GB2117470A - Gas connector - Google Patents

Abstract

A gas connector for interconnecting a gas supply pipe and a gas distribution pipe and simultaneously engaging the edge of a wall through which the connector extends, for example the wall of a gas distribution box, comprises a flange 19 and a further member e.g. a split washer 21 between which the edge of the wall is trapped, one or both of the flange and the member being a snap fit on a tubular body 14 of the connection by passage over a frusto-conical surface 17. The flange and member may be defined by separate elements 19,21, or may be defined by a single element. <IMAGE>

Description

SPECIFICATION Gas connector The present invention relates to a gas connector.

Gas is distributed to individual small consumers premises via a low pressure network of plastics pipes. At the point of entry to the consumers premises a gas connector is provided for connecting the plastics pipe to a distribution pipe leading to a gas meter and gas outlets within the premises. This connector is conventionally mounted in a box which is secured to a wall and to the interior of which the consumer does not normally have access.

The known connectors comprise a tubular body defining at one end an insert suitable for insertion into a plastics pipe and defining at the other end a threaded portion to which pipes can be connected in a conventional manner. A central section of the body supports a flange which is intended to bear against the edges of a hole cut in a box and is threaded to enable the edges of the hole to be clamped between the flange and a nut screwed onto the central section of the body.

Despite the relatively simple structure of the known connector it is expensive to manufacture.

This is because the body must have a fairly large maximum outer diameter (the diameter of the flange) and three separate accurately formed sections, that is the insert which must have an external formation of predetermined dimensions to achieve good sealing with the plastics pipe, the threaded central portion onto which the nut is screwed to secure the connector to the box, and the threaded end portion. To obtain the necessary dimensional accuracy at least some manufacturers have produed connectors by machining bar stock of the same ouside diameter as the flange. This is obviously expensive both in terms of materials and machining.

It is an object of the present invention to provide a gas connector which can be fabricated at lower cost than the conventional connector described above.

According to the present invention there is provided a gas connector comprising a tubular body having means for connection to a plastics gas pipe at one of its ends and means for connection to a gas distribution pipe at its other end, a flange supported by the tubular body for bearing against one side of the edge of a hole in a wall through which the connector extends in use, and a member positioned relative to the flange such that the edge of the hole is trapped between it and the flange, wherein the flange and/or the member are a snap fit on the tubular body.

Preferably the flange is in the form of a washer which can be threaded over the tubular body and pressed into engagement with a retraining rim on the tubular body. The member can be in the form of a split washer which can be pushed radially onto the tubular body between a retaining surface on the tubular body and the flange.

Alternatively, the member may be defined by a resilient skirt integral with a further washer, the resilient skirt being a snap fit in the hole into which the connector is to be inserted.

By providing a snap fit flange the maximum outer diameter of the tubular body is considerably reduced so that the initial bar stock from which the connector is produced can be of reduced diameter and the amount of material wasted is thereby reduced. By providing a snap fit split washer or resilient skirt instead of a washer and put the need for a threaded central portion on the tubular body is removed. Each of these savings is significant but together they result in a very considerable reduction in the cost of manufacture. The snap fit flang and split washer can be fabricated from any suitable material, for example various plastics materials, at low cost.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a conventional gas connector; Figure 2 shows an embodiment of the present invention; Figure 3 shows in detail a split washer incorporated in the connector of Figure 2; and Figure 4 shows a further embodiment of the present invention.

Referring to Figue 1, the conventional connector comprises a tubular body defining an insert 1 which in use is pushed inside a plastics gas pipe (not shown), a threaded end portion 2 for connection to a gas distribution pipe within a consumers premises, and a central portion comprising a flange 3, a shoulder 4 which is a loose fit within a hole through the wall 5 of a box, and a threaded portion 6. A steel washer 7 bearing against a nut 8 forces a resilient washer 9 against the box wall 5. A nut shaped portion 10 enables the tubular body to be firmly gripped as connections are made to it.

It will be noted that sections 1, 2 and 6 require careful machining and that the outside diameter of flange 3 is considerably more than that of the rest of the connector.

