JP2003185066A - Pipe joint for metal pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe joint in which extra bell mouth working is unnecessary, connection is firmly executed by conventional tools, the completion of inserting the pipe into a normal position is easily ascertained, and workability is excellent. <P>SOLUTION: A sleeve arranging a plurality of steel balls circumferentially at equal intervals and two O-ring are installed on the inner surface of a main body having a bolt thread on the end. A nut having a nut thread on one end is engaged with the main body in the form of encapsulating the steel balls arranged in the sleeve. Thus, a joint is assembled to insert a pipe to be connected. The nut is tapered. When the nut is fastened to the main body, the plurality of balls held by the sleeve are pressed in the axial direction of the metal pipe to be connected by the taper part of the nut. The outer and inner surfaces of the sleeve are provided with O-rings respectively, the outer side O-ring sealing between the joint body and the sleeve and the inner side O-ring sealing between the sleeve and the pipe. Thus, the joint body and the pipe seal each other. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a mechanical pipe joint for metal pipes, which is connected by fastening a nut.

[0002]

2. Description of the Related Art Mechanical pipe joints for metal pipes, which are connected by fastening nuts, have ends that are to be expanded or grooved in addition to cutting and chamfering the metal pipes to be connected in order to obtain a pulling-out preventing force. The types of pipe joints that require pipe end machining and those that do not require special pipe end machining other than cutting and chamfering are roughly classified. The representative of the former is Jikken 02-037015 (Jpn.
5, "connection mechanism between thin-walled stainless steel pipe and joint"), JP-A-9-178063 (Japanese Patent Application No. 7-335037, "Pipe joint with tightening confirmation") and the like, and the latter representative is Japanese Patent No. 3122385. (Japanese Patent Application No. 9-52308, "Pipe Joint"), Japanese Patent Application Laid-Open No. 2001-12666 (Japanese Patent Application No. 11-18).
2302, "pipe fitting") and the like.

[0003]

A conventional pipe joint requiring pipe end machining requires a special pipe expanding machine or groove machining machine for machining the pipe end into a shape such as a taper, a convex shape, or a groove. Generally, they are heavy to carry, and there is a problem in that workability is poor because it is necessary to insert a nut into the pipe in advance to process the pipe end.

The related pipe joint based on the above-mentioned Japanese Patent No. 3122385, which requires no special pipe end processing other than cutting and chamfering of the pipe, has the following problems. (1) Since the pipe rotates together with the nut when it rotates, it is necessary to rotate the nut while fixing the main body and the pipe with a tightening tool, and it may be necessary to use two people to work with both hands. It was (2) Since the pipe and the pipe joint rotate relatively easily even after the pipe is fastened, it is necessary to support the pipe when an eccentric load is applied to the bent pipe, which makes the construction difficult. there were. (3) When you try to connect the pipe by inserting the pipe into the pipe fitting without marking the outer circumference of the pipe in advance and connecting it by rotating the nut, the nut rotates endlessly, so the limit to stop the nut is unknown and the retainer After the contact with the main body, there is a problem in that the inserted tube may be pushed out to the outside and the tube may come off the seal portion.

The present invention does not require any special pipe end machining other than cutting and chamfering the pipe, and therefore does not require any special pipe expanding or grooving tools, and uses conventional tools such as monkey wrenches or pipe wrenches. , By fixing the pipe joint body and tightening the nut without specially fixing the pipe to be connected, it is possible to firmly connect without rotating the pipe, and when inserting the pipe into the pipe joint It is an object of the present invention to provide a pipe joint with good workability, in which it is easy to confirm completion of insertion of a pipe to a normal position without the need to attach a special mark.

[0006]

In order to achieve the above object, a sleeve in which a plurality of steel balls are circumferentially arranged at equal intervals and two O-rings are formed on the inner surface of a main body having an external thread at an end thereof. And a nut having a female thread at one end is engaged with the main body in such a manner as to wrap a steel ball arranged in the sleeve to form a set of joints, and a pipe to be connected can be inserted.

Further, the inner surface of the nut is tapered, and when the nut is tightened to the main body, a plurality of steel balls held by the sleeve are pressed toward the center of the metal pipe to be connected by the tapered portion of the nut. To do.

