GB2305481A

GB2305481A - Pipe coupling with gasket and housing

Info

Publication number: GB2305481A
Application number: GB9619619A
Authority: GB
Inventors: Ian Smith
Original assignee: GLYNWED FOUNDRY PROD Ltd
Current assignee: GLYNWED FOUNDRY PROD Ltd
Priority date: 1995-09-19
Filing date: 1996-09-19
Publication date: 1997-04-09
Anticipated expiration: 2016-09-19
Also published as: GB9519131D0; GB9619619D0; GB2305481B

Abstract

The coupling comprises the gasket 2 to fit as a sleeve over adjacent end portions of metal pipes or conduits 20, 21, the metal housing 3 encompassing and clamping about the gasket, with inwardly directed projections 19 extending past opposite gasket ends, penetrating coated surfaces of the pipes or conduits, as the housing is clamped so as to provide equipotential bonding between the connected pipes or conduits through the housing. Preferably the projections 19 are formed integrally with the housing 3, are in the form generally of teeth or spikes and project inwardly a distance corresponding to, or slightly less than, the overall thickness of the gasket 2 in its relaxed state. The housing 3 is a single band or comprises two parts clamped together by fasteners.

Description

PIPE COUPLING This invention relates to a pipe coupling for connecting two metal pipes or conduits together end-to-end and comprising an annular sealing gasket which fits, as a sleeve, over the adjacent end portions of the pipes or conduits to be connected, and is encompassed by a housing which clamps about the gasket and end portions to secure the connection. The pipe coupling may be used, for example, in the connection of drain, soil, waste, vent and water supply pipes.

Herein, the terms "pipe" and "conduit" are intended to include not only pipes, tubes and the like but also hollow fittings such as bends, elbows and T-junctions which may be included in pipe runs.

It is desirable for connected metal pipes or conduits which are used above the ground to have equipotential bonding (electrical continuity) so that they can provide a means of earthing. There have been difficulties in providing the equipotential bonding when pipe couplings of the kind referred to are used having sealing gaskets of rubber, plastics or other electrically insulating material.

The present invention provides a pipe coupling which is aimed at facilitating the provision of equipotential bonding between pipes or conduits it connects when in use.

According to the present invention a pipe coupling is provided which comprises an annular sealing gasket adapted to fit as a sleeve over adjacent end portions of metal pipes or conduits to be connected end-toend, and a metal housing which encompasses, and is adapted to be clamped about, the gasket and which has inwardly-directed projections positioned to extend past axially opposite ends of the gasket and adapted to penetrate coated surfaces of the end portions of pipes or conduits to which the coupling is applied for use, as the housing is clamped about the gasket to secure the connection, thereby to provide equipotential bonding between the connected pipes or conduits through the housing.

Equipotential bonding between pipes or conduits to which the pipe coupling is applied is established, therefore, simply by the process of clamping the housing about the gasket to secure the connector. The fitter does not have to take additional measures to establish the required continuity.

Preferably the projections are formed integrally with the housing.

They may be in the form generally of teeth or spikes. There may be just one projection for each of the opposite ends of the gasket, but preferably there are two or more of the projections.

The housing may be of composite form comprising part-circular components which clamps together around the gasket. It may alternatively be in the form of a single band which contains and substantially encircles the gasket. In either form the metal of the housing may be cast to shape.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a perspective view, partly cut away, of a pipe coupling in accordance with the present invention; Figure 2 is an enlarged side view of a component part of a housing of the pipe coupling, and Figure 3 is an enlarged fragmentary section on the line 3-3 of Figure 1.

As shown in Figure 1, a pipe coupling 1 comprises an annular sealing gasket 2 and a housing 3 which clamps around the gasket.

The gasket 2 is of a known form made as a moulding from a suitable flexible synthetic rubber or other insulating material. It has a tubular body 4. Internally of the body 4 is an integral, annular, central rib 5 of rectangular section, and groups of integral, shallower, annular ribs 6, Figure 3, of part-circular section spaced at either side of the central rib 5, with intervening plain annular surface portions 7 between the central rib and each of the groups of shallower ribs 6. Externally of the body 4 are two diametrically opposed ears 8, Figure 1, which extend along the length of the body parallel to its central axis. The ears 8 taper radially outwardly.Extending circumferentially between the ears 8 at the external surface of the body 4 are integral, broad, raised central bands 9 and, at either side of those central bands, groups of ribs 10 of similar part-circular section to, and directly opposite, the shallower ribs 6 inside the body. The external surface may be plain at least for some uses of the pipe coupling.

