Connector for coupling tubes

Abstract: The disclosure relates to a connector (10) for coupling a tube to an annular boss of (11) a vessel wall. The connector comprises a coupling body (14) having spaced end portions (16,18) with a throughway (15) extending between the end portions. A first end portion (16) is adapted to receive and hold an end of a tube and a second end portion has encircling sealing means (21) and detent means (23) to engage and hold the end portion in the boss. The coupling body has a sleeve (24) mounted thereon which encircles said second end portion with an annular gap between the sleeve and end portion in which the boss is engageable whereby the sleeve supports the wall of the boss in engagement with the sealing means and detent means of the second end portion.

Description: This invention relates to connectors for coupling tubes and is particular although not exclusively applicable to connectors for coupling tubes to bosses on vessel walls. In our European Patent Specification No. 0756125 we describe and illustrate a tube connector which is preferably formed in plastics and which has a coupling body formed with a socket containing a collet device for receiving and locking an end of a tube in the coupling body. The coupling body has a spigot at the other end of the body which could be provided with an encircling steel grab ring for engaging and holding the spigot in a thin-walled plastic sleeve or boss to which the coupling body is to be connected. One example of such an application is a vehicle fuel tank formed in plastics with an integral moulded boss on the tank to receive a connector for securing a tube to the tank. Such tanks which are supplied to the car manufacturer are invariably complex assemblies including fuel feed/return lines, vapour recovery and other "plumbing" fitments already attached ready for coupling to the various services of the vehicle. In current designs, such further components are hot-plated moulded to the tank but this has obvious restrictions, particularly where the tank is formed from high density polyethylene (HDPE) because it is only possible to weld high density polyethylene to high density polyethylene. A further difficulty is that high density polyethylene tends to swell in contact with fuel as much as up to three percent and so any coupling to the tank must control or allow for this. US-A-5307995 discloses a lawn and garden sprayer having a hose compression connector for coupling a dispensing hose to a supply tube inside the liquid-containing dispensing tank. The hose compression connector comprises a threaded boss projecting from the dispensing tank, a hose adapter having a raised annular shoulder, over which the dispensing hose extends, located at the dispensing-hose receiving end thereof, and a threaded nut having a knurled exterior for easy gripping and an interior, annular compression surface, whereby the hose is clamped between the compression nut and the upper annular surface of the shoulder, and between the boss and the lower surface of the shoulder. It is an object of the present invention to provide a sleeve which supports an annular boss of a vessel wall intended to receive a coupling for connection to the vessel without requiring a screw thread on the annular wall to hold the sleeve and connector in place. This invention provides a connector for coupling a tube to an annular boss of a vessel wall, the connector comprising a coupling body having spaced end portions with a throughway extending between the end portions, a first end portion being adapted to receive and hold an end of a tube and a second end portion having encircling sealing means to engage in the boss, the coupling body having a sleeve mounted thereon which encircles said end portion with an annular gap between the sleeve and end portion in which the boss is engageable, wherein the said second end portion of the coupling body has an encircling detent means mounted thereon to engage and grip in the boss, and in that the sleeve is a plain sleeve having a close fit with the wall of the boss to support the boss where it is engaged by the sealing means and detent means. The sleeve of the coupling body provides extra mechanical support to hold the boss on the tank in engagement with the seals and detent means of the end portion of the coupling body and to resist swell of the boss resulting from contact with the fuel contained in the tanks. The sleeve, by providing extra mechanical support may also be attractive in other non-related applications where the port or boss on a tank is not mechanically strong enough by itself to carry the coupling. 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 sectional view through one form of connector to a tank; and Figure 2 is a diagrammatic sectional view through another form of connector to a tank. Referring firstly to Figure 1 of the drawings, there is shown a tube connector indicated generally at 10 mounted on an annular boss or up stand 11 formed at a port 12 in a moulded plastics vessel 13 such as vehicle fuel tank. The boss is of annular form. The connector comprises a coupling body 14 in the form of an elbow with a central throughway 15 running through the elbow. The elbow has one limb 16 forming a stub pipe with a "fir tree" form outer profile indicated at 17 to receive an end portion of a length of plastic tubing (not shown) which is forced onto the stub pipe and is retained by the detent action of the "fir tree" formation on the stub pipe. The other limb 18 of the elbow projects into the boss 11 on the fuel tank and is a close fit therein. Nearest the end of the limb there are two annular grooves 19,20 in the outer periphery of the limb at spaced locations along the limb in which O-ring or similar seals 21 are mounted to seal with the inner surface of the boss of the fuel tank. Spaced further from the end of the limb there is a further annular groove 22 encircling the outer periphery of the limb in which a star washer form grab ring 23 is mounted to engage the inner surface of the boss 11 and hold the limb in the boss. The boss 11 on the fuel tank has a relatively thin wall and the nature of the plastics material is such that the wall of the boss has a degree of flexibility. In addition, the plastics material used for fuel tanks is such that contact with fuel can cause the plastics to expand. To reinforce the boss against flexing and expansion which could result in the release of the connector from the boss, an external metal or hard plastics sleeve is mounted on limb 18 of the connector at the end adjacent the apex of the connector to encircle with a close fit the outer side of the boss 11. The boss is thereby held firmly in engagement with the limb and with the grab ring 23 and seals 21. The sleeve 24 is retained on the limb of the connector by means of an inturned annular flange 25 at the end of the sleeve remote from the open end of the limb 18. The limb 18 adjacent the apex of the connector has an annular shoulder 26 with which the flange 25 engages. To hold the flange in position, there is a raised annular detent 27 on the limb spaced from the flange 26 by a distance slightly greater than the thickness of the flange 25 and which is dimensioned so that in locating the sleeve 24 on the limb 18 of the connector, the flange has to be snapped over the detent 27 and is then retained by the detent on the limb loosely in engagement with the flange 26. It will be appreciated that many other arrangements may be provided for retaining the flange on the limb. Figure 2 of the drawings shows an alternative construction in which like parts have been allotted the same reference numeral. In the arrangement of Figure 2, the connector is a straight form connector and in place of male stub 16 of the arrangement of Figure 1, there is a collet type connector for receiving and securing an end of a tube in the connector by simply pushing the tube into the connector. The connector is indicated generally at 20. A more detailed description of the connector is to be found in our European Patent Specification No. 0756125. The arrangement is otherwise similar to that of Figure 1.

