GB2268238A - A snap fit tube connector - Google Patents

Abstract

A tube connector has a connector body 16 to which a tube 10 is to be connected and sealed. The seal is made by an O-ring 24 which is trapped between an annular surface 28 on the connector body and a shoulder 12 on the tube, and the shoulder 12 is retained in the connector body by a retention clip 26. When the tube is pushed into the connector body the clip 26 snaps home behind the shoulder to indicate that the joint is assembled, and at this moment the tube 10 is both locked in the connector body and sealed to the connector body. <IMAGE>

Description

A TUBE CONNECTOR This invention relates to a tube connector of the quick-fit type in which a fluid tight sealed joint is made by pushing together two tubular components. Such joints are frequently used in motor vehicle assembly, notably in connecting the fuel lines between the fuel tank and the engine of a vehicle.

Conventional connectors used for this purpose tend to have a sealing mechanism and a locking mechanism, the sealing mechanism being provided to make the fluid tight seal and the locking mechanism being provided to secure the parts together to prevent the seal becoming dislodged. In some of these connectors the seal is made before the locking mechanism is engaged and such connectors (see for example EP 0343036 A) are less than satisfactory because it is possible for the two components to be joined on the assembly line to produce a fluid tight seal so the joint appears satisfactory when it is first tested. However if the locking part of the mechanism is not properly engaged then the joint may work loose during service with adverse results. For example if the connection is in a fuel line and the joint comes undone then fuel may spill into the open and there may be a fire hazard.

Other types of connector (see for example GB 1520742) lock before they seal. In the case of these connectors if the connector is not properly assembled ie the lock is engaged but the seal is not made, then this will become apparent on first testing of the vehicle because the lack of a seal will reveal itself in leaking fluid.

It is however desirable to avoid either of these failure modes, and accordingly the invention provides a quick-fit connector in which the locking and sealing functions are performed simultaneously and in which the correct making of the joint is clearly signalled to the operative carrying out the assembly.

According to one aspect of the invention therefore there is provided a tube connector for connecting a tube end which has an annular shoulder adjacent to but spaced from the end thereof to another component, the connector having a socket with a first portion for receiving the tube end and a second larger diameter portion for receiving the annular shoulder, an O-ring housed within the second socket portion and adapted to form a seal between the annular shoulder and a wall of the socket, a retention mechanism for engaging behind the annular shoulder to hold the tube end against the O-ring and the o-ring against a wall of the socket, and means for connecting another component into communication with the socket.

The wall of the socket against which the O-ring forms a seal is preferably an annular wall which lies at an acute angle to the axis of the connector. There may be one or more 0ring in this position, and if there is more than one o-ring then the O-rings are preferably of different diameters.

The retention mechanism is preferably arranged so that it is pushed aside on insertion of the tube end, and is resiliently loaded so that it snaps into its retaining position as soon as the annular shoulder has passed. The retention mechanism may be formed by a single resilient U-shaped clip, the limbs of which can be forced apart to allow entry of the shoulder and which spring back together to prevent exit of the shoulder once the shoulder has passed. In order to disassemble the joint, the retention clip may be removable by radial movement.

The shape of the annular shoulder on the tube end is preferably designed in conjunction with the shape of the socket, to produce an annular space which becomes narrower as the distance away from the axis of the connector increases. This provides the added advantage that when pressure on the O-ring resulting from fluid pressure passing through the connector, increases then the force on the 0ring pushes the O-ring outwards into a narrower part of the space to enhance the seal.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a connector in accordance with the invention, partly in cross section; Figure 2 is a section taken on the lines IT-II from Figure 1; Figure 3 is a detailed view showing the angles of certain surfaces in the connector of Figure 1; Figure 4 is a view corresponding to Figure 1 but showing the connector during the course of assembly; Figure 5 is a view corresponding to Figure 1 but showing a second embodiment of the invention; and Figures 6, 7 and 8 are schematical views showing three further embodiments of the invention.

Figure 1 shows a tube end 10 which has an annular shoulder 12 formed close to its free end 14. The shoulder 12 is formed by upsetting the end of the tube, in a well-known manner.

The connector has a connector body 16, preferably moulded from a plastics material, which has a first socket portion 18 and a second socket portion 20. The diameter of the first socket portion 18 is such that the tube end 14 is received therein as a snug (but not sealing) fit. The walls of the socket 18 may include longitudinal grooves 22. An Oring 24 is received within the second socket portion 20 and, in the position shown in Figure 1, a retention clip 26 locates behind the shoulder 12 to lock the tube end into the connector body 16.

In Figure 1, it will be seen that the O-ring 24, which performs the sealing function for the connector, is supported between an inclined annular wall 28 of the body 16 and an inclined wall 30 of the shoulder. As can be seen in Figure 3, the wall 28 makes angle a to a plane 32 which lies at right angles to the axis of the connector. The surface 30 of the shoulder 12 makes an angle to the plane 32 which is less than the angle a, such that an angle ss is formed between the two surfaces 28 and 30.

In use, when the tube end 10 and the connector body 16 are assembled as shown in Figure 1, with the retention clip 26 engaged behind the shoulder 12, then the O-ring 24 is compressed between the surfaces 28 and 30 to form a seal.

