JP2000310375A - Connecting device of flexible pipe and coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and speedily carry out piping work by relatively rotating a coupling and a flexible pipe around a shaft by simple operation as well as to improve reliability and economy by holding a connected state having certain watertightness for a long period of time. SOLUTION: An end part of a flexible pipe 1 is inserted into the inside of a connecting port of a coupling 4 in this connecting device. An O ring 18 is arranged on a trough part of the end part of the flexible pipe 1, interposed on a pressure contact surface 11 of the coupling 4 in a pressure contact state and kept in a watertight state. A split bush 19 is fitted between a bellows part of the flexible pipe 1 and an interval holding surface 14 of the coupling 4, movement of the flexible pipe 1 in the axial direction is prevented, and an interval between an outer periphery of the flexible pipe 1 and an inner periphery of the coupling 4 is maintained roughly uniform. The split bush 19 is prevented from slipping off by a slip-off preventive means of a washer 23, a C type spring 22, etc. The O ring 18 is formed of rubber for low friction or the pressure contact surface 11 of the coupling 4 is coated with a material of a low friction coefficient, and it is possible to reduce sliding resistance of the O ring 18 and the pressure contact surface 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting a flexible pipe to a water supply pipe by connecting a flexible pipe used for a sprinkler head mounting pipe or the like in a sprinkler fire extinguishing system. The present invention relates to a connection device between a flexible pipe and a joint suitable for use in a case where it is required to relatively rotate around an axis while maintaining watertightness.

[0002]

2. Description of the Related Art In a conventional sprinkler fire extinguishing piping system, a flexible pipe having bellows-shaped peaks and valleys is used as a sprinkler head mounting pipe, and a sprinkler head is connected to one end of the flexible pipe. And then
A configuration is adopted in which the other end of the flexible pipe is screwed to a joint connected to a water supply branch pipe by a joint.
The flexible pipe and the joint as described above cannot be connected at a construction site from the viewpoint of workability, quality reliability, and the like, and are previously connected at a factory or the like. On the other hand, if the sprinkler head to which the flexible pipe is connected is attached to the field edge, the flexible pipe cannot be rotated around the axis. Therefore, in order to improve the workability of the pipe, even if the rotation of the flexible pipe around the axis is restricted, the joint is rotated around the axis in a watertight state with respect to the flexible pipe, and the joint is turned on the side of the water supply branch pipe. It must be configured to be screwed to the joint.

Conventionally, as one example of this type of connection device, as described in Japanese Patent Application Laid-Open No. 10-103577, an O-ring disposed at a valley at the end of a flexible pipe is provided on the inner peripheral surface of a joint. At the position pressed away from the end of the tube than the position where the O-ring is disposed, it is straddle-shaped or deformable across the trough of the flexible tube and the storage groove formed on the inner peripheral surface of the joint. A configuration in which a retaining member made of a linear material is provided is known.

[0004]

According to the prior art described above, a watertight structure between the flexible tube and the joint and a structure for preventing the joint from coming off in the axial direction can be obtained by using the bellows shape of the flexible tube as it is. Therefore, there is an advantage that it is not necessary to perform special processing on the flexible tube. However, according to the above conventional example, not only can the bellows-like portion of the flexible tube not be set with high dimensional accuracy, but also the valley portion of the flexible tube and the storage groove portion of the joint cannot be completely matched. For this reason, it is difficult to insert the retaining member from the insertion hole of the joint over the valley of the flexible pipe and the storage groove of the joint. In order to insert the retaining member relatively easily across the valley of the flexible pipe and the storage groove of the joint, a relatively wide gap is required between them, and the outer circumference of the flexible pipe is inferior due to poor precision of the flexible pipe. A relatively wide gap is required between the joint and the inner peripheral surface of the joint. For this reason, if the axis of the protruding portion from the joint in the flexible pipe is inclined or bent with respect to the axis of the joint, the inner part of the joint in the flexible pipe also is inclined or bent with respect to the axis of the joint. And may deform the flexible tube,
As a result, the O-ring is deformed, so that the O-ring cannot be uniformly pressed against the inner peripheral surface of the joint over the entire periphery of the O-ring, and there is a possibility that reliable watertightness cannot be obtained over a long period of time. .

