JPH0645750Y2 - Flexible expansion joint - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is used for indoor and outdoor pipes, particularly pipes required to have earthquake resistance and flexibility, and pipes buried in the ground. Expansion and contraction flexible pipe joint.

[Prior art]

FIG. 6 shows a conventional expandable flexible pipe joint of this type. 1,
Reference numeral 2 is a pipe to be connected, 3 is a tubular joint body having male threads at both ends, and 4 is a cap nut screwed into each end portion of the joint body 3. Between the inner peripheral surface of the joint body 3 and the outer peripheral surface of the pipe 1 to be connected, artificial rubber packings 5 are mounted, respectively. A washer 6 made of synthetic resin is interposed between both end surfaces of the tubular joint body 3 and the step portion 4a on the inner surface of the cap nut 4 in order to reduce frictional resistance during tightening. When the cap nut 4 is tightened, the packing 5 is axially compressed via the stepped portion 4a and the washer 6, and thus is compressed radially inward with respect to the connected pipe 1 to prevent water leakage. The cap nut 4 has an annular recess 7 formed by a tapered inner peripheral surface 4b and a cylindrical inner peripheral surface 4c, and a ball race 10a made of an elastic material such as rubber as a pipe pullout preventing means 10.
And a plurality of balls 10b circumferentially arranged on the ball race 10a. When an external force for pulling out the pipe acts, a wedge effect is generated between the tapered inner peripheral surface 4b of the cap nut 4 and the outer peripheral surface of the pipe 1 by the ball 10b, and the pipe is pulled out with a pulling load within a certain specified range. Is prevented.

In addition, 8 shows an O ring.

[Problems to be solved by the device]

At the pipe connection work site, when inserting the connected pipes 1 and 2 from both ends of the expansion and contraction flexible pipe joint in which the cap nut 4 is loosely screwed into the joint body 3, the insertion length of the pipes 1 and 2 Although the pipe is marked with a mark to make it uniform, if a worker on the spot overlooks the mark and inserts one pipe too deeply into the pipe joint, the insertion depth of the other pipe will decrease. There was a problem that the packing 5 did not come into contact with the peripheral surface of the pipe end portion due to lack of the liquid, which could cause leakage of the carrier liquid.

An object of the present invention is to provide a telescopic flexible pipe joint configured to easily regulate the insertion length of the pipe to be connected to the pipe joint.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the expansion and contraction flexible pipe joint according to the present invention is configured such that the pipe withdrawal preventing means is composed of a retaining ring having a truncated conical tubular portion longitudinally split at one axial position. At the small-diameter side end of the frustoconical tubular part, an inwardly projecting annular projecting part that fits in a circumferential groove provided in the connected pipe is provided. The inner diameter of the part is approximately equal to or smaller than the root diameter of the peripheral groove of the pipe to be connected, and the tubular part of the retaining ring has a fixed length extending from both ends in a staggered manner parallel to the axial direction. It is characterized by having put.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings by an embodiment used in a water supply pipe.

FIG. 1 shows a longitudinal section of an expansion and contraction flexible pipe joint incorporating the pipe withdrawal prevention means according to the present invention. This fitting is line X
The structure is symmetrical with respect to -X, but the right half is omitted.

2 and 3 show an embodiment of the pipe withdrawal preventing means according to the present invention. The retaining ring 20 formed as this pipe withdrawal preventing means is composed of a truncated conical tubular portion 21 and a cylindrical portion 22 integrally adjacent to this tubular portion, and has a slit 23 parallel to the axial direction. It is vertically divided by one place. An annular semicircular protrusion 24 that protrudes inward is integrally formed at the small-diameter side end of this truncated cone, and when the connected pipe 1 or 2 is inserted into the pipe joint, The connecting pipe is fitted in a peripheral groove 1a (Fig. 1) which is provided in advance at a constant distance from the pipe end surface. This retaining ring
20 has a radially expandable / contractible means, and the radial expandable / contractible means comprises a plurality of cuts 2 of constant length extending alternately from the respective end faces of the tubular portions 21, 22 in parallel to the axial direction.
It is composed of 5 and 26. At that time, those notches 2
The tip portions of 5, 26 are also staggered in the circumferential direction at intervals. The inner diameter of the annular protrusion 24 of the retaining ring 20 is preferably substantially equal to or smaller than the root diameter of the circumferential groove 1a of the connected pipe 1. Also, the retaining ring
Stainless steel is a suitable material for the 20.

