IMPROVEMENTS IN OR RELATING TO BRANCHED HOSE

Abstract: A branched hose is constructed using a substantially rigid connection device (10) having at one end a flange (12) for in­ sertion through an opening in a main pipe (16) to bear against the internal surface of the main pipe, and an annular abutment (14) spaced from the flange (12) and dimensioned so as to re­ sist any tendency for the connection device to fall into the main pipe during assembly when a branch hose (15) is force fitted over a portion of the connection device remote from the flange. The assemply so formed is surrounded by mouldable (20) ma­ terial which is caused to occupy any spaces between the abut­ ment (14) and the main and branch pipes (15, 16) and then cured.

Description: IMPROVEMENTS IN OR RELATING TO BRANCHED HOSE This invention is directed to improvements in or relating to branched hose, i.e. hose comprising a main pipe having one or more branch pipes connected thereto, and to a method of manufacture of branched hose. Branched hose frequently is used in vehicle cooling systems to connect the main fluid circuit including the radiator and engine cylinder block to secondary fluid circuits such as the heating system. Usually the hose is flexible and made of rubber or other elastomeric material having an embedded textile reinforcement to withstand the operating conditions, typically relatively high fluid temperatures and pressures. The connection between the flexible main pipe and the branch pipe conventionally is achieved by cutting a hole in the wall of the main pipe, inserting the end of the branch pipe into the hole and securing the two together by means of a moulding operation. This method has several disadvantages. Thus the end of the branch pipe is exposed to the working fluid which could possibly enter and work its way progressively along any embedded reinforcement to result in delamination of the branch pipe and ultimately failure of the hose. The end of the branch pipe usually protrudes into the bore of the main pipe and consequently thereby restricts the flow of the working fluid through the main pipe. It is an object of the present invention to provide a branched hose and method of manufacture thereof in which the aforediscussed disadvantages are mitigated or overcome. According to one aspect of the present invention there is provided a branched hose comprising: a flexible main pipe having an opening in the wall thereof; a branch pipe the bore of which is in communication with the bore of the main pipe via said opening; a substantially rigid connection device located in the bore of the main and branch pipes and comprising a tubular body having at least in part an external diameter which locates in the bore of the branch pipe, said tubular body having integral therewith and at one end thereof a flange which extends outwardly from the bore of the tubular body, and an- abutment also formed integral with the tubular body and axially spaced from the flange, the abutment being dimensioned normally to resist entry through the opening of the main pipe during insertion of the connection device into the ain pipe; ; said connection device being positioned in said main and branch pipes with the tubular body extending through said opening and secured in position relative to the branch pipe with the flange in contact with the surface of the bore of the main pipe surrounding said opening and the abutment disposed external of the main pipe between the main pipe and branch pipe, and externally of the connection device a band of material moulded to interconnect the pipes and form a fluid seal therebetween. According to another aspect of the present invention a method for the manufacture of a branched hose comprises:- providing a flexible main pipe having an opening in the wall thereof; providing a substantially rigid connection device comprising a tubular body having at least in part an an external diameter for location in the bore of a branch pipe, said tubular body having integral therewith and at one end thereof a flange which extends outwardly from the bore of the tubular body, and an abutment also formed integral with the tubular body and axially spaced from the flange, the abutment being dimensioned normally to resist entry through the opening of the main pipe during insertion of the connection device into the main pipe; ; inserting the connection device into the main pipe such that the wall of the main pipe lies between the flange and abutment with the flange positioned within the main pipe for contact with the bore thereof; attaching a branch pipe to the tubular body of the connection device to surround only that part of the connection device which lies to that side of the abutment remote from the flange; providing mouldable material externally of the connection device, and moulding said mouldable material to form a band which interconnects the pipes and forms a fluid seal therebetween. The abutment, which preferably is of a substantially annular form, is to serve to prevent the connection device from falling into the main pipe during assembly and therefore it is required to extend outwardly from the tubular body so as to be larger than the opening in the main pipe. It is envisaged, however; that normally it need not extend outwardly from the tubular body as far as the flange extends from the tubular body. Preferably the branch pipe seats against the abutment which may be contoured so that the surface facing the main pipe has a curvature similar to that of the main pipe. Thus the confronting ends of the wain and branch pipes are separated by the abutment and the risk of working fluid wicking into the branch pipe is thereby minimized. Usually, but not necessarily, the abutment will be of a kind which extends continuously around the tubular body; particularly where the abutment is of an annular but discontinuous fo#rm it is preferable that the mouldable material be caused to fully occupy the spaces between confronting edge surfaces of the main and branch pipes at which pipe reinforcement is exposed. The moulded material may be elastomeric and preferably extends around the branch pipe over a length thereof substantially equal to, but preferably less than, that distance which the tubular body portion of the connection device projects into the branch pipe. The band may be arranged also to extend completely around the main pipe but for a compact construction preferably does not extend completely around said main pipe. In one preferred construction the band of material extends around no more than approximately half the circumference of the main pipe as considered in cross-section of the main pipe in the region of the opening therein. The moulded material may be a polymeric material, preferably an elastomeric material, of a kind having embedded therein a reinforcement of a plurality of staple fibres whereby the band is rendered substantially inelastic. The reinforcement fibres may be fibres of a textile material such as nylon, polyester, cotton, rayon or cellulose, but fibres of other materials such as Kevlar or glass may be used. The individual fibres may have a relatively short length, for example in the order of 10 mm or less, and preferably are treated with an appropriate adhesion promoting agent to facilitate adhesion to the embedding polymeric material. Preferably the fibres have