WO2000001565A1

WO2000001565A1 - Air cushion vehicle

Info

Publication number: WO2000001565A1
Application number: PCT/NZ1999/000099
Authority: WO
Inventors: Stephen John Preest
Original assignee: Pacific Hovercraft New Zealand Limited
Priority date: 1998-07-01
Filing date: 1999-07-01
Publication date: 2000-01-13
Also published as: AU4806899A

Abstract

An air cushion vehicle (1) includes a substantially rigid hull structure (2) and an air cushion skirt (6). The air cushion skirt (6) extends substantially about the periphery of the hull structure (2) and is attached to the hull structure (2) at or towards the periphery (14) of the hull structure (2). Part of the air cushion skirt (6) comprises an inflatable bag portion (7). The air cushion vehicle (1) also includes an air supply means to provide a source of pressurised air to inflate the air cushion skirt (33) apart from the inflatable bag portion (7). Instead, the inflatable bag portion (7) is sealed such as to maintain an inflated configuration on inflation thereof, independently of the operation of the air supply means.

Description

ATR CIJSHTON VEHICLE Field of the Invention

This invention relates to air cushion vehicles and to air cushion skirts used on such vehicles. In particular, although not exclusively the invention relates to a single or double occupant pleasure craft.

Background to the Invention

Hovercraft particularly as smaller recreational and pleasure craft have not become popular partly because the operational characteristics of the craft can present problems to a driver not experienced and skilled. One of the problems is that incorrect operation can cause the air cushion containing skirt to collapse or "tuck under" causing the vehicle to contact the surface in what is described as ploughing. This can abruptly change the momentum of the vehicle causing problems for the occupants. Thus with existing hovercraft a relatively high level of skill is required for satisfactory and safe operation.

It is an object of the present invention to provide an air cushion vehicle which will be more user friendly and which will have other operational characteristics that are advantageous.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided an air cushion vehicle including: a substantially rigid hull structure; an air cushion skirt extending substantially about the periphery of the hull structure and attached to the hull structure at or towards the periphery of the hull structure, wherein a part of the air cushion skirt comprises an inflatable bag portion; and an air supply means to provide a source of pressurised air to inflate the air cushion skirt apart from the inflatable bag portion; wherein the inflatable bag portion is sealed such as to maintain an inflated configuration on inflation thereof, independently of the operation of the air supply means.

Preferably the inflatable bag portion includes one or more air inlet valves. Whilst it is intended that the inflatable bag portion would normally remain permanently inflated between each individual usage of the vehicle, the vehicle might be initially supplied with the bag portion deflated to reduce size and hence transport costs. Furthermore, the bag portion might be deflated for regular servicing or maintenance. The bag portion may be inflated by simply connecting the one or more air inlet valves to a source of pressurised air eg. from an air hose. The vehicle might even include an auxiliary attachment to selectively connect the air supply means to the bag portion.

Desirably, the inflatable bag portion is attached to the hull structure with a substantial part of the bag portion disposed outboard of the hull structure so as to provide a fender around the vehicle.

In a most preferred form of the invention, the inflatable bag portion comprises an outer bag portion and an inner bladder means. The inner bladder means might be constructed from air impermeable vinyl sheeting. Most desirably, the inflatable bag portion is adapted to be inflated to a pressure up to 10 times the pressure within the flexible skirt segments when they are inflated by the air supply means.

The air cushion vehicle is most desirably in the form of a pleasure craft for a maximum of one or two people.

In accordance with a second aspect of the present invention, there is provided, an air cushion skirt for an air cushion vehicle adapted to be attached to a substantially rigid hull structure of the air cushion vehicle, wherein part of the air cushion skirt comprises an inflatable bag portion comprising: an outer bag portion and an inner inflatable bladder means.

The air cushion skirt may have any of the features described above in connection with the first aspect of the present invention. For example, the air cushion skirt may include dependently disposed flexible skirt segments each having air inlet means wherein the flexible skirt segments are fluidly unconnected to the inflatable bladder means.

