GB2264762A

GB2264762A - Compression pipe joint with elastic pipe insertion indicator

Info

Publication number: GB2264762A
Application number: GB9303862A
Authority: GB
Inventors: Hiroshi Ohya; Shuji Fukushima; Shinichi Fujita; Yutaka Inagaki
Original assignee: Hitachi Metals Ltd
Current assignee: Proterial Ltd
Priority date: 1992-02-25
Filing date: 1993-02-25
Publication date: 1993-09-08
Anticipated expiration: 2013-02-25
Also published as: KR960006180B1; DE4304866A1; GB2264762B; GB9303862D0; KR930018189A; DE4304866C2

Description

2264762 1 - Pipe Joint This invention relates to a pipe joint. Marking

pipes precisely at a plumbing site is a practically troublesome, complicated task, and if a pipe is not provided with a precise mark, it is difficult to confirm a complete insertion of a pipe in pipe coupling operations with the conventional pipe joint. Furthermore, it is practically impossible in a connected state to tell whether the end portion of a pipe is marked in advance or not. Actually, it would be possible to mark the pipe after insertion. Therefore, this has not been considered a certain method for preventing an incomplete pipe insertion.

Japanese Utility Model Laid-Open No. 2-56994 discloses a pipe joint which has been conventionally used for coupling resin pipes, etc. This pipe joint comprises, a joint body member having on one end thereof an annular recess for receiving a pipe, a sleeve member having teeth portions on the inner surface, and a nut threadedly engageable with the joint body member with the sleeve member disposed between the joint body member and the nut, whereby the teeth portions of the sleeve member bite into the wall of the pipe.

However, this conventional pipe joint tends to suffer from withdrawals of a pipe or leakage because makeups of connection are sometimes effected without inserting the pipe into the annular recess of the joint body member completely. To avoid these troubles, it has been necessary to mark the end portion of the pipe before inserting it into a pipe joint so that it can be confirmed whether the pipe is inserted thereinto completely or not.

For the same purpose of avoiding troubles such as withdrawals of a pipe, leakage, etc., there has been also proposed a pipe joint having an outer tubular portion and an inner tubular portion extending from a joint member, the outer tubular portion being provided with a small hole so that a complete insertion of a pipe into a gap between the outer and inner tubular portions can be confirmed by seeing the inserted pipe through the hole. However, since the makeup of the connection is conducted by assembling separate components of the pipe joint at a plumbing site in both of the above conventional pipe joints, some components may happen to be lost or wrongly disposed during the makeup, thereby failing to effectively seal the connected portion or to properly grip the inserted pipe end. This also causes troubles such as a leakage, a withdrawal and cutting-off of a pipe, etc. Viewed from one aspect there is provided a pipe joint according to the present invention comprising: (a) a joint member comprising an outer tubular portion and an inner tubular portion projecting on the same side of a body portion such that there is a gap therebetween for receiving a tip end of the pipe, the outer tubular portion having a threaded outer surface, the joint member being provided with a notch axially extending from a tip end of the outer tubular portion to the body portion; (b) a nut having a threaded inner surface engageable with the threaded outer surface of the joint member; (c) a sleeve member having a slit axially extending along the entire length thereof so that an inner diameter of the sleeve member can be reduced when the nut is turned for tightening with the sleeve member disposed between the pipe inserted into the gap and the nut; and 3 - (d) an elastically deformable member having a first portion engageable with a tip end of the pipe and a second portion which is elastically deformed to project outside the joint member through the notch when the pipe is fully inserted into the gap.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:- Fig. 1 is an exploded view showing a pipe joint according to the first embodiment of the present invention; Fig. 2 is a cross-sectional view of Figure 1 showing the components of the pipe joint according to the first embodiment of the present invention; Fig. 3 is a partially cross-sectioned view showing the pipe joint according to the first embodiment of the present invention which is in a preassembled state; Fig. 4 is a partially cross-sectioned view showing the pipe joint according to the first embodiment of the present invention after fully inserting a pipe into the pipe joint; Fig. 5 is a partially cross-sectioned view showing the,pipe joint according to the first embodiment of the present invention after completely tightening the pipe joint with the nut; Fig. 6 is a partially cross-sectioned view showing a pipe joint according to the second embodiment of the present invention, which is in a preassembled state; Fig. 7 is a partially cross-sectioned view showing the 'pipe joint according to the second embodiment of the present invention after fully inserting a pipe into the pipe joint; Fig. 8 is a partially cross-sectioned view showing a joint member according to the third embodiment of the present invention; Fig. 9 is a partially cross-sectioned view showing the pipe joint according to the third embodiment of the present invention, which is in a preassembled state; Fig. 10 is a front view showing a nut having a recess usable in the pipe joint according to the third embodiment of the present invention; Fig. 11 is a perspective view showing a sleeve member usable in the pipe joint according to the third embodiment of the present invention; Fig. 12 is a partially cross-sectioned view showing the pipe joint according to the third embodiment of the present invention after fully inserting a pipe into the pipe joint; Fig. 13 is a perspective view showing a sleeve member usable in a pipe joint according to the fourth embodiment of the present invention; Fig. 14 is a partially cross-sectioned view showing the pipe joint according to the fourth embodiment of the present invention in a preassembled state, which is taken along a plane passing through a slit of a sleeve member; Fig. 15 is a partially cross-sectioned view showing the pipe joint according to the fourth embodiment of the present invention after completely tightening the pipe joint with the nut, which is taken along a different plane from that in Fig. 14; Fig. 16 is a cross-sectioned view showing an annular flange of the sleeve member usable in the pipe joint according to the fourth embodiment of the present invention; Fig. 17 is a graph showing the relation between the axiLl movement of a nut and a nut-tightening torque in the pipe joint according to the fourth embodiment of the present invention; and Fig. 18 is a partially cross-sectioned view showing a conventional pipe joint.

