JPH0631664B2 - Pipe fitting - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint used for connecting a water supply pipe, a drain pipe, and the like. Of the structure in which a packing made of an elastic body such as rubber is interposed between the inner peripheral edge of the end of the and the outer circumference of the pipe, and the packing is compressed by tightening a pressing body such as a flange or a cap nut to connect the pipe. Regarding pipe fittings.

(Prior Art) Conventionally, as an example of such a pipe joint, as shown in FIG. 3, a pipe B connected to the inside of the main body A of the pipe joint is fitted and formed in a tapered shape at the inner peripheral edge of the end portion of the main body A. The packing C is interposed between the packing receiving concave portion and the outer circumference of the pipe B, and the flange D as a pressing body is tightened by a screw member to keep watertight by its elasticity and wedge effect.
There is a structure to connect. An example of such a technique is proposed in Japanese Utility Model Laid-Open No. 56-32187. However, in such a conventional pipe joint, since it retains watertightness by compressing the packing C and utilizing the elasticity and wedge effect, the safety is too much, and the screw is inevitable. It is easy to over-tighten the member. This is true even if the instruction manual clearly states that "bolts should be tightened with a torque of 200 kgcm." This cannot be regulated in practice.

Therefore, after the packing C is tightened, the packing C tends to deeply enter the inside of the main body with a large deformation as shown in the figure with respect to the state before tightening shown by the two-dot chain line in the figure. As a result, the watertightness at the beginning of construction is certainly enhanced. On the other hand, however, the packing C has a drawback that it suffers from a large permanent set due to compression and its life is shortened, and as a result, the watertightness cannot be maintained for a long time.

Inevitably, the number of replacements of the packing C will increase, but since the packing C is almost entirely in the main body, there is a problem that it is very difficult to remove it. .

In Japanese Utility Model Publication No. 59-10471, the cross-sectional shape is such that two large and small tapered surfaces having the same angle are formed in a stepwise manner in the axial direction, and a flange portion protruding toward the outer diameter side is provided at the large diameter end. A pipe connecting device is disclosed in which a sleeve made of an elastic material is used and a flange portion of the sleeve is sandwiched between a pressing ring having an L-shaped cross section and a flange pipe.

However, the collar portion of this sleeve has an inclined surface whose cross-sectional shape on the contact side with the pressing ring has an inclination angle with respect to the end surface of the pressing ring. The inner diameter side of the inner diameter side abuts, and as the tightening proceeds, the range is expanded from the inner diameter side to the outer diameter side. Therefore, the tightening force of the pressing ring gradually increases in proportion to the expansion of the contact surface,
The maximum level is reached when the entire inclined surface comes into contact.

Therefore, although it is possible to prevent abnormal tightening of the pressing ring,
In the tightening process, the tightening force continuously and gradually increases, so there is a risk that the tightening will be completed before reaching the maximum level. As a result, the tightening of a plurality of tightening bolts becomes uneven over the entire circumference of the pressing ring, and there is a problem that partial tightening occurs. In addition, since the flange portion has a watertight effect by being brought into close contact with the flange surface facing the pressing ring, there is a problem that the water leakage preventing effect is impaired when partial tightening occurs.

(Problems to be Solved by the Invention) The present invention is intended to solve the problems in such conventional pipe joints, and restricts the packing from being abnormally tightened beyond an appropriate value, and compressed. It is an object of the present invention to provide a pipe joint in which the water-tightness is maintained for a long period of time by reducing the permanent strain due to and the pipe joint can be easily removed even when it is replaced.

(Means for Solving Problems) A means for solving the above problems is to receive a packing formed by fitting a pipe in a main body of a pipe joint and forming an inner peripheral edge of a flange at an end portion of the main body. In a pipe joint in which a packing is interposed between the recess and the outer circumference of the pipe and the packing is compressed by tightening a pressing body to connect the pipe, the packing can face the packing receiving recess. A pressure receiving portion having a wedge surface portion, and a discontinuous collar-shaped narrow fitting portion radially formed on the outer circumference of the pressure receiving portion, and the cross-sectional shape of the narrow fitting portion is on the end face of the flange. When the packing is formed in parallel rectangular shapes and protrudes outward from an extension line of the surface of the wedge surface portion, and the packing is interposed between the flange and the pressing body, the narrow attachment portion is Narrow between the end face of the flange and the pressing body. It is a structure to be worn.

(Operation) Since the pipe joint according to the present invention has the above-described structure, the pipe is fitted in the main body, and the packing is interposed between the packing receiving recess and the outer circumference of the pipe. When the pressing body is tightened, the packing is compressed and the elastic force presses against the packing receiving recess and the outer circumference of the pipe to maintain watertightness.However, as the pressing body is further tightened, the packing outer circumference Since the narrow fitting portion is tightly fitted between the end surface of the flange on the outside of the packing receiving recess of the main body and the pressing body, at that stage, the tightening force sharply increases, and the flange end surface is pressed. While maintaining a certain distance from the body,
Tightening of the pressing body becomes so-called difficult, and it exerts the effect of suppressing or regulating unnecessarily tightening and reducing the permanent strain which it receives due to compression.

(Example) An example of the pipe joint according to the present invention will be described with reference to Figs. 1 and 2.

