NZ263554A

NZ263554A - Tube connector with ramped surface and extension to free end of connector for providing a more secure joint with expanded self-reconvertable tube

Info

Publication number: NZ263554A
Application number: NZ263554A
Authority: NZ
Inventors: Friedrich Imgram
Original assignee: Wirsbo Rohrprod Und Vertr Gmbh
Priority date: 1993-03-27
Filing date: 1994-03-21
Publication date: 1997-10-24
Also published as: SK17496A3; HU219524B; DK0694143T3; PL310885A1; CZ249695A3; PL174049B1; FI954549A; SK280788B6; WO1994023237A1; DE4310000A1; EP0694143B1; SK280978B6; FI954549A0; IL109047A0; GR3026330T3; HUT72196A; NO953810D0; NO953810L; AU6428494A; KR960701331A

Abstract

The pipe joint proposed includes a connector (1) with at least one spigot (2, 2', 2") on which the end (6) of a pipe made of thermoelastic, cross-linked polyolefin is fixed by opening out and self-reforming to form a secure, gastight joint. The spigots (2, 2', 2") have a surface feature (3, 3', 3") and, beyond it, an extension (4, 4', 4") with chamfered end (5, 5', 5").

Description

<div class="application article clearfix" id="description"> New Zealand No. 263554 International No. PCT/EP94/00874 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 27.03.1993; Complete Specification Filed: 21.03.1994 Classification: (6) F16L47/00 Publication date: 24 October 1997 Journal No.: 1421 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Pipe joint, pipe connector and hydraulic device for producing pipe joints Name, address and nationality of applicant(s) as in international application form: WIRSBO ROHRPRODUKTION UND VERTRIEBS-GmbH, a German company of Ernst-Leitz-Strasse 18, D-63150 Heusenstamm, Federal Republic of Germany * 26 3 5 54 l Amended Documents Presented Durincr Examination Tube Conduit Connection, Tube Conduit Connector and Hydraulic Apparatus for Making Tube Conduit Connections 5 The invention relates to a tube conduit connection containing a tube conduit connector having a connecting member which comprises a surface structure, and a tube end which has been expanded at ambient temperature and which is formed at the end of a tube which is self-reconvertable at 10 ambient temperature, the tube end being firmly and sealingly connected to the connecting member. The invention also relates to a tube conduit connector which contains at least one connecting member having a 15 surface structure, for producing a firm and sealing connection to tube conduits which have a tube end expanded at ambient temperature and formed of a tube which is self-reconvertable at ambient temperature. 20 Finally, the invention also relates to a method of using a hydraulic pulling device for connecting a tube conduit connector to a tube end, which pulling device contains at least one hydraulic cylinder-piston unit, retaining means for respectively retaining a tube end or the tube conduit 25 connector, movable retaining means for respective! retaining the tube conduit connector or the tube end, hydraulic pump connected to the at least one hyd fetulic cylinder-piston unit. 30 From published European Patent Application No. 0,530, there is known to produce firm and gas-tight tube conduit connections at ambient temperature using tubes made of -a material like medium density, high density or thermo-elastic, cross-linked polyolefins. Therefore, the tube end 35 is reversibly expanded and applied to the connecting member £ 26 3 5 5 2 of the tube conduit connector. An expanding mandrel is usually employed for this purpose. Even under these conditions, the material, particularly the thermo-elastic cross-linked polyolefin is subject to self-reconversion 5 into the original condition. The self-reconversion is of sufficient rate also at ambient temperature in order to form a firm and gas-tight connection to the tube conduit connector after expansion. The firm and gas-tight connection therein is effected by means of a surface 10 structure which is present at the connecting member of the tube conduit connector and about which the expanded tube end contracts due to the self-reconversion so that there is formed a large surface area, very tight connection between the tube end and the connecting member of the tube conduit 15 connector. From British Patent No. 773,033 there is known a tube connector which is connectable to an expanded end of a PVC tube. The tube connector contains a connecting member 20 having a surface structure in the form of an annular expansion. A smooth tube-shaped end extends from the surface structure and carries a seal. The tube end of the PVC tube is heated until it is softened and, then, expanded by means of a mandrel which is pulled out from the expanded 25 end after it has cooled. The tube connector is, then, inserted into the expanded tube end which subsequently is re-heated up to the softening temperature. During this operation, the expanded tube end re-contracts and is firmly and sealingly applied to the tube-shaped end which is 30 provided with the seal, and the tube connector and its annular expansion. From German Gebrauchsmuster (Utility Model) No. 89 14 321 there is known a hydraulic tube mounting apparatus 35 containing a hydraulic cylinder and a double-acting piston. 