[0005] Further, according to the configuration of the conventional example as described above, the joint can be rotated about the axis with respect to the flexible pipe. By the way, as described above, the bellows-shaped portion of the flexible pipe cannot be manufactured with high dimensional accuracy, and in order to obtain sufficient watertightness between the flexible pipe and the joint, generally, the surfaces of the machined surfaces are not joined together. The compression of the O-ring must be increased more than necessary, as compared with the case where watertightness is obtained. However, when a large compression is applied to the O-ring, the repulsive force increases, and the sliding resistance between the O-ring and the press contact surface of the joint increases, so that the rotational torque increases,
Without the use of a tool, the joint cannot be rotated about the axis with respect to the flexible pipe, and the screwing work efficiency is poor. In particular, when the joint is connected to the end of the flexible pipe in advance using an O-ring and a retaining member as described above, and the joint is connected to a joint such as a water supply branch pipe after a certain period of time, start-up is required. The frictional resistance is increased, and the screwing operation requires an even greater force, resulting in poor working efficiency.

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned conventional problems, and can obtain a watertight structure with a joint and a structure for preventing the joint from coming off in the axial direction by utilizing the bellows shape of a flexible tube. In such a configuration, the flexible pipe and the joint can be connected at a substantially uniform interval on the circumference, that is, the O-ring can be connected in a substantially uniform compression state over the entire circumference thereof. Even if a force that inclines or bends the projecting portion of the pipe from the joint, deformation or the like inside the joint of the flexible pipe can be prevented, and therefore, a connection having reliable watertightness over a long period of time. The present invention provides a connection device between a flexible pipe and a joint capable of maintaining a state and improving reliability, economy, and the like. In addition, the joint and the flexible pipe can be relatively rotated around the axis by a simple operation of maintaining a watertightness and applying a relatively small force, so that the piping work can be performed easily and quickly. It is an object of the present invention to provide a connecting device for a flexible pipe and a joint, which is capable of performing the following.

[0007]

In order to solve the above-mentioned first problem, an apparatus for connecting a flexible pipe to a joint according to the present invention comprises O-rings formed on an inner periphery and an outer periphery of an inner periphery of a joint opening of the joint. It has a pressure contact surface and a space holding surface, a bellows-shaped peak portion and a valley portion, and is disposed in a valley portion of an end portion of a flexible pipe inserted into a connection port portion of the joint. The O-ring interposed in the press-contact state is fitted between the bellows-like portion of the flexible pipe and the space holding surface of the joint at a position further away from the pipe end than the position where the O-ring is provided, A split bush that prevents movement of the pipe in the axial direction and maintains a substantially uniform interval between the outer circumference of the flexible pipe and the inner circumference of the joint; and a retaining means for preventing the split bush from coming off the joint. And the joint and the flexible And Bull tube, in which is configured to be capable of permitting relative rotation about an axis while maintaining the water-tight state by the O-ring.

In the above structure, as the retaining means, an annular engagement groove formed on the inner peripheral surface of the connection port of the joint, and a C having an outer peripheral portion locked in the engagement groove.
A mold spring and a washer interposed between the C-shaped spring and the split bush can be provided.

In order to solve the above-mentioned second problem, a connecting device for a flexible pipe and a joint according to the present invention, wherein the O-ring is formed of rubber having a low coefficient of friction in each of the above structures, The surface is coated with a material having a low coefficient of friction or a combination of the two.

According to the present invention configured as described above,
Since the split bush can prevent the flexible pipe from coming off in the axial direction with respect to the joint, and since the outer periphery of the flexible pipe and the inner peripheral surface of the joint can be maintained at a substantially uniform interval over the entire circumference, The O-ring can be connected to the flexible pipe and the joint in a substantially uniform compressed state over the entire circumference, that is, in a reliable watertight state, and
Even if a force is applied to the outwardly protruding portion of the flexible pipe from the joint in the inclined direction and the bending direction, the deformation of the flexible pipe can be prevented by the split bush.

