JPH0340035Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to flexible electrical conduits.

(Conventional technology) Hard PVC pipes, FRPM pipes, steel pipes, etc. have traditionally been used to protect power cable lines.
In the case of PVC pipes, they are constructed by heating and softening them using a surface heating element, but this heating and softening process takes several hours and significantly impedes the progress of the factory. In addition, in the case of rigid pipes such as FRPM pipes, various bent pipes must be prepared in advance, and depending on the buried state of the existing pipes, there may be cases where the prepared bent pipes cannot be used, resulting in a delay in the construction period. Sometimes.
Furthermore, in the case of steel pipes, bending is carried out on site using a steel pipe bending machine, but this bending machine must be delivered to the site using a truck or the like, and specialized heavy machinery is also required.

For this reason, a flexible electrical conduit with excellent bendability has been developed, as disclosed in Japanese Patent Application Laid-Open No. 157311/1983.

This electric conduit will be explained with reference to FIGS. 4 and 5. Fig. 4 is a partially vertical cross-sectional front view, and Fig. 5 is an enlarged cross-sectional view of a main part of a bent part. A wire rod 3 made of metal or the like is wound around a groove 2 on the outer peripheral surface of the inner tube 1, and the outer circumference of the inner tube 1 containing the wire rod 3 is covered with an outer tube 4 made of synthetic resin.

[Problem that the invention attempts to solve]

This flexible electric conduit has the inner tube 1 corrugated to prevent damage to the inner circumferential surface of the inner tube 1 due to the electric wires inserted therethrough, and to improve bendability. .

However, since the reinforcing wire 3 is wound around the trough 2 on the outer periphery of the inner tube 1 in this conduit, when the conduit is bent, the compressed side is The wire rod 3 was pressed by the valley portion 2, and the wire rod 3 restricted the bending process.

Therefore, the present invention provides a flexible electrical conduit with even greater bendability.

[Means for solving problems]

The present invention has been developed in view of the above points, and is a flexible electrical conduit in which the outer circumferential surface of a synthetic resin inner tube whose inner and outer circumferential surfaces are wavy in the axial direction is coated with a synthetic resin outer tube. It is characterized in that a band material having a substantially U-shaped cross section is wound around the valley portion of the outer circumferential surface of the synthetic resin inner tube.

[Function] Therefore, with the above configuration, when bending a flexible conduit, the approximately U-shaped strip bends to a position where it closes the opening of the strip, so that The bendability of the electric conduit becomes even better.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a vertical cross-sectional front view of a flexible conduit, and FIG. 2 is an enlarged cross-sectional view of a main part of a bent part.
A steel strip 12 having a substantially U-shaped cross section is wound around the valley portion 11 of an inner tube 10 made of a hard plastic synthetic resin whose inner and outer peripheral surfaces are undulated in the axial direction. The outer peripheral surface of the inner tube 10 is covered with a smooth outer tube 13 made of soft plastic synthetic resin.

The inner tube 10 has a wavy shape with concavities and convexities formed at regular intervals in the tube axis direction and perpendicular to the tube axis.
A ring-shaped strip 12 is attached to the trough 11 on the outer peripheral surface.
are wound up with their respective openings 12a facing inward. The inner tube 10 around which the band material 12 is wound is covered with the outer tube 13 without adhesive.

Therefore, in the flexible electric conduit constructed in this way, the band material 12, the inner tube 10, and the outer tube 13 are loosely integrated with each other without bonding, so that, for example, when bending them vertically as shown in the figure, In this case, it can be expanded by the wavy irregularities on the upper side, and compressed at the lower side to make it follow. In addition, since the strip material 12 has a substantially U-shaped cross section, it can be bent to a position that closes the opening 12a, and has greater bendability than conventional wire material wound. Become.

Furthermore, the strip material 12 having a substantially U-shaped cross section and the inner tube 10 made of hard plastic synthetic resin increase the moment of inertia of the area (increase rigidity), thereby increasing the flat strength. The flatness of the wire is also small and does not impede the passage of cables, etc.

Since the outer tube 13 is made of soft plastic synthetic resin, the conduit tubes can be joined using conventional sockets, making installation easy.
Artificial variations in bonding quality are also reduced.

FIG. 3 is a longitudinal cross-sectional front view showing another embodiment of the present invention, in which the flexible conduit tube of this embodiment has an inner tube 20 made of hard plastic synthetic resin with irregularities spirally formed in the axial direction. A steel strip 22 having a substantially U-shaped cross section is wound spirally around the trough 21 of the inner tube 20 with its opening 22a facing the outside of the tube. The outer tube 23 is covered with a smooth outer tube 23 made of soft plastic synthetic resin, and can provide the same functions and effects as those of the embodiments described above.

Furthermore, in the flexible electric conduit tubes of both of the above embodiments, a woven fabric or a nonwoven fabric may be interposed between the inner tube and the band material. By doing so, a sliding effect can be produced between these without damaging the inner tube, so that bending workability can be reliably improved.

[Effect of idea]

As described above, the flexible conduit according to the present invention is
Since a band material having a substantially U-shaped cross section is wound around the troughs on the outer circumferential surface of the synthetic resin inner tube whose inner and outer circumferential surfaces are wavy in the axial direction, when bending the electric conduit tube, the conduit material is approximately U-shaped.
Since the character-shaped strip material can be bent to a position where it closes the opening, the conduit has greater bendability and the construction time can be shortened. Furthermore, since there is no need to prepare various bent pipes, the number of types of inventory can be reduced.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the flexible conduit according to the present invention. Figure 1 is a vertical cross-sectional front view of one embodiment, and Figure 2 is an enlarged view of the main part of the bent part. 3 is a vertical cross-sectional front view showing another embodiment, FIGS. 4 and 5 are a conventional flexible conduit, and FIG. 4 is a partial vertical cross-sectional front view, and FIG. FIG. 5 is an enlarged sectional view of the main part of the bent part. 10,20...Inner pipe, 11,21...Tanibe, 1
2, 22... band material, 12a, 22a... opening,
13,23...outer tube.

Claims (1)

[Scope of utility model registration request] In a flexible electrical conduit in which a synthetic resin outer tube is coated on the outer circumferential surface of a synthetic resin inner tube whose inner and outer circumferential surfaces are wavy in the axial direction, the troughs on the outer circumferential surface of the synthetic resin inner tube are A flexible electrical conduit characterized by winding a strip material with a substantially U-shaped cross section.