeral 3a denotes a connection terminal, and a power supply terminal of the heater 3. When a magnetic metal heater 3 by induction heating is used as a heater, it is heated by a work coil (not shown) instead of the terminal.

[0004]

When the plastic pipe 2 is welded by the above-mentioned means, there is no problem when the SDR of the pipe is up to about 17 or less, but the SDR is set to a value larger than the above value, for example, 21 or more. In such a case, there is a problem that poor bonding occurs.

[0005] Here, the SDR indicates that the larger the ratio (D / S) between the wall thickness (S) of the tube wall and the diameter (D) of the tube is, the smaller the wall thickness is with respect to the tube diameter. Therefore, the above SDR
However, when the value is 21 or more as described above, the absolute wall thickness of the tube becomes thin, and a sufficient surface pressure cannot be obtained, resulting in the above-described poor connection.

Particularly, in the case of a large-diameter pipe, the above-mentioned problem becomes remarkable because the pipe wall is made thinner for the purpose of reducing material costs and increasing the effective sectional area of the flow rate. Therefore, conventionally, in such a case, a reinforcing core 3 is inserted into the inner surface of the pipe 2 to be connected to secure an appropriate surface pressure at the time of fusion.

However, since the reinforcing core 3 remains in the pipe even after the pipe is connected, there is a problem that the inner diameter is reduced by the thickness of the core and causes pressure loss in the pipe. Further, even in the case of a tube having a small SDR that does not require such a core, the joint may be corrected to a state close to a perfect circle, and thus the core 3 may have to be used. Was.

The present invention solves the above-mentioned problems, and a resin which can be fused with a sufficient resin pressure without leaving a core inside even a pipe having a large SDR, and can be easily corrected to a perfect circle. The purpose of the present invention is to provide a jig for welding a pipe.

[0009]

A jig for welding a resin pipe according to the present invention is a cylindrical body whose outer surface is a parallel surface and whose inner surface is an inclined surface increasing in thickness toward one end, and which is formed in a circumferential direction. A plurality of equally divided split cylinders, and a base that supports one end side of each of the split pieces of the split cylinder so as to be able to translate in the radial direction,
A truncated cone-shaped member arranged concentrically with the outer circumference along the inclined surface in a space surrounded by the divided pieces of the cylindrical body, and a driving member for forcibly moving the truncated cone-shaped member toward the base. It consists of

According to the present invention, since the divided pieces of the cylindrical body are moved in parallel so as to expand radially outward by the forcible movement of the truncated conical member, the resin pipe connecting the outer surfaces of the cylindrical bodies is formed. If it is inserted into the inner surface, the connection portion of the resin pipe can be supported from the inner surface without using a coring, and a sufficient surface pressure can be obtained or the roundness can be corrected.

[0011]

Next, an embodiment of the present invention will be described. FIG. 1 is a sectional view of a different-diameter pipe connection joint according to Embodiment 1 of the present invention.

In the following, the same members as those in the related art are denoted by the same reference numerals, and detailed description is omitted. In FIG.
Reference numeral 4 denotes a metal or heat-resistant synthetic resin divided piece obtained by equally dividing a cylindrical body into a plurality of pieces in the circumferential direction, and an outer surface 4a has a parallel surface and an inner surface has an inclined surface 4c whose thickness increases toward one end 4b.
It has been.

In the illustrated example, the divided pieces 4 of the cylindrical body are divided into three equal parts, and one end 4b side is supported on the base 5 so as to be movable in parallel in the radial direction. The base 5 has a cylindrical portion 5a and a flange portion 5b abutting on a tube end of the plastic tube 2, and a female screw hole 5c is formed at the center.

5d are slide grooves, which are formed radially in the radial direction on the surface of the base 5 as shown in FIG.
Are fitted, and are slidable along the slide grooves 5d... 5d.

Reference numeral 6 denotes a truncated conical member, which is arranged concentrically in a space 7 surrounded by divided pieces 4... 4 of a cylindrical body. A driving member 8 forcibly moving toward the base 5 is connected to the truncated conical member 6.