a length in the range 3 to 5 mm and a diameter in the range 20 to 30 microns. The fibres may be generally randomly orientated within the polymeric material or may be preferentially orientated, for example in a circumferential direction of a surrounded portion of the branch hose. Moulding of the mouldable material preferably is undertaken in a manner which causes the material to fully penetrate and occupy any space between the main hose and abutment and also any space between the branch hose and abutment. The flexible main pipe typically will be of elastomeric material and the branch pipe typically flexible and preferably also of elastomeric material. The main and/or branch pipe may include an embedded reinforcement which may comprise one or more layers of textile material, for example a knitted rayon or polyester sleeve or a ply woven fabric. Alternatively the reinforcement may comprise discontinuous fibres which #may be randomly distributed or orientated in a specific direction, e.g. axially, radially, or circumferentially as described in U K Patent Publication 2038437. Preferably the connection device is moulded in one piece and preferably is formed from settable plastics material, for example nylon 66 (coolant resistant type), although other materials such as thermoplastics plastics may be used provided that they are resistant to the conditions pertaining to the use of the product. For example the material should be resistant to solvent attack when used for automotive applications. Preferably the connection device is sized so that the diameter of the portion of the tubular body between the flange and abutment is the same as that of the opening in the main pipe which is therefore not distorted in use, i.e. is about the same size as it would be in the absence of the connection device. The size of the flange will be such that it may be inserted through the opening in the main pipe by distorting the opening. The flange may be angled relative to the longitudinal axis of the body to provide any desired joint angle between the main and branch pipes. Preferably the external surface of the body is provided with means, for example one or more annular ribs, to grip the bore of the branch pipe. Additionally or alternatively an adhesive may secure or assist in securing the tubular body in position relative to the branch pipe. Optionally adhesive may be provided to secure the flange of the connection device to the bore of the main pipe. One embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings wherein: Figure 1 shows in cross-section part of a branched elastomeric hose according to the present invention; Figure 2 is a side view of a connection device for use in a branched elastomeric hose according to the present invention; Figure 3 is another side view of the connection device shown in Figure 2 in a direction perpendicular to that of the view of Figure 2, and Figure 4 is a plan view of the connection device shown in Figures 2 and 3. Referring to Figures 1 to 4, a connection device 10 moulded from nylon 66 (coolant resistant type) comprises a cylindrical hollow body 11 having an annular outwardly extending flange 12 at one end. A thickened annular region 13 (see Figure 1) lies between the distal end of the flange and the tubular body 11. In a region generally remote from the flange the tubular body 11 is provided with four external annular ribs 9 of a serrated configuration arranged for retention of a branch pipe 15 force fitted over the tubular body. Positioned between the annular ribs 9 and the thickened annular region 13 is an annular abutment 14 which is spaced from the outwardly extending flange 12 by a distance greater than the wall thickness of a main pipe 16 so that it is not in contact with the main pipe when the bore thereof is contacted by e flange 12. The annular abutment 14 is contoured so that e surface of the abutment facing the flange 12 matches the curvature of the outer surface of the main pipe 16. The external diameter of the annular abutment 14 is selected so as to be sufficient both to provide an abutment against which the branch hose 15 may be force fitted over the serrations 9 and also sufficient to ensure that the abutment 14 and portion of the tubular body remote from the flange 12 will not enter the bore of the main pipe during assembly. As described in the specification of our co-pending application claiming priority from U K Patent Application No. 8431736, the annular flange 12 has a generally inwardly facing surface 17 the curvature of which conforms generally to the curvature of the bore of the main pipe 16. However, the other, generally outwardly facing surface 18, of the flange which faces generally towards the annular abutment 14 preferably is angled such that the angle between the surface 18 and the longitudinal axis of the tubular body is less than the angle between the inwardly facing surface 17 and the longitudinal axis for a reason which is explained below. To manufacture the branched hose assembly shown in Figure 1 an annular opening 19 is formed in the wall of the main pipe, the diameter of the annular opening being substantially the same as that of the external diameter of that portion of the tubular body between the abutment 14 and flange 12. The flange 12 is inserted through the opening 19 by deforming the wall of the main pipe 16. A branch pipe 15 is then pushed onto the body 11 until the end of the pipe abuts the annular abutment 14. During this operation the annular abutment serves to resist any tendency for the connection device to fall into the main pipe 16. Subsequent to fitting of the branch hose to the tubular body 11 the connection device is pulled slightly away from the main hose such that the outer surface 18 of the flange 12 contacts the inner surface of the main pipe and causes distortion of the marginal portion of the opening 19. In consequence the cut edge of the main pipe defining the opening is slightly upturned to face in general towards the abutment 14. With the abutment 14 maintained slightly spaced from the main pipe and the main pipe in contact with said surface 18 a band 20 of mouldable uncured rubber is positioned around the joint and subject to a moulding operation whereby it is caused to fill all spaces between the annular abutment 14 and the main and branch pipes and subsequently is cured thereby to intereconnect the main and branch pipes and form a fluid seal therebetween. The use of an annular abutment 14 a surface of which conforms generally to the curvature of the outer surface of the main pipe results in the assembled condition in a substantially uniform spacing between the abutment and main pipe, and thus subsequent to application of the mouldable material 20 there is a uniform filling of that mouldable material between the main pipe and abutment. By virtue of the use of a connection device of a kind having an abutment the resultant branch hose assembly of the invention has a number of advantages. Thus, the abutment prevents the connection device falling into a main pipe. Where the branch pipe abuts the abutment, and particularly where the abutment is of an annular form, the abutment assists in ensuring that the branch pipe is protected from attack by working fluid wicking from the main pipe. A further advantage which may be attained is that of increased burst pressure for the joint.