The preferred embodiments of the present invention will be described in detail below with reference to the attached drawings.

Referring to Figs. 1 and 2, the pipe joint according to the first embodiment of the present invention comprises a joint member 1, a nut 3, a sleeve member 4 and an elastically deformable member 5.

The joint member 1 comprises an outer tubular portion 11 and an inner tubular portion 12 projecting on the same side of a hexagonal body 13 such that there is formed a gap 17 therebetween for receiving a tip end of a pipe (not shown), a threaded tubular portion 14 projecting on the other side of the hexagonal body 13, and a path 19 running axially through the entire length of the joint member 1 from the inner tubular portion 12 to the threaded tubular portion 14. The outer tubular portion 11 has a threaded outer surface 11a. A notch 15 axially extends from a tip end 11b of the outer tubular portion 11 to a predetermined portion of the hexagonal body 13. The inner tubular portion 12 has a plurality of annular projections 12a,12a,... on the outer surface.

The nut 3 has a threaded inner surface 31 engageable with the threaded outer surface 11a of the outer tubular portion 11, and a tapered inner surface 32 near the rear end (axially outer end) thereof which functions to reduce the diameter of the sleeve member 4 during the makeup of the connection.

The sleeve member 4 is a C-shaped member having a slit 41 axially extending along the entire length thereof, and its inner surface is provided with a plurality of annular teeth 42, 42,... which bite into the'pipe wall to prevent withdrawal of the pipe end from the pipe joint. The sleeve member 4 also has near the rear end thereof a tapered outer surface 43 complementary with the tapered inner surface 32 of the nut 3. The slit 4 of the sleeve member 4 has a little wider breadth than that of the elastically deformable member 5 so that the elastically deformable member 5 can - 6 be received therein.

The elastically deformable member 5 is a bent plate or rod made of a material with an appropriate rigidity and elasticity such as a synthetic resin or a metal such as steel, etc. The elastically deformable member 5 has such a width as to permit the elastically deformable member 5 to be received in the notch 15 of the joint member 1 and the slit 41 of the sleeve member 4.