Claims: A connector for coupling a tube to an annular boss of a vessel wall, the connector (10) comprising a coupling body (14) having spaced end portions (16,18) with a throughway (15) extending between the end portions, a first end portion being adapted to receive and hold an end of a tube and a second end portion (18) having encircling sealing means (21) to engage in the boss (11), the coupling body having a sleeve (24) mounted thereon which encircles said end portion with an annular gap between the sleeve and end portion in which the boss is engageable, characterised in that the said second end portion of the coupling body has an encircling detent means (23) mounted thereon to engage and grip in the boss (11), and in that the sleeve is a plain sleeve having a close fit with the wall of the boss to support the boss where it is engaged by the sealing means and detent means. A connector as claimed in claim 1, characterised in that the annular sleeve (24) is formed separately from the coupling body (14), the sleeve extends along said second portion (18) of the coupling body and means (25) are provided at the end of the sleeve remote from the end of the coupling body for mounting the sleeve on the coupling body. A connector as claimed in claim 2, characterised in that the means to mount the sleeve on the coupling body comprise an inturned annular flange (25) on said end of the sleeve and the connector body has an annular mounting in which the annular wall engages. A connector as claimed in claim 3, characterised in that the coupling body is formed with an annular shoulder (26) adjacent the second end portion of the coupling body and facing towards the end of the coupling body against which the annular wall on the sleeve engages and detent means (27) encircling the coupling body spaced opposite the annular shoulder over which the annular wall on the sleeve is snapped to be trapped against the shoulder of the coupling body. A connector as claimed in any of the proceeding claims, characterised in that the sealing means on the second end portion of the coupling body comprises at least one annular groove (19,20) encircling the second end portion having a resilient seal (21) mounted therein to engage the inner surface of the boss. A connector as claimed in claim 5, characterised in that said sealing means comprise two annular grooves (19,20) encircling said second end portion of the coupling body and two annular sealing rings (21) located in the respective grooves to engage the inner surface of the boss. A connector as claimed in any of the preceding claims, characterised in that the detent means to hold the second end portion of the coupling body in the boss comprise a grab ring (23) mounted in an annular groove (22) in the second end portion of the coupling body to engage the inner surface of the boss (11) and hold the end portion of the body in the boss. A connector as claimed in claim 7, characterised in that the sealing ring or rings (21) are mounted on the end portion (16) of the coupling body nearer to the end of the coupling body than the grab ring (23) so that the sealing ring or rings engage a surface of the boss which the grab ring has not passed through. A connector as claimed in any of the proceeding claims, characterised in that the first and second end portions (16,18) of the connector extend at right angles to each other to form an elbow connector. A connector as claimed in claim 9, characterised in that the first end portion (16) of the connector has an external "fir tree" profile (17) for receiving and gripping in a tube to be coupling to the connector. A connector as claimed in any of claims 1 to 10, characterised in that the first end portion (16) of the connector (10) is provided with a push-in device (28) for receiving and securing an end of a tube therein.

Inventors: GUEST TIMOTHY S, GUEST, TIMOTHY S.
Applicants: GUEST JOHN ENG, JOHN GUEST ENGINEERING LIMITED
Application year: 1998
Main classification: F16L41
IPC codes: F16L41, F16L21