GB2138527A

GB2138527A - Improvements in or relating to branched elastomeric hose

Info

Publication number: GB2138527A
Application number: GB08409830A
Authority: GB
Inventors: Richard Samuel Preston
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1983-04-18
Filing date: 1984-04-16
Publication date: 1984-10-24
Also published as: GB8409830D0; GB2138527B

Abstract

A branched elastomeric hose, such as used in a vehicle cooling system, comprises main and branch pipes 6, 7 secured together in fluid-tight manner by the combination of a substantially rigid connection device (1, Fig. 1) situated within said pipes and a band- like fillet 10 of moulded material external of the pipes around the region of their interconnection. The connection device comprises a tubular body which extends through the opening 9 in the wall of the main pipe and is secured within the branch pipe, and at one end of the tubular body an external flange which matches the curvature of the bore of the main pipe and contacts the main pipe around said opening. <IMAGE>

Description

SPECIFICATION Improvements in or relating to branched elastomeric hose This invention concerns improvements in or relating to branched elastomeric hose, i e hose comprising a main pipe having one or more branch pipes connected thereto.

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, for example the heating system. Usually the hose is made of rubber or other elastomeric material having an embedded textile reinforcement to withstand the operating conditions i e relatively high fluid temperatures and pressures.

The connection between the main pipe and the branch pipe conventionally is made 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 the embedded reinforcement to result in delamination of the branch pipe and ultimately failure of the hose. The end of the branch pipe protrudes into the bore of the main pipe and consequently restricts the flow of the working fluid through the main pipe. The hole cut in the wall of the main pipe must be at least equal to the outside diameter of the branch pipe which limits the range of main and branch pipe sizes that can be connected.

It is an object of the present invention to provide a branched elastomeric hose in which the above-discussed disadvantages are mitigated.

According to one aspect of the present invention there is provided a branched elastomeric hose comprising:- a 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 substantial rigid connection device located in the bore of said main and branch pipes and comprising a tubular body having an external diameter which locates in the bore of the branch pipe, and integral with the tubular body and at one end thereof an external flange having a curved profile which matches the curvature of the bore of the main pipe, said 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 and with the external flange in contact with the surface of the bore of the main pipe surrounding said opening, and externally of the main and branch pipes a band of elastomeric material moulded to interconnect the pipes and form a seal therebetween.

The band of elastomeric material preferably extends around the branch pipe over a length thereof substantially equal to, but preferably less than, that length of the tubular body portion of the connection device which projects from the main pipe. The band may be arranged also to extend completely around the main pipe but for a compact construction preferably does not extend wholly around said main pipe. In one preferred construction the band of elastomeric 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 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, circumferentially, as described in U K Patent Publication 2038437.

Preferably the device is moulded from plastics material, for example nylon 66 (coolant resistant type), although other materials may be used.

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 external flange of the connection device to the bore of the main pipe.

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.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings wherein Figure 1 is a side view of a connection device for use in a branched elastomeric hose according to the present invention; Figure 2 is a plan view of the connection device shown in Figure 1, and Figure 3 shows in section on the line Ill-Ill of Figure 1 a branched hose in accordance with the present invention and incorporating the connection device shown in Figures 1 and 2.

The connection device shown in Figures 1 and 2 of the accompanying drawings for connecting a branch pipe to a main pipe to form a branched hose is moulded from nylon 66 (coolant resistant type). Device 1 comprises a cylindrical hollow body 2 having an external, i e radially outwardly extending, annular flange 3 at one end and five external annular ribs 4 at axially spaced positions along the length of the body. Flange 3 is of curved profile for a purpose to be explained in more detail below.

Referring now to Figure 3 there is shown a branched hose 5 comprising a main pipe 6 and a branch pipe 7 connected by the above-described connection device 1. Each pipe 6, 7 is made of rubber having an embedded knitted rayon reinforcement sleeve 6a, 7a respectively. The main pipe 6 has an internal cylindrical bore 8 the curvature of which is the same as the curvature of the flange 3.