The elastically deformable member 5 which is received in the notch 15 of the joint member 1 may be formed in various shapes, as long as it has a first portion 51 which comes into contact with a tip end of a pipe and is pushed axially inwardly by it, a second portion (deformable portion) 52 which is elastically so deformed that it projects outside the joint member 1 through the notch 15 when the pipe is fully inserted, a third portion 53 which is brought into contact with a rear end (axially outer end) wall 15a of the notch 15 of the joint member 1, and a fourth portion 54 which is engageable with the slit 41 of the sleeve member 4.

Figs. 3 and 4 respectively show a pipe joint according to the first embodiment of the present invention before and after the insertion of a pipe.

Referring to Fig. 3, the elastically deformable member 5 is received in the notch 15 of the joint member 1 and partially inserted into the slit 41 of the sleeve member 4. The nut 3 is then engaged to the threaded outer surface 11a of the outer tubular portion 11 of the joint member 1 by a predetermined distance. In this state, a front end (axially inner end) surface 45 of the sleeve member 4 abuts on a tip end surface 11b of the outer tubular portion 11 of the joint member 1.

since there is a space between the inner tubular portion 12 of the joint member 1 and the sleeve member 4, a pipe 2 can be inserted thereinto with a small force. However, after the tip end of the pipe 2 reaches the first portion 51 of the elastically deformable member 5, further insertion of the pipe 2 cannot be effected without pushing the pipe 2 by a stronger force.

Referring to Fig. 4, when the pipe 2 is fully inserted into the gap 17 of the joint member 1, the elastically deformable member 5 is pushed axially inwardly in the notch 15 of the joint member 1 by the tip end of the pipe 2 at the first portion 51 and compressed between the rear end wall 15a of the notch 15 of the joint member 1 and the tip end of the pipe 2. As a result, the elastically deformable member 5 is elastically bent in the second portion (deformable portion) 52, whereby the second portion 52 projects outside the joint member 1. Since the deformation of the elastically deformable member 5 is an elastic one, the elastically deformable member 5 restitutes to its original state when the pipe 2 is withdrawn from the pipe joint by an external force. As a result, the second portion 52 of the elastically deformable member 5 becomes hidden from the outside again, thereby indicating that the pipe 2 is accidentally withdrawn from the pipe joint.

Since the second portion 52 of the elastically deformable member 5 projects from the pipe joint in a state where the pipe 2 is fully inserted into the pipe joint, the elastically deformable member 5 may be called an "indicating member". With the elastically deformable member 5 called an "indicating member", the full insertion of the pipe 2 can be confirmed.

After the pipe 2 is fully inserted into the gap 17 of the joint member 1, the nut 3 is further rotated to complete the makeup of the connection as shown in Fig. 5. The advancement of the nut 3 reduces the diameter of the sleeve member 4 by pushing the tapered outer surface 43 with the tapered inner surface 32 of the nut 3. As a result, the annular teeth 42 of the sleeve member 4 bite into the pipe wall to effect a seal between the inner surface of the pipe 2 and the outer surface of the inner tubular portion 12 and to effectively prevent withdrawal of the end portion of the pipe 2 from the pipe joint, thereby completing the makeup of a fluid-tight connection. Further, since the fourth portion 54 of the elastically deformable member 5 remains engaged with the slit 41 of the sleeve member 4, when the nut 3 is rotated for further tightening, the sleeve member 4 is prevented from rotating in accordance with the rotation of the nut 3. As a result, a twist of the pipe 2 can be prevented.

As described above in detail, the complete insertion of a pipe can be easily confirmed in this embodiment by means of the elastically deformable member 5 partially projecting from the pipe joint, thereby preventing insufficient pipe connection in the pipe joint. Also, a twist of the pipe can be prevented in this pipe joint.

Figs. 6 and 7 respectively show a pipe joint according to the second embodiment of the present invention before and after the insertion of a pipe.

The pipe joint according to the second embodiment has substantially the same structure and components as those of the first embodiment except for the shapes of a nut 3 and an elastically deformable member 6, and it further comprises a pin member 36. It should be noted that the same reference numerals are assigned to the same components as in the first embodiment.

The nut 3 has a similar structure as that of the first embodiment except that it further comprises a pin hole 33 penetrating through a side wall thereof, into which a pin member 36 is fitted after the completion of preassembling the pipe joint components.

