JPH0416050Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement in an expansion joint that does not expand or contract beyond a certain amount of play under normal conditions, but expands and contracts only when internal pressure or external force above a predetermined level is applied.

[Conventional technology]

Conventionally, as a expandable joint used for water pipes, etc., there is disclosed Japanese Patent Application Laid-Open No. 59-80595 (Conventional Example 1).
and Utility Model Application Publication No. 59-155388 (Conventional Example 2), etc., but these have a structure in which the joint body and the joint pipe located therein are slidable via a plurality of rings and packings. .

Another configuration is to prevent expansion and contraction by separately engaging a load shearing ring at the sliding joint between the joint pipe and the ball sleeve, as seen in Japanese Utility Model Application Publication No. 57-175888 (Conventional Example 3). The structure has also been developed.

[The problem that the idea attempts to solve]

In the conventional examples 1 and 2, it is possible to expand and contract even with a slight change in pressure, but it is rather inconvenient to constantly repeat expansion and contraction even under normal conditions after the piping is completed.

Conventional Example 3 is an improvement on these, but with this configuration, a groove must be machined in the joint pipe in order to engage the load shear ring with the joint pipe, which weakens this part, so even if the joint Even if JIS standard products are used for pipes, strength cannot be guaranteed.
The withstand pressure had to be measured individually. Furthermore, since the load shear ring breaks when a load exceeding a predetermined value is applied, it has to be replaced each time, and the joint also has to be disassembled when replacing it.

In order to solve these problems, this invention normally does not expand or contract beyond a certain amount of play, but expands and contracts only when a predetermined amount of pressure is applied, and there is no need to replace any parts to recover from expansion or contraction. To provide an expansion joint that can be restored without further disassembling the main body.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention is an expansion joint in which a joint pipe is inserted into a joint body and made watertight at a sealing part, and a flange provided at the tip of the joint pipe. A spacer ring, which has a cylindrical part of a thin elastic body extending in the direction of the flange, is inserted between the flange and the seal part, and the cylindrical part is made of a thin elastic body that expands in the outer circumferential direction when it disengages from the flange at a predetermined pressure or higher. there was.

Further, a guide portion was extended from the thin cylindrical portion of the spacer ring to the outer peripheral surface of the collar portion.

Furthermore, a method of providing a notch in a part of the spacer ring was also used.

[Effect]

In the expansion joint of the present invention, the joint pipe is inserted into the joint body and watertightness is maintained by the seal part, but the spacer ring inserted between the collar part and the seal part of the joint pipe is Under normal conditions, expansion and contraction of the joint pipe is restricted except for a certain amount of play.

On the other hand, if the internal pressure rises abnormally or an external force exceeding a certain level is applied, the cylindrical part of the spacer ring is pressed by the joint pipe and compressed, deforming elastically in the outer circumferential direction and expanding its diameter. is disengaged from the spacer ring and fitted into this cylindrical portion, resulting in the effect of extending the joint pipe.

Since the diameter of the cylindrical portion of the spacer ring has only expanded due to elastic deformation, it will return to its original state when the collar portion is unfitted.

In addition, the guide part extending from the cylindrical part to the outer periphery of the flange ensures more secure engagement between the spacer ring and the flange, so even if the expansion joint is flexible and the axis changes, it can withstand a predetermined pressure. is never unstable.

Furthermore, the notch provided in a portion of the spacer ring has the function of easily disengaging the spacer ring from the flange.

〔Example〕

To further explain the configuration of the present invention in detail based on an example, Fig. 1 shows the case of an expansion joint with a fixed shaft in the example, 1 is a joint body, 2 is a joint pipe inserted into this, and 3 is a joint body. A flange part provided at the tip of the joint pipe 2, 4 a packing, 5 a seal ring, and 6 a packing cover, these three parts constitute a seal part. 7 is a spacer ring fitted into the joint pipe 2 between the collar portion 3 and the seal portion, and is made of a relatively thin soft material (for example, medium-soft plastic or medium-hard rubber); A cylindrical portion 8 made of a thin elastic body extends in the direction of the collar portion 3. 9 is for play.

When the expansion joint with the above configuration is installed on the primary side or secondary side of a water meter, etc., when the internal pressure is normal, the spacer ring 7
It is located between the joint pipe 2 and the seal part, and no pressure is applied to it, but if there is an abnormal increase in external or internal pressure, such as due to overload of earth pressure or an earthquake, the joint pipe 2
is pushed in the extending direction, and the spacer ring 7 is compressed. The cylindrical part 8 maintains engagement with the flange part 3 until a certain pressure is reached, but if the pressure exceeds a predetermined value, the cylindrical part 8 cannot withstand this and is elastically deformed in the outer circumferential direction and expands in diameter. However, the engagement with the flange part 3 is released, and the flange part 3 fits into the inside of the cylindrical part 8. The pressure resistance can be set in advance depending on the material of the spacer ring 7 or the wall thickness of the cylindrical portion 8. Incidentally, if the play 9 is provided, the construction at the time of piping becomes easier, but the margin width for the play is arbitrary, and furthermore, the play 9 may not be provided at all.