In accordance with a third aspect of the present invention, there is provided, an air cushion vehicle including a substantially rigid hull structure and an air cushion skirt extending substantially about the periphery of the hull structure and attached to the hull structure at or towards the periphery of the hull structure, wherein part of the air cushion skirt comprises an inflatable bag portion comprising an outer bag portion and an inner inflatable bladder means.

Preferably, the air cushion vehicle includes dependently disposed flexible skirt segments each having air inlet means wherein the flexible skirt segments are fluidly unconnected to the inflatable bladder means. In a most preferred form of the invention, the inflatable bag portion is attached to the hull structure with a substantial portion of the bag portion disposed outboard of the hull structure.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

Brief Description of the Drawing(s)

In order that the invention may be more fully understood, one preferred form of the invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a perspective view of an air cushion vehicle in accordance with a preferred form of the present invention; and

Figure 2 is which is a diagrammatic section through an air cushion skirt of the air cushion vehicle illustrated in Figure 1.

Preferred Embodiment of the Invention

As shown in Figure 1 , the air cushion vehicle 1 is in the form of a one or two man pleasure craft . The air cushion vehicle 1 has a hull 2 formed as a substantially rigid structure from fibreglass or any other suitable material. The hull 2 is shaped as shown to include a suitably shaped bow portion 22, a recess 24 for seating the operator and a stern portion having an integrally mounded fan guard 26 for a propulsion fan 28 driven by an on-board motor (not shown). Additionally, the moulded hull 2 includes air intake regions 29 towards the stern. A steering wheel 32 and other appropriate controls are provided for operator control of the craft.

An air cushion skirt 6 extends about the periphery of the craft 1. The air cushion skirt has an inflatable bag portion 7 constructed of flexible material and a plurality of flexible skirt segments 33 dependently disposed relative to the bag portion 7.

As shown further in Figure 2, the air cushion skirt 6 incorporates an outer bag portion 8 which is secured to the craft at the outer edge of the hull as indicated by numeral 14. Most of the bag portion is outboard of the hull as shown. An internal web 9 is attached to a portion 15 of the hull as shown which is lower and inboard compared to the attachment point 14. The internal web 9 forms a lower boundary of the chamber 5 which is otherwise defined by the side wall of the hull and a side of the inflatable bag portion 7. As shown, the skirt segments 33 are defined by a series of spaced side walls 11. The outer end walls of the segments 33 are each inclined at about 45 degrees whereas the inner ends are open so that air flowing into the segments 33 will provide an air cushion in the space 40 below the hull and above the water surface. Airflow apertures 10 are provided through the web 9 to deliver air into the skirt segments 11 in accordance with known technology. See for example US Patent No. 4 131 175, the contents of which are hereby incorporated herein by reference.

As shown in Figure 2, the hull 2 includes an air flow chamber 3 which is supplied with a flow of air by the motor and fan in the conventional manner. This hovercraft technology is well known and accordingly is not described here in detail. The air in the chamber 3 passes through an air flow aperture 4 to enter the air flow chamber 5 defined in part by the cushion skirt 6.

A bladder means 12 is located within the outer bag portion 8. One or more valve means 13 is provided to enable the bladder to be permanently inflated to a relatively high pressure. It would be possible for more than one bladder each inflated by a separate valve to make up the bladder means if this was desired for safety reasons to ensure that the puncture would not cause a major change in the operational characteristics of the craft. Likewise, the outer bag portion may have individual compartments. Any satisfactory bladder means within the outer bag portion 8 to provide the required inflation would be acceptable within the bounds of the present invention.

The bladder may be formed from any suitable air impermeable material including suitable rubber bladders but we have in the preferred form used an air impermeable vinyl sheeting formed to the required bladder shape. The tube within which the bladder is located is formed from a material which is abrasion resistant and again in the preferred form of the invention a suitable vinyl sheet is acceptable.

