GB2401919A

GB2401919A - A pipe joint for use in an amphibious vehicle

Info

Publication number: GB2401919A
Application number: GB0311501A
Authority: GB
Inventors: Timothy Richard Goodwin
Original assignee: Gibbs Technologies Ltd
Current assignee: Gibbs Technologies Ltd
Priority date: 2003-05-19
Filing date: 2003-05-19
Publication date: 2004-11-24
Anticipated expiration: 2023-05-19
Also published as: GB2401919B; GB0311501D0

Abstract

A flexible pipe joint connecting at least two pipes 2, 12 in an amphibious vehicle comprises inner sleeve 4, which may be tested to automotive safety standards, and outer sleeve 6, which may be tested to marine safety standards. Clips 8 may be provided at positions B to clamp both sleeves to both pipes, and also optionally at positions A and/or C. Annular spacers (14, 16 fig2), may be provided to support sleeve 6 around sleeve 4, so that sleeve 6 is not crushed around clips 8 on sleeve 4. Pipes 2, 12 may be made of aluminium, other metal, plastics, or composite materials. The joint may be used in an amphibious vehicle fuel feed pipe. With further spacers and seals, more than two pipes may be joined. The joint allows vibration damping, and movement of one vehicle module relative to another; avoiding sudden or fatigue-induced pipe fractures, or leakage through pipe fretting.

Description

I'd h 1_\ ' ' t' -

J 1 -

A PIPE JOINT FOR

USE IN AN AMPHIBIOUS VEHICLE

The present invention relates to a pipe joint and, in particular, to a pipe joint for use in an amphibious vehicle.

The nature of construction of an amphibious vehicle determines that pipelines, for example fuel lines, must pass through a number of bulkheads along their length. This poses two problems for the manufacturers of amphibious vehicles.

First, rigid pipes passing through bulkheads are subject to vibrations and distortions, caused by, for example, vehicle or passenger movements and differential thermal expansion. As a result, rigid pipes are susceptible to fatigue and stress, leading to potential failure of the pipelines. It is therefore desirable to reduce the fatigue and stress loads that rigid pipes are subjected to.

Second, due to the modular construction of an amphibious vehicle there is a tolerance build up between modules leadlog to inexact routing for rigid pipelines.

There is therefore a requirement for a flexible pipe joint which may be positioned at any location through which a rigid pipe passes, for example, a bulkhead, in order to isolate the rigid pipe from any vibrations or relative displacements associated with that location and to compensate for any misalignment of respective lengths of the rigid pipe(s).

As an alternative to a bulkhead fitting, one rigid pipe of the connection may be connected, for example, to a chassis rail or other fixed body component; whereas the other pipe may be fitted to a relatively movable component, such as an engine. In theory of course, an engine is fixed to the vehicle; but in practice, engine torque and the transmission reaction thereto will tend to swing the engine around its mountings. There will also be some movement of the engine relative to the body as the D73 UK O 2 - vehicle passes over bumps in the road; or in an amphibious vehicle, over rough water. Similarly, a fuel tank may be allowed to move within a vehicle, if this is regarded as a safer alternative than allowing it to be stressed and therefore potentially damaged.

Although joints according to the invention are described below with short gaps between two rigid pipes, for ease of illustration and understanding, other variations are possible.

For example, a substantial length of flexible pipe may be provided between the two rigid pipes; hence allowing not just fatigue and stress resistance, but also substantial differences in alignment and position between the two rigid pipes.

Furthermore, one or both of the two rigid pipes may be in the form of short stub pipes extending, for example, from fuel system components such as a fuel tank or fuel pump fitting, or other part of an engine fuel system; for example, a fuel filter housing, carburettor, or fuel injection system. Thus, the one or more rigid pipes in question may simply be provided on a component for connecting that component into a system.

Within an amphibious vehicle, flexible joints may be required along a number of different fluid carrying pipelines.

For example, flexible joints may be required in pipelines carrying brake fluid, clutch fluid, fuel, oil, or cooling water.

The use of a flexible joint in a fuel line of an amphibious vehicle presents a particular problem with regard to compliance with the requirements of both marine and automotive safety and environmental standards for fuel transfer.