26 3 5 54 3 Each one of one end of the cylinder and the free end of the piston are respectively connected to tube retaining means for the tube ends of respective one of two tubes which are guided on rolls. One of the two tube ends is provided with a bushing or expansion and a bushing seal is located between the tube ends to be connected. The two tube ends are moved into each other by operating the hydraulic cylinder whereby a firm and sealing connection is produced due to the inserted bushing seal. It has been found in practice that the initially mentioned tube conduit connections which are produced at ambient temperature using the expanding mandrel, can be produced with good success when using tube diameters in the range of 50 mm and above. With smaller diameters, there exists a problem in that such narrower tube conduit is relatively flexible and that the tube end eventually can become disconnected from the connecting member of the tube conduit connector to a small extent upon bending of the tube conduit. This small extent is sufficient for causing an undesired leak at the location of the connection. In correspondence therewith it is the object of the invention to provide a tube conduit connection to the tube conduit connector which tube conduit connection is sufficiently tight even upon bending of the tube conduit, and to further provide a tube conduit connector which renders possible producing such sufficiently tight connection. According to the invention, this object is achieved with respect to the tube conduit connection in that the connecting member comprises an elongation in the form of a structureless cylindrical tube which extends from the • 26 3 5 54 3a surface structure and forms the free end of the connecting member. A tube conduit connector according to the invention is 5 characterized in that the connecting member comprises an elongation in the form of a structureless cylindrical tube which extends from the surface structure and forms the free end of the connecting member. 10 With respect to the method of using the hydraulic pullig device, this object is achieved in that this hydraulic pulling device is employed for producing the inventive tube conduit connection by means of the inventive tube conduit connector. 15 In this manner it is achieved that even tube ends of tubes having relatively small diameters can be applied to the connecting member of the respective tube conduit connector in a manner such that the tube conduit connection 20 does not produce a leak under bending stress. Also the tube end containing the elongation is firmly and sealingly connected to the connecting member by using the hydraulic pulling device without any preceding deformation or the interposition of a seal. 25 It cam be expedient that the outer diameter of the elongation can be smaller than the outer diameter of the connecting member. 30 Advantageous further developments of the inventive tube conduit connection and tube conduit connectors are characterized in the dependent claims. 35 Likewise it has been found in practice that the expansion of the tube end using an expanding mandrel may result in 3b 26 3 5 5 4 problems in the case of smaller tube diameters. It has been found that a hydraulic pulling device which is known as such for producing connections using plastic tubing can also be used with advantage for producing connections in 5 the case of tubes which are made of relatively stiff materials such as thermo-elastic cross-linked polyolefin, particularly at ambient temperature and in a manner such that a firm and gas-tight connection is formed at ambient temperature due to the self-reconversic:i of the material. 10 Exemplary embodiments of the invention are illustrated in the drawings and will be explained and described hereinbelow in detail by means of the reference characters. There are shown in 15 Figure 1 a sectional view of a tube conduit connection according to the invention; and Figure 2 a schematic view of a hydraulic pulling device for 20 producing the tube conduit connection as shown in Figure 1. N.Z. PATENT QFRC'c: - 8 JAN 1997 *k 263 5 54 As used herein, the term "surface structure" means a feature formed upon the surface of the pipe connector, this feature being adapted to facilitate holding and sealing of the inside surface of a pipe onto the connector. Typically, this feature may be annular. Also typically, the feature may extend radially outwardly from the surface of the pipe connector. More particularly, the feature may consist of a reinforcement ring, bead or the like. In the sectional view of Figure 1, there will be recognized a tube conduit connector 1 in the form of a T-piece having three connecting members 2, 2', and 2". Each one of the connecting members 2, 2', and 2" contains a respective surface structure in the form of a reinforcement 3, 3' and 3", which may also be constructed as a groove or bead or the like. In the illustrated embodiment the reinforcements steeply descend inwardly to the outer diameter of the respective connecting member whereas the reinforcements taper outward.ly to the free end. There is thus formed a structure which facilitates sliding on the tube end due to the ramp shape but which otherwise presents sufficient resistance against pulling off the applied tube end again due to the inner steep descent. The reinforcements 3, 3', and 3" are adjoined toward the exterior by respective elongations 4, 4*, and 4" which have the same inner diameter as the associated connecting members 2, 2', and 2" but which may have, if desired, an outer diameter slightly reduced relative to that of the respective connecting member, as illustrated. The free end of the elongations 4, 4', and 4" is provided with respective chamfers 5, 5', and 5" in order to