The elastically deformable member 6 receivable in the notch 15 of the joint member 1 is a bent plate or rod having a first portion 61 engageable with the tip end of a pipe 2, a second portion 62 projectable from the joint member 1 through the notch 15 when a hinge portion (deformable portion) 62a is elastically bent, a third portion 63 engageable with the rear end wall 15a of the notch 15 of the joint member 1 and a fourth portion 64 receivable in the slit 41 of the sleeve member 4.

The pin member 36 is made of an easily-tearable material such as plastics including polyacetal, metals including brass, etc. in such a diameter that is easily torn off when the nut 3 is rotated with a tool for the further tightening.

As shown in Fig. 6, the elastically deformable member 6 is received in a notch 15 of the joint member 1 in the preassembled state. The third portion 63 of the elastically deformable member 6 is in contact with the rear end wall 15a of the notch 15 of the joint member 1, the second portion 62 is near the radially outer edge of the notch 15, and the fourth portion 64 is received in the slit 41 of the sleeve member 4. In this embodiment, the pin member 36 is inserted into the pin hole 33 of the nut 3 to prevent the nut 3 from rotating. As a result, the pipe joint is kept in a preassembled state. In this state, a front end (axially inner end) surface 45 of the sleeve member 4 abuts on a tip end surface 11b of.the outer tubular portion 11 of the joint member 1.

As seen in Fig. 7, when the pipe 2 is fully inserted, the elastically deformable member 6 is pushed into the notch 15 of the joint member 1 until the tip end of the pipe 2 reaches the rear end wall 17a of the gap 17. As a result, the elastically deformable member 6 is elastically so bent that the second portion 62 projects outside the joint member 1 through the notch 15, thereby making it possible to confirm that the pipe 2 is completely inserted. In this embodiment too, the restitution of the elastically deformable member 6 takes place if the pipe 2 is accidentally withdrawn from the pipe joint by an external force. Thus, the elastically deformable member 6 is also considered to function as an "indicating member".

After the pipe 2 is fully inserted into the gap 17 of the joint member 1, the nut 3 is forcibly rotated with a tool, whereby the pin member 36 is torn off and the nut 3 is rotated for further tightening to complete the makeup of the connection.

A twist of the pipe 2 can be also prevented in the second embodiment, because the fourth portion 64 of the elastically deformable member 6 remains engaged with the slit 41 of the sleeve member 4, thereby preventing the sleeve member 4 from rotating in accordance with the rotation of the nut 3 when the nut 3 is rotated for further tightening of the pipe joint.

In this embodiment, the same effects as in the first embodiment can be obtained. Further, the connecting operation is easy and there are no such troubles as losses or wrong dispositions of some components in this embodiment.

Referring to Figs. 8-11, the pipe joint according to the third embodiment has substantially the same structure and components as those of the first embodiment except for the shapes of an outer tubular portion 21 of a joint member 1, a nut 30, a sleeve member 40 and an elastically deformable member 7. It should be noted that the same reference numerals are assigned to the same components as in the preceding embodiments.

As seen in Fig. 8, the outer tubular portion 21 of the joint member 1 has a tapered inner surface 21a on the tip end side thereof.

Referring to Figs. 9 and 10, the nut 30 has an inwardly projecting flange 34 having a flat inner surface 34a at the rear end, and a recess 35 on the inner surface at the front end (axially inner end) where a part of the elastically deformable member 7 is received to prevent the rotation of the nut 30. The nut 30 is provided with a threaded inner surface 31 also in this embodiment.

The elastically deformable member 7 is a bent plate or rod having a first portion 71 engageable with the tip end of a pipe 2, a second portion 72 receivable in the recess 35 of the nut 30 in a preassembled state, thereby preventing the rotation of the nut 30, and a third portion 73 engageable with the rear end wall 15a of the notch 15 of the joint member 1.

Incidentally, since the second portion 72 of the elastically deformable member 7 does not project from the nut 30 in the preassembled state, it is unlikely that the elastically deformable member 7 is disengaged from the recess 35 of the nut 30 by accidentally pushing the second portion 72 of the elastically deformable member 7 from the outside.