Due to the fire risk inherent in the build up of fuel vapour in sealed compartments within a marine vehicle, the fire resistance requirements for flexible marine hose are stringent; and as a result, automotive flexible hose does not meet those requirements. However, marine hose has a greater permeability to fuel than automotive hose and consequently does not meet the automotive safety and environmental standards. By using both types of hoses in a concentric configuration; for example, an automotive hose clamped to the rigid fuel lines and a marine hose D73 UK O l 3 - clamped over the automotive hose; the requirements for both fire resistance and permeability are met. Furthermore, both requirements may be met by using an inner hose comprising an automotive fuel hose with greater resistance to permeability, sleeved with a fire resistant sleeve. Said resistant sleeve may be an automotive component, but it has been found that this combination meets both automotive and marine standards.

Accordingly, the present invention provides a flexible pipe joint connecting at least two pipes in an amphibious vehicle, the pipe joint comprising: a flexible inner sleeve adapted to fit over and provide a first connection between the ends of the at least two pipes; a flexible outer sleeve adapted to fit over both the flexible inner sleeve and the at least two pipes to provide a second connection between the ends of the at least two pipes, wherein: each of the flexible inner and outer sleeves provides a sealed connection between the at least two pipes.

Preferably, one or more of the at least two pipes is a rigid pipe.

Preferably, clamping means are provided to maintain the flexible outer and inner sleeves in sealing engagement with the at least two pipes.

Advantageously, the ends of the pipes are not in contact with each other. Indeed, the ends of at the at least two pipes to be joined may be distant from one another, so that the flexible pipe joint acts as a pipe run between the respective pipes.

Preferably, the inner sleeve complies with automotive safety and environmental standards.

Preferably, the outer sleeve complies with marine safety and environmental standards.

Alternatively, the combination of the inner sleeve and a D73 UK1 0 fire resistant outer sleeve complies with the marine safety and environmental standards.

Typically, the flexible outer sleeve encloses the flexible inner sleeve. Furthermore, the flexible outer sleeve may extend beyond the ends of the flexible inner sleeve in the longitudinal direction so as to fully contain the flexible inner sleeve.

Alternatively, the flexible inner sleeve may extend beyond lO the ends of the flexible outer sleeve in the longitudinal direction.

Preferably, the flexible outer sleeve is clamped over the flexible inner sleeve to a pipe at each end.

Preferably, the flexible inner sleeve is also clamped to a pipe at each end. More preferably, the flexible outer sleeve may also be clamped to the pipes at each outer end of the flexible outer sleeve.

In a second embodiment, an annular spacer is located substantially at each end of the flexible outer sleeve between the flexible outer sleeve and each of the rigid pipes. In this case, the spacer acts as a seal between the outer sleeve and each rigid pipe.

The pipe joint described may be used in an amphibious vehicle; particularly in a fuel feed pipe therefor.

Preferred embodiments of the pipe joint according to the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a cross sectional view of a first preferred embodiment of pipe joint according to the present invention; and Figure 2 is a cross sectional view of a pipe joint according to a second embodiment of the present invention.

Figure 1 shows a pipe joint 1 joining two rigid pipes 2, i 12. The rigid pipes 2, 12 are preferably aluminium, but may be of D73

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any suitable rigid material, e.g. any metal, metal alloy, plastic, polymer, composite or rubber material. The joint 1 comprises a flexible inner sleeve 4, preferably a length of automotive grade flexible hose, a flexible outer sleeve 6, preferably a length of marine grade flexible hose and clamping means 8, which may be any appropriate pipe clip, for example a Jubilee (RTM) clip.

The flexible inner sleeve 4 has an internal diameter JO corresponding substantially to the external diameter of the rigid pipes 2, 12, or such as to enable it to be positioned on the rigid pipes 2, 12 by virtue of the inherent elasticity of inner sleeve 4. The flexible outer sleeve 6 has an internal diameter that is large enough to enable it to be passed over the flexible inner sleeve 4 when in position on the rigid pipes 2, 12, again whether this is by simple geometry or achieved by the inherent elasticity of outer sleeve 6. Preferably the flexible outer sleeve 6 is longer than the inner flexible sleeve 4 so that when located over the flexible inner sleeve 4 the ends of the flexible outer sleeve 6 can be clamped directly to the rigid pipes 2, 12 such that the flexible inner sleeve 4 is entirely enclosed.

The rigid pipes 2 may have flared sections or ribs 10 to provide improved sealing with the more compliant flexible inner sleeve 4.

