GB2159223A

GB2159223A - Pipe coupling

Info

Publication number: GB2159223A
Application number: GB08504384A
Authority: GB
Inventors: Giorgio Ravotti
Original assignee: Gilardini SpA
Current assignee: Marelli Europe SpA
Priority date: 1984-05-23
Filing date: 1985-02-20
Publication date: 1985-11-27
Also published as: ES285890U; GB8504384D0; DE3506697A1; FR2564939A1; IT8453420V0; NO850665L; SE8500802D0; SE8500802L; FR2564939B3; ES285890Y

Abstract

A fitting for connecting a household appliance (2) to a gas supply, e.g. a standard L.P.G. cylinder or gas mains outlet pipe, on which an undulated metal pipe (9), is connected integral in gastight manner at both ends to a tubular connecting member (8) designed to receive a tubular insert (5, 6) integral with the said appliance or with the said gas supply; the said tubular connecting member (5) defining internally a variable-volume chamber (24) housing a tubular member (25) made of elastically- deformable material, designed to receive the said insert (5) and having an undeformed inside diameter at least equal to the outside diameter of the insert (5). <IMAGE>

Description

SPECIFICATION Metal fitting for connecting a household appliance to a gas supply The present invention relates to a metal fitting for connecting a household appliance to a gas supply.

Household appliances, such as cooking ranges, are generally connected to the gas mains or an L.P.G. cylinder over a reinforced rubber pipe, the ends of which are forced over respective tubular inserts constituting, at one end, the outlet on the said mains or on the said cylinder reducer and, at the other, the inlet on the said household appliance.

The outer surface of each of the said tubular inserts is usually provided with annular, serrated ribs engaging in watertight manner with the inner surface on the said pipe, the end of the latter usually being tightened on to the tubular insert by means of an external clamp which performs a dual function, firstly, of preventing any leakage of gas and, secondly, of preventing the said pipe from being detached accidentally from its insert.

Connecting pipes of the aforementioned type involve a number of drawbacks owing to the fact that the rubber from which they are made gradually undergoes a process of natural ageing, aggravated by contact with the gas, which results, in a relatively short time, in hardening of the pipes themselves. Such hardening is especially dangerous on the said pipe sections next to the ends of the said tubular inserts. Not only are these pipe sections subjected to tension and contact with the gas, but are also the only ones subjected to accidental tensile and bending stress when the appliance is moved, e.g. for cleaning purposes, thus resulting in the connecting pipe being stretched.

The aim of the present invention is to provide a fitting, for connecting a household appliance to a gas supply, involving practically none of the aforementioned drawbacks, i.e. one subject to essentially no natural ageing and, once assembled, having no highstrain points capable of producing breakage or subsequent gas leakage.

With this aim in view, the present invention relates to a metal fitting for connecting a household appliance to a gas supply, characterised by the fact that it comprises a pipe and a tubular connecting member connected integral in gastight manner to each end of the said pipe for connecting the latter to a tubular end insert integral with the said appliance or with the said gas supply; each said tubular connecting member defining a a variable-volume inner chamber and comprising a tubular body of elastically-deformable material housed inside the said chamber and having an undeformed inside diameter at least equal to the outside diameter of the respective said tubular insert.

A non-limiting arrangement of the present invention will now be described with reference to the attached drawings in which: Figure 1 shows a view in perspective of a household appliance connected to a gas supply over a fitting according to the present invention; Figure 2 shows an exploded view and partial axial section of the Fig. 1 fitting.

Number 1 on the attached drawings indicates a fitting for connecting a household appliance 2, in the example shown, a gas cooking range, to a gas supply 3 consisting, in the example shown, of a gas mains end pipe 4.

As shown in Fig. 1, the free end of pipe 4 is connected to an axial tubular insert 5, whereas an identical tubular insert 6 is connected to the inlet on household appliance 2.

Tubular inserts 5 and 6, hereinafter referred to as "pipe holders", each present a cylindrical axial appendix 7 usually provided with annular, serrated outer ribs (not shown). Each appendix 7 is locked axially in gastight manner inside a respective tubular connecting member 8 at each end of fitting 1.

Tubular members 8 are connected together by an undulated metal pipe 9 and each comprise two essentially-cup-shaped bodies 10 and 11 with their concave sides facing each other. Bodies 10 and 11 have respective cylindrical side walls 12 and 13 having respective bottom through axial holes 14 and 15.

