JPH09229264A - Bendable and expansible universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive bendable and expansible universal joint having the high degree of freedom, for connecting pipes for a communication cable. SOLUTION: Two sets of joint sets each of which is composed of a first spherical part provided joint pipe 10 in which a first spherical part 11 is formed on one end, and a second spherical part provided joint pipe 20 in which a second spherical part 21 to be slidably fitted to the first spherical part 11 is formed on one end are arranged between two pipes C, D, the end on one side of a slide pipe 30 is fitted to one second spherical part provided joint pipe 20 so as to be freely slid (expanded) in the longitudinal direction, and the end on the other side of the slide pipe 30 is fitted to the other second spherical part provided joint pipe 20 so as to be freely slid in the longitudinal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication cable which is inserted, intervenes in the connection of pipes buried in the ground, and which follows the fluctuation of the buried ground, The present invention relates to a bending / expanding universal joint that easily bends / expands.

[0002]

2. Description of the Related Art Conventionally, even if a communication cable is inserted and intervenes in connecting pipes buried in the ground, and there is a change in the buried ground, it is possible to easily bend and bend it. As a bending / expanding universal joint that expands and contracts, one having a structure as shown in FIG. 7 has been proposed (for example, Japanese Patent Publication No. 64-7275).

That is, the joint body 1a and the joint pipe A, which are screwed into one pipe C, are formed by the former convex spherical portion 4
Are slidably fitted into the concave spherical surface portion 6 of the latter, so that they are flexibly connected to each other. The other pipe D
Similarly, the joint body 1b and the joint tube B screwed together are also bendably connected via the convex spherical surface portion 4 and the concave spherical surface portion 6. Moreover, the joint pipe A and the joint pipe B are fitted to each other so as to be slidable (or expandable) in the longitudinal direction.

Accordingly, the pipe C and the pipe D are
The joint body 1a, the joint pipes A and B, and the joint body 1b are connected so that they can be bent and expanded and contracted. In addition, the joint bodies 1a and 1b, the convex spherical surface portion 4, and the concave spherical surface portion 6 each have a communication hole through which a communication cable can be inserted.

Further, an annular space S having a predetermined length is formed between the inner surface of the joint pipe A and the outer surface of the joint pipe B, and a ring-shaped stopper body 2s is attached at a desired position in the length direction. ing. Further, annular stoppers 2a and 2b that limit the annular space S are provided at the tip of the joint pipe A and inside the tip by a predetermined length.

With the above structure, the joint pipes A, B
Of the joint pipes A and B
Irrespective of the length of the joint, only by changing the positions of the blocking body 2b and / or the stopper body 2s, the expansion / contraction length of the joint is limited to a desired range, and the manufacturing cost is reduced.

[0007]

However, since the joint bodies 1a and 1b and the joint pipes A and B have complicated structures, they depend on expensive castings, and therefore the lengths of the joint pipes A and B are also required. Limited to the shortest one. Therefore, when the communication cable is buried in the ground where the expansion and contraction length is short and the ground subsidence is expected to be remarkable, a large number of universal joints are required at short intervals, which has a disadvantage of increasing cost.

Therefore, the present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and its purpose is to:
The present invention provides a flexible / expandable universal joint that can sufficiently cope with underground where it is expected that ground fluctuation will be significant, is inexpensive, and can be easily changed in length by cutting at the site.

[0009]

In order to achieve the above-mentioned object, a communication cable is inserted, and the pipes (C, D) buried in the ground are intervened to connect the pipes (C, D), and the ground is buried. The flexible joint of the present invention, which flexes and expands and contracts easily even when there is a change in the temperature, has a first spherical surface portion (11) at one end between two pipes (C, D). ) Is formed, and a second spherical surface portion (21) slidably fitted to the first spherical surface portion (11) and the first spherical surface portion (11).
A plurality of sets of joint sets, each of which is composed of a joint pipe (20) with a second spherical portion formed at one end thereof, are arranged, and one joint pipe (20) with a second spherical portion is provided on one side of the slide pipe (30). Of the slide pipe (30) slides in the longitudinal direction, and the other end of the slide pipe (30) slides in the other second spherical joint pipe (20) in the longitudinal direction. The slide tube (30) is telescopically fitted, and at the end of each second spherical joint pipe (20) on which the slide tube (30) is fitted.
A stopper (25) for stopping the drop-out preventing projection (35) provided at the end fitted to the second spherical joint pipe (20) is provided (Claim 1).