FIG. 2 shows a case of a flexible expansion joint according to an embodiment of the present invention, where 10 is the joint body, 11 is a joint pipe, 12 is a collar, and 13 is a flexible expansion joint whose inner circumferential surface is a spherical recess. Department. Further, 14 is an O-ring, 15 is a back-up ring for reinforcing this, and 16 is a stop ring, which constitute a sealing portion and correspond to the flexible portion 13. 17 is a spacer ring, 18 is a cylindrical portion, and 19 is a guide portion extending further from the cylindrical portion 18 along the outer circumference of the collar portion 12.

Note that 20 is an allowance.

In this embodiment, a guide portion is further extended to the spacer ring 7 shown in FIG. 1. To explain this function, in the case of a flexible expansion joint, there is no problem if the joint body 10 and the joint pipe 11 expand and contract on the same axis, but if the axes of the two are misaligned, the cylindrical part Since torsional force is applied to the flange 18, the engagement with the flange 12 becomes uneven, and the engagement with the flange 12 becomes disengaged at a pressure lower than the predetermined pressure resistance value. The idea is to keep it uniform.

Next, FIG. 3 shows a state in which an abnormal load is applied to the flexible expansion joint shown in FIG. 2, and the engagement between the collar portion 13 and the cylindrical portion 18 is disengaged. In this case, in order to restore the original state, if the joint pipe 11 is pushed in the direction of contraction, the tip of the guide part 19 will come into contact with the wall of the joint body 10, and if it is pushed further, the collar part 12 will fit into the cylindrical part 18. can be removed, so there is no need to disassemble the joint.

FIG. 4 is an enlarged perspective view of the spacer ring 7, and 21 is a notch inserted in the axial direction of the ring as necessary. In addition, the notch 21 may be inserted through the spacer ring 7 as shown in the figure, or may be fixed in the front half of the spacer ring 7, but in any case, by providing the notch 21, the pressure resistance is improved. It is easier to set up and also easier to restore.

[Effect of idea]

Since the present invention uses the above structure, normally it does not expand or contract beyond a certain amount of play, and only when an abnormal load is applied, the engagement between the cylindrical part and the flange of the spacer ring is disengaged, and the excess can absorb loads,
Accidents that may damage other components can be prevented.

In addition, since there is no need to provide grooves on the joint pipes as in the past, the strength of the joint pipes can be guaranteed, and even if JIS standard products are used, the strength guarantee can be complied with, and there is no need to measure each individual pipe. do not have.

Furthermore, by extending the guide part, even if the axis of the flexible joint is misaligned, the cylindrical part and the flange part can be evenly engaged, which can prevent variations in pressure resistance. do not have.

Even if the cylindrical part and the flange become disengaged due to a load exceeding a predetermined value and the flange fits into the cylindrical part, if the joint pipe is pushed, the cylindrical part tip or the guide part tip will touch the wall of the joint body. Since it is possible to make contact and release the fitting of the flange, there is no need to disassemble the joint during restoration work, and the work can be done quickly and easily.

In addition, even if it becomes necessary to replace the joint pipe due to some kind of damage on the secondary side, a JIS standard pipe is sufficient without the need for a special pipe with a groove, so it can be easily replaced on site. Is possible.

Furthermore, by providing a notch in the spacer ring, it becomes easier to set the withstand pressure, and restoration work is also made easier, which provides great effects.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing a fixed shaft expansion joint according to one embodiment of the present invention, Fig. 2 is a half-cut sectional view showing a flexible expansion joint according to another embodiment, and Fig. 3 is a cross-sectional view showing a flexible expansion joint according to another embodiment of the present invention. FIG. 4 is a half-cut sectional view showing a place where an abnormal load is applied to the expansion joint, and FIG. 4 is an enlarged perspective view showing a spacer ring. In the figure, 1, 10...joint body, 2, 11...
Joint pipe, 3, 12... collar part, 7, 17... spacer ring, 8, 18... cylindrical part, 19...
Guide portion, 21...notch.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. An expansion joint in which a joint pipe 2, 11 is inserted into a joint body 1, 10 to make it watertight at a sealed portion, and a flange 3, 1 provided at the tip of the joint pipe.
2 and the seal portion, a spacer ring 7 having a thin elastic cylindrical portion 8, 18 extending in the direction of the flange, which disengages from the flange at a predetermined pressure or higher and expands in the outer circumferential direction; An expansion joint characterized by having No. 17 inserted therein. 2 Thin cylindrical portion 8 of spacer ring 7, 17,
2. The expansion joint according to claim 1, further comprising a guide portion 19 extending on the outer peripheral surface of the collar portions 3, 12. 3 Notch 2 in part of spacer ring 7, 17
3. The expansion joint according to claim 1, further comprising: 1.