The housing 3 of the pipe coupling comprises two similar, substantially semi-circular, coupling members 11, 12 which are steel castings. Each coupling member 11, 12 has a central internal, annularlyextending, recess 13 complementary in cross-section to the raised central bands 9 of the body 4 of the gasket, and outwardly-directed flanges 14 at its opposite ends. Each flange 14 is formed with a central plain hole 15.

One coupling member 11 has parallel raised beads 16 spaced to either side of the hole 15 in each of its flanges 14 on the surface of the flange adjoining the semi-circular external surface of the coupling member. The corresponding surfaces of the flanges of the other coupling member 12 are plain. Screws 17 passed through the holes 15 from the coupling member 11 and fitted with retaining nuts 18 connect the coupling members together, heads of the screws seating between the parallel beads 16 to be restrained from turning. The coupling members 11, 12 are of a width slightly greater than the axial length of the gasket. Together they substantially enclose the gasket. The ears 8 of the gasket locate between the flanges 14 and the screws 17 pass between the flanges, beyond the ears.Engagement of the raised bands 9 in the recesses 13 of the coupling members locates the gasket centrally with respect to the coupling members.

Instead of just the one hole 15 in each flange there may be two holes offset towards the opposite sides of the flange. This is suitable for larger size couplings, typically for pipes having an external diameter of 150mm or more. For improved security against unauthorised release of the pipe coupling, and vandalism, when the coupling is secured the screws 17 may be socket head screws which require a key for turning them. If such screws are used the two coupling members 11,12 may be of the same form, both having the parallel beads 16.

At the opposite arcuate edges of each of the coupling members 11, 12 integral, radially-inwardly projecting, teeth 19 are formed. As shown in Figure 2, there are three equi-angularly spaced teeth 19 on each edge but there may be more or fewer of the teeth, if desired. The teeth 19 project inwardly a distance corresponding to, or slightly less than, the overall thickness of the gasket at the ribs 6 and 10 on the inside and outside of the body 4 when the gasket is in a relaxed state. They are disposed to extend closely past the opposite ends of the body.

In the application of the pipe coupling for the connection together, for example, of two pipes 20, 21 of similar diameter, end-to-end, as shown in Figure 1, the adjacent end portions of the pipe are entered into the opposite ends of the tubular body 4 of the gasket until their end faces abut against the central rib 5. The coupling members 11, 12 may be removed from, or be loosely applied to, the gasket while the pipe ends are being entered into the gasket. When the pipe ends are in place the coupling members are clamped together to secure the connection by tightening the screws 17 in the nuts 18 at the flanges 14. As the screws are tightened the gasket is sealingly compressed annularly onto the pipes to seal the connection. The ears 8 are gripped between the flanges 14 to prevent the gasket lifting away from the pipes between the ends of the coupling members. Also as the screws are tightened and the gasket is compressed the teeth 19 of the coupling members are urged against and dig into the surfaces of the pipes 20, 21. They are able to pierce through any protective paint or other coating of the pipes to the bare metal of the pipes.

When the pipe coupling is fully secured to the pipes, therefore, not only is the connection sealed but equipotential bonding is established between the connected pipes through the coupling members, by the digging of the teeth 19 into the metal of the pipes.

Claims

1. A pipe coupling comprising an annular sealing gasket adapted to fit as a sleeve over adjacent end portions of metal pipes or conduits to be connected end-to-end, and a metal housing which encompasses, and is adapted to be clamped about, the gasket and which has inwardly-directed projections positioned to extend past axially opposite ends of the gasket and adapted to penetrate coated surfaces of the end portions of pipes or conduits to which the coupling is applied for use, as the housing is clamped about the gasket to secure the connection, thereby to provide equipotential bonding between the connected pipes or conduits through the housing.

2. A pipe coupling according to claim 1 wherein the projections are formed integrally with the housing.

3. A pipe coupling according to claim 1 or claim 2 wherein the projections are in the form generally of teeth or spikes.

4. A pipe coupling according to any preceding claim wherein the projections project inwardly a distance corresponding to, or slightly less than, the overall thickness of the gasket when the gasket is in a relaxed state.

5. A pipe coupling according to any preceding claim wherein there are two or more of the projections for each of the opposite ends of the gasket.

6. A pipe coupling according to any preceding claim wherein the housing comprises part-circular components which clamp together around the gasket.

7. A pipe coupling according to any of claims 1 to 5 wherein the housing comprises a single band which contains and substantially encircles the gasket.

8. A pipe coupling substantially as described herein with reference to the accompanying drawings.