Because the free end 14 of the tube 10 is not a sealing fit in the first portion 18 of the connector body, the fluid being passed through the connector will flow around the outside of the free end 18, along the axial grooves 22, to reach the inner surface of the 0-ring and as the fluid pressure increases, so the O-ring will be pushed in a radially outward direction by the pressure. Because of the angles of the surfaces 28, 30 as the O-ring is pushed outwards so it will be compressed between these surfaces to enhance the seal formed by the O-ring between the surfaces.

At the opposite end of the connector body to the sockets 18, 20 there is a spigot 32 onto which a flexible hose 34 can be fitted and retained in a known manner. In alternative embodiments however the connector body may be moulded integrally with a component to which the tube 12 is to be connected or may be formed as another connector, possibly with mirror images of the socket portions 18, 20 or may be provided with any other arrangement by which the fluid path represented by the tube 10 can communicate with another component.

The retention clip 26 is shown in more detail in Figure 2.

As can be seen in that Figure the clip 26 is generally Ushaped having two limbs 36, 38 joined by a head 40. The limbs are of a resilient material and have arcuate recesses 42 centred on the axis of the connector and lying on a circle, the diameter of which is less than the diameter of the shoulder 12 but greater than the diameter of the tube 10.

When the tube end is pushed into the connector body, the free end 14 passes through the clip without disturbing the clip but when the shoulder 12 arrives, the tapered wall 30 of the shoulder expands the limbs 36, 38 in a radial direction to allow the shoulder to pass, and the limbs snap back into place as soon as the shoulder has passed this position. The action of the retention clip 26 will provide a positive feel for the assembly operation, so that the assembly operator will be informed by feel of when the joint to the connector has been properly assembled.

As soon as the shoulder 12 is retained behind the clip 26, then the O-ring 24 will be compressed to form a seal which, as already described, will be enhanced when there is fluid pressure within the connector.

The clip 26 is prevented from falling out of the connector body 16 prior to insertion of the tube end 10, by inwardly turned tips 44 at the free ends of the limbs 36, 38.

.However when it is desired to disassemble the joint it is possible by pulling on the head 40 to withdraw the clip 26 entirely from the connector body 16 so that the tube 10 can be withdrawn. The joint can readily be reassembled by reinserting the clip 26 and then pressing in the tube 10.

Figure 5 shows an alternative embodiment which operates in the same way as that shown with respect to Figures 1-4, but where the retention clip 126 operates in a different way.

In this embodiment, in order to release the assembled joint an extension 128 which forms part of the clip 126 is pressed radially inwardly and this causes the retaining part of the clip 126 to lift out of engagement with the annular shoulder 12 to allow the tube to be withdrawn. As a result it is not necessary to remove the clip 126 from the housing 16.

Under certain circumstances it may be desirable to include two O-rings to form the seal between the tube 10 and the housing body 16. The Figures 6, 7 and 8 show three alternative ways in which two O-rings can be housed, with the O-rings being of different diameter so that they both form seals between the two components, in the same area. As can be seen, the profile of the shoulder 12 (and thus the position of the sealing surface 30) varies in these three alternatives, and in the same way the shape of the sealing surface 28 on the body 16 thereis to produce the desired sealing action.

The connector described here provides effective sealing and has the advantage that the assembly operator will notice a definite "click" to indicate that the joint# has been properly made and when the joint is made in this way, the tube end will be simultaneously locked and sealed to the connector body.

Claims (8)

Claims

1. A tube connector for connecting a tube end which has an annular shoulder adjacent to but spaced from the end thereof to another component, the connector having a socket with a first portion for receiving the tube end and a second larger# diameter portion for receiving the annular shoulder, an Oring housed within the second socket portion and adapted to form a seal between the annular shoulder and a wall of the socket, a retention mechanism for engaging behind the annular shoulder to hold the tube end against the O-ring and the O-ring against a wall of the socket, and means for connecting another component into communication with the socket.

2. A tube connector as claimed in Claim 1, wherein the wall of the socket against which the o-ring forms a seal is an annular wall which lies at an acute angle to the axis of the connector.

3. A tube connector as claimed in Claim 1 or Claim 2, wherein more than one O-ring is provided, and wherein the 0rings are of different diameters.

4. A tube connector as claimed in any preceding claim, wherein the retention mechanism is arranged so that it is pushed aside on insertion of the tube end, and is resiliently loaded so that it snaps into its retaining position as soon as the annular shoulder has passed.

5. A tube connector as claimed in Claim 4, wherein the retention mechanism is formed by a single resilient U-shaped clip, the limbs of which can be forced apart to allow entry of the shoulder and which spring back together to prevent exit of the shoulder once the shoulder has passed.

6. A tube connector as claimed in any preceding claim in combination with a tube end for connection thereto, wherein the shape of the annular shoulder on the tube end is designed in conjunction with the shape of the socket, to produce an annular space which becomes narrower as the distance away from the axis of the connector increases.

7. A tube connector substantially as herein described with reference to any one embodiment shown in the accompoanying drawings.

8. The combination of a tube connector and a tube end for connection thereto, substantially as herein described with reference to any one embodiment shown in the accompoanying drawings.