Further, the O-ring is formed of rubber having a low friction coefficient, or the O-ring press-contact surface of the joint is coated with a material having a low friction coefficient, or by using a combination thereof to press the O-ring and the joint together. Reduce the sliding resistance with the surface and temporarily connect the joint to the flexible pipe via an O-ring and split bush.
Even if the ring is left in contact with the press contact surface for a long time, the starting frictional resistance between the O-ring and the press contact surface of the joint can be reduced. It can be relatively rotated around the axis by a simple operation with a weak force.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a connecting device between a flexible pipe and a joint according to an embodiment of the present invention, and FIG. 2 shows a piping construction example in which a flexible pipe and a joint connected by the connecting device are applied to a sprinkler fire extinguishing piping system. FIG. 3 is a schematic diagram showing the change in the rotational torque value with the passage of time between the O-ring and the press-contact surface of the joint according to each embodiment used in the connection device.

As shown in FIGS. 1 and 2, the flexible tube 1 is made of, for example, stainless steel, and is formed such that an annular crest 2 and a valley 3 have a bellows shape. Fitting 4
Is made of metal, and a male screw 6 is formed on the outside of the connection portion 5 side,
A polygonal bulge 8 is formed on the outside on the connection port 7 side. A flow path 9 is formed inside the connection portion 5 side.
On the inside of the connection port 7 side, an inclined surface 10 that gradually expands is formed following the inner end of the flow path 9 and then to the outer end, and a cylindrical shape is formed following the expanded portion side of the inclined surface 10. An O-ring press contact surface 11 having an intermediate diameter is formed, and the inclined surface 12 gradually expands gradually following the O-ring press contact surface 11 to the outer end side.
The engagement step 13 is formed on the outer peripheral side of the inclined surface 12 following the expanded portion side, and the cylindrical large-diameter part is formed following the outer peripheral edge of the engagement step 13. . The engagement step 13 side of the large diameter portion is formed as a spacing surface 14, and an annular engagement groove 16 is formed on the open portion 15 side of the large diameter portion.

The end of the flexible pipe 1 is inserted into the connection port 7 of the joint 4 from the opening 15 side, and the ridge 2 of the pipe end is inserted.
Reaches the vicinity of the inclined surface 10, and the flow path 17 inside the flexible pipe 1 communicates with the flow path 9 of the joint 4. An O-ring 18 is provided at one end of the flexible pipe 1, in the illustrated example, at one point of the valley 3 following the peak 2 of the pipe end.
8 is interposed in a compressed state between the slopes of the valleys 3 and the ridges 2 of the flexible pipe 1 and the pressure contact surface 11 on the inner periphery of the joint 4,
An O-ring 18 keeps the space between the flexible pipe 1 and the joint 4 in a watertight state. The O-ring 18 is made of a low friction rubber made by mixing a lubricant into a rubber material. Thereby, the ridge 2 and the valley 3 of the flexible pipe 1 have low dimensional accuracy, and the O-ring 18 is set to have a large compression in order to maintain a reliable watertight state between the flexible pipe 1 and the joint 4. Even so, the sliding resistance between the joint 4 and the press contact surface 11 is reduced.

The bush 19 is formed of, for example, a synthetic resin material having a low coefficient of friction in two parts (the part may be divided into three parts, and the number of divisions is not limited). Annular valleys 20 and peaks 21 corresponding to the valleys 3
Is formed, and the outer periphery is formed as a cylindrical smooth surface. The split bush 19 is located at a position more distant from the pipe end than the position where the O-ring 18 is provided in the flexible pipe 1, and a valley 20 and a peak 21 inside the split bush 19 are formed on the peak 2
And the valley 3 and the outer smooth surface is
Is rotatably fitted in a contact state (or a close state) with the space holding surface 14. This split bush 19 prevents the flexible tube 1 from moving in the axial direction (prevents the flexible tube 1 from coming off),
In addition, the distance between the outer circumference of the flexible pipe 1 and the inner circumference of the joint 4 can be kept substantially uniform over the entire circumference. Accordingly, the O-ring 18 is maintained in a state in which the entire circumference thereof is interposed between the flexible pipe 1 and the press-contact surface 11 of the joint 4 in a substantially uniform compressed state. 1 can rotate relatively around axis C.