The flexible Joint 1 acts to isolate rigid pipes 2, 12 from any vibrations which would have passed into them, were such a joint 1 not provided, through rigid contact between a rigid pipe 2 and/or 12 and the structure of the amphibious vehicle. The; flexible joint 1 may be attached by any suitable means to the structure of the vehicle, for example by a bracket incorporated into the clamping means 8. Such brackets could include vibration absorbing means and/or positional adjustment(s), as is known in the automotive engineering art. Any vibrations passing from the vehicle to the rigid pipes 2, 12 will be damped as a result of the properties of the respective sleeve materials 4, 6 and the vibration absorbing mounts, where used. Similarly if one part of the amphibious vehicle moves relative to another part, e.g. the D73 UK] O 6 - engine moving relative to the body, the flexible joint can accommodate relative movement between pipes 2 and 12.

As a further measure to prevent vibrations continuing along the rigid pipes 2, 12, it is ensured that the ends of the rigid pipes 2, 12 joined by the flexible joint 1 are retained at a distance apart from each other so that no vibrations may be passed by contact between one pipe and the other.

In the embodiment shown in Figure 1, three clamping positions A, B. and C are shown. Position A ls towards the outside ends of inner sleeve 4; but necessarily not at the very outside ends of sleeve 4, to allow room for a further clip 8 to be fitted in the position B on the outer sleeve as shown in Figure 1. Position C is at the extreme ends of outer sleeve 6.

Marine fuel regulations require two clips to be fitted at each end of any flexible hose. These could be fitted as shown in Figure 1, at positions B and C. Alternatively, two clips could be provided at each position B. or at each position C. A more secure joint can be provided if required, by providing further clips 8 at positions A, outside inner sleeve 4 but within outer sleeve 6. Indeed, inner sleeve 4 may be clipped or otherwise fastened at respective positions A prior to being encased by outer sleeve 6. In such a case, a circlip, wire ring or other suitable fastening means may be employed which, when in place, does not protrude substantially beyond the outer surface of inner sleeve 4, thus not impinging on outer sleeve 6 when affixed. In theory, clips may be provided singly or in multiple at any combination of positions A, B. and/or C, so long as marine regulations are complied with; though clearly, clips must be applied to the inner sleeve before clipping the outer sleeve, for access reasons.

A particularly suitable form of clip is the Stepless (RTM) ear clamp with tolerance compensation, made by Oetiker (RTM), and obtainable from their UK office at Foundry Close, Horsham, Sussex RH13 SEX, United Kingdom. More than one clamp may be used if required, at each part of each joint, for example positions A, B. and C. D73 UK] O 7 - In the embodiment shown in Flqure 1 the rigid pipes 2, 12 are substantially the same diameter and are substantially axially aligned. It is envisaged that the pipe joint 1 of the present invention may be used to join pipes having different diameters and/or pipes having offset axial alignments; which may or may not be parallel. In such a case, extended lengths of the flexible pipe joint 1 may be utilised. Indeed, entire lengths of a pipe run may be effected using the flexible pipe joint 1 as an effective pipe, even to the extent that two components to be joined, each having small rigid pipe protrusions, may be joined entirely by the flexible pipe joint 1 according to the present invention.

It will be appreciated by those skilled in the automotive engineering art, that provision of clips 8 at positions A and B will tend to lead to distortion of outer sleeve 6, and may lead to difficulty in fitting the clip at position B. Accordingly, a second embodiment of the present invention shown in Figure 2 is designed to avoid this problem. Parts in common with the Figure 1; embodiment have the same reference numerals. In this case, however, the flexible pipe joint 11 comprises annular spacers 14 and 16 provided between respective sleeves 4 and 6, so that outer sleeve 6 does not have to be distorted around clamps 8 provided on inner sleeve 4. In this case, a fully secure joint may be provided with four clips 8 in total. However, the spacers 14 and 16 must be fitted to pipes 2, 12 before they are flared or ribbed at positions 10, or they must be sufficiently compliant to enable passage over the flare or rib 10 into position. Alternatively, the spacers 14, 16 may be formed of two or more portions or halves which are brought together in sealing engagement around the rigid pipe. It is also preferred that sealing arrangements are provided between spacers 14 and 16 and rigid pipes 2 and 12, within bores 18 and 20. This could be achieved, for example, by l use of sealants, adhesives, or O-ring seals. l Furthermore, it is envisaged that the pipe joint of the present invention may be used to join more than two pipes; for example, by providing a spacer corresponding to spacer 14 or 16 D73 UK'O 8 - within sleeve 4 or sleeve 6, and provided with two or more bores corresponding to bores 18 and 20 in spacers 14 and 16; thus allowing a plurality of smaller diameter pipes to be assembled into one end of the flexible joint. It will be appreciated that in this case, spacer 14 or 16 would have to have a corresponding plurality of bores; and that each smaller pipe would have to be sealed to the spacers, as described above. Alternatively, the inner and outer sleeves may be provided in the form of T. Y or H pieces as necessary to join a variety of pipe configurations.

