JPH0132396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a packing-type pipe joint having means for preventing pipes from coming off.

[Prior art] A packing chamber is formed on the inner peripheral surface of the end of a joint body, a packing made of an elastic material such as rubber is attached, and the packing is pressed by a pressing member such as a cap nut that engages with the joint body. The packing-type pipe joint seals between the outer surface of the inserted pipe and the inner surface of the joint body, and as a means to prevent the pipe from coming off, it also prevents the pressure member from digging into the outer surface of the pipe. It is often required to incorporate a ring.

In particular, with regard to pipe fittings used for underground piping, in order to prevent excessive stress from concentrating on parts other than the pipe fitting due to ground subsidence, etc., rather than pipe fittings that connect pipes rigidly, Pipe fittings that allow for flexibility are preferred. In addition, in recent years, external resin cladding has often been used for buried pipes from the perspective of improving corrosion resistance, but in order to use such resin cladding, it is necessary to pierce the resin cladding and corrode the base of the steel pipe. There is a need for pipe fittings that have a large amount of penetration.

As a packing-type pipe joint that has such a means for preventing the pipe from coming off, is flexible, and has a relatively large biting amount, there is a pipe joint disclosed in Japanese Patent Application Laid-open No. 134226/1983. As shown in FIG. 9, the biting ring in FIG. It was formed smaller than the cross section of the ring chamber.

[Problems to be solved by the invention] Since the conventional pipe joints described above have steel balls held in rubber, the steel balls often fall when joining pipes, resulting in poor workability. There was a problem, and since the cross section of the steel ball was formed smaller than the cross section of the cutting ring chamber, the steel ball would not cut into the tube surface unless the pipe was actually pulled out, and even if it did, the steel ball would not cut into the pipe surface. There is a problem that a large pulling-out prevention force cannot be obtained due to rotation, and since steel balls are used, the inner surface of the steel ball bites into the outer surface of the pipe, and at the same time, the outer surface also bites into the inner surface of the pressing member. There was a problem that the amount of biting into the pipe was reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a packing-type pipe joint that does not have the above-mentioned problems and has means for preventing pipes from coming off.

[Means for Solving the Problems] The present invention has been made to achieve the above object, that is, a packing chamber is provided on the inner peripheral surface of the end of the joint body into which the pipe to be connected is inserted, and an elastic body is provided. A press member for pressing the seal is provided in engagement with the joint main body, an inner circumferential tapered surface with a large diameter side opening is provided on the end surface side of the press member that presses the seal, and A biting ring chamber is formed between a circumferential tapered surface, the packing, and the pipe, and a biting ring is installed in the biting ring chamber to engage with the inner circumferential tapered surface of the pressing member. , on the inner surface of an annular portion having a notch at one location on the inner periphery and an outer surface that contacts the inner periphery tapered surface of the pressing member formed uniformly in the circumferential direction, integrally with the annular portion and spaced at substantially equal intervals in the circumferential direction. A cross section of the biting protrusion is formed such that the biting protrusion bites into the outer surface of the pipe when the pressing member is engaged with the joint body. The pipe joint is characterized in that it is formed so as to protrude from the biting ring chamber.

[Operation] When the pressing member, biting ring, packing, and joint body are inserted in that order into the pipe to be connected, and then the pressing member is engaged with the fitting body and tightened, the biting ring is formed to protrude from the biting ring chamber and is tightened. The biting protrusions of the biting rings, which are provided at approximately equal intervals on the circumference, bite deeply into the pipe surface to fix the pipe fitting to the pipe, and the biting rings that engage with the inner circumferential tapered surface of the pressing member prevent the pipe from being pulled out. exerts great stopping power against

In this case, the main pipe joint does not grip the pipe in a planar manner or in multiple rows in the axial direction, but rather by gripping the pipe in a single row in the axial direction and with biting protrusions spaced apart in the circumferential direction. Therefore, the contact area with the tube decreases, and the amount of digging into the outer surface of the tube inevitably increases. Similarly, the main pipe joint does not grip the pipe in a planar manner or in multiple rows in the axial direction, but instead grips the pipe in a single row in the axial direction with biting protrusions that have a rounded axial cross section. The grip provides a degree of flexibility to the tubes connected by the mains fitting. Moreover, the biting protrusions are provided on the inner surface of the biting ring at intervals in the circumferential direction, whereas the outer surface side that comes into contact with the inner circumferential tapered surface of the pressing member is formed uniformly in the circumferential direction. The force uniformly received from the pressing member is concentrated on the biting protrusion, so the biting ring does not bite into the inner circumferential tapered surface of the pressing member, and the amount of biting into the pipe becomes large.