One side of the split bush 19 is engaged with the engagement step 13 of the joint 4, whereby the advance position of the flexible tube 1 at the time of insertion into the joint 4 is regulated, and the end of the tube end of the flexible tube 1 is restricted. The peak 2 is preferably a slope 10
To avoid contact with Groove 16 for engagement of joint 4
, The outer periphery of the C-shaped spring 22 is resiliently engaged. A washer 23 is interposed between the C-shaped spring 22 and the other side surface of the split bush 19. Then, the split bush 19 and the flexible pipe 1 are prevented from coming off by the washer 23 and the C-shaped spring 22, and the split bush 19 can rotate relatively smoothly with a small resistance to the washer 23. The inner diameter of the washer 23 is formed to be slightly larger than the outer diameter of the top of the peak 2 of the flexible pipe 1 so that the washer 23 can be easily fitted to an arbitrary position of the flexible pipe 1.

In the above configuration, the connection procedure between the flexible pipe 1 and the joint 4 will be described below. First, a C-shaped spring 22 and a washer 23 are fitted into the flexible pipe 1 from its pipe end in a loose state, and an O-ring 18 is mounted on the valley 3 of the pipe end by utilizing its elastic deformation. The valley portion 2 and the crest portion 21 of the split bush 19 are fitted to the portion 2 and the valley portion 3. Next, the end of the flexible tube 1, O
Connect the ring 18 and the split bush 19 to the connection port 7 of the joint 4.
The O-ring 18 is forcibly inserted from the opening 15 side by utilizing the elastic deformation of the O-ring 18, and one side surface of the split bush 19 is brought into contact with the engaging step 13 of the joint 4. Thereby, the pipe end of the flexible pipe 1 can reach the vicinity of the inclined surface 10 of the joint 4 to allow the flow path 17 of the flexible pipe 1 to communicate with the flow path 9 of the joint 4. The flexible pipe 1 and the joint 4 are maintained in a water-tight state by being interposed in a compressed state between the slopes of the valleys 3 and the peaks 2 and the press-contact surface 11 of the joint 4. At this time, the O-ring 18 is
2 can be easily pressed into the press contact surface 11.

Next, the washer 23, which is loosely fitted to the flexible pipe 1, is inserted into the connection port 7 of the joint 4 by the opening 1
It is inserted from the fifth side and is brought into contact with the side surface of the split bush 19.
Next, the C-shaped spring 22 which is loosely fitted to the flexible pipe 1 is forcibly pressed into the connection port 7 of the joint 4 from the open portion 15 side by utilizing its elastic deformation, and is inserted into the engagement groove 16. By engaging the outer periphery of the C-shaped spring 22 resiliently and engaging the C-shaped spring 22 with the washer 23, the split bush 19 and the flexible pipe 1 are joined.
Can be connected to the joint 4 in a retaining state. According to the present embodiment, since the connection can be performed only by fitting and inserting the respective members, the configuration can be simplified, and the connection operation can be performed easily and reliably.

