Tube end support for a tube coupling

Abstract: The disclosure relates to a tube end support (10) for locating a tube end in a tube coupling, comprising a sleeve (11) to be received in a tube having an encircling end head (12) adjacent one end of the sleeve to limit entry of the sleeve into the tube. Encircling gripper means (16) on the sleeve grip on the internal diameter of a tube to hold the tube on the sleeve and a separate annular seal (19) is supported in a groove (18) in the head (12) to seal with the internal diameter of a tube coupling in which the assembly of the end support and tube are located.

Description: This invention relates to a tube end support for locating a tube end in a tube coupling. EP-A-0756126 discloses a tube coupling comprising a coupling body having a throughway open at one end to receive a tube, the diameter of the throughway increasing towards said open end at a first step to form a first enlarged diameter portion to receive a tube and a second step to form a second enlarged diameter portion to receive a tube locking device to hold a tube in the coupling body. A thin wall sleeve has one end engageable in the throughway and the other engageable in the tube to be located in the coupling body so that, in use, the sleeve extends from the tube past the first step into the throughway. The sleeve has a sealing engagement with the internal diameter of the tube to prevent leakage between the sleeve and tube and the end of the sleeve projecting from the tube has an annular seal with seals with the throughway in the coupling body to prevent leakage between the sleeve and coupling body. Documents FR-A-1 496 737, EP-A-0 268 251 and DE 29506835 U1 disclose a tube and support according to the first part of claim 1. FR-A-1496737 discloses a coupling comprising a socket force fitted into a pipe. The socket comprises a collar provided with an O-ring seal which ensures fluid tightness with a coupling which covers the collar. The socket includes peripheral teeth which become embedded in the pipe to ensure that the socket is retained therein. European Patent Publication No. 0268251 discloses a tube joint for connecting a multi ward tube assembly in which the inner tube receives a sleeve having an enlarged head at one end encircled by an O-ring seal in a groove in the head to engage in a coupling body and the other end of the sleeve is reduced in diameter and is force fit in the inner tube of the double walled tube. Adjacent the end of the sleeve, the sleeve has an enlargement which is a force fit in the tube to assist in retaining the sleeve in the tube. DE 295068351U1 discloses a tube coupling in which a tube is supported in a coupling by means of a sleeve having a head at one end having an annular groove in which an O-ring seal is mounted to seal with a part of the body. The sleeve has an enlargement partway along the sleeve where it engages in the tube to assist in holding the sleeve in the tube. This invention provides a tube end support for a tube coupling comprising a sleeve to be received an end of a tube, an encircling end stop adjacent one end of the sleeve to limit entry of the sleeve into the tube, encircling gripper means on the sleeve to grip on the internal diameter of the tube to hold the tube on the sleeve and a separate annular seal supported by the end stop and projecting radially outwardly thereof to seal with the internal diameter of the tube coupling in which the assembly of the end support and tube are located; characterised in that said one end of the sleeve has an encircling head projecting outwardly of the sleeve, the gripper means comprises an annular barb formed integrally with the outer side of the sleeve at a spaced location from the head to grip the internal diameter of the tube inserted over the sleeve and a collar of elastomeric material extends around the sleeve between the barb and head with an outwardly projecting annular flange adjacent the head extending beyond the outer periphery of the head to provide the annular seal with the inner diameter of a tube coupling in which the assembly is located the annular flange providing the encircling end stop (15) to limit entry of the sleeve into the tube. More specifically the elastomeric collar may have a raised annular ridge encircling the outer periphery of the collar to seal with the internal diameter of the tube. The following is a description of some specific embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is a diagrammatic illustration of a tube end support not in accordance with the invention for locating a tube end in a tube coupling body by way of background information; Figure 2 is a diagrammatic illustration of a first form of tube end support in accordance with the invention; Figure 3 is a similar view of a second form of tube support in accordance with the invention. Referring firstly to Figure 1, of the drawings (which shows an arrangement not in accordance with the invention), there is shown a tube end support indicated generally at 10 for locating in an end part of a tube to be inserted in the throughway of a coupling body of a tube coupling having a locking device such as a collet to engage the tube end and seals to seal with the tube end. The tube end support comprises a hard plastics sleeve 11 having an annular head 12 at one end thereof. The sleeve has an internal bore 13 having a flared end 14 at said head end of the sleeve. The head 12 of the sleeve provides a radially annular face 15 directed along the sleeve which forms an end stop to limit insertion of the sleeve into a tube end by engagement with the end of the tube. Spaced along the sleeve from the face 15 is an annular barb 16 formed integrally with the outer diameter of the sleeve over which the tube is forced as the sleeve is pressed into the tube to grip and hold the sleeve in the tube. The outer periphery 17 of the head is formed with an annular groove 18 in which an O-ring seal 19 is mounted to seal with the internal bore or throughway in the tube coupling body referred to above. There is a significant length of sleeve 11 between the barb 16 and the end of the sleeve 20 remote from the head which is inserted into the tube. To facilitate entry of the sleeve end into the tube, the outer diameter of the sleeve is bevelled or chamfered, as indicated at 21. The significant length of sleeve between the end of the sleeve and barb, and the barb itself, provide an effective seal between the tube and the sleeve to prevent leakage of fluid between the tube and sleeve. The O-ring seal 19 provides an effective seal between the assembly and the internal bore or throughway in the coupling body to prevent leakage between the tube and coupling body. Figure 2 shows an arrangement in accordance with the present invention in which the O-ring 19 and groove 18 of the above embodiment are omitted. The annular barb 16 is formed somewhat larger than the barb shown in Figure 1 and the outer diameter of the sleeve is formed with an encircling groove 25 between the barb 16 and head 12. An elastomeric collar 26 is located in the groove, the collar having a radially outwardly projecting annular flange 27 in engagement with the end face 15 of the head. The collar 26 projects outwardly beyond the head and the outer surface of the collar provides an annular seal with the internal diameter of the bore or throughway in the connector body. The elastomeric collar 26 is further formed with an annular ridge 28 mid-way along the collar to engage the inside diameter of a tube in which the sleeve is inserted to seal with the internal diameter. The flange 27 at the end of the collar provides an end stop which the end of the tube engages. The raised barb 16 grips the internal diameter of the tube as before but also lifts the tube over the seal when the sleeve is inserted into the tube. The arrangement is otherwise similar to that described with reference to Figure 1 above. Figure 3 shows a modification to the arrangement of Figure 2 in which the moulded in annular ridge 28 on elastomeric collar is omitted. Instead, the base of groove 25 is formed with a moulded in annular ridge 40 and collar 26 takes up the shape of ridge 40 where it extends over the ridge to produce a corresponding annular ridge 41 encircling the outer periphery of the collar. It is easier to mould in ridge 40 in the groove 25 of sleeve 11 than preform the ridge in collar 25.