facilitate the introduction into the related tube end. 5 26 3 554 Identically formed tube ends 6 which are applied to the connecting members 2, 2*, and 2", will be recognized at the respective connecting members 2, 2', and 2". In particular, these tube ends or tubes are designed such that their inner diameter is substantially equal to the inner diameter of the respective. connecting members 2, 2', and 2". In this manner it will be avoided that edges are formed on the inside at the transition from the tube ends 6 to the respective connecting members which edges represent flow resistances to the throughflow of the medium respectively flowing therethrough. If such flow resistances are no object, other relative inner diameter relations can, of course, be selected. In the illustrated exemplary embodiment, the tubes or tube ends 6 are made of thermo-elastic cross-linked polyolefin which is expanded at ambient temperature and applied to or pushed onto the respective connecting member 2, 2', or 2" in the expanded condition. It will be recognized that the expanded tube end 6 will be tightly applied to the respective connecting member upon self-reconversion and thereby contracted around the respective reinforcement 3, 3', and 3". Due to the elongation 4, 4', and 4" the length of the connection will be increased and, due to the hold at the surface structure of the respective connecting member, there will be formed a large surface area connection, which remains firm and gas-tight even under bending stress effective at the associated tube. As a result of the expanding operation, the tube conduit cohnection described hereinbefore may eventually still contain a reinforcement 20, see Figure 2, which is applied to the outside in the region adjacent the expanded tube end 6. Such reinforcement 20 may consist of an elastomeric, thermoplastic or thermo-elastic material having higher 6 26 3 5 5 4 elasticity than the material of the tube, however, may also . be made of the same material as the tube. In the illustrated exemplary embodiment, the tube conduit 5 connector 1 is constructed as a T-piece. Instead, the tube conduit connector 1 may have a Y-shape or may be differently shaped, for example, also as a simple tube connector having just two connecting members. In the most simple case, the connecting member may also be formed by a 10 correspondingly constructed tube end in the event that a direct connection is intended to be formed between two tube ends. In the illustrated exemplary embodiment, the tube conduit connector consists of metal, particularly bronze; it may also consist of other materials like glass or lb plastic and also of thermo-elastic cross-linked polyolefin. For producing the connection between a connecting member of the aforementioned type and a tube end, there may serve, for instance, a hydraulic pulling device as schematically 20 illustrated in Figure 2; such pulling device is known as such for use in connection with plastic tubes. It has been found that this hydraulic pulling device can also be used with advantage for reversibly expanding at ambient temperatures the tube ends of tubes which are made of 25 thermo-elastic cross-linked polyolefin. Two hydraulic cylinders 7 and 8 will be recognized in Figure 2 and are arranged parallel to each other and bridged by first retaining means 9. The first retaining 30 means 9 include a knurled screw 10 or the like at one of its ends and a hinge 11 at the other end. Two retaining members of the first retaining device 9 are interconnected by means of the hinge 11 such that the retaining members can be opened and receive a tube end 6 of a tube 12 35 therebetween and retain the same in the closed ^taSt^ATEMT OFFICE - 8 JAN 1997 RECEIVED 7 26 3 5 5 4 From the hydraulic cylinders 7 and 8 respective piston rods 13 and 14 protrude and extend parallel to each other; free ends thereof are bridged by second retaining means 15. The second retaining means also comprise hinge-connected retaining members between which a tube connector, for example, a tube connector 1, can be received and retained such that, as shown, a connecting member 2 protrudes from the second retaining means 15 towards the tube end 6. A manually operable hydraulic pump 16 is connected through a hydraulic conduit 17 to connectors 18 and 19 at the respective hydraulic cylinders 7 and 8. It will be recognized that, upon actuating the hydraulic pump 16, the piston rods 13 and 14 are retracted into the respective hydraulic cylinders 7 and 8. As a result, the second retaining means 15 conjointly with the connecting member 2 is pulled towards the free tube end 6 and into the same. There is directly obtained in this manner a firm and gas-tight connection between the connecting member 2 and the tube end 6. For supporting the tube end 6 against deformation during the pulling-in operation of the connecting member 2, it is provided that the tube end 6 is surrounded by a reinforcement 20, which is made of an elastomeric, thermoplastic or thermo-elastic material, in the region which protrudes beyond the first retaining means 9 and which is not applied to the connecting member 2 or adjoins the tube end 6 which is intended to be expanded. The material of the reinforcement 20 may be more elastic than the material of the tube but may also be made of the same material. After expansion of the tube end 6, the reinforcement 20 may be removed or left to remain at the tube end 6 . l; N.Z. PATENT -8 'JAN 1997 -8- 26 3 5 5 4 </div>