The flexible pipe 1 connected as described above
With reference to FIG. 2, a description will be given of a procedure for installing the joint 4 in the piping system. In FIG. 2, reference numeral 24 denotes a water supply auxiliary pipe, 25 denotes a water supply branch pipe having one end connected to the water supply auxiliary pipe 24, 26 denotes a multi-port joint connected to the other end of the water supply branch pipe 25, and 26 denotes a field joint. It is an edge. First, the end of the flexible pipe 1 on the side opposite to the joint 4 is connected to the spring clamp head 28. Next, the sprinkler head 28 is attached to the ridge 27 with the attachment 29. next,
Support the position of the flexible pipe 1 near the joint 4 with one hand,
The swollen portion 8 of the joint 4 is rotated with the other hand. At this time, since the O-ring 18 is formed of rubber for low friction as described above, the sliding resistance of the joint 4 with respect to the press-contact portion 11 is reduced. The male screw 6 of the joint 4 can be screwed into the connection port 30 of the multi-joint joint 26 by being relatively lightly and smoothly rotated around the axis C. Then, by engaging the tool with the bulging portion 8 at the end and rotating the joint 4, the male screw 6 and the connection port 30 of the multi-port joint 26 can be connected in a tightened state. At this time, the split bush 19 does not rotate if the frictional resistance of the flexible pipe 1 is large, and rotates together with the joint 4 if the frictional resistance with the joint 4 is large.

As described above, since the joint 4 can be rotated around the axis while maintaining a watertight state with respect to the flexible pipe 1, the sprinkler head 28 is attached to the ridge 27 so that the flexible pipe 1 is rotated around the axis. The joint 4 can be connected to the joint 26 even if it cannot be rotated. If it is necessary to correct the orientation of the sprinkler head 28 after such connection, the sprinkler head 28 can be corrected by rotating the joint 4 together with the flexible pipe 1 around the axis. As described above, the interval between the outer circumference of the flexible pipe 1 and the inner circumference of the joint 4 can be maintained almost uniformly over the entire circumference by the split bush 19, so that the flexible pipe 1 protrudes from the joint 4. Even if the pipe is inclined or curved with respect to the axis C of the joint 4, the joint 4
Since the axis C of the inner part can be supported by the split bushing 19 so as to be substantially coincident with the axis C of the joint 4, the O-ring 18 is brought into contact with the flexible pipe 1 and the press contact surface 11 of the joint 4 over the entire circumference. It is possible to always maintain a substantially uniform pressure contact state, that is, a reliable watertight state.

In the above-described embodiment, the O-ring 18 is formed of rubber for low friction so as to reduce the sliding resistance between the O-ring 18 and the press-contact surface 11 of the joint 4. However, as another embodiment of the present invention, Alternatively, the pressure contact surface 11 of the joint 4 may be coated with a material having a low coefficient of friction such as glass or Teflon to reduce the sliding resistance with the O-ring 18. In this case, a general commercially available product that does not particularly use the rubber for low friction can be used as the O-ring 18,
Further, by forming the O-ring 18 from a low friction rubber and using it in combination with the above-mentioned coating layer, the pressing surface 11 can be further improved.
The joint 4 and the flexible pipe 1 can be relatively smoothly rotated about an axis while maintaining a watertight state by reducing the sliding resistance between the joint 4 and the O-ring 18.

If the joint 4 and the flexible pipe 1 are relatively rotated around the axis by a tool or the like, the O
A commercially available product can be used as the ring 18, and the press contact surface 11 does not need to be coated with a material having a low coefficient of friction.

[0023]

Example 1 As Example 1, an O-ring (mini-flick: trade name, manufactured by Mitsubishi Cable Industries, Ltd.) 18 formed of rubber mixed with a lubricant was used, and the press-contact surface 11 was kept machined and kept low. No coating treatment with a friction material was performed. In Example 2, a commercially available O-ring 18 was used, and the press contact surface 11 made of a glass coat layer was used. In Example 3, a commercially available O-ring 18 was used, and the press contact surface 11 made of a Teflon coat layer was used. As Example 4, commercially available O
Using the ring 18, the press-contact surface 11 was machined, and was not coated with a low-friction material.