Referring now to Figure 2, the illustrated embodiment of the invention comprises an insert 11, threaded end 12, and nut shaped portion 13 exactly the same as portions 1,2 and 10 of Figure 1. The central portion of the tubular body is however different in that it comprises a tubular portion 14 extending between surface 15 defined by the nut shaped portion 13 and a small rim 16. Afrustoconical surface 17 runs from the rim 16 to the insert 11.

Awasher like member 18 defining a flange 19 and shoulder 20 is a tight fit on the tubular portion 14.

The washer is positioned by threading it over the insert 11 and then applying pressure to cause it to rise up the surface 17 and snap over the rim 16. Once snapped in position it cannot be pulled back over the rim 16. A split washer 21 (Figure 3) is a snap fit on the portion 14 of the tubular body, the distance between surfaces 22 being slightly less than the diameter of the portion 14 and the radius of the surface 23 being equal to the diameter of the portion 14. The split washer 21 is forced onto the tubular body between the surface 15 and the flange washer 18, threby defining an annular groove between surface 24 and surface 20. When installed the wall of the box (equivalent to wall Sin Figure 1 but not shown in Figure 2) is trapped between the sufaces 20, 24. The connector is thus firmly held in position.

The member 18 defining the flange 19 is in the illustrated embodiment in the form of a washer completely encircling the tubular portion 14. The member 18 is positioned by threading it over the insert 11. It may be however that it is desired to position the member 18 without th reading it over either end of the tubular body and if this is the case the member 18 may be in the form of a split ring so that it can be pushed on from one side of the tubular body in exactly the same way as that used for the split ring shown in Figure 3.

The surface 20 may be provided with an annular groove to receive an O-ring, the O-ring improving the seal between the flange 19 and the box wall (not shown).

Figue 4 illustrates a further embodiment of the invention which in many respects is similar to that of Figures 2 and 3, the same reference numerals being used to identify identical features in Figures 2 and 4.

In the embodiment of Figure 4 however the split ring 21 is dispensed with and its functions are performed by a resilientformation on a further washer 25.

In the embodiment of Figure 4, the washers 18 and 25 fill all of the space between surface 15 and rim 16.

The end of the washer 25 adjacent the surface 15 supports a resilientfrustoconical skirt 26 the bottom edge of which is spaced from the surface 20 of the flange 19 by a distance slightly greater than the thickness of the box wall to which the connector is to be fitted.

In use, a hole is provided in a box wall which is a snug fit around the central portion of the washer 18 and the connector is pushed into the hole with the end 12 leading. The skirt 26 is compressed as the connector is inserted and springs back behind the box wall, thereby preventing subsequent removal of the connector from the box. An O-ring 27 located in a groove 28 in the flange 19 takes up any slack in the assembly to ensure that the box wall and connector are firmly held together.

The advantage of the arrangement of Figure 4 is that it is not necessary to have access to both sides of the box wall when the connector is being secured to the box wall.

Claims (6)

1. A gas connector comprising a tubular body having means for connection to a plastics gas pipe at one of its ends and means for connection to a gas distribution pipe at its other end, a flange supported by the tubular body for bearing against one side of the edge of a hole in a wall through which the connector extends in use, and a member positioned relative to the flange such that the edge of the hole is trapped between it and the flange, wherein the flange and/or the member are a snap fit on the tubular body.

2. A gas connector according to claim 1, wherein the flange is in the form of a washer which can be threaded over the tubular body and snapped into engagement with a retaining rim defined by the tubular body.

3. A gas connector according to claim 1 or 2, wherein the member comprises a split washer which can be pushed radially onto the tubular body betwee#n a retaining surface defined by the tubular body and the flange, the split washer being a snap fit on the tubular body.

4. A gas connector according to claim 2, wherein the member comprises a resilient skirt supported by a further washer, the resilient skirt being a snap fit in the hole through which the connector extends in use.

5. A gas connector according to any preceding claim, wherein the flange supports a resilient O-ring.

6. A gas connector substantially as hereinbefore described with reference to Figures 2 and 3 or Figure 4 of the accompanying drawings.