GB2118264A - Branch pipe joint - Google Patents

Abstract

A pipe joint for fitting into a hole in the wall of a pipe comprises inner (2) and outer (1) tubular telescoping members, one of said members having pins (8) projecting from one end of it for locating in the hole, and the other member having longitudinal slits (16) at the corresponding end for locating the pins and enabling the slitted end to be resiliently stressed and thereby to vary its external dimensions. Interengagement of the members as they are telescoped together causes stressing at or adjacent the slitted end, thereby enabling the slitted end (15) to engage behind the hole, either by expansion caused by release of the stress or by expansion caused by the stressing. <IMAGE>

Description

SPECIFICATION Improvements relating to boss assemblies This invention relates to boss assemblies which are designed to be fitted into holes in the walls of pipes to enable branch fittings to be attached to the pipes.

More particularly, but not exclusively, the invention relates to boss assemblies for fitting into holes in the stack pipes of soil systems for the disposal of soil effluent from domestic, commercial or industrial buildings. The boss assemblies are used to connect branch pipes leading from sanitary appliances, i.e. sinks, wash basins and w.c. pans, to the stack pipes.

Currently several methods are used for fitting boss assemblies to stack pipes. In one such method the boss assembly has two telescoping tubular members the inner one of which has a flange which can be manipulated through an appropriately sized hole in the stack pipe and then brought up against the inside surface of the stack pipe. The other tubular member has a saddle which covers the hole. The inner tubular member is drawn towards the outer tubular member by a nut which is held captive by the outer tubular member and threadedly engages the inner tubular member. Thus the flange and saddle clamp the wall of the stack pipe between them around the periphery of the hole. Additionally for sealing purposes, the flange and the saddle can be bonded to the stack pipe.

For example when the stack pipe and tubular members are of plastics material solvent welding can be used. The inner tubular member defines a socket for receiving a branch pipe.

In another method the boss assembly is strapped to the outside of the stack pipe and bonded to it.

The object of the present invention is to provide a boss assembly having a more convenient method of fitting to a soil stack than hitherto.

According to the invention a boss assembly for fitting into a hole cut in a pipe comprises inner outer tubular telescoping members, one of said members having pins projecting form one end of it for locating in said hole, and the other member having longitudinal slits at the corresponding end for locating said pins and enabling the slitted end to be resiliently stressed and thereby to vary its external dimensions, interengagement of said members as they are telescoped together causing stressing of said other member at or adjacent the slitted end, thereby enabling the slitted end to engage behind said hole to trap the assembly in said hole.

Thus if the slitted end is provided on the inner member, it can engage behind the hole by the release of stress after it has passed through the outer member in a contracted condition. If the slitted end is provided on the outer member then it can be of a size to fit in its unstressed condition in the hole and then be expanded by the stressing.

Two constructions of boss assembly will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a top plan view of one element of the first boss assembly.

Figure 2 is a section on the line Il-Il of Fig.

1, Figure 3 shows a top plan view of the other element of the first boss assembly, Figure 4 is s section on the line IV-IV of Fig. 3, Figure 5 is a section on the line V-V of Fig.

6 of the first boss assembly fitted to a stack, Figure 6 is a front view of the first boss assembly.

Figure 7 shows a sectional view of the second boss assembly prior to it being fitted together, Figure 8 shows a sectional view on the line VIlI-VIlI of Fig. 9 of the second boss assembly fitted together, and Figure 9 is a front view of the second boss assembly.

For convenience the boss assemblies are described hereafter using terms such as "upper" and "lower" to correspond to their orientations shown in the drawings. However it will be appreciated that the assemblies can and will be used in other orientations.

Referring to Figs. 1 to 6 of the drawings, the boss assembly comprises outer and inner telescoping tubular members 1 and 2 made of plastics material.

The outer tubular member 1 has a cylindrical portion 3 and an integral saddle portion 4 which is cylindrically curved so that it seats on a plastics stack pipe 5 (Fig. 5). The inner surface of portion 3 is stepped radially outwardly at shoulder 7 to provide a recess at the upper end of the portion 3. The member 1 is also provided with four locating keys 8 which are spaced from each other at 90 about the longitudinal axis of the cylindrical portion 3.