For the above Examples 1 to 4, the results of measuring the rotational torque value of the joint 4 with respect to the O-ring 18 over time were as shown in FIG. From this measurement result, in particular, in order to rotate the joint 4 and the flexible pipe 1 around the axis with a relatively light force, use the O-ring 18 containing a lubricant as in the first embodiment, or use the O-ring 18 as in the second embodiment. It has become clear that it is preferable to provide a glass coat layer on the press contact surface 11. Of course, if an O-ring 18 containing a lubricant is used, it can be used in combination with a glass coat layer.
Although the rotational torque value is larger than that of the glass coat layer, it can be easily estimated that the rotational torque value can be further reduced by combining with the Teflon coat layer.

In the above embodiment, the O-ring 18 is provided at one place, but the present invention is not limited to this, and the O-ring 18 may be provided at two or more places. In addition, the present invention can be variously changed in design without departing from the basic technical idea.

[0026]

As described above, according to the present invention, the split bush can prevent the flexible pipe from coming off in the axial direction with respect to the joint, and the outer circumference of the flexible pipe and the inner peripheral surface of the joint can be separated. Since the O-ring can be maintained at a substantially uniform interval over the entire circumference, the O-ring can be connected to the flexible pipe and the joint in a substantially uniform compression state over the entire circumference, that is, a reliable watertight state, In addition, the flexible pipe has an outwardly projecting portion from the joint,
Even if a force is applied in the bending direction, the deformation of the flexible tube can be prevented by the split bush. Therefore,
It is possible to maintain a connection state having reliable watertightness over a long period of time, thereby improving reliability, improving economic efficiency, and the like.

The O-ring may be formed of rubber having a low coefficient of friction, or the O-ring of the joint may be coated with a material having a low coefficient of friction on the press-contact surface which comes into contact with the O-ring. Reduces the sliding resistance between the joint and the pressure contact surface. Even if the joint is connected to the flexible pipe via an O-ring and split bush in advance, the contact time between the O-ring and the pressure contact surface becomes longer, Since the starting frictional resistance with the press contact surface of the joint can be reduced, the joint and the flexible pipe can be relatively rotated around the axis by a simple operation with a relatively weak force while maintaining watertightness. . Therefore, piping work can be performed easily and quickly.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a connection device between a flexible pipe and a joint according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of piping construction in which a flexible pipe and a joint connected by the connection device are applied to a sprinkler fire extinguishing piping system.

FIG. 3 is a graph showing a change in a rotational torque value over time between an O-ring and a press-contact surface of a joint according to each embodiment used in the connection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible pipe 2 Crest part 3 Valley part 4 Joint 11 Pressure contact surface 13 Engagement step part 14 Interval maintenance surface 16 Engagement groove 18 O-ring 19 Split bush 20 Crest part 21 Valley part 22 C type spring 23 Washer

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[Procedure amendment]

[Submission date] May 11, 1999 (1999.5.1
1)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (4)

[Claims] 1. An O-ring press contact surface and an interval holding surface formed inward and outward on an inner periphery of a connection port of a joint,
An O-ring having a bellows-shaped peak and a valley, disposed at a valley at an end of a flexible pipe inserted into a connection port of the joint, and interposed in a press-contact state with a press-contact surface of the joint; The flexible tube is fitted between the bellows-like portion of the flexible tube and the space holding surface of the joint at a position more distant from the tube end than the position where the O-ring is provided, thereby preventing the flexible tube from moving in the axial direction. A split bush that blocks the outer circumference of the flexible pipe and the inner circumference of the joint; and a retaining means for preventing the split bush from coming off from the joint. A connection device between a flexible pipe and a joint, which is configured to allow relative rotation about the axis of the flexible pipe while maintaining a watertight state by the O-ring. 2. A method according to claim 1, wherein said retaining means comprises: an annular engaging groove formed on an inner peripheral surface of a connection port of the joint; a C-shaped spring having an outer peripheral portion locked in said engaging groove; 2. The connecting device according to claim 1, further comprising a washer interposed between the spring and the split bush. 3. The connecting device according to claim 1, wherein the O-ring is formed of rubber having a low coefficient of friction. 4. The connecting device according to claim 1, wherein the O-ring press-contact surface of the joint is coated with a material having a low coefficient of friction.