JPH0727262A - Corrugated tube - Google Patents

Abstract

PURPOSE:To provide a corrugated tube where the pulling-out strength when the tube is screwed into a joint or the like is large, the connection by the screwing which can be connected/disconnected and the excellent watertightness by the O-ring can be obtained, and the tube can be connected at any part in the longitudinal direction of the tube. CONSTITUTION:In a corrugated tube, a bottom part 1 and a top part 2 are provided on the outer circumference of a tube along the circumferential direction orthogonal to the longitudinal direction of the tube, and a second bottom part 3 which is shallower than the bottom part 1 is formed on the top part 2 so as to be along the spiral direction where the longitudinal direction of the tube is the axis of the spiral.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrugated pipe used for laying electric wires and the like.

[0002]

2. Description of the Related Art There are two types of conventional corrugated pipes. One is a trough portion and a mountain portion formed on the outer periphery of the corrugated pipe. A pipe with an independent wave provided along the circumferential direction orthogonal to the direction,
The other is a spiral corrugated tube in which the valley portion and the mountain portion are provided spirally.

When connecting such a pipe with an independent wave using a joint or the like, a water-tight pipe can be easily connected by using an O-ring. However, once the joint is connected, the connection can usually be released only by breaking the joint in two and opening or disassembling. Therefore, various joints for independent wave pipes have been proposed which can easily release the connection, but the structure such as the engaging projections of the joints becomes complicated and becomes expensive.

On the other hand, when the spiral corrugated pipe is connected by using a joint or the like, the spiral corrugated pipe is screwed into a joint having a spiral groove for fitting the spiral corrugated pipe on the inner surface, so that the connection strength is high. The connection can be made. Further, the connection of the spiral corrugated pipe connected to the joint can be easily released simply by turning the joint. However, it is difficult for the spiral corrugated pipe to have watertightness with an O-ring etc. at the time of connection like the independent corrugated pipe. There was a cost problem.

In order to solve such a problem
In Japanese Patent Laid-Open No. 36187/1993, a parallel portion 10 in which a valley portion and a mountain portion are provided on the outer circumference of the pipe along a circumferential direction orthogonal to the length direction of the pipe, as shown in FIG. There has been proposed a corrugated tube characterized in that a spiral portion 9 having a spiral portion and a spiral portion 9 are sequentially provided.

When connecting the corrugated pipe, the corrugated pipe is easily cut by cutting the corrugated pipe at the spiral portion 9 and screwing the cut portion into a joint having a spiral groove for fitting with the spiral portion 9 on the inner surface. A strong connection is possible. Further, the connection of the spiral corrugated pipe connected to the joint can be easily released by simply rotating the joint. Moreover, if the O-ring is fitted in the valley portion of the parallel portion 10, watertightness can be easily obtained. However, in this corrugated pipe, the parallel portion 10 and the spiral portion 9 having different shapes are sequentially provided on the outer periphery of the pipe, so that the connection points are limited. For example, when it is necessary to bend and lay this corrugated pipe at a corner or the like, the spiral portion 9 of the corrugated pipe is
It does not always come to a straight line laying place. That is, if the spiral portion 9 comes to the corner portion where the corrugated pipe is bent and laid and the above-mentioned connection is made, the joint comes to the bent portion, and the pipe cannot be bent smoothly and cannot be laid.
Occasionally, the installation work must be redone.

The present invention has been made as a result of extensive studies in view of the above circumstances, and has a large pull-out strength by being screwed into a joint or the like, and a connection by screwing that can be easily disconnected, and an O-ring at the same time. An object of the present invention is to provide a corrugated pipe which has good watertightness and can be connected to any portion in the longitudinal direction of the pipe.

[0008]

According to the present invention, a valley portion 1 and a mountain portion 2 are provided on the outer circumference of a pipe along a circumferential direction orthogonal to the length direction of the pipe, and the mountain portion (hereinafter referred to as a parallel mountain). Part) 2
In addition, a second valley portion (hereinafter, spiral valley portion 3), which is shallower than the valley portion (hereinafter, parallel valley portion) 1, is formed along a spiral direction whose axis is the length direction of the pipe. The above problem was solved by the corrugated pipe.