Further, one O-ring is provided on each of the inner and outer surfaces of the sleeve, the outer O-ring seals between the joint body and the sleeve, and the inner O-ring seals between the sleeve and the pipe. Thus, the joint body and the pipe are sealed together.

Further, at least one position on the outer circumference of the sleeve is provided with an axial convex portion which serves as a sleeve anti-rotation guide portion, and a notch portion corresponding to the axial convex portion is provided at the end portion of the main body so as to be fitted to each other, and the nut is fitted. The structure is such that the sleeve does not rotate with respect to the main body when tightening.

Further, the sleeve is made of an elastic resin, and the diameters (d and d ') of the inner and outer openings of the plurality of holes for accommodating the steel balls arranged at equal intervals on the circumference are steel. Molded with a diameter slightly smaller than the diameter (D) of the ball, and after forming the sleeve, push the steel ball into the outer opening of the hole to prevent it from falling outside the sleeve normally, and in the state where the nut is not tightened, the steel ball Has a structure that does not protrude inward beyond the inner diameter of the sleeve.

Further, a small protrusion is provided on the sleeve detent guide portion which fits into the cutout portion of the end portion of the main body, and the small protrusion in the axial direction causes the small protrusion to come into contact with the end portion of the main body so that the sleeve is further extended. The structure does not enter the inside of the main body, and when the sleeve is pushed axially inward into the main body of the joint through the pipe to be connected, the small projections are deformed and the sleeve can enter the inside of the main body. .

Further, when the nut is tightened to the normal position in a state where the sleeve has normally reached the inside of the main body through the pipe, the small-diameter side end surface of the nut and the small-diameter side end surface of the sleeve are aligned so that the outside of the small-diameter side of the sleeve is aligned. The diameter part has a structure that is not exposed from the end surface of the small diameter side of the nut.On the contrary, when the nut is tightened to the normal position with the sleeve not reaching the inside of the body, the end surface of the small diameter side of the sleeve protrudes from the end surface of the small diameter side of the nut. The outer diameter of the small diameter side of the sleeve is exposed from the nut.

Further, the indicator ring A whose outer circumference is colored is attached so as to be in contact with a vertical surface at the inner side of the male threaded portion of the main body so that it can be inscribed in the outer circumference of the indicator ring A and the color of the outer circumference of the indicator ring A is clear. The indicator rings B of different colors are attached in series, and when the tightening of the nut is completed, the end surface of the nut sandwiches the indicator ring B with the vertical surface of the main body to completely cover the indicator ring A.

When the pipe is fastened to the joint, the inner diameter of the pipe, the inner diameter of the sleeve inner diameter surface, and the inner diameter of the main body inner diameter surface are approximately the same.

[0015]

In the metal pipe pipe joint of the present invention constructed as described above, after inserting the pipe into the sleeve, the nut having a tapered inner surface is tightened to press a plurality of steel balls against the pipe surface. Since a recess is formed in the tube, it is possible to ensure the function of preventing the tube from being pulled out.

Further, the sleeve detent guide portion provided on a part of the outer circumference of the sleeve is fitted with the notch portion provided at the end portion of the joint body, so that the sleeve and the pipe are inserted through the steel ball when the nut is tightened. Can be prevented from rotating relative to the body. This serves to prevent the tubes from rotating in the direction of loosening when the tubes to be connected are already fastened at the other end.

The diameters (d and d ') of the inner and outer openings of the plurality of holes for housing the steel balls arranged at equal intervals on the circumference of the sleeve are made of elastic resin. By molding with a diameter slightly smaller than the diameter (D) and pressing the steel ball from the outer opening of the hole after molding the sleeve, it will normally not fall outside the sleeve, so the assembly work of parts becomes easy. Become. Further, by adopting a structure in which the steel ball does not project inward beyond the inner diameter of the sleeve when the nut is not tightened, the pipe can be easily inserted into the sleeve and the workability is improved.