Wherever the term "longitudinal direction" is used, this should be understood as meaning "along the direction of fluid flow in the pipe", even where the rigid pipes 2, 12 connected by; the joint are at an angle to each other.

Wherever the term "rigid pipe" is used, this should be understood as simply implying a degree of resistance to elastic deformation. D73 UK] O 9 -

Claims

1. A flexible pipe joint connecting at least two pipes in an amphibious vehicle, the pipe joint comprising: a flexible inner sleeve adapted to fit over and provide a first connection between the ends of the at least two pipes; a flexible outer sleeve adapted to fit over both the flexible inner sleeve and the at least two pipes to provide a second connection between the ends of the at least two pipes, wherein: each of the flexible inner and outer sleeves provides a sealed connection between the at least two pipes.

2. A flexible pipe joint as claimed in claim l wherein one or more of the at least two pipes is a rigid pipe.

3. A flexible pipe joint as claimed in claim l or claim 2 wherein the sealed connection between each of the inner and outer sleeves and the at least two pipes is achieved using a clamping; means.

4. A flexible pipe joint as claimed in any one of the preceding claims wherein the ends of the pipes are not in contact with each other.

5. A flexible pipe joint as claimed in any one of the preceding claims wherein the ends of the at least two pipes to be joined are distant from one another and the flexible pipe joint acts as a pipe run between the respective pipes to be joined.

6. A flexible pipe joint as claimed in any one of the preceding claims, wherein the inner sleeve complies with automotive safety and environmental standards.

7. A flexible pipe joint as claimed in any one of the preceding claims, wherein the outer sleeve complies with marine; safety and environmental standards. D73

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8. A flexible pipe joint as claimed in any one of the preceding claims, wherein the outer sleeve is a fire resistant sleeve.

S

9. A flexible pipe joint as claimed in any one of the preceding claims wherein the combination of the inner sleeve and the outer sleeve complies with both marine and automotive safety and environmental standards.

10. A flexible pipe joint as claimed in any one of the preceding claims, wherein the flexible outer sleeve encloses the flexible inner sleeve.

11. A flexible pipe joint as claimed in any one of the preceding claims, wherein the flexible outer sleeve extends beyond the ends of the flexible inner sleeve in the longitudinal direction so as to fully contain the flexible inner sleeve.

12. A flexible pipe joint as claimed in any of claims 1 to 9, wherein the flexible inner sleeve extends beyond the ends of the flexible outer sleeve in the longitudinal direction.

13. A flexible pipe joint as claimed in any one of the preceding claims, wherein the flexible outer sleeve is clamped to the flexible Inner sleeve at points corresponding to the ends of the flexible inner sleeve, so that both inner and outer sleeves are clamped to the pipes to be joined.

14. A flexible pipe joint as claimed in any one of the preceding claims, wherein the flexible inner sleeve is clamped to a pipe at each end.

15. A flexible pipe joint as claimed in any one of the preceding claims, wherein the flexible outer sleeve is clamped to the pipes at each end of the flexible outer sleeve.

16. A flexible pipe joint as claimed in any one of the preceding claims, further comprising an annular spacer located substantially at each end of the flexible outer sleeve between D73 UK] O the flexible outer sleeve and each of the pipes.

17. Use of a flexible pipe joint as claimed in any one of the preceding claims in an amphibious vehicle. s

18. Use of a flexible pipe joint as claimed in any one of the preceding claims in a fuel feed pipe in an amphibious vehicle.

19. A pipeline incorporating a flexible pipe joint as claimed in any one of claims 1 to 16.

20. A pipeline as claimed in claim 19, wherein the flexible pipe joint is longer than the pipes.

21. A flexible pipe joint substantially as hereinbefore described with reference to or as shown in the accompanying drawings.

22. An amphibious vehicle incorporating a flexible pipe joint substantially as hereinbefore described with reference to or as shown in the accompanying drawings. D73

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