[Example] An example of the present invention will be described with reference to the drawings. 1st
The figure is a longitudinal cross-sectional view of the main part showing a state in which pipes are connected by the pipe joint of the present invention. A sealing chamber 4 is formed on the back side following the female screw 3. Reference numeral 5 denotes a pressing member which has a thread 6 on the outer surface of its end and engages with the female thread 3 of the joint body 1. A packing 9 made of an elastic material such as rubber is attached to the packing chamber 4 of the joint body 1, and seals between the fitting and the outer surface of the pipe 20 inserted to be connected. The pressing member 5 is inserted into the pipe 20 in advance, and is screwed into the connecting end 2 of the joint body 1 to release the collar 10.
Press the packing 9 through the .

The end of the pressing member 5 is provided with an inner tapered surface 7 whose large diameter side is open at the end surface 8, and a biting ring chamber is defined as an area surrounded by the inner tapered surface 7, the collar 10, and the tube 20. A biting ring 11 is mounted in this biting ring chamber. The biting ring 11 has a hardness equal to or higher than that of a pipe or a pipe fitting member, and when the pressing member 5 is screwed in, it presses the seal 9 through the collar 10, and the reaction force causes the biting ring itself to tighten around the inner periphery of the pressing member. It is tightened in the radial direction via the tapered surface 7, and the biting projections 15 provided on the inner circumferential surface bite into the outer circumferential surface of the tube 20 to firmly grip the tube 20.

As shown in FIG. 2, the biting ring 11 has several biting protrusions 15 provided on the inner peripheral surface of an annular portion 12 whose outer surface is formed uniformly in the circumferential direction at approximately equal intervals on the circumference. The annular portion 12 is cut out at a location 13 on the circumference so that the diameter can be reduced by pressing. Further, the cross section of the annular portion 12 is semicircular as shown in FIG. 4, and the outer circumferential surface 14 having an arcuate cross section engages with the inner circumferential tapered surface 7 of the pressing member 5. Biting protrusion 1
5 is a hemispherical protrusion, as is clear from FIGS. 1 to 4. The shape of this protrusion is not particularly limited, as long as the axial cross section of the biting ring is rounded, and a small flat portion may remain at the top of the biting protrusion. In addition, when the biting protrusion is sharpened with a pair of inclined surfaces parallel to the axis of the biting ring, and the axial cross section of the biting ring is shaped like a rounded wedge, the axis of the biting ring is This is preferable because the direction is corrected so that it faces in the tube axis direction.

5 to 7 show other embodiments of the biting protrusion of the biting ring, and the biting protrusion 16 in this example is a small half formed in the remaining semicircular cross section of the annular portion 12 having a semicircular cross section. It has a shape in which a cylindrical part is sharpened by cutting a pair of inclined surfaces 17, 17 facing each other from both sides thereof. When a biting ring having this biting protrusion 16 is attached to a pipe joint, since the top of the protrusion is wedge-shaped, it bites deeply into the outer surface of the pipe, and the inclined surface forming the wedge is parallel to the axis of the biting ring. Since the axial cross section of the biting ring of the biting protrusion 16 is arcuate, the direction of the biting ring in which the axis of the biting ring faces the tube axis can be easily corrected, which is preferable.

The shape of the annular part of the biting ring is preferably one in which the outer peripheral surface has an arcuate cross section, so that even if the biting ring is slightly twisted or tilted when attached to a pipe joint and a pipe is connected, the pressing member It is suitable because it easily adapts to the inner peripheral tapered surface. However, as shown in FIG. 8, an annular portion 12' having a trapezoidal cross section has an outer circumferential tapered surface 19 that matches the inner circumferential tapered surface of the pressing member.
It may also have the following.

As explained above, the pipe joint according to the present invention has a biting ring in which a plurality of biting protrusions are provided at relatively large intervals on the inner peripheral surface, and the protrusions bite deeply into the outer surface of the pipe. be able to. Therefore, it is suitable for steel pipes whose outer surfaces are coated with a thick resin, which is often used in underground city gas piping in recent years, and the protrusion of the ring can easily penetrate into the steel pipe base metal. can.

In addition, since the axial cross section of the biting ring of the biting protrusion is rounded, the connected pipe can flex to a certain extent, and therefore excessive force is applied to connecting parts other than the main pipe fitting on the pipe. It is prevented from doing so. Furthermore, while the outer surface of the biting ring is uniform in the circumferential direction, the inner surface has biting protrusions spaced apart in the circumferential direction, so the force received from the outer surface is concentrated on the biting protrusions on the inner surface, causing As a result, it does not bite into the pressing member, but only bites into the outer surface of the tube, increasing the amount of biting into the tube.