Claims: CLAIMS: 1. A branched hose comprising a flexible main pipe (16) having an opening (19) in the wall thereof, a branch pipe (fizz the )ore (af which is in communication with the bore of the main pipe (16) via said opening, a substantially rigid connection device (10) located in the bore of the main and branch pipes and comprising a tubular body (11) having at least in part an external diameter which locates in the bore of the branch pipe, said tubular body (11) having integral therewith and at one end thereof a flange (12) which extends outwardly from the bore of the tubular body, characterised in that an abutment (14) is formed integral with the tubular body (11) and axially spaced from the flange (12), the abutment (11) being dimensioned normally to resist entry through the opening (19) of the main pipe (16) during assembly of the connection device into the main pipe (16),said connection device being positioned in said main and branch pipes with the tubular body (11) extending through said opening (19) and secured in position relative to the branch pipe with the flange (12) in contact with the surface of the bore of the main pipe (16) surrounding said opening and the abutment (14) disposed external of the main pipe between the main pipe and branch pipe (15), and externally of the connection device a band (20) of material moulded to interconnect the pipes and form a fluid seal therebetween. 2. A branched hose according to claim 1 characterised in that the branch pipe (15) abuts against the abutment (14). 3. A branched hose according to claim 1 or claim 2 characterised in that the abutment (14) is of an annular form. 4. A branched hose according to any one of claims 1 to 3 characterised in that the abutment is of an annular but peripherally discontinuous form. 5. A branched hose according to any one of the preceding claims characterised in that the abutment (14) extends outwardly from the tubular body (11) less than the flange (12) extends outwardly from the tubular body. 6. A branched hose according to any one of the preceding claims characterised in that the moulded material (20) extends around the branch pipe (15) over a length thereof substantially equal to the length for which the tubular body (11) projects into the branch pipe. 7. A branched hose according to any one of the preceding claims characterised in that the moulded material (20) comprises a fibre reinforced polymeric material. 8. A branched hose according to any one of the preceding claims characterised in that an adhesive secures or assizes in securing the tubular body (11) in position relative to the branch pipe (15). 9. A method for the manufacture of a branched haste characterised in that it comprises : - providing a flexible main pipe (16) having an opening (19) in the wall thereof; providing a substantially rigid connection device (10) comprising a tubular body (11) having at least in part an external diameter for location in the bore of a branch pipe (15), said tubular body (11) having integral therewith and at one end thereof a flange (12) which extends outwardly from the bore of the tubular body (11) and an abutment (14) also formed integral with the tubular body, and axially spaced from the flange (12), the abutment (14) being dimensioned normally to resist entry through the opening (19) of the main pipe (16) during insertion of the connection device into the main pipe inserting the connection device (10) into the main pipe (16) suchy that the wall of the main pipe lies between the flange (12) and abutment (14) with the flange positioned within the main pipe for contact with the bore thereof; attaching a branch pipe (15) to the tubular body (11) to surround only that part of the connection device which lies to that side of the abutment remote from the flange; providing mouldable material externally of the connection device, and moulding said mouldable material to form a band (20) which interconnects the pipes and forms a fluid seal therebetween. 10. A method according to claim 9 characterised in that the flange (12) is maintained in contact with the bore of the main pipe (16) surrounding said opening (19) during moulding of the mouldable material.

Inventors: BUNYAGA, SEMAMBO
Applicants: DUNLOP LIMITED
Application year: 1985
Main classification: F16L31
IPC codes: F16L31, F16L47, F16L41