As shown in Fig. 11, the sleeve member 40 is also a C-shaped member having the slit 41 axially extending along the entire length thereof, and its inner surface is provided with a plurality of annular projections 46 which bite into the pipe wall to prevent withdrawal of the pipe end from the pipe joint. Further, the sleeve member 40 has a tapered outer surface 44 on the front side (axially inner side), which is complementary with the tapered inner surface 21a of the outer tubular portion 21 of the joint member 1, and a frustoconical brim 47 having a reduced thickness on the rear side (axially outer side).

In a preassembled state shown in Fig. 9, the elastically deformable member 7 is received in the notch 15 of the joint member 1, with the second portion 72 received in the recess 35 of the nut 30. In this state, the accidental rotation of the nut 30 is prevented to keep the pipe joint in the preassembled state.

As seen in Fig. 12, when the pipe 2 is fully inserted, the elastically deformable member 7 is pushed deeply into the notch 15 of the joint member 1 until the tip end of the pipe 2 reaches the bottom of the gap 17.

As a result, the elastically deformable member 7 is elastically so deformed that the second portion 72 is disengaged from the recess 35, thereby enabling the nut 30 to threadedly advance, and that the second portion 72 of the elastically deformable member 7 projects outside the joint member 1 through the notch 15, thereby making it possible to confirm that the pipe 2 is completely inserted. Thus, upon confirming the complete insertion of the pipe 2, the nut 3 is rotated to complete the makeup of connection.

In this embodiment too, the restitution of the elastically deformable member 7 takes place in case the pipe 2 is accidentally withdrawn from the pipe joint by an external force. Thus, the elastically deformable member 7 is also considered to function as an "indicating member". Further, since the elastically deformable member 7 has another function to prevent the rotation of the nut 3 in a preassembled state, the elastically deformable member 7 may be called a "lock member".

The tapered inner surface 21a of the outer tubular portion 21 of the joint member 1 reduces the diameter of the sleeve member 40 by pushing the tapered outer surface 44 during the advancement of the nut 30. Also, since there is a great deal of sliding resistance between the tapered outer surface 44 of the sleeve member 40 and the tapered inner surface 21a of the outer tubular portion 21 of the joint member 1, the rotation of the sleeve member 40 in accordance with the rotation of the nut 30 occurs less than in those pipe joints of the'preceding embodiments even after a front portion (rear end portion) 75 of the elastically deformable member 7 is disengaged from the slit 41 of the sleeve member 40. Therefore, the pipe 2 is scarcely rotated in accordance with the rotation of the nut 30.

In this embodiment, the same effects as in the preceding embodiments can be obtained.

Fig. 13 shows a sleeve member usable in a pipe joint according to the fourth embodiment of the present invention, and Figs. 14 and 15 respectively show the pipe Joint before the full insertion of a pipe and after the completion of tightening.

The pipe joint according to the fourth embodiment has substantially the same structure and components as those of the third embodiment except for the shapes of a nut 30, a sleeve member 40 and an elastically deformable member 8. It should be noted that the same reference numerals are assigned to the same components as in the preceding embodiments.

As seen in Fig. 13, the sleeve member 40 has a structure similar to that of the third embodiment, but it further comprises an annular flange 48 on the outer surface at a position adjacent to the tapered outer surface 44.

Referring to Fig. 14, the nut 30 has a structure similar to that of the third embodiment but it comprises a pin hole 33 instead of the recess 35, into which a pin member 36 is fitted after the completion of preassembling the pipe joint components.

The elastically deformable member 8 is a bent plate or.rod having a first portion 81 engageable with the tip end of a pipe 2, a second portion (deformable portion) 82 projectable from the joint member 1 through the notch 15 when the pipe is fully inserted, a third portion 83 which is brought into contact with the end wall 15a of the notch 15 of the joint member 1, and a fourth portion 84 which is engageable with the slit 41 of the sleeve member 40.