The keys 8 are provided on the inner surface of the cylindrical portion 3 and extend longitudinally of it from the shoulder 7 to form pins projecting beyond the saddle portion 4.

The inner member 2 is of cylindrical form with a thickened wall portion 10 at its upper end which when the two members 1 and 2 are fully fitted together as shown in Fig. 5 locates in the recess at the upper end of member 1 with its rim against the upper edge of the member 1. The thickened wall portion 10 has a groove 12 extending around its outer surface for locating a resilient "0" ring 17 which seals against the inner surface of the member 1.

At the lower end of the member 2 a skirt portion 13 extends from internal shoulder 14.

At its lower extremity the skirt portion 13 has a radially outwardly projecting lip or bead 15.

Four longitudinal slits 16 extend from the lower edge of the member 2 up to the thickened portion 10. These slits are spaced at 90 to each other about the longitudinal axis of the member 2 and are of a width that they can locate the keys 8 on the member 1 as shown in Fig. 5.

In order to enter the member 2 into the member 1 through the upper end of the member 1, the slits 16 have to be aligned with the keys 8 and the skirt 13 has to contracted radially inwardly. The slits 16 permit this contraction and at the same time there is a resilient stressing of the skirt.

In order to fit the boss assembly into the stack pipe 5, a hole is cut into the stack pipe 5 of a diameter such that the projecting pins of the keys 8 just fit into it; to facilitate this the projecting pins are bevelled. The members 1 and 2 are pre-assembled so that the contracted skirt 13 of member 2 lies part way along the member 1 and the keys 8 extend part-way along the slits 16. This pre-assembly can be carried out by the manufacturer. The boss assembly is then offered to the hole so that the projecting pins of the keys 8 locate in the periphery of the hole. The member 2 is then pushed further into the member 1 until the bead 15 moves beyond the projecting pins of the keys 8 and, due to the stressing of the skirt 13, snap behind the hole in the stack pipe 5 as shown in Fig. 5, to trap the boss assembly in position.It will be appreciated that the projecting pins of the keys 8 guide the skirt 13 of the member 2 into the hole.

Referring now to Figs. 7 to 9, the boss assembly shown again comprises outer and inner telescoping tubular members 21 and 22 made of plastics material. The outer tubular member 21 has a cylindrical portion 23 and an integral saddle portion 24 so that it seats on a plastics stack pipe 25. The member 21 is formed internally of the cylindrical portion 23 with an annular sloping shoulder 26 extending from the inner surface of the cylindrical portion 23. A skirt 27 depends from the radially inner edge of the shoulder 26 so that it is radially inwards of the cylindrical portion 23. The skirt 27 projects out of the cylindrical portion and beyond the adjacent undersurface of the saddle portion 24. The skirt 27 is provided with slits 28 which also extend into the shoulder 26 to increase its deflectability.

The inner tubular member 22 is provided at its lower end with integral pins 31 corresponding in number to the number of slits 28 in the skirt 27, the pins 31 projecting axially from the lower end of the member 22. The lower edge of the member 22 is provided with a bevel 32 whose slope is greater than that of the shoulder 26. At its upper end the member 22 is provided with an outwardly extending flange 33 and part-way along its length is provided with an internal shoulder 34.

The boss assembly is completed by a nut 35 and an '0' sealing ring 36 which fits around the member 22 and within the re cessed upper end of the member 21 to pro vide a seal between the internal surface of the member 21 and the outer surface of the member 22. The nut 35 screws on to the upper threaded end of the member 21 and in so doing engages the flange 33 on the mem ber 22.

To fit the boss assembly into the stack pipe 25 a hole is cut into the stack pipe 25 of a diameter such that the skirt 27 just fits into the hole. The member 21 is then fitted to the pipe so that the skirt 27 locates in the hole and the saddle seats on the surface of the pipe around the hole. The member 22 is then fitted into the member 21 with the pins 31 aligned with the slits 28 in the skirt 27, so that the pins 31 pass into the slits 28 and the bevel 32 comes up against the shoulder 26.