A small protrusion is provided on the sleeve detent guide portion that fits into the notch at the end of the main body, and the small protrusion in the axial direction causes the small protrusion to come into contact with the end portion of the main body, so that the sleeve is no longer attached to the main body. With a structure that does not enter inside,
When the sleeve is pushed axially inward into the main body through the pipe to be connected, the small projections are deformed so that the sleeve can enter the main body.Therefore, it is inside the nut before connecting the pipe. Unless the sleeve unit is intentionally pushed in, the axial position of the sleeve with respect to the main body serves as an index for confirming whether or not the pipe is properly inserted.

When the nut is tightened to the normal position in a state where the sleeve has normally reached the inner part of the body through the pipe, the small diameter side end surface of the nut is aligned with the small diameter side end surface of the sleeve. Is not exposed from the end surface of the small diameter side of the nut, and conversely, when the nut is tightened to the normal position with the sleeve not reaching the inner part of the body, the nut and sleeve have a certain axial distance in advance. Since the thrust force that pushes the sleeve inward is not generated by the nut even when the nut is tightened to the normal position, the end surface of the small diameter side of the sleeve protrudes from the end surface of the small diameter side of the nut and the outer diameter part of the sleeve is exposed from the nut. By adopting a structure that
For example, if the color of the outer diameter portion on the small diameter side of the sleeve is more conspicuous than the outer surface color of the nut, normal insertion of the pipe after the pipe connection work can be easily determined. That is, the construction confirmation becomes easy.

Two kinds of indicator rings A and B having different colors and dimensions are provided on the outer periphery of the main body, and the indicator ring B (white, for example) is pushed by the end surface of the nut when the nut tightening is completed, and the indicator ring A (white, for example). ) Is completely hidden, the nut tightening completion can be easily judged from a distant position, and it works to prevent forgetting to tighten in terms of construction management.

When the pipe is fastened to the joint, the inner diameter of the pipe, the inner diameter of the sleeve inner diameter surface, and the inner diameter of the central portion of the main body inner diameter are made to be substantially the same, so that the cross-sectional change inside the joint is minimized. Vortex resistance can be reduced. That is, a joint with less pressure loss can be provided.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described based on examples with reference to the drawings. In FIG. 1, the lower part of the cross-sectional view shows a state in which the left and right sides are in a state before tightening the nuts and a metal pipe to be connected is partially inserted. The upper left portion of the cross-sectional view shows a state in which the nut is completely tightened after the metal pipe is normally inserted. The upper right part of the cross-sectional view shows a state in which the nut has been tightened with the metal tube inserted incompletely. The external view on the upper side of FIG. 1 shows the positional relationship between the main body and the sleeve, the left half shows the state where the sleeve is pushed to the normal position, and the right half shows the relationship when the sleeve is not pushed to the normal position.

Inside the main body (1) having a male thread at the end thereof, a sleeve (3) having a plurality of steel balls (4) housed in steel ball mounting holes (3h) arranged at equal intervals on the circumference is provided. The inner O-ring groove (3) provided on the inner surface of the sleeve (3)
The outer O-ring provided on the outer diameter surface (3e) of the sleeve (3) on the large-diameter side of the sleeve (3) by attaching the O-ring 1 (5) to j) to seal the outer surface of the metal tube (9) O in the groove (3k)
With the ring 2 (6) attached, the inner diameter surface (1
The structure is to be sealed with c).

At least one of the outer circumference of this sleeve (3)
A sleeve detent guide portion (3 m) is provided in a position in the axial direction, and a main body end cutout portion (1 g) is provided at a corresponding opposing position so as to be fitted to each other. Further, a sleeve protrusion portion (3n) is provided on the sleeve rotation preventing guide portion (3m), and when the sleeve (3) is assembled to the main body (1), the sleeve protrusion portion (3n) has the main body end cutout portion. The structure is such that it abuts the end of (1g) and does not enter further. Sleeve middle end face (3p) and body end face (1
e), and the same constant distance (δ) is provided between the end surface (3d) on the large diameter side of the sleeve and the end surface (1h) on the inner diameter side of the main body.