In a preassembled state, the elastically deformable member 8 is received in the notch 15 of the joint member 1 with the third portion 83 in contact with the end wall 15a of the notch 15 of the joint member 1 and the fourth portion 84 received in the slit 41 of the sleeve member 40. The annular flange 48 of the sleeve member 40 engages a tip end surface 21b of the outer tubular portion 21 of the joint member 1, whereby the sleeve member 40 is prevented from further entering into the gap 17 of the joint member 1.

Since the sleeve member 40 has the frustoconical brim 47, a tip end of a pipe 2 is smoothly introduced into a space between the sleeve member 40 and the inner tubular portion 12 of the joint member 1 even when the inner diameter of the sleeve member 40 is a little smaller than the outer diameter of the pipe 2. Further, since the annular flange 48 is engaged with the tip end surface 21b of the outer tubular portion 21 of the joint member 1, the sleeve member 40 can remain correctly disposed between the joint member 1 and the nut 30 without being tilted when the pipe 2 is inserted into the pipe joint.

When the pipe 2 is fully inserted into the gap 17 of the joint member 1, the elastically deformable member 8 is pushed deeply into the notch 15 of the joint member 1 and elastically so deformed that the second portion 82 projects outside the jointmember 1 through the notch 15, thereby making it possible to confirm that the pipe 2 is completely inserted. In this embodiment too, the restitution of the elastically deformable member 8 takes place in case the pipe 2 is accidentally withdrawn from the pipe joint by an external force. Thus, the elastically deformable member 8 is also considered to function as an "indicating member."

As shown in Fig. 16 in detail, in the process of rotating the nut 30 to complete a fluid-tight connection, the annular flange 48 of the sleevemember 40 is deformed or destroyed by the urging force of the nut 30.

In this state, the relation of a nut-tightening torque and the advancement of the nut 30 is shown in Fig. 17. Specifically, the nut- tightening torque first increases as the nut 30 advances. However, when the nut reaches a position A, the nut-tightening torque drastically decreases because the annular flange 48 of the sleeve member 40 is deformed or destroyed. Thereafter, the nut-tightening torque increases again. At a point B, an increase in the nut-tightening torque becomes slow, because the frustoconical brim 47 starts to be deformed. Finally, at a point C, the advancement of the nut 30 is completed. By sensing the change of the nut-tightening torque with a hand, it is possible to confirm whether or not the nut tightening is properly conducted.

Incidentally, in the process of the nut-tightening, the sleeve member 40 is pushed radially inwardly along the tapered inner surface 21a of the outer tubular portion 21 of the joint member 1, whereby the diameter of the sleeve member 40 is reduced. As a result, the annular projections 46 of the sleeve member 40 bite into the pipe wall to effect a seal between the inner surface of the pipe 2 and the outer surface of the inner tubular portion 12 and to effectively prevent a withdrawal of the end portion of the pipe 2 from the pipe joint.

For the purpose of achieving a desirable relation between the nuttightening torque and the deformation of a sleeve member 40, for example, an annular flange 48 of the sleeve member 40 may have a thickness of 0.20.5 mm. in a pipe joint for connecting a pipe having a diameter of 10-50 mm. Also, since the frustoconical brim 47 has such a thickness as to show a deformation resistance greater than that of the annular flange 48 in this embodiment, the frustoconical brim 47 may be about twice or three times as thick as that of the annular flange 48.

In this embodiment, the same effects as in the third embodiment can be obtained. Further, because of the annular flange 48 of the sleeve member 40, the sleeve member 40 is kept stable in the pipe joint during the insertion of the pipe 2.

Each embodiment of the present invention has been explained above, but it should be noted that any modifications can be made as long as such modifications do not alter the scope of the present invention. For instance, each component of the pipe joint may be shaped differently unless it fails to perform the same function. Also, components in one embodiment may be used in another embodiment to effect substantially the same functions.

The pipe joint of the present invention is suitable for fluid-tight connection of not only plastic pipes such as polybutene pipes but also composite pipes such as aluminum pipes with polyethylene coating and layer.

