GB2249150A

GB2249150A - A tube connector

Info

Publication number: GB2249150A
Application number: GB9023099A
Authority: GB
Inventors: Ronald Pardy
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1990-10-24
Filing date: 1990-10-24
Publication date: 1992-04-29
Also published as: WO1992008074A1; GB9023099D0

Abstract

A tube connector has a cylindrical body 26 into which a tube 14 with a shoulder 20 can be inserted to form a locked, fluid-tight joint. The tube 14 is first inserted into a collar 32 which provides the locking function, and the collar and the tube are then slid further into a cylindrical body portion 26 until the end of the tube is sealed against O-rings 28. During this sliding movement and once the seal is made, the collar is prevented from moving in a direction out of the connector body by sprag teeth supported on the collar 32 which bite into the connector body <IMAGE>

Description

A TUBE CONNECTOR FIELD OF THE INVENTION This invention relates to a tube connector for use in making a sealed and locked connection between two tubes or tubular bodies through which a fluid will flow.

BACKGROUND TO THE INVENTION Tube connectors for providing a push-together or 'quickfit' connection are well known. In one type (shown for example in UK Patent 1 520 742), the locking function of the connector becomes operative before the sealing function. This is advantageous because it prevents the possibility of the connection forming a seal but not being mechanically locked. In such a situation, the connector could work loose as a result of vibration during operation to a position where the joint would leak. However connectors of this type have the disadvantage that the mechanical lock is achieved by sprag teeth which bite into the material of the tube and damage the tube surface. If the tube has to be disassembled and reassembled, this damage can result in a leak. A connector of this type also requires that the tube material and the tooth material be compatible.If the tube has a hard surface (eg chrome plating), then the teeth will rapidly wear unless they are of an equally hard finish.

In another type, the sealing function is achieved before the mechanical lock. This type of connector relies on a shoulder formed on the tube to be pushed in to the connector and thus requires an additional manufacturing step. It does however avoid any damage to the part of the tube surface which provides the seal.

SUMMARY OF THE INVENTION According to the present invention, there is provided a tube connector for connecting a tube which has a radial shoulder to a fluid line, the connector comprising a connector body with a through bore for communicating with the fluid line, sealing means in the bore for providing a seal with an inserted tube, and an axially movable collet assembly, the collet assembly comprising an annular collar for receiving and holding the shoulder on a tube, and a sprag toothed component providing a connection between the collar and the internal surface of a cylindrical portion of the connector body.

The combination of the locking action of the collar on the tube shoulder, and the axial movement of the collet assembly allows the best features of the two prior art connectors to be combined. The connector has the 'lock before seal' feature of the first type of prior art connector, combined with the avoidance of any damage to those surfaces of the tube which have to engage with the connector seal.

The sprag toothed component may be a sprag washer (preferably metal) fitted around a central ring on the collar. However there are other possibilities. For example, the. sprag teeth may be formed individually or as a group and may then be moulded into a plastics collar to from part of the collar. In another embodiment, the collet assembly, consisting of the annular collar and the sprag toothed component may be of all metal construction.

The cylindrical portion of the connector body may have a retaining lip to prevent the sprag toothed component, and the collar, from being removed from the body.

The collar preferably has an annular recess into which the shoulder on the tube can be snap-fitted using a push-in action, and the collar itself may be moulded from plastics material.

The connector body may also be moulded from plastics material, and may have a spigot with annular ridges onto which a flexible tube can be fitted at the end of the body remote from the cylindrical portion.

In order to allow disassembly of a joint formed using this connector, the connector body may be provided with a release mechanism which presses the sprag teeth away from the wall of the cylindrical portion and slides along the cylindrical portion with the collar and the sprag toothed component until the shoulder on the tube can be disconnected from the collar.

DESCRIPTION OF THE DRAWINGS The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a view of an assembled connector in accordance with the invention; Figures 2,3,4 and 5 show sequential steps in the making of a tube joint with a connector in accordance with the invention. In all these figures the connector is shown in section with only that part of the connector above the centreline being shown; Figure 6 is a view corresponding to Figures 2 to 5, but illustrating disassembly of the connector; Figure 7 is a section through Figure 6 on the lines VII-VII; Figure 8 shows a sprag washer for use in the connector; Figure 9 shows a view corresponding to Figure 2 and illustrating an alternative form of collar; and Figure 10 is a perspective view of the collar of Figure 9.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Figure 1 shows an assembled connector with a connector body 10 and a spigot 12 for receiving a flexible tube in a known manner. A tube 14 with a shoulder (not visible in Figure 1) is connected into the body 10. A release trigger 16 and a slot 18 are also visible and will be described later.

In Figure 2, the shoulder 20 on the tube 14 can be seen.