In more detail, wall 12 on body 10 has a cylindrical inner surface with a thread 16. and is blended with hole 14 by an outwardlytapered, truncated-cone surface 17, whereas wall 13 on body 11 has a cylindrical outer surface with a thread 18 engaged in adjustable manner by thread 16. and is bordered internally by a truncated-cone surface 19.

At the base of wall 13, body 11 is provided with a hexagonal-edged, outer annular flange 20 the outer contour of which is essentially identical with that of hexagonal surface 21 externally bordering wall 12 on body 10.

Body 11 also comprises a tubular appendix 22 extending from flange 20, coaxial with hole 15 and wall 13 and on the opposite side to the latter. Tubular appendix 22 is connected in gastight manner to a respective end of pipe 9, in the example shown in Fig. 2, by means of welding. Nevertheless, by appropriately shaping the ends of appendix 22 and, possibly, also of pipe 9, appendix 22 and pipe 9 may easily be connected, for example, by seaming.

Pipe 9 is preferably made of thin stainless steel sheet and is undulated so as to form a series of annular ribs 23 which may easily be set axially by exerting pull or compression so as to vary the length of fitting 1 within a given range.

When connected together, bodies 10 and 11 define an inner chamber 24 communicating, on one side, externally via hole 14 and, on the other, with pipe 9 via hole 15, and the volume of which may be varied by screwing body 10 more or less on to body 11.

Chamber 24 houses a tubular body 25 of elastically-deformabie elastomer, a cylindrical wall 26 of which presents two truncated-cone outer end surfaces 27 and 28, similar to and engaging respectively with surfaces 17 and 19, and two annular end surfaces 29 and 30, and is run through by a hole 31 coaxial with holes 14 and 15 and having, prior to deformation of body 25, a diameter at least equal to the outside diameter of respective appendix 7.

Fitting 1 is connected to pipe holders 5 and 6 extremely quickly by unscrewing bodies 10 off bodies 11 by such an amount that the length of respective chambers 24 is at least equal to that of respective bodies 25, thus enabling hole 31 on each body 25 to receive appendix 7 on respective pipe holder 5 or 6 smoothly.

Having inserted the said appendix 7, each body 10 is gradually screwed on to respective body 11 in such a manner as to reduce the volume of respective chamber 24 and compress respective body 25 axially. As any radial outward deformation of body 25, as a result of the said axial compression, is prevented by wall 26 contacting wall 12, body 25 is deformed inwardly, consequently reducing the section of hole 31.

By screwing each body 10 further on to respective body 11, one single operation, performable by anyone using ordinary everyday tools, produces two effects, i.e. that of causing the surface of hole 31 to adhere in gastight manner to the outer surface of respective appendix 7, and that of compressing body 25 between respective appendix 7 and respective wall 12, so as to lock the said appendix 7 axially inside respective tubular connecting member 8. With regard to bodies 25, which act as both mechanical connecting and sealing members, it should be pointed out that wall 26 is gripped between respective appendix 7 and the inner surface of chamber 24. Consequently, bodies 25 come into contact with the gas flowing through fitting 1 solely on annular surfaces 29 and 30, the size of which is relatively small and such as essentially to eliminate any danger of bodies 25 breaking as a result of the elastomer they are made of coming into contact with the gas.

Claims

1. Metal fittng for connecting a household appliance to a gas supply, characterised by the fact that it comprises a pipe and a tubular connecting member connected integral in gastight manner to each end of the said pipe for connecting the latter to a tubular end insert integral with the said appliance or with the said gas supply; each said tubular connecting member defining a variable-volume inner chamber and comprising a tubular body of elastically-deformable material housed inside the said chamber and having an underformed inside diameter at least equal to the outside diameter of the respective said tubular insert.

2. Fitting according to Claim 1, characterised by the fact that both the said chamber and the said tubular body are cylindrical in shape with coaxial, truncated-cone ends; the said chamber being of axially-deformable volume.

3. Fitting according to Claim 2, characterised by the fact that each tubular connecting member comprises two cup-shaped bodies arranged with their concave sides facing each other, so as to define the said chamber, and connected together in adjustable manner by means of a screw, so as to regulate the volume of the said chamber; the said two cupshaped bodies having respective bottom axial holes coaxial with the said tubular body and communicating both externally and with the said pipe.

4. Fitting according to any one of the foregoing Claims, characterised by the fact that the said pipe is an undulated metal pipe that may be set for adjusting the length of the fitting within a given range.

5. A fitting for connecting a household appliance to a gas supply substantially as hereinbefore described with reference to the accompanying drawings.

6. Method of connecting a household appliance to a gas supply substantially as hereinbefore described with reference to the accompanying drawings.