JPH06712Y2 - Spiral tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) 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) Conventionally, as a spiral tube of this type, for example, Japanese Patent Publication No. 36-2
The one described in Japanese Patent No. 0034 and the one shown in FIG. 6 are known. The spiral tube disclosed in the above publication is provided with a winding edge and a tubular edge integrally on both side edges of a tape-shaped band made of synthetic resin or rubber, and the tape-shaped band is spirally wound and adjacent to each other. The winding edge and the tubular edge are fitted and connected. Further, the spiral tube shown in FIG. 6 has a fitting portion a, which is bifurcated at one side edge and has retaining portions b, b which are opposed to each other at the inner edge of the opening end, and the fitting portion a at the other side edge. A band-shaped synthetic resin profile d having a locking portion c slidably fitted and locked in the portion a is spirally wound, and is engaged with the fitting portions a adjacent to each other in the wound state. It is formed into a cylindrical shape by fitting the stopper c. The spiral tube thus configured can be expanded and contracted or bent by sliding the locking portion c in the fitting portion a in the axial direction of the tube. The pipe diameter can be freely changed by sliding the pipe in the circumferential direction of the pipe in a.

In addition to the spiral tube as described above, a corrugated tube (corrugated tube) as shown in FIG. 7 has been conventionally used as a protective tube for electric wires, cables and the like. This corrugated pipe has a large rigidity in which a large number of corrugated portions g ... Are formed along the circumferential direction on the pipe wall over the entire length of the pipe at a constant pitch.

(Problems to be solved by the invention) However, although the conventional spiral pipes described above are excellent in flexibility and stretchability, they are generally low in rigidity and therefore reliable in underground use. There was a problem with sex. Further, if the thickness of the tape-shaped strip or the profile is increased to increase the rigidity, the weight of the entire pipe increases, the production cost rises, and there is a problem that it becomes difficult to produce the pipe in the cold. It was

On the other hand, in the corrugated tube, although there are few problems as described above in the spiral tube, since the corrugated tube has a large number of corrugated portions, it has almost no flexibility and therefore cannot be bent at the input at all, There is a problem in that workability is inferior because it bends back even if it is once bent.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a spiral tube that is lightweight, yet has high rigidity, and is excellent in flexibility.

(Problems to be Solved by the Invention) In order to achieve the above object, a spiral tube according to the present invention has a fitting portion having a bifurcated shape at one side edge and a retaining portion opposite to an inner edge of an open end. Then, the other side edge has a locking portion slidably fitted and locked in the fitting portion, and a hollow portion having a rectangular cross section is formed between the fitting portion and the locking portion. A strip-shaped profile made of synthetic resin is spirally wound with the hollow portion as an outer side, and the fitting portion and the locking portion which are adjacent to each other in the wound state are fitted to each other to form a tubular shape. It will be.

(Function) The hollow portion formed between the fitting portion and the locking portion enhances the rigidity of the pipe without increasing the weight of the pipe and impairing the flexibility, and at the time of pipe manufacturing. In, the deformation of the profile is prevented. Further, after the pipe is manufactured, the refrigerant can be circulated in the hollow portion, and the inside of the spiral pipe can be cooled.

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

1 is a partially cutaway front view showing a spiral tube according to the present invention, and FIG. 2 is a front view showing a synthetic resin profile constituting the spiral tube shown in FIG.

This spiral tube has a fitting part 1 which is bifurcated at one side edge and has retaining portions 11 and 11 opposite to each other at the inner edge of the opening end, and slides in the fitting part 1 at the other side edge. Locking part 2 that can be fitted and locked
And a strip-shaped synthetic resin profile 4 formed by forming a hollow portion 3 having a rectangular cross section between the fitting portion 1 and the locking portion 2, and spirally winding the hollow portion 3 outside. The fitting portion 1 and the locking portion 2 which are rotated and are adjacent to each other in the wound state are fitted to each other to form a tubular shape. The spiral tube thus configured can be expanded and contracted or bent by sliding the locking section 2 in the fitting section 1 in the axial direction of the tube.
The diameter of the pipe can be freely changed by sliding the locking portion 2 in the fitting portion 1 in the circumferential direction of the pipe.

The profile 4 is continuously manufactured by extrusion-molding a thermoplastic resin having a small friction coefficient such as polyfluorinated ethylene, polyamide, polyacetal, polystyrene, etc. The hollow portion 3 formed in the profile 4 is It is preferable that the shape satisfy the following conditions.

Hereinafter, the condition will be described with reference to FIGS. 2, 4, and 5.

In FIG. 2, reference numeral H indicates the height of the hollow portion 3, reference numeral T indicates the wall thickness of the hollow portion 3, and reference numeral W indicates the width of the hollow portion 3. The relationship between the height H of the hollow portion 3 and the wall thickness T is H = 7T
, The weight of the pipe is about 3/4 of the weight of the pipe due to the profile in which the hollow portion 3 is not provided at all, and H
When> 7H, it becomes difficult to bend the profile 4 in the cold state and the pipe manufacturing performance deteriorates. Therefore, it is considered that H = 7T is the limit of the height of the hollow portion 3. Further, the width W of the hollow portion 3 has a relationship with the wall thickness T of W in order to secure the sliding amount of the locking portion 2 along the axial direction of the pipe, that is, the flexibility of the pipe.
The width is preferably 3T to 5T.