Further, in the pipe joint according to the present invention, the protrusion on the inner circumferential surface bites into the outer surface of the pipe while the outer circumferential surface of the biting ring simply engages with the inner circumferential tapered surface of the pressing member. When the tube is pulled in the detachment direction, that is, in the right direction in the figure, from the connection state shown, the biting ring moves to the back side of the inner circumferential tapered surface of the pressing member, that is, to the small diameter side, while remaining bitten into the tube, and the annular portion The diameter of the tube is further reduced, and as a result, the biting protrusion further increases the depth of biting into the outer surface of the tube, and prevents the tube from coming out with a strong force.

In addition, the pipe joint according to the present invention may have a thread at the connecting end of the joint body and engage the pressing member as a cap nut with a female thread, or the joint body and the pressing member may be opposed to each other at the flange surface. It can also be implemented as a structure that is connected by bolting. Moreover, there is no need to provide a particular color. Furthermore, it goes without saying that the configuration of the biting ring, which is the essential part of the present invention, may be implemented in other forms within the scope of the technical idea of the present invention.

[Effects of the Invention] In the pipe joint according to the present invention, the cross section of the biting protrusion of the biting ring protrudes from the biting ring chamber of the pressing member, so that the biting ring can be connected simply by fastening the pressing member to the joint body. The protrusions that bite into the tube surface are arranged in a line in the axial direction intermittently in the circumferential direction, and the cross section in the axial direction is rounded, so the biting depth is deep and exerts a large blocking force against the tube being pulled out. At the same time, it gives the tube a certain degree of flexibility. In addition, although the outer surface of a biting ring is uniform in the circumferential direction, the inner surface has biting protrusions spaced apart in the circumferential direction, so the force received from the outer surface is concentrated on the biting protrusions on the inner surface. The amount of penetration increases. Furthermore, since the biting protrusion is formed integrally with the annular portion, it is easy to handle and has excellent workability.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the main parts showing a state in which pipes are connected with a pipe joint according to an embodiment of the present invention, FIG. 2 is a front view of a biting ring, and FIG. 3 is a view taken in the direction of arrow A in FIG. 2.
4 is a sectional view taken along line BB in FIG. 2, FIG. 5 is a partial front view showing another embodiment of the biting ring, FIG. 6 is a view taken along arrow C in FIG. 5, and FIG. DD sectional view in the figure, FIG. 8 is a vertical sectional view showing still another embodiment of the biting ring, and FIGS. 9 and 10 are a perspective view of the biting ring and the main part of the pipe joint in the conventional example, respectively. FIG. 1... Joint body, 4... Packing chamber, 5... Pressing member, 7... Inner peripheral tapered surface, 9... Packing,
10... Color, 11... Biting ring, 12...
...Annular part, 13...Notch, 14...Outer peripheral surface, 1
5, 16... biting protrusion, 17... slope.

Claims (1)

[Claims] 1. A packing chamber is provided on the inner peripheral surface of the end of the joint body into which the pipe to be connected is inserted, a packing made of an elastic body is attached, and a pressing member that presses the packing is engaged with the joint body. The pressing member is provided with an inner circumferential tapered surface whose large diameter side is open on the end surface side that presses the packing, and a biting ring chamber is formed between the inner circumferential tapered surface, the packing and the pipe, and In a pipe joint in which a biting ring that engages with the inner tapered surface of the pressing member is installed in the biting ring chamber, the biting ring is cut out at one point on the circumference and an outer surface that comes into contact with the inner tapered surface of the pressing member is formed. The inner surface of the annular part is formed uniformly in the circumferential direction, and a row of biting protrusions with rounded axial cross sections are provided integrally with the annular part and at approximately equal intervals in the circumferential direction, A pipe joint characterized in that a cross section of the biting protrusion is formed so as to protrude beyond the biting ring chamber so that the biting protrusion bites into the outer surface of the pipe when the pressing member is engaged with the joint body. 2. The pipe joint according to claim 1, wherein the annular portion of the biting ring has a semicircular cross section, and the outer circumferential arcuate portion engages with the inner circumferential tapered surface of the pressing member. 3. The pipe joint according to claim 1, wherein the annular portion of the biting ring has a trapezoidal cross section, and the outer circumferential tapered portion engages with the inner circumferential tapered surface of the pressing member. 4. Claims 1, 2, or 3 in which the biting protrusion on the inner surface of the annular portion of the biting ring is hemispherical or wedge-shaped with a pair of sloped surfaces parallel to the axis of the biting ring. Pipe fittings described in any of the above. 5. The biting protrusion of the biting ring is formed by sharpening a small semi-cylindrical part formed in the remaining semicircular cross section of the annular part having a semicircular cross section with a pair of opposing slopes from both sides. Pipe joint described in Section 2.