When the metal pipe (9) is fitted and inserted into the sleeve pipe receiving portion (3a) in the sleeve (3), after the metal pipe end (9a) contacts the sleeve pipe receiving end (3b), By pushing the tube (9) further inward,
The sleeve protrusion portion (3n) is crushed, and the sleeve rotation prevention guide portion (3m) is provided with the body end cutout portion (1).
The structure is such that it reaches the deep end of g). At this time, the sleeve large diameter side end surface (3d) and the main body inner diameter inner end surface (1
The structure should be such that it is in close contact with h).

In such a state, when the nut (2) is tightened to the normal position, the small diameter side end surface of the nut and the small diameter side end surface of the sleeve are aligned. In addition, when the sleeve (3) is inserted into the main body in the normal position and the nut is tightened in the main body with respect to the normal position, the nut and the sleeve have a certain axial interval, that is, a margin. To do. This should be
The structure is such that the nut does not interfere with the sleeve in the axial direction even if the nut is tightened in the state where the metal pipe is not inserted in the normal position, that is, in the state where the sleeve is not in the normal position. This means that the function of confirming the completion of tightening of the nut, which will be described later, can be done only by the indicator, and the function of confirming the insertion of the metal pipe to the normal position is confirmed by the relative positional relationship between the nut and the sleeve. .

At the upper side of the sectional view of FIG. 1, the nut (2)
When tightening is completed, the indicator A (7) has an outer diameter portion which is colored in a different color, the indicator B (8) has both side surfaces on the nut screw side end surface (2c) of the nut (2) and the outside of the main body 1 It is obscured by the vertical surface (1f).

FIG. 2 shows the AA cross section and the BB cross section of FIG. AA cross section shows the state after tightening the nut,
The BB cross section shows a state before tightening the nut. Steel ball mounting holes (3h) provided at equal intervals on the circumference of the sleeve (3) made of an elastic material such as resin holds the steel balls (4) at a fixed position in the direction perpendicular to the axis. Since the diameters (d and d ′) of the holes opened on the inner diameter side and the outer diameter side are slightly smaller than the diameter (D) of the steel ball (4) so that they can be pushed in, it is possible in the normal state. Each of the steel balls (4) is held in a state in which it does not project to the inner diameter side of the sleeve (3) and does not fall off to the outer diameter side.

On the left side of the sectional view of FIG. 1, the sleeve (3) is pushed to a normal position through the metal pipe (9) to be connected, and then the nut (2) is screwed into the main body (1) side, whereby the nut (2) is screwed. The steel ball (4) is pressed in the direction perpendicular to the axis of the metal pipe (9) by the wedge effect of the inner tapered portion (2b),
As shown in the upper side of the sectional view of FIG. 2, the surface of the metal pipe (9) forms a metal pipe recess (9b) along the outer shape of the steel ball (4). This is performed until the nut screw side end surface (2c) sandwiches the indicator A (7) and the indicator B (8) on the outer surface of the main body vertical surface (1f) and stops.

At this time, a force is generated to rotate the metal tube (9) in the same direction via the steel ball (4) with respect to the rotation of the nut (2), but the steel ball (4) is held. Sleeve anti-rotation guide part (3
Since the rotation of the sleeve (3) around the tube axis is prevented by fitting the m) and the notch (1g) on the body end, the steel ball (4) itself is a metal tube on the surface of the metal tube (9). Recess (9
It does not rotate in b) and does not rotate the metal tube (9) around the tube axis.

[0031]

Since the present invention is constructed as described above, it has the following effects. (1) As long as there are no abnormalities such as burrs or protrusions on the outer shape of the cut surface of the pipe to be connected, use the normal tool without cutting the pipe and performing special pipe end processing such as pipe expansion and grooving. Easy to connect. (2) Since the pipes do not rotate together when tightening the nut, it is only necessary to rotate the nut relative to the joint body and tighten it, so it is only necessary to use a pair of monkey wrench or pipe wrench, and it is easy for one person to use both hands Can be connected to.

(3) It is not necessary to disassemble the pipe joint such as removing the nut from the main body at the time of connecting the pipe, and the pipe can be directly inserted into the joint to start the connection work. (4) It is possible to easily confirm the complete insertion of the pipe to the normal position without performing work such as marking the surface of the pipe when connecting the pipe. In other words, an abnormal pipe insertion state can be easily discriminated, so that construction errors can be prevented. (5) The completion of tightening the nut can be easily determined by using two types of indicators colored in different colors and covering the indicator of one color.