In the figure, reference numeral 1 denotes a main body of the pipe joint (hereinafter, simply referred to as a main body), and its inner diameter is formed to be slightly larger than the outer diameter of the pipe P so that the pipe P to be connected can be fitted. An outer peripheral flange 2 is provided at an end portion thereof, and a packing receiving recessed portion 3 having a tapered surface whose diameter increases toward the end portion is provided at an inner peripheral edge thereof.

Next, 4 is a packing pushing flange as a pressing body for pressing the packing described below, which is formed in an annular shape having an inner diameter slightly larger than the outer diameter of the pipe P and has an inner peripheral edge on the packing side. Packing pressing surface 5 formed in an inclined shape at the side
And a surface portion 7 facing the end surface 6 on the outer side of the packing receiving concave portion 3 of the main body 1.

Now, 8 is a packing made of an elastic material such as rubber and formed in an annular shape. The packing 8 is a packing receiving recess 3
A pressure receiving portion 10 having a wedge surface portion 9 capable of facing each other and having a substantially trapezoidal transverse cross section, and a non-continuous flange-shaped narrow attachment portion 11 formed radially on the outer peripheral side of the pressure receiving portion 10. Has been formed.

The narrowed portion 11 is composed of a plurality of collar-shaped pieces,
Are arranged on the outer periphery of the gear teeth at predetermined intervals. Further, the narrow fitting portion 11 is formed in a rectangular shape whose cross-sectional shape is parallel to the end surface 6 of the flange 2, and is formed so as to project outward from an extension line of the surface of the wedge surface portion 9. The opposite side of the wedge surface portion 9 of the pressure receiving portion 10 is formed by an inclined surface along the packing pressing surface 5.

When the packing 8 is interposed between the flange 2 and the packing pushing flange 4, one surface of the narrow fitting portion 11 faces the end surface 6 of the flange 2 in parallel, and the other surface thereof faces the packing pushing flange 4. Faces the surface portion 7 in parallel and is configured to maintain a predetermined distance between the end surface 6 and the surface portion 7 when the packing 8 is tightened. The narrow-fitting portion 11 may be insert-molded on the pressure receiving portion 10.

Then, in this embodiment, when the bolts and nuts mounted on the flange 2 of the main body 1 and the packing pushing flange 4 are tightened, the packing 8 is compressed, and the sealing is maintained by the wedge effect and the pressure contact by its elasticity. Become.
Then, when the packing 8 is further tightened, the packing 8 is deformed in the direction of being accommodated in the main body together with the wedge effect as shown in FIG.
Is tightly attached between the end surface 6 of the main body 1 and the surface portion 7 of the packing pressing flange 4, so that a large torque is required for subsequent tightening, and tightening is automatically restricted at that stage. The operator can know the completion of tightening with the proper torque.

As a result, the packing 8 will not be abnormally tightened beyond the proper value, and the size of its permanent set due to compression will be suppressed to a considerably small level, and as a result, long-term watertightness will be maintained.

Further, when the packing is replaced, when the packing pushing flange 4 is removed, the narrow fitting portion of the packing 8 is exposed from the main body 1, so to speak, so that it can be easily removed.

The packing in this embodiment has a trapezoidal sectional shape of the pressure receiving portion, but in the present invention, it is obvious from the constitution that there is no problem even if it is circular. Also, the pressing body of the packing can be arbitrarily selected such as a so-called cap nut type.

(Effect) In the pipe joint according to the present invention, when the packing is tightened, the narrow fitting portion keeps the distance between the flange and the pressing body properly and uniformly over the entire circumference, and the pressure receiving portion exceeds the appropriate value. Since abnormal tightening can be regulated and permanent set due to compression can be suppressed, there is an effect of increasing durability regarding sealing property and an effect of facilitating replacement work of packing.

[Brief description of drawings]

1 and 2 are cross-sectional views of an essential part showing an embodiment of the pipe joint according to the present invention. FIG. 1 shows a state before tightening of a pressing body, and FIG. 2 shows a state after tightening of a pressing body. Indicates the status. Further, FIG. 3 is a sectional view of an essential part showing an example of a conventional pipe joint. 1 ... Main body, 3 ... Packing receiving recess 4 ... Packing pressing flange (pressing body) 6 ... End face, 8 ... Packing 11 ... Narrow fitting part, P ... Pipe

Claims (1)

[Claims] 1. A pipe is fitted in a main body of a pipe joint, and a packing is interposed between a packing receiving recess formed in an inner peripheral edge of a flange at an end of the main body and an outer circumference of the pipe. A pipe joint for connecting the pipe by compressing the packing by tightening a pressing body, wherein the packing has a pressure receiving portion having a wedge surface portion that can face the recess for receiving the packing, and a radial shape on an outer circumference of the pressure receiving portion. A non-continuous flange-shaped narrow fitting portion formed in a protruding manner, and the cross-sectional shape of the narrow fitting portion is formed in a square parallel to the end surface of the flange, and an extension line of the surface of the wedge surface portion. Structure that is formed so as to project further outward than the flange, and the packing is interposed between the flange and the pressing body, the narrow fitting portion is narrowly fitted between the end surface of the flange and the pressing body. The pipe joint characterized by the above.