That is, as the shape of the hollow portion 3 of the profile 4,
In order to satisfy all of the tube weight, rigidity and flexibility, the height H is up to 7 times the wall thickness T in the hollow portion 3, and the width W is 3 times the wall thickness T. It is preferable that the shape is such that the condition of being twice to five times is satisfied.

The table below shows the results (actually measured values) of simulations of a shape in which the wall thickness T and height H of the hollow portion 3 are changed and the tube weight is reduced while increasing the rigidity of the tube, and FIG. Is a graph of the table. The values in the following table are the values when all pipes are manufactured so that the inner diameter of the pipes is 100 mm, and when the pipes are completely retracted (the engagement part 2 is fully inserted in the fitting part 1). is there. Also, the fourth
The second moment of area in the figure is the second moment of area around the neutral axis per effective length in the fully degenerated state.

From the graph of FIG. 4, the profile 4 having the hollow portion 3 is shown.
According to this, it is understood that the rigidity of the pipe can be increased while reducing the weight of the pipe.

FIG. 5 is a graph showing the relationship between the rigidity of the pipe and the bending load of the pipe. Note that this graph is also for the case where the profile 4 is manufactured into a pipe having an inner diameter of 100 mm by a pipe manufacturing machine. From this graph, it can be seen that the rigidity of the pipe is increased and the bending performance is hardly changed. In the graph shown in FIG. 5, the curved line shown by the broken line shows the case of a corrugated pipe as shown in FIG. 7. In this corrugated pipe, if the rigidity of the pipe is increased, the bending performance becomes significantly poor (bending The load becomes large).

Note that the hollow portion 3 is not limited to the shape protruding only to one side as in the above example, and the center of the hollow portion 3 is on the extension line of the locking portion 2 as shown in FIG. 3, for example. The shape may be positioned, and the steel strip 5 may be embedded in the wall portion of the hollow portion 3. The embedding of the strip steel 5 is performed during extrusion molding of the profile 4.

When a coolant such as water or freon is passed through the hollow portion 3 of the profile 4 as described above, the spiral tube of the present invention is particularly suitable for use as a protective tube for a power cable or the like in which heat is a problem. is there. That is, the spiral tube has a hollow portion (space in the fitting portion 1) in the cross section of the tube due to its structure, but this hollow portion acts as a heat retaining layer, and heat inside the tube generated by energizing the power cable or the like. Has the property of not radiating heat to the outside of the pipe. Such a property
This is preferable when it is used as a protective tube for those requiring heat retention, but on the contrary, it becomes a problem when used as a protective tube for those requiring cooling. For example, when the power cable is passed through the inside of the pipe, the heat generated from the power cable when electricity is applied accumulates inside the pipe, and the temperature inside the pipe rises to about 90 ° C in some cases. There is an inconvenience that the electric resistance of the power cable becomes high and the power loss becomes large. However, if the refrigerant is passed through the hollow portion 3 to cool the entire tube as described above, the above-mentioned problem of heat radiation can be solved.

(Effect of the Invention) As described above, since the spiral tube of the present invention is manufactured by the profile in which the hollow portion is formed between the fitting portion and the locking portion, it is lightweight and flexible. It has excellent properties and high rigidity, and can exhibit high reliability when used underground. At the same time, pipe manufacturing is easy, there is no risk of the profile being deformed during pipe manufacturing, and bending back hardly occurs, so workability is excellent. Furthermore, since the hollow portion of the profile can be used as the flow path of the refrigerant, it can be used as a protective tube that requires cooling, and is particularly effective for power cables and the like.

[Brief description of drawings]

1 is a partially cutaway front view showing a spiral tube according to the present invention, FIG. 2 is a front view showing an example of a synthetic resin profile forming the spiral tube shown in FIG. 1, and FIG. 3 is a synthetic resin FIG. 4 is a front view showing another example of the profile, FIG. 4 is a graph showing the relationship between the height of the hollow portion of the profile and the second moment of area of the pipe and the relationship between the height and the weight of the pipe, and FIG. 5 is the rigidity of the pipe. Is a graph showing the relationship between the bending load of the pipe and FIG. 6, FIG. 6 is a sectional view showing a conventional spiral pipe, and FIG. 7 is a sectional view showing a conventional corrugated pipe. DESCRIPTION OF SYMBOLS 1 ... Fitting part 11 ... Preventing part 2 ... Locking part 3 ... Hollow part 4 ... Synthetic resin profile

Claims (1)

[Scope of utility model registration request] 1. A one-sided edge has a fitting portion which is bifurcated and in which an inner edge of the opening end is provided with a stopper portion, and the other side edge is slidably fitted and locked in the fitting portion. A belt-shaped synthetic resin profile formed by forming a hollow portion having a rectangular cross section between the fitting portion and the locking portion is wound spirally with the hollow portion as the outside. The spiral tube is characterized in that the fitting portion and the locking portion which are adjacent to each other in the wound state are fitted to each other and formed into a tubular shape.