In the second bending / expanding universal joint of the present invention, at least a part of the slide tube (30) of claim 1 is bent or curved as required (claim 2). ). Symbols in parentheses indicate corresponding elements or corresponding matters in the embodiments of the invention shown in the drawings and described later.

According to the first aspect of the present invention, compared with the conventional example, the length of expansion and contraction is remarkably increased, the followability is extremely high, and the expansion and contraction portions are dispersed in two places, even if one does not operate. The reliability is improved because the other corresponds. Moreover, since it is possible to use an inexpensive gas pipe, necessary castings can be made inexpensive, and the manufacturing cost can be reduced. The two joint sets are usually used so as to face each other, but the present invention is not limited to this, and three or more sets can be connected.

According to the invention of claim 2, the degree of freedom of construction is increased and the cost is reduced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. 1 is a cross-sectional view showing a basic configuration of an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a state of following the ground movement of the embodiment of FIG. 1, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a partial sectional view showing details of the example, FIG. 4 is a sectional view showing a basic configuration of another embodiment, FIG. 5 is a sectional view showing a basic configuration of a third embodiment, and FIG. It is sectional drawing which shows the state which followed the ground movement of the example of embodiment.

If a communication cable is inserted and the pipes C and D buried in the ground are intervened in connection with each other and there is a change in the buried ground, it can be easily bent and expanded and contracted by following it. The main constitution of the embodiment of the bending / expanding universal joint of the present invention is as follows.

That is, between the two pipes C and D, the first spherical joint pipe 10 and the second spherical joint pipe 20 are provided.
Two joint sets made of (both are cast products) are arranged so as to face each other. Further, a concave first spherical surface portion 11 is formed at one end of the first spherical portion-equipped joint pipe 10, and the first spherical surface portion 11 has a convex portion formed at one end of the second spherical portion-equipped joint pipe 20. The second spherical surface portion 21 is slidably fitted, and the first spherical surface portion-equipped joint pipe 10 and the second spherical surface portion-equipped joint pipe 20 are mutually bendable.

The above-mentioned pair of second spherical joint pipes 20, 20
Both ends of a slide pipe 30 made of a gas pipe or the like, which is inexpensive and easy to work such as cutting and bending, are slidably fitted in the longitudinal direction. Moreover, in order to prevent the slide pipes 30 fitted therein from coming out of the respective second spherical joint pipes with spherical parts 20, the slide pipes 30 are prevented from coming off at the ends of the slide pipes 30 fitted to the second spherical joint pipes 20. The protrusion 35 is provided, and a stopper 25 that stops the drop-out preventing protrusion 35 is provided at the end of the second spherical joint pipe 20 on which the slide pipe 30 is fitted. The combination of the joint sets is not limited to the above-mentioned ones, and two slide pipes 30 connected by a union or the like and a fitting pipe 20 with the second spherical portion can be fitted as necessary. A combination in which the other end of the formed slide tube 30 is screwed and connected to another first spherical surface-equipped joint tube 10 (another second spherical surface-equipped joint tube 20 is fitted) is also possible. . It is also possible to use three or more joint sets as a whole by interposing another joint set between the two joint sets.

Further, instead of the first joint pipe 10 with a spherical surface portion having a concave first spherical portion 11 formed at one end and the second joint pipe 20 having a spherical portion with a second spherical portion 21 formed therein. In addition, as shown in FIGS. 5 and 6, a first spherical joint pipe 40 with a convex first spherical portion 41 is formed at one end thereof.
And a second spherical joint pipe 50 with a second spherical portion having a concave second spherical portion 51 slidably fitted in the first spherical portion 41 at one end.
May be used.