The depths of the parallel valley portion 1 provided in the corrugated pipe of the present invention and the spiral valley portion 3 provided in the parallel mountain portion 2 are not particularly limited, but the parallel valley portion 1 has a spiral valley. Must be deeper than Part 3. If the parallel valleys 1 are shallower or have the same depth, the liquid such as water leaking from the corrugated pipe flows along the spiral valleys 3 even if the O-ring 8 or the like is used to obtain watertightness at the time of connection. Therefore, after all, the watertightness comparable to that of the spiral wave tube is obtained. The pitch of the spiral valley portions 3 provided in the corrugated pipe of the present invention is not particularly limited and may be different from or the same as the pitch of the parallel mountain portions 2.

In order to manufacture the corrugated pipe of the present invention, the synthetic resin melted and softened by the extruder is formed into a tubular shape by a die and introduced into a caterpillar type molding machine. The inner surface of the mold of this caterpillar molding machine is formed in a shape corresponding to the desired outer shape of the tube. By applying an internal pressure to the tubular synthetic resin introduced into the mold or sucking the inside of the mold, a corrugated pipe shaped into a desired shape can be manufactured.

[0011]

In the corrugated pipe of the present invention, since the parallel valley portion 2 is provided with the spiral valley portion 3 having the length direction of the pipe as an axis, the spiral corrugated pipe is used by utilizing the spiral valley portion 3. Similar connections can be made. Further, since the depth of the spiral valley portion 3 is shallower than that of the parallel valley portion 1, the watertightness similar to that of the independent corrugated pipe is obtained due to the step. Further, since the same shape is continuous in the longitudinal direction of the pipe, it is possible to connect at any position in the longitudinal direction of the pipe.

[0012]

EXAMPLES The present invention will be specifically described below based on examples. (Embodiment 1) FIG. 1 is a schematic view of a corrugated pipe of this embodiment, in which a parallel valley portion 1 and a parallel mountain portion 2 are provided on the outer circumference of the pipe along a circumferential direction orthogonal to the length direction of the pipe. And
A spiral valley portion 3 shallower than the parallel valley portion 1 is provided in the parallel mountain portion 2 so as to extend along a spiral direction whose axis is the length direction of the tube. The tube is made of cross-linked polyethylene and has a wall thickness of 3 mm. The distance from the outer circumference of the parallel mountain portion 2 provided in this pipe to the central axis of the pipe is 75 mm, and the distance from the outer circumference of the parallel valley portion 1 to the central axis of the pipe is 60 mm.
Is. The parallel peak portion 2 is provided with a spiral valley portion 3 formed along two parallel spirals whose axes are in the length direction of the pipe. The pitch of the spiral valley portion 3 is 1/2 of the pitch of the parallel mountain portion 2. The distance from the outer circumference of the spiral valley portion 3 to the central axis of the pipe is 70 mm, which is 10 mm shallower than the parallel valley portion 1.

The corrugated tube of this embodiment can be connected as follows. That is, as shown in FIG. 5, an O-ring 8 is previously fitted in the parallel valley portion 1 of this corrugated pipe, and the convex portion 5 and the taper portion 7 which are fitted to the spiral valley portion 3 are formed on the inner surface.
It can be connected by being screwed into the sleeve 6 having.

When the corrugated pipe is connected in this way, the convex portion 5 on the inner surface of the sleeve 6 is fitted in the spiral valley portion 3, so that a connection having an excellent pull-out strength is possible and the sleeve 6 The connection can be easily released simply by screwing out the corrugated pipe. Further, since the depth of the spiral trough 3 is 10 mm shallower than that of the parallel trough 1, the flow path of liquid such as water leaking from the corrugated pipe can be cut off by the step and the O-ring 8. Therefore, the same good watertightness as that of the conventional pipe with independent wave can be obtained. Moreover, by compressing the O-ring 8 by the taper portion 7 of the sleeve 6, even better watertightness can be obtained. Further, since the same shape is continuous in the longitudinal direction of the pipe, it is possible to connect at any position in the longitudinal direction of the pipe.