Claims

1. A tube conduit connection containing a tube conduit connector, which includes a connecting member having a surface structure (as hereinbefore defined), and further containing a tube end which has been expanded at ambient temperature and which is formed at the end of a tube which is self-reconvertable at ambient temperature, the tube end being firmly and sealingly connected to the connecting member, wherein the connecting member comprises an elongation in the form of a cylindrical tube free of any surface structure (as hereinbefore defined) which extends from the surface structure and forms the free end of the connecting member.

2. The tube conduit connection according to claim 1, wherein the elongation has an outer diameter which is smaller than the outer diameter of the connecting member.

3. The tube conduit connection according to claim 1 or 2, wherein the surface structure consists of a reinforcement which tapers towards the elongation and merges therewith.

4. The tube conduit connection according to claim 2 or 3, wherein the free end of the elongation is chamfered.

5. The tube conduit connection according to any one of claims 1 to 4, wherein the tube end has an inner diameter which is equal to the inner diameter of the connecting member.

6. The tube conduit connection according to any one of the preceding claims, wherein the tube conduit connector is selected from a tube connector, a multiple connector or a tube end.

7. The tube conduit connection according to any one of the preceding claims, wherein the tube is selected from medium density, high density or thermo-elastic cross-linked polyolefin. [k!7. 7 53/vyrfin -9- 26 3 5 5 4

8. The tube conduit connection according to any one of claims 1 to 7, wherein the tube is provided with a reinforcement adjacent the expanded tube end which is connected to the connecting member, the reinforcement being made of an elastomeric material and surrounding the tube end, in the region adjacent to the and surrounding the tube end.

9. A tube conduit connector suitable for producing a firm and sealing connection between at least two tube ends which are expanded at ambient temperature and which is formed at a tube which is self-reconvertable at ambient temperature, the tube conduit connector containing at least one connecting member having a surface structure (as hereinbefore defined), wherein the connecting member comprises an elongation in the form of a cylindrical tube free of any surface structure (as hereinbefore defined) which extends from the surface structure (as hereinbefore defined) and forms the free end of the connecting member.

10. The tube conduit connector according to claim 9, wherein the elongation has an outer diameter which is smaller than the outer diameter of the connecting member.

11. The tube conduit connector according to claim 9 or 10, wherein the surface structure consists of a reinforcement which tapers towards the elongation and merges therewith.

12. 1 2. The tube conduit connector according to claim 10 or 11, wherein the free end of the elongation is chamfered.

13. , The tube conduit connector according to any one of claims 9 to 12, wherein the connector is selected from a tube connector, a multiple connector or a tube end.

14. A method of usinn a hydraulic pulling device for producing a tube conduit connection according to any one of claims 1 to 8 by means of a tube conduit connector according to any one of claims 9 to 13 to a tube end, containing at least one hydraulic cylinder-piston unit, retaining means for a tube end or the -10- 26 3 5 5 4 tube conduit connector, respectively, movable retaining means for respectively retaining the tube conduit connector, or the tube end, and a hydraulic pump which is connected to the at least one hydraulic cylinder-piston unit, for connecting a tube which is made of a thermo-elastic cross-linked polyolefin, to the tube conduit connector.

15. The method of using the pulling device according to claim 14, wherein the end of the tube or the tube conduit connector, respectively, which end is to be hydraulically expanded, is provided with a reinforcement which is made of an elastomeric material, in a region adjacent the tube end to be expanded.

16. The method of using the pulling device according to claim 14 or 15, wherein the hydraulic cylinder-piston unit comprises a cylinder which includes a piston and an oil reservoir and which is connected to a manually operating pump, and that there are provided stationary retaining means for the tube connector or the tube end, respectively, and movable retaining means, which is guided in guide means, for the tube end or the tube connector, respectively.

17. The method of using the pulling device according to claim 14 or 15, wherein there are provided two hydraulic cylinder-piston units each including a hydraulic cylinder and a piston rod, that the stationary retaining means bridges the two hydraulic cylinders which are arranged parallel to each other, and that the movable retaining means is attached to the piston rods which extend parallel to each other and protrude from the hydraulic cylinders.

18. A tube conduit connection substantially as herein described with reference to the accompanying drawings.

19. The method of claim 14 substantially as herein described.

20. A method of using a hydraulic pulling device for producing a tube conduit connection substantially as herein described with reference to the accompanying drawings. end of claims ASPEC39579 ^WTENTu; f 8 JAN 1997 HECrfiv'ED