The slide tube 30 is not limited to a linear shape, and a part of the slide tube 30 may vary depending on the condition of the ground and the structure.
If necessary, it is possible to bend or bend in the field, or connect a plurality of pieces to make them longer, and further cut them to a required length. In this embodiment, a commercially available 5.5 m gas pipe was used.

Explaining the details of each part, in the first spherical joint pipe 10 with a spherical surface, an inner screw 15 is formed on the inner surface of one end so that the pipe can be screwed, and the other side is gradually enlarged. The first spherical surface portion 11 is formed inside the large diameter portion at the tip. In this concave first spherical surface portion 11, the inner surface of the flange portion formed inside the large diameter portion and having an appropriate width in the longitudinal direction and an appropriate thickness in the radial direction is a part of the spherical surface. Is.

The second spherical joint pipe 20 has a straight pipe portion at one end so that a convex second spherical portion 21 is formed at one end.
It has a shape in which hollow spheres coaxially formed with circular holes having the same diameter as the diameter of the straight pipe portion are joined on opposite sides.
The second spherical surface portion 21 is slidably fitted in a state in which the convex second spherical surface portion 21 is fitted so as not to come off from the concave first spherical surface portion 11. And an external screw 1 on the outer surface of the joint tube 10 with the first spherical portion on the side of the first spherical portion 11
A cap nut 17 is screwed onto the screw 6. In addition, the end surface of the first spherical surface portion 11 and the portion that slides with the second spherical surface portion 21 have O
A ring 18 is attached.

Further, the stopper 25 is provided at the end of the straight pipe portion of the second spherical joint pipe 20 with a flange-shaped projection inwardly. On the other hand, the slip-out preventing projection 35 stopped by the stopper 25 is formed by bending the end of the slide tube 30 outward. In addition, on the end surface of the straight pipe part,
With the cap nut 27 screwed into the external screw 26 on the outer surface of the end of the straight pipe portion of the convex spherical joint pipe 20, the slide pipe 30
The packing 28 and the washer 29 on which the slides are fixed. In addition, around the straight pipe portions of the cap nuts 17, 27, the first spherical joint pipe 10 and the second spherical joint pipe 20, when tightening or loosening the screw, grasping with a pipe wrench or the like is sure. , A non-slip protrusion T is provided.

An example of the assembling procedure will be described. First, the pipe C is screwed onto the first spherical joint pipe 10. Next, the side of the slide tube 30 on which the drop-out preventing projection 35 is provided is located on the straight tube portion of the second spherical section-equipped joint tube 20.
1 side is fitted, and the cap nut 2 is attached to the outer screw 26 of the straight pipe portion.
7 are screwed together and fastened with packing 28 and washer 29. Next, the first spherical surface portion 11 of the joint pipe 10 with the first spherical surface portion
The second spherical surface portion 21 of the second spherical surface-equipped joint pipe 20 is fitted in. Further, the O-ring 18 is filled in the end surface of the first spherical surface portion 11 and the sliding portion with the second spherical surface portion 21. Next, in order to prevent the second spherical surface portion 21 from coming off from the first spherical surface portion 11, the cap nut 1 previously passed through the straight pipe portion of the second spherical portion-equipped joint pipe 20.
7 is screwed into the outer screw 16 on the outer surface on the first spherical surface 11 side. After that, the same operation is performed on the side of the pipe D, so that the pipes C and D are connected.

The first spherical surface portion 11, for explaining the operation,
The pipe C (D) screwed to the joint pipe 10 with the first spherical portion via the second spherical portion 21 and the slide pipe 30 fitted to the joint pipe 20 with the second spherical portion are arranged in the vertical and horizontal directions. It can be refracted over a considerable angular range. Further, since the slide pipe 30 can slide within the straight pipe portion of the fitted fitting spherical surface-equipped joint pipe 20, the slide pipe 30 can expand and contract by a length corresponding to the length of the substantially straight pipe portion.