[Brief description of drawings]

FIG. 1 is a pipe joint showing an embodiment of the present invention, in which a lower section shows an axial sectional view, and an upper section shows a combined external view of essential parts. In the sectional view of the lower part, the lower half shows the state before inserting the tube, and the upper half shows the state after inserting the tube. Further, the upper left half view of the lower sectional view and the left half view of the upper external view each show the state in which the nut is tightened after inserting the tube and the sleeve 3 into the normal position. Further, the upper right half view of the lower sectional view and the right half view of the upper external view each show a state in which the nut 2 is tightened in a state in which the tube and the sleeve 3 are not inserted to the normal position.

FIG. 2 is a cross-sectional view of a sleeve 3 holding a steel ball 4 of a pipe joint showing an embodiment of the present invention in a direction perpendicular to an axis, the upper half shows the AA cross section of FIG. 1, and the lower half shows FIG. 3 shows a cross section taken along line BB of FIG.

[Explanation of symbols]

1: Main body, 1a: Main body spanner hanging portion, 1b: Main body inner diameter central portion, 1c: Main body inner diameter surface, 1d: Main body screw portion, 1e: Main body end surface, 1f: Main body outer vertical surface, 1g: Main body end portion cutout portion 1h: End surface of inner diameter of main body, 2: Nut, 2a: Female thread portion of nut, 2b: Tapered portion of nut inner side, 2c: End surface of nut screw side, 2d: Parallel portion of nut inner side, 2e: End surface of small diameter side of nut 3: Sleeve, 3a: Sleeve tube receiving part,
3b: sleeve pipe receiving end, 3c: sleeve inner diameter surface, 3
d: sleeve large-diameter side end surface, 3e: sleeve large-diameter side outer surface, 3f: sleeve taper surface, 3g: sleeve small-diameter side end surface, 3h: steel ball mounting hole, 3j: inner O-ring groove, 3k:
Outer O-ring groove, 3m: Sleeve anti-rotation guide part, 3
n: sleeve protrusion, 3p: sleeve intermediate end face, 3q:
Small diameter side outer diameter part, 4: Steel ball, 5: O-ring 1,
6: O-ring 2, 7: Indicator A, 8: Indicator B, 9: Metal tube, 9a: Metal tube end, 9b: Metal tube recess,

Claims (10)