Fig. 18 shows a pipe joint according to Japanese Utility Model Laid-Open No. 2-56994 which comprises a joint body member 90 having on one end thereof an annular recess 92 for receiving a pipe 91, a sleeve member 93 having teeth portions on the inner surface, and a nut 94 threadedlyengageable with the joint body member 90 with the sleeve member 93 disposed between the joint body member 90 and the nut 94, whereby the teeth portions of the sleeve member 93 bite into the wall of the pipe 91.

However, this conventional pipe joint tends to suffer from withdrawals of a pipe or leakage because makeups of connection are sometimes effected without inserting the pipe 91 into the annular recess 92 of the joint body member 90 completely. To avoid these troubles, it has been necessary to mark the end portion of the pipe 91 before inserting it into a pipe joint so that it can be confirmed whether the pipe 91 is inserted thereinto completely or not.

Accordingly, it can be seen that the embodiments disclosed provide a pipe joint for a fluid-tight connection with a pipe having such a structure that a complete insertion of a pipe into the pipe joint can be easily confirmed at the time of connecting operation, thereby preventing insufficient pipe connection. According to further embodiments a pipe joint is provided that is capable of being used in a preassembled state, thereby preventing troubles such as losses and wrong dispositions of some components.

Thus in at least preferred embodiments, there is provided a pipe joint having such a structure that a complete insertion of a pipe can be easily confirmed during the makeup of a connection, thereby preventing insufficient pipe connection; and there is provided a pipe joint capable of being used in a preassembled state to conduct a makeup of fluid-tight connection with a pipe without losses or wrong dispositions of components; and there is provided a pipe joint having such a structure that a pipe can be introduced thereinto smoothly and properly.

Claims

A pipe joint comprising:

(a) a joint member comprising an outer tubular portion and an inner tubular portion projecting on the same side of a body portion such that there is a gap therebetween for receiving a tip end of said pipe, said outer tubular portion having a threaded outer surface, said joint member being provided with a notch axially extending from a tip end of said outer tubular portion to said body portion; (b) a nut having a threaded inner surface engageable with said threaded outer surface of said joint member; (c) a sleeve member having a slit axially extending along the entire length thereof so that an inner diameter of said sleeve member can be reduced when said nut is turned for tightening with said sleeve member disposed between said pipe inserted into said gap and said nut; and (d) an elastically deformable member having a first portion engageable with a tip end of said pipe and a second portion which is elastically deformed to project outside said joint member through said notch when said pipe is fully inserted into said gap.
2. The pipe joint according to claim 1, wherein said nut is provided with a small hole penetrating a side wall thereof, said pipe joint further comprising a pin member fitted into said hole of said nut and projecting into said notch of said joint member for preventing said nut from rotating by a small force to keep said pipe - 19 joint in a preassembled state, said pin member being torn off when said nut is forcibly rotated for tightening.
3. The pipe joint according to claim 1, wherein said nut is provided with a recess on said inner surface at a front end thereof, a part of said elastically deformable member being received in said recess of said nut for preventing said nut from rotating in a preassembled state, said elastically deformable member received in said notch of said joint member being elastically deformed when said pipe is fully inserted into said gap, thereby disengaging said elastically deformable member from said nut, so that said nut can be further advanced.
4. The pipe joint according to any preceding claim, wherein said outer tubular portion further comprises a tapered inner surface on the tip end side, and said sleeve member comprises a tapered outer surface on the front side, said tapered inner surface being in contact with said tapered outer surface of the sleeve member.
5. The pipe joint according to any preceding claim, wherein said sleeve member further comprises an annular flange adjacent to said tapered outer surface, said annular flange being in contact with a tip end of said outer tubular portion of said joint member in a preassembled state and being deformed or destroyed when said nut is rotated for tightening.
6.. A pipe joint substantially as hereinbefore described with reference to Figures 1-5 of the accompanying drawings.
7. A pipe joint substantially as hereinbefore described with reference to Figures 6-7 of the accompanying drawings.

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8. A pipe joint substantially as hereinbefore described with reference to Figures 8-12 of the accompanying drawings.
9. A pipe joint substantially as hereinbefore described with reference to Figures 13-17 of the accompanying drawings.