In addition, since there are two expandable and contractible portions on the pipe C side and the pipe D side, if the length of one straight pipe portion is 250 mm, the extendable and retractable length is doubled to 500 mm.
Therefore, the followability is extremely higher than that of the conventional example. In addition, even if one of the stretchable portions does not work for some reason, the other stretchable portion corresponds to the stretchable portion, so that the probability of danger avoidance is higher than in the conventional example having one stretchable portion. , Increase reliability.

In addition, the introduction of the slide tube 30, which can be made of inexpensive material such as a gas tube, significantly simplifies the structure of the second spherical joint pipe 20 and reduces the manufacturing cost. Further, the slide tube 30 can be easily cut to a required length on-site, and moreover, only one kind of the first and second spherical surface joint pipes 10 and 20 need to be prepared, so that the manufacturing cost is further reduced. It In addition, the slide tube 30 has a high degree of freedom such that it can be bent or curved on site depending on the condition of the ground and the structure, if necessary.
Further, as shown in FIG. 5, one end of the slide pipe 30 is screwed and connected to another first spherical surface-equipped joint pipe 10, so that it is possible to locally follow a more complicated ground movement.

[0026]

Since the present invention is configured as described above,
The following effects are exhibited. That is, (a) since the expansion / contraction length is remarkably increased as compared with the conventional example, the followability is extremely high. (A) Since the stretchable portions are dispersed in two places, even if one does not work depending on the state of the ground or the structure, the other may be able to be dealt with, so the reliability is high. (C) The slide tube is inexpensive because it can be used as a commercial product instead of an expensive cast product, and the production cost is significantly reduced by combining slide pipes that can be easily cut, bent or bent on site. As a result, the degree of freedom in use is increased, and the overall cost is reduced. (D) It is applicable not only to communication cable pipes, but also to connection of water pipes and other pipes buried underground.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the basic configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state of following the ground movement according to the embodiment of FIG.

FIG. 3 is a partial cross-sectional view showing details of the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the basic structure of another embodiment of the present invention.

FIG. 5 is a sectional view showing the basic configuration of a third embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a state of following the ground movement according to the embodiment of FIG.

FIG. 7 is a partial cross-sectional view showing details of a conventional example.

[Explanation of symbols]

 10 First spherical joint pipe 11 Spherical part 15 Inner screw 16 Outer screw 17 Cap nut 18 O-ring 20 Second spherical joint pipe 21 Second spherical part 25 Stopper 26 Outer screw 27 Cap nut 28 Packing 29 Washer 30 slide tube 35 projection for preventing slippage 40 joint tube with first spherical surface portion 41 first spherical surface portion 50 joint tube with second spherical surface portion 51 second spherical surface portion 55 stopper A joint pipe B joint pipe C pipe D pipe S annular space T non-slip protrusion

Claims (2)

[Claims] 1. A communication cable is inserted to intervene in connecting pipes buried in the ground, and even if the buried ground changes, it flexes and expands and contracts easily following the fluctuation. In the bending / expanding universal joint, a joint pipe with a first spherical portion having a first spherical portion formed at one end between two pipes, and a second pipe slidably fitted to the first spherical portion. A plurality of sets of joint sets each including a second spherical joint pipe with a spherical portion formed at one end are provided, and one end of the slide pipe is longitudinally attached to one of the second spherical joint pipes. The other end of the slide tube is slidably and telescopically fitted, and the other end of the slide tube is slidably and telescopically fitted in the other second joint with the second spherical portion. The end of the fitting tube with the slide tube is fitted to the fitting tube with the second spherical section of the slide tube. Side of the stop for prevention protrusion provided at an end bend telescopic joint stopper, characterized in that is provided. 2. The bending / expanding universal joint according to claim 1, wherein at least a part of the slide tube is bent or curved.