Claims: A tube end support for a tube coupling, comprising a sleeve (11) able to receive an end of a tube, an encircling end stop (15) adjacent one end of the sleeve to limit entry of the sleeve into the tube, encircling gripper means (16) on the sleeve to grip on the internal diameter of a tube to hold the tube on the sleeve and a separate annular seal (27) supported by the end stop and projecting radially outwardly thereof to seal with the internal diameter of a tube coupling in which the assembly of the end support and tube are located; characterised in that said one end of the sleeve has an encircling head (12) projecting outwardly of the sleeve, the gripper means comprises an annular barb (16) formed integrally with the outer side of the sleeve at a spaced location from the head to grip the internal diameter of a tube inserted over the sleeve and a collar (26) of elastomeric material extends around the sleeve between the barb and head with an outwardly projecting annular flange (27) adjacent the head extending beyond the outer periphery of the head to provide the annular seal with the inner diameter of the tube coupling in which the assembly is located, the annular flange limiting the entry of the sleeve into the tube. A tube end support as claimed in claim 1, characterised in that the elastomeric collar (26) has a raised annular ridge (28) encircling the outer periphery of the collar to seal with the internal diameter of the tube.

Inventors: GUEST JOHN DEREK, GUEST, JOHN DEREK
Applicants: JOHN GUEST LTD, JOHN GUEST LIMITED
Application year: 1999
Main classification: F16L33
IPC codes: F16L33