The connector body 10 has a through bore 22, a seal housing portion 24 and a cylindrical portion 26. Two O-rings 28 are fitted in the seal housing portion, and are retained there by a retaining ring 30.

An annular collar 32 is supported in the mouth of the cylindrical portion 26, and is held there by a sprag washer 34 which engages between an internal lip 36 on the collar and the internal wall of the cylindrical portion 26. The collar has an outer neck 38 with a bead 40. When the shoulder 20 on the tube 14 is pushed into the neck 38, the bead 40 yields resiliently to allow the shoulder to pass.

The bead then snaps back into position to retain the shoulder. This is the position shown in Figure 3. At this point, the tube 14 is locked to the connector, but there is no seal.

Next, the tube is pushed further into the connector body, and the outer ends of the sprag teeth on the washer 34 slide along the wall of the cylindrical portion 26. This movement continues until the tube end is received within the O-rings 28, whereupon the tube 14 is both locked and sealed to the connector body.

As the tube 14 is pushed in to the connector body, the teeth of the sprag washer 34 slide along the internal wall of the connector body and if an attempt is made to remove the tube simply by pulling it in the opposite direction, then the teeth will bite into the connector wall and resist movement. Thus the sprag teeth will act against the connector wall, where there is no sealing function, instead of against the tube wall as in the prior art, and this will avoid any damage to the tube wall.

Because of the shape of the neck 38, it will be apparent that it can only yield to admit the shoulder 20 when the collar is in its extreme left-most position as shown in Figure 2. Once the collar has completely entered the cylindrical portion 26, the neck can no longer yield to allow the shoulder to escape.

When it is necessary to separate the joint, this can be done with the help of a release mechanism. The mechanism comprises an internal ring 42 with an external grip 16. If the ring is pulled to the right as shown in Figure 6, it will lift the sprag teeth away from the wall of the cylindrical portion 26 and will pull the collar to the left until the starting position of Figure 2 is reached again.

Excessive movement of the collar is prevented by a retaining lip 48. At this point, the tube 14 with its shoulder 20 can be pulled free from the collar.

Figure 8 shows one typical form for the sprag washer which has sprag teeth 44 around the outer perimeter of an annulus 46. The diameter of the release ring 42 will be substantially equal to the diameter of the teeth, so that the ring will bear against the teeth when it is pushed to the right, and force the teeth out of contact with the internal wall of the cylindrical portion 26.

Figure 9 shows an alternative embodiment where the collar 32 and the sprag-toothed component are combined in one metal collet 50. As can be seen in Figure 10, the collet has a central aperture 52 which will be a sliding fit on the tube 14, and a number of arms (eg six arms) 54, each of which carries a sprag tooth 56. The freer ends of the arms 54 are bent over so that when these ends are forced radially inwards (this happens when the tube is fully inserted, the bent over ends engage behind and trap the shoulder 20 on the tube.

A release mechanism can also be used with this embodiment, working in the same way as with the preceding embodiment, with a release ring 42.

The embodiment described thus has the advantages of both types of prior art connector without suffering the disadvantages of these connectors. The manufacture of the connector shown will be no more complicated than manufacture of the prior art connectors.

Claims

1. A tube connector for connecting a tube with a radial shoulder to a fluid line, the connector comprising a connector body with a through bore for communicating with the fluid line, sealing means in the bore for providing a seal with an inserted tube, and an axially movable collet assembly, the collet assembly comprising an annular collar for receiving and holding the shoulder on a tube, and a sprag toothed component providing a connection between the collar and the internal surface of a cylindrical portion of the connector body.

2. A tube connector as claimed in Claim 1, wherein the sprag toothed component is a sprag washer fitted around a central ring on the collar.

3. A tube connector as claimed in Claim 1, wherein the sprag teeth are formed individually or as a group and are moulded into the collar to from part of the collar.

4. A tube connector as claimed in any preceding claim, wherein the cylindrical portion of the connector body has a retaining lip to prevent the sprag toothed component, and the collar, from being removed from the body.

5. A tube connector as claimed in any preceding claim, wherein the collar is moulded from plastics material and has an annular recess into which the shoulder on the tube can be snap-fitted using a push-in action.

6. A tube connector as claimed in any preceding claim, wherein the connector body is moulded from plastics material, and has a spigot with annular ridges onto which a flexible tube can be fitted at the end of the body remote from the cylindrical portion.

7. A tube connector as claimed in any preceding claim, wherein the connector body is provided with a release mechanism which presses the sprag teeth away from the wall of the cylindrical portion and slides along the cylindrical portion with the collar and the sprag toothed component until the shoulder on the tube can be disconnected from the collar.

8. A tube connector substantially as herein described with reference to the accompanying drawings.