[Claims] 1. A pipe joint for connecting metal pipes, wherein a plurality of steel balls (4) are circumferentially arranged inside a main body (1) having a main body male thread portion (1d) at an end thereof. A sleeve (3) housed in the steel ball mounting holes (3h) arranged at intervals, an O-ring 1 (5), and an O-ring 2 (6) are provided, and a nut (N) having a female screw thread portion (2a) at one end is provided. A pipe joint for a metal pipe, which is assembled in 2). 2. When the nut (2) is fastened to the body (1), the steel ball (4) is pressed toward the center of the metal pipe (9) by the inner taper portion (2b) of the nut (2). The pipe joint for a metal pipe according to claim 1, wherein 3. Inner O provided on the inner surface of the sleeve (3)
The O-ring 1 (5) was mounted in the ring groove (3j) to seal the outer diameter surface of the metal tube (9), and was provided on the outer diameter surface (3e) of the sleeve (3) on the large diameter side. The O-ring 2 (6) is attached to the outer O-ring groove (3k) to form a structure for sealing with the inner diameter surface (1c) of the main body (1). Pipe fittings for metal pipes. 4. A sleeve detent guide portion (3m) is provided in at least one location on the outer circumference of the sleeve (3) in the axial direction, and a main body end cutout portion (1g) is provided at a corresponding opposing position, The pipe joint for a metal pipe according to claim 1, wherein the pipe joint has a fitting structure. 5. The inner and outer sides of a plurality of steel ball mounting holes (3h) in which the sleeve (3) is made of a resin having elasticity, and the steel balls (4) arranged at equal intervals on the circumference are accommodated. The diameter (d and d ') of the opening is formed to be slightly smaller than the diameter (D) of the steel ball (4), and the steel ball (4) is formed into the steel ball mounting hole (3h) after sleeve molding. It is pushed from the outside opening so that it will not normally fall outside the sleeve (3), and when the nut (2) is not tightened, the steel ball (4) jumps out inside the inner diameter of the sleeve (3). The pipe joint for a metal pipe according to any one of claims 1 to 4, wherein the pipe joint has a structure that does not prevent it. 6. A sleeve protrusion portion (3n) is provided on the sleeve detent guide portion (3m) of the sleeve (3),
When the sleeve (3) is assembled to the main body (1), the sleeve protrusion (3n) is in contact with the end of the main body end cutout (1g) so as not to further enter, and the sleeve intermediate end face (3p ) And the end surface (1e) of the main body, and between the end surface (3d) on the large diameter side of the sleeve and the end surface (1h) of the inner diameter portion of the main body, the same constant interval (δ) is provided, and the metal pipe (9) ) The sleeve tube receiving part (3) in the sleeve (3)
When the metal pipe end (9a) abuts the sleeve pipe receiving end (3b) at the time of fitting and insertion into a), the metal pipe (9) is pushed further inward so that the sleeve protrusion (3n) ) Is crushed so that the sleeve guide portion (3 m) reaches the inner end of the body end cutout portion (1 g). At this time, the sleeve large-diameter side end surface (3
The pipe joint for a metal pipe according to any one of claims 1 to 5, characterized in that the structure (d) and the end surface (1h) of the inner diameter of the main body are in close contact with each other. 7. The indicator ring A (7) is attached such that at least the outer periphery thereof is colored so that the indicator ring A (7) of which the outer circumference is colored is in contact with the outer vertical surface (1f) of the main body externally threaded portion (1d) of the main body (1). An indicator ring B (8) which can be inscribed in the outer circumference and has a color which is clearly different from the color of the outer circumference of the indicator ring A (7) is attached, and when the tightening of the nut (2) is completed, the nut of the nut (2) is attached. The end surface (2c) on the screw side is the indicator ring B.
The structure in which (8) is sandwiched between the body outer vertical surface (1f) of the body (1) to completely cover the indicator ring A (7). 6. A pipe joint for a metal pipe according to 6. 8. A sleeve large-diameter side end surface (3d) of the sleeve (3) is inserted through the metal pipe (9) so as to be in close contact with a main body inner diameter inner end surface (1h) of the main body (1), And when the nut screw side end surface (2c) of the nut (2) is screwed into the main body (1) so as to sandwich the indicator A (7) and the indicator B (8) between the main body outer vertical surface (1f). In the above, a constant gap (α) is provided between the inner taper portion (2b) of the nut and the taper face (3f) of the sleeve in a direction perpendicular to the plane, and the gap (α) is the distance converted in the axial direction. Keep the distance (δ) or more, the small diameter side end surface (2e) of the nut is the same as the small diameter side end surface (3g), and the small diameter side outer diameter portion (3q) is inside the nut Completely encased in the parallel part (2d) The pipe joint for a metal pipe according to any one of claims 1 to 7, wherein the pipe joint is not exposed to the outside. 9. The sleeve (3) comprises the metal tube (9).
The nut (2) when not fully inserted
When screwing in, the sleeve protrusion (3
n) interferes with the main body end face (1e), between the sleeve large diameter side end face (3d) and the main body inner diameter inner end face (1h), and between the main body end face (1e) and the sleeve intermediate end face (3p). And a constant gap (δ) in the axial direction between the sleeve and the small diameter side end face (3g) and the nut small diameter side end face (2e) in the same axial direction (δ). 9. The pipe fitting for metal pipe according to claim 1, wherein the outer diameter portion (3q) on the small diameter side of the sleeve is exposed from the nut (2). 10. The inner diameter of the inner diameter surface (3c) of the sleeve (3) and the inner diameter of the main body inner diameter central portion (1b) of the main body (1) are set to be substantially the same as the inner diameter dimension of the metal tube (9). The pipe joint for metal pipe according to claim 1, which is characterized in that.