JPH0444950Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a stretchable and flexible spiral tube that is widely used, for example, as a protective tube for electric wires and cables.

(Prior art) As this type of spiral tube, for example,
The one published in the publication is known. As shown in FIG. 3, the spiral tube has a fitting part a on one side edge that is bifurcated and has a fitting part a facing each other on the inner edge of the open end, and a fitting part a on the other side edge. A band-shaped synthetic resin profile d having a locking part c that is slidably fitted and locked into the fitting part a is wound in a spiral shape, and the fitting parts are adjacent to each other in the wound state. a
and a locking part c are fitted to form a cylindrical shape,
The locking portion c is laminated with a soft sealing material e, while the opposing surfaces of the retaining portions b are provided with sawtooth irregularities f, f. Such a spiral tube can be expanded, contracted, or bent by sliding the locking part c in the axial direction of the tube within the fitting part a, and the locking part c can be moved into the fitting part a. The tube diameter can be freely changed by sliding it in the circumferential direction of the tube within a.
Furthermore, the soft sealing material e provided on the locking part c comes into airtight contact with the inner wall surface of the fitting part a, and the soft sealing material e bites into the serrated irregularities f of the retaining parts b and b. Therefore, it is possible to obtain watertightness and airtightness.

(Problems to be Solved by the Invention) However, the conventional spiral tube described above has the following problems.

In other words, if the amount of soft sealing material e applied is insufficient or the application is uneven, or if dirt or sand is deposited between the retaining parts b, b of fitting part a and the soft sealing material e during underground burying work. In case of intrusion,
There is a problem that the water stop function of the soft sealing material e is impaired, and groundwater etc. can enter the inside of the pipe from between the retaining part b on the outer circumferential side and the soft sealing material e through the inside of the fitting part a. Ta. In addition, even if the retaining part b on the outer circumferential side
Even if it is possible to prevent groundwater, etc. from entering between the space between If it flows around the pipe in the space between the wall surface and the locking part c and enters the inside of the pipe from the connection part between the spiral pipe and the coupling member (the member that connects the spiral pipe and another pipe). I had a problem.

Furthermore, as years passed after the pipe was buried underground, the soft sealing material e exposed particularly on the outer circumferential side deteriorated, causing problems such as groundwater etc. infiltrating into the pipe as in the case described above.

Furthermore, since the soft sealing material e is provided so as to wrap around the entire locking portion c, the rigidity of the entire profile d increases, impairing the flexibility that is the original function of the spiral pipe, and reducing workability. I had a problem that I thought was bad.

Moreover, this kind of spiral tube can of course be freely bent into a desired shape when buried;
After burial, it is desirable to maintain the initially determined shape and protect the electric wires and cables inserted inside from damage caused by ground movement, but the conventional spiral pipes described above always have a locking part c. Because it is designed to slide freely within the fitting part a, if the ground changes after burial, the bent shape will easily change due to the movement, and as a result, in some cases, the bending shape may change. There was a risk that excessive tension would be applied to the electric wires and cables inside the pipe, causing accidents such as wire breakage.

(Means for Solving the Problems) The spiral tube according to the present invention has a fitting portion on one side edge that is bifurcated and has a retaining portion opposite to the inner edge of the open end, and on the other edge, A band-shaped synthetic resin profile having a locking part that is slidably fitted and locked into the fitting part is spirally wound and engaged with the fitting parts adjacent to each other in the wound state. A spiral tube having elasticity and flexibility formed into a cylindrical shape and fitted with a stop part, wherein at least one of the stop parts of the fitting part is on the outer peripheral side in the rolled state. A heating element is embedded inside, and the heat generated by the heating element causes the retaining part and the locking part to be thermally welded.

(Function) The function of the present invention will be described in the first example showing one embodiment of the present invention.
This will be explained with reference to the figures and FIG.

After installing the spiral pipe in a predetermined position while bending it into a predetermined shape, a power source is connected to the heating elements 4, 4, and electricity is applied to generate heat until the retaining parts 11, 11 of the fitting part 1 reach a temperature sufficient to melt them. let Then, the retaining parts 11, 11 melt, and these retaining parts 11, 11
and the locking portion 2 are tightly welded together. As a result, the helical pipe is fixed in a predetermined bent shape, ensuring the desired axial tensile strength and compressive strength, and preventing infiltration of groundwater etc. over the entire length of the pipe (particularly at the retaining part 11). It is reliably blocked between the outer peripheral side of the tube) and the locking part 2.

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

FIG. 1 is a partial perspective view showing a synthetic resin profile 1 constituting a helical tube according to the present invention, and FIG. 2 is a partially cutaway front view of the helical tube.