(Example 2) As shown in Fig. 2, a corrugated tube similar to that of Example 1 was obtained except that the pitch of the spiral valley portions 3 was made the same as the pitch of the parallel peak portions 2. Even in such a corrugated tube, the same operation and effect as in Example 1 were obtained.

(Embodiment 3) As shown in FIG. 3, except that the parallel valley portion 2 is formed with a spiral valley portion 3 along a single spiral having the length direction of the pipe as an axis. A corrugated tube similar to that in Example 1 was obtained. Even in such a corrugated tube, the same operation and effect as in Example 1 were obtained.

(Embodiment 4) FIG. 4 is an external view of a corrugated pipe of this embodiment, in which a parallel valley portion 1 and a parallel valley portion 1 are provided on the outer periphery of the pipe along the circumferential direction orthogonal to the length direction of the pipe. The parallel valley portion 2 is provided with a spiral valley portion 3 which is shallower than the parallel valley portion 1 so as to extend along a spiral whose axis is the length direction of the pipe. The tube is made of cross-linked polyethylene and has a wall thickness of 3 mm. The distance from the outer periphery of the parallel peak portion 2 provided in this pipe to the central axis of the pipe is 75 mm, and the distance from the outer periphery of the parallel valley portion 1 to the central axis of the pipe is 60 mm. The parallel peak portion 2 is provided with a spiral valley portion 3 formed along two parallel spirals whose axes are in the length direction of the pipe. The pitch of the spiral valley portion 3 is 1/2 of the pitch of the parallel mountain portion 2. Also, the distance from the outer circumference of this spiral valley part 3 to the central axis of the pipe is 75
mm, which is 15 mm shallower than the parallel valley 1. Further, the spiral mountain portion 4 formed between the spiral valley portion 3 and the spiral valley portion 3 has a semicircular cross section.
Even in such a corrugated tube, the same operation and effect as in Example 1 were obtained.

[0018]

As described above, according to the present invention, since the spiral valley portion 3 is provided in the parallel mountain portion 2, the spiral valley portion 3 is used to achieve the same connection as that of the spiral corrugated pipe. It can be carried out. Further, since the depth of the spiral valley portion 3 is shallower than that of the parallel valley portion 1, the watertightness similar to that of the independent corrugated pipe is obtained due to the step. Further, since the same shape is continuous in the longitudinal direction of the pipe, it is possible to connect at any position in the longitudinal direction of the pipe. Therefore, according to the present invention, the pull-out strength by screwing into the joint or the like is large,
And the connection by screwing that can be easily disconnected, and O at the same time
The ring provides good water tightness and can provide a corrugated tube that can be connected at any point in the longitudinal direction of the tube.

[Brief description of drawings]

FIG. 1 is a schematic view showing a corrugated tube of the present invention.

FIG. 2 is a schematic view showing a corrugated tube of the present invention.

FIG. 3 is a schematic view showing a corrugated tube of the present invention.

FIG. 4 is a schematic view showing a corrugated tube of the present invention.

FIG. 5 is a partial cross-sectional view showing a method of connecting corrugated pipes.

FIG. 6 is a schematic view showing a conventional corrugated tube.

[Explanation of symbols]

 1 valley part, parallel valley part 2 mountain part, parallel mountain part 3 second valley part, spiral valley part 4 spiral mountain part 5 convex part 6 sleeve 7 taper part 8 O-ring 9 spiral part 10 parallel part

Claims (1)

[Claims] 1. A valley portion (1) and a mountain portion (2) are provided on the outer circumference of the pipe along a circumferential direction orthogonal to the length direction of the pipe,
A second valley portion (3), which is shallower than the valley portion (1), is formed in the mountain portion (2) so as to be along a spiral direction whose axis is the length direction of the pipe. Corrugated tube.