In the illustrated example, the driving member 8 is constituted by a T-head bolt 8a which is screwed into the female screw hole 5c. Next, the usage state of the jig for welding the resin pipe will be described.

FIGS. 1 and 3 are cross-sectional views showing a state in which a plastic tube, for example, a polyolefin-based plastic tube such as polyethylene or polypropylene is being thermally welded. First, as shown in FIG. 1, after the collar joint 1 is externally fitted to the plastic pipe 2 to be welded and positioned, the flange 5b of the base 5 is brought into contact with the pipe end of the plastic pipe 2, and the welding heater is provided. The divided cylindrical body 4 is located at a position corresponding to 3.

Next, the T-head bolt 8a is rotated around the axis, and the frustoconical member 6 is moved in the axial direction with respect to the substrate 5 as shown by an arrow in FIG. The divided pieces 4... 4 move radially outward due to the movement of the truncated conical member 6 and are pressed against the inner surface of the plastic pipe 2.

In this state, the heater 3 is heated to weld the collar joint 1 and the plastic tube 2 together. At this time, since a pressure is applied outward from the inner surface of the plastic tube 2, a sufficient surface pressure acts on the welded portion, and the hot melted portion is reliably welded.

After welding, the jig for fusing the resin pipe can be easily removed by loosening the T-head bolt 8a after cooling and waiting. In addition,
Although the welding of the short pipe portion has been described above, in the case of a long pipe, as shown in FIG.
a, whereby the T-head bolt 8a is remotely operated for attachment and detachment.

The T-head bolt 8 is shown as a driving means of the frusto-conical member 6 in the above embodiment, but as shown in FIG.
An engagement hole 6a may be provided in the truncated conical member 6, and a bolt 8a may be rotatably engaged with the engagement hole 6a. In the drawing, reference numeral 6b denotes a lid closing the engagement hole 6a, which is attached by a bolt nut 6c.

Although the case where the cylindrical body is divided into three equal parts has been described, the invention is not limited to this, and the cylindrical body may be divided into four equal parts or more.

[0023]

As described above, according to the present invention, when a resin tube is heat-welded, a necessary internal pressure can be obtained by arranging the resin tube on the inner surface of the welded portion and expanding the diameter, or a perfect circle can be corrected. In addition, it is possible to weld a pipe without preparing a core corresponding to the pipe diameter as in the related art.

Further, since the core is not used, there is no decrease in the effective section of the tube after welding. In addition, the amount of diameter expansion can be adjusted by adjusting the amount of axial movement of the frusto-conical member, so it can be used for various pipe diameters with a kind of welding jig, and a core that matches the pipe diameter as before is available This has the effect of eliminating the need for complicated operations.

[Brief description of the drawings]

FIG. 1 is a sectional view of a jig for welding a resin tube according to an embodiment of the present invention.

FIG. 2 is a partially omitted sectional view taken along line XX of FIG. 1;

FIG. 3 is an explanatory diagram of a use state of the embodiment of the present invention.

FIG. 4 is a diagram illustrating another use state of the embodiment of the present invention.

FIG. 5 is a sectional view showing another configuration example of the embodiment of the present invention.

FIG. 6 is a sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Collar joint 2 Plastic pipe to be connected 3 Heater 4 Cylindrical divided body 5 Base 6 Truncated conical member 7 Space 8 Drive member

Claims (1)

[Claims] 1. A split cylindrical body whose outer surface is a parallel surface and whose inner surface is an inclined surface increasing in thickness toward one end, wherein the split cylindrical body is divided into a plurality of equal parts in the circumferential direction, and the split cylindrical body is divided. A base that supports one end of each piece so as to be able to move in parallel in the radial direction, and a truncated conical member that is concentrically arranged along the inclined surface in a space surrounded by the divided pieces of the cylindrical body, A driving member for forcibly moving the frustoconical member toward the base;