It will be seen that a substantial portion of the tube with the inflated bladder forms a fender around the periphery of the craft and also provides for additional buoyancy for the craft should the air cushion skirt for any reason collapse.

It will therefore be appreciated that an cushion vehicle with the skirt according to the present invention will have a number of advantages. Firstly it is very stable minimising the possibility of ploughing during operation. This means it is less operator dependent for giving abnormal operational actions and thus much more suited for recreational or pleasure use with an inexperienced operator.

The highly inflated tube is also a means of providing additional buoyancy when the craft is over water. Further the bag portion 7, because of its location, provides a fendering action in the event of the craft coming against another obstacle.

Finally the air cushion vehicle incorporating the present invention is more efficient because it is unnecessary for the engine power to be required to maintain the bag portion 7 of the air skirt inflated.

There would normally be a significant differential between the pressure in this permanently inflated bladder and that of the air cushion skirt. This can be by a factor of ten or more which has not previously been possible in air cushion skirts of the type where both the bag portion and the dependent segments are inflated by a source of pressurised air.

Claims

CLAIMS:

1. An air cushion vehicle including: a substantially rigid hull structure; an air cushion skirt extending substantially about the periphery of the hull structure and attached to the hull structure at or towards the periphery of the hull structure, wherein part of the air cushion skirt comprises an inflatable bag portion; and an air supply means to provide a source of pressurised air to inflate the air cushion skirt apart from the inflatable bag portion; wherein the inflatable bag portion is sealed such as to maintain an inflated configuration on inflation thereof, independently of the operation of the air supply means.

2. The air cushion vehicle as claimed in claim 1 wherein the inflatable bag portion includes one or more air inlet valves.

3. The air cushion vehicle as claimed in claim 1 or claim 2 wherein the inflatable bag portion is adapted to normally remain permanently inflated between each individual usage of the vehicle.

4. The air cushion vehicle as claimed in claim 3 wherein the permanently inflated bag portion is attached to the hull structure with a substantial part of the bag portion disposed outboard of the hull structure.

5. The air cushion vehicle as claimed in any one of the preceding claims wherein the inflatable bag portion comprises an outer bag portion and an inner bladder means.

6. The air cushion vehicle as claimed in claim 5 wherein the inner bladder means is constructed from air impermeable vinyl sheeting.

7. The air cushion vehicle as claimed in any one of the preceding claims wherein the air cushion skirt further comprises a plurality of flexible skirt segments disposed substantially below the inflatable bag portion and wherein the inflatable bag portion is adapted to be inflated to a pressure up to 10 times the pressure within the flexible skirt segments when they are inflated by the air supply means.

8. The air cushion vehicle as claimed in any one of the preceding claims wherein the vehicle is a pleasure craft for a maximum of one or two people.

8. An air cushion skirt for an air cushion vehicle adapted to be attached to a substantially rigid hull structure of the air cushion vehicle, wherein part of the air cushion skirt comprises an inflatable bag portion comprising an outer bag portion and an inner inflatable bladder means.

9. The air cushion skirt as claimed in claim 8 further including a plurality of dependently disposed flexible skirt segments each having air inlet means wherein the flexible skirt segments are fluidly unconnected to the inflatable bladder means.

10. An air cushion vehicle including a substantially rigid hull structure and an air cushion skirt extending substantially about the periphery of the hull structure and attached to the hull structure at or towards the periphery of the hull structure, wherein part of the air cushion skirt comprises an inflatable bag portion comprising an outer bag portion and an inner inflatable bladder means.

11. The air cushion vehicle as claimed in claim 10 further including a plurality of dependently disposed flexible skirt segments each having air inlet means wherein the flexible skirt segments are fluidly unconnected to the inflatable bladder means.

12. The air cushion vehicle as claimed in claim 10 or claim 11 wherein the inflatable bag portion is attached to the hull structure with a substantial portion of the bag portion disposed outboard of the hull structure.

13. The air cushion vehicle or the air cushion skirt substantially as hereinbefore described with reference to the accompanying figures.