This spiral tube has a fitting part 1 on one side edge that is bifurcated and has retaining parts 11, 11 provided oppositely on the inner edge of the open end, and has a fitting part 1 on the other side edge that can be slid into the fitting part 1. A band-shaped synthetic resin profile 3 having a locking part 2 that can be fitted and locked is spirally wound, and the fitting part 1 and the locking part 2 are adjacent to each other in the wound state. are fitted into a cylindrical shape, and heating elements 4, 4 are embedded inside the retaining parts 11, 11 of the fitting part 1, respectively.

Examples of the material for the synthetic resin profile 3 include polyolefin, polyvinyl chloride,
Thermoplastic synthetic resin such as polycarbonate is used. This profile 3 is manufactured continuously by extrusion. Note that the cross-sectional shape of the profile 3 is not limited to the illustrated example.

The heating element 4 is something that generates heat when energized, and for example, a nichrome wire or a copper wire is used, but its form is not limited to the wire shown in the illustration, but may also be in the form of a strip. good. In addition, this heating element 4
The material used here has enough heat generation to melt the retaining parts 11, 11 of the profile 3 and thermally weld them to the locking part 2 fitted into the fitting part 1. The heating element 4 constructed in this way is manufactured by the extrusion molding of the profile 3 at the same time as the retaining part 1 of the fitting part 1.
1 and 11, but it is preferable that the embedding position be closer to the opposing surface of the retaining parts 11, 11. Note that the heating element 4 is not necessarily attached to the retaining parts 11, 1.
It is not necessary to embed both of them, but it is sufficient to embed them at least in the retaining part 11 that is on the outer peripheral side in the rolled state of the profile 3 (assembled into a spiral tube).

Next, the construction procedure of the spiral pipe of the present invention as described above will be explained.

First, a spiral pipe is laid in a predetermined position while being bent into a predetermined shape. Normally, spiral pipes are often used for curved parts, such as parts that bypass existing buried structures (for example, gas pipes, water pipes, etc.).

Next, connect a power source to the heating elements 4, 4, and
Electricity is applied to generate heat until the retaining parts 11, 11 reach a temperature sufficient to melt them. Then, the retaining part 1
1 and 11 are melted and welded to the portion of the locking portion 2 that is in contact with these retaining portions 11 and 11. As a result, the helical tube is fixed in a predetermined bent shape, and the desired axial tensile strength and compressive strength are ensured. Incidentally, the power supply can be easily connected to the heating elements 4, 4 if both ends of the heating elements 4, 4 are made to protrude an appropriate length from the end of the profile 3 in advance.

Once the above-mentioned fixing is completed, the excavated soil is backfilled, and finally underground objects (wires, cables, etc.) are pulled into the spiral pipe to complete the construction.

(Effects of the invention) As explained above, in the spiral tube of the present invention, a heating element is embedded in the retaining part of the fitting part, and the retaining part is melted by the heating element and welded to the locking part. Therefore, it is possible to reliably prevent the infiltration of groundwater, etc. over the entire length of the pipe between the retaining part and the locking part, and prevent groundwater from entering the inside of the pipe by passing through the fitting part as in the past. Or, if underground water or the like collects in the space between the inner wall surface of the fitting part and the locking part, it flows around the pipe and enters the inside of the pipe from the end of the pipe. Therefore, the electric wires, cables, etc. inside the spiral tube can be safely protected.

In addition, since the retaining part and the locking part are heat welded,
A predetermined bent shape can be maintained, and the tube has high tensile strength and compressive strength in the axial direction. As a result, even if the ground changes after being buried underground, the bent shape will not change, and the wires, cables, etc. inside the helical pipe can be safely and reliably protected at all times.

Furthermore, since the profile is simply a heating element embedded in its retaining portion, flexibility is not impaired and the tube can be easily bent into a predetermined shape. Therefore, it has excellent workability.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the spiral tube according to the present invention, FIG. 1 is a partial perspective view showing a synthetic resin profile constituting the spiral tube, and FIG. 2 is a part of the spiral tube. The cutaway front view and FIG. 3 are partial sectional views showing a conventional spiral tube. DESCRIPTION OF SYMBOLS 1... Fitting part, 11... Removal prevention part, 2... Locking part, 3... Profile, 4... Heat generating element.

Claims (1)

[Claims for Utility Model Registration] One side edge has a fitting part that is bifurcated and has a retaining part opposite to the inner edge of the opening end, and the other side edge has a fitting part that is slidably fitted into the fitting part. A band-shaped synthetic resin profile having a locking portion is wound spirally, and in the wound state, the fitting portion and the locking portion that are adjacent to each other are fitted to form a cylindrical shape. A spiral tube having stretchability and flexibility, wherein a heating element is embedded in at least the retaining part of the fitting part that is on the outer circumferential side in the rolled state, and the heat generating element is A helical tube characterized in that a retaining part and a locking part are thermally welded together by heat generated by the body.