Connection of the pipes 6, 7 is carried out as follows. An annular opening 9 is formed in the wall of the main pipe 6, the opening having a diameter equal to the diameter d of the body 2 of the device 1, and the flanged end portion of the insert 1 is inserted through the opening 9 deformation of the wall of the main pipe 6 in the region of the opening 9 to change the shape of the opening may be required - and positioned with the flange 3 engaging the internal surface of the main pipe 6 around the opening 9 and the body 2 projecting outwards from the main pipe. The branch pipe 7 is pushed into the body 2 until the end surface engages the external surface of the main body around the opening. The ribs 4 engage the inner surface of the branch pipe 7 and are shaped to resist removal of the branch pipe.A band-like annular fillet 10 of uncured rubber is positioned around the joint and cured in a subsequent moulding operation to permanently connect the pipes 6, 7 and seal the joint.

It will be understood that by virtue of the use of connection device 1 and external fillet 10 the resultant branched hose 5 has a number of advantages. Thus the end of the branch pipe 7 abuts the outer surface of the main pipe 6 and does not protrude into the main pipe. The joint is therefore less susceptible to failure due to delamination of the branch pipe as compared with the prior art branched hose in which the branch pipe is inserted into an opening in the main pipe and the end surface exposed to the working fluid.

The contouring of the flange 3 to match the curvature of the bore of the main pipe enables the bore cross-section to be maintained in the subsequent moulding operation to permanently connect the pipes and seal the joint by means of the fillet 10. The effect of the joint on the flow of the working fluid through the hose is therefore less than in the known branched hose in which the branch pipe protrudes into the main pipe. The size of the opening 9 to receive the body 2 may be less than that required to receive the branch pipe, thereby increasing the joint strength and allowing a wider range of main and branch pipe sizes to be connected.

The tensile strength of the joint is improved by virtue of the flange 3 engaging the inner surface of the main pipe 6 and the ribs 4 engaging the inner surface of the branch pipe 7 without requiring any additional bonding system.

Other advantages of using the device 1 and band-like fillet 10 to connect main and branch pipes are that the fatigue life of the joint is improved and the branch pipe may be connected at angles other than 900 by angling the flange 3 relative to the longitudinal axis of the body 2 so that the latter projects through the opening in the main pipe at the desired angle.

Claims

1. A branched elastomeric hose comprising:- a 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 substantial rigid connection device located in the bore of said main and branch pipes and comprising a tubular body having an external diameter which locates in the bore of the branch pipe, and integral with the tubular body and at one end thereof an external flange having a curved profile which matches the curvature of the bore of the main pipe, said 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 and with the external flange in contact with the surface of the bore of the main pipe surrounding said opening, and externally of the main and branch pipes a band of elastomeric material moulded to interconnect the pipes and form a seal therebetween.

2. A branched elastomeric hose according to claim 1 wherein said band of elastomeric material extends around the branch pipe over a length thereof substantially equal to the length of the tubular body projecting from the main pipe.

3. A branched elastomeric hose according to claim 1 or claim 2 wherein the band of elastomeric material does not extend wholly around the main pipe.

4. A branched hose according to any one of the preceding claims wherein at least one of the main and branch pipes has an embedded reinforcement comprising discontinuous fibres.

5. A branched hose according to any one of the preceding claims wherein the external surface of the tubular body is provided with means to grip the bore of the branch pipe.

6. A branched hose according to claim 5 wherein said means comprises one or more annular ribs.

7. A branched hose according to any one of the preceding claims wherein an adhesive secures or assists in securing the tubular body in position relative to the branch pipe.

8. A branched hose according to any one of the preceding claims wherein the flange is angled relative to the longitudinal axis of the tubular body such that the branch pipe lies at an acute angle relative to the main pipe.

9. A branched elastomeric hose constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.