When connecting pipes in the field, all parts are assembled in the flexible expansion joint as shown in Fig. 1.
Loosen the cap nut (14) from the joint body (13) and move it back before connecting the pipes. When the connected pipe 1 is inserted through the hole of the cap nut 14 of this pipe joint and the connected pipe 1 hits the annular projection 24 of the retaining ring 20, the retaining ring 20 is loosened and expanded in the axial direction. Although it is pushed into the recess 17 in the nut 14, the retaining ring 20 is expanded radially outward by the alternating cuts 25 and 26, so that the pipe to be connected can be easily inserted into the pipe joint. Can be plugged into. Further, the pipe 1 to be connected is inserted while slipping on the inner circumference of the annular protrusion 24 of the retaining ring 20, and finally the annular protrusion 24 is inserted into the circumferential groove 1a of the pipe 1 to be radially inward to its original shape. Since it is fitted by the restoring force that tries to shrink toward one side, this is sensed by the worker and the insertion of the connected pipe 1 can be stopped. Then, when the cap nut 14 is tightened, the taper inner peripheral surface 14a of the cap nut 14 becomes the tapered portion 2 of the retaining ring 20.
By pressing 1 the annular protrusion 24 bites into the circumferential groove 1a of the pipe 1 to be connected, preventing the pipe from coming out.

4 and 5 show another embodiment of the retaining ring as a pipe withdrawal preventing means according to the present invention. In these figures, parts similar to those in FIGS. 2 and 3 are provided with similar reference numerals plus 10. This retaining ring
The difference between 30 and the retaining ring of the first embodiment is that there is only a tapered portion.

[Effect of device]

In the pipe joint of the present invention, the pipe pull-out preventing means housed in the recess in the cap nut is formed of a retaining ring having a truncated conical tubular portion longitudinally divided in one axial direction, At the small-diameter side end of the frusto-conical tubular portion, an inwardly projecting annular protrusion that fits into a circumferential groove provided in the connected pipe is provided. Make the inner diameter approximately equal to or smaller than the root diameter of the peripheral groove of the pipe to be connected, and make a cut in the tubular part of the retaining ring with a certain length extending alternately from both ends in parallel with the axial direction. Therefore, when the pipe to be connected is inserted into the pipe joint having the pipe withdrawal prevention means of the present invention, the pipe end hits the annular projection of the retaining ring, whereby the retaining ring is easily expanded by its radial expansion / contraction means. You can insert the pipe to be connected, The connected pipe can be inserted and stopped until the annular projection of the retaining ring fits into the circumferential groove of the connected pipe by the restoring force of the radial expansion / contraction means that attempts to shrink the retaining ring to its original shape. It is possible to prevent the connecting pipe from being inserted too much. Furthermore, when the cap nut is tightened on the joint body,
The tapered inner peripheral surface of the cap nut presses the retaining ring inward in the radial direction so that the annular protruding portion of the cap nut bites into the peripheral groove of the pipe, thereby preventing the pipe from coming out.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an expansion and contraction flexible pipe joint provided with a retaining ring as a pipe withdrawal preventing means according to the present invention, and FIG. 2 is a longitudinal sectional view of a retaining ring according to a first embodiment of the present invention. , Fig. 3 is an end view seen from the direction of arrow III in Fig. 2,
FIG. 4 is a longitudinal sectional view of a second embodiment of the retaining ring according to the present invention, FIG. 5 is an end view as seen from the direction of arrow V in FIG. 4, and FIG. 6 shows a conventional pipe withdrawal preventing means. It is a longitudinal cross-sectional view of a telescopic flexible pipe joint provided. 1,2 ...... Connected pipe, 1a ... Circumferential groove, 13 ... Joint body, 14 ...
… Cap nut, 14a …… Frustal-conical tubular part, 15 …… Packing, 17 …… annular recess, 20 …… Pipe withdrawal prevention means, 24
…… Annular protrusion, 25, 26 …… Notch

Claims (1)

[Scope of utility model registration request] 1. A tubular joint body having a screw at one end, an annular packing made of an elastic material mounted between an inner peripheral surface of the joint body and an outer peripheral surface of a pipe to be connected, and tightened to a screw of the joint body. In a telescopic flexible pipe joint having a cap nut having an annular recess and a pipe withdrawal preventing means arranged in the annular recess, the pipe withdrawal preventing means is axially aligned with each other. It consists of a retaining ring that has a truncated cone-shaped tubular portion that is vertically divided at a point, and the small diameter side end of the truncated cone-shaped tubular portion fits into the circumferential groove provided in the connected pipe. An inwardly projecting annular protrusion with a semi-circular cross section is provided, and the inner diameter of this annular protrusion is made approximately equal to or smaller than the root diameter of the circumferential groove of the pipe to be connected. On the tubular part of the retaining ring, stagger from both ends in the axial direction. Telescopic flexible type pipe coupling, characterized in that it placed a certain cut length extending in the row.