Thereafter the nut is screwed onto the mem ber 21 so that it engages the flange 33 and forces the member 22 into the member 21 to cause the bevel 32 to resiliently deflect the shoulder 26 and so cause flaring of the skirt 27 to deflect it behind the hole and so trap the boss assembly in position. This deflection causes the angle between the bevel 32 and the shoulder 26 to decrease until at the end of the movement they lie flat against each other as shown in Fig. 8.

It will be appreciated that the functioning of the two boss assemblies described is some what similar, but that the functioning of the respective members 21 and 22 has been reversed.

In the boss assembly shown in Figs. 7 to 9 the slope of the bevel 32 need not be differ ent from that of the shoulder 26. Also, as an alternative to the bevel 32, the lower edge of the member 22 could be simply radiused so that it made line contact with the shoulder 26.

In Figs. 5 and 6 the first boss assembly is shown fitted with a branch pipe 18. This is fitted after the boss assembly has been fitted to the pipe 5. The shoulder 14 provides an abutment for the end of the pipe 5. In Figs. 7 to 9 the second boss assembly is shown with a similarly fitted branch pipe 38 which abuts shoulder 34.

To seal the boss assemblies in position a film of solvent or adhesive is applied to the underside of the saddle prior to the fitting of the boss assemblies. Another method is to locate an '0' ring on the underside of the saddles which thus seals with the surfaces of the pipes around the hole.

Claims (13)

1. A boss assembly for fitting into a hole in the wall of a pipe, said assembly compris ing inner and outer tubular telescoping members, one of said members having pins projecting from one end of it for locating in said hole, and the other member having longitudinal slits at the corresponding end for locating said pins and enabling the slitted end to be resiliently stressed and thereby to vary its external dimensions, interengagement of said members as they are telescoped together causing stressing of said other member at or adjacent the slitted end, thereby enabling the slitted end to engage behind said hole to trap the assembly in said hole.

2. A boss assembly according to Claim 1, wherein said slitted end is on the inner member and has an external dimension in its unstressed condition which is larger than the internal dimension of said outer member so that as it is pushed through said outer member it is in a contracted condition to pass into said hole and then snaps behind said hole as it passes beyond said outer member by release of the stress.

3. A boss assembly according to Claim 2, wherein said slitted end is provided with a bead at its extremity which snaps behind said hole.

4. A boss assembly according to Claim 3, wherein said external dimension is provided by said bead.

5. A boss assembly according to any one of Claims 2 to 4, wherein said slitted end has to be contracted prior to fitting it into the outer member.

6. A boss assembly according to Claim 1, wherein said slitted end is provided on said outer member and is expanded as said inner member is pushed onto it.

7. A boss assembly according to Claim 6, wherein said slitted end is formed by a skirt which is disposed radially inwards of the adjacent portion of the outer member and connects therewith through an internal annular shoulder said shoulder being engaged by the end of said inner member to resiliently deflect said shoulder and thereby flare said skirt so that it engages behind said hole.

8. A boss assembly according to Claim 7, wherein said shoulder is a sloping shoulder and the engaging end of said inner member is bevelled at a steeper angle than said shoulder so that as said shoulder is deflected its angle with the bevel decreases.

9. A boss assembly according to Claim 7 or Claim 8, wherein said inner member is pushed into said outer member by a nut screwed onto one of said members.

10. A boss assembly according to any preceding claim, wherein said inner and outer members are sealed together by a sealing ring between them.

11. A boss assembly according to any preceding claim, wherein the outer member has a saddle for engaging the outer wall surface of the pipe.

12. A boss assembly substantially as hereinbefore described with reference to Figs. 1 to 6 of the accompanying drawings.

13. A boss assembly substantially as hereinbefore described with reference to Figs. 7 to 9 of the accompanying drawings.