GB2438844A

GB2438844A - Amphibious vehicle with retractable tracked drives

Info

Publication number: GB2438844A
Application number: GB0611139A
Authority: GB
Inventors: Alan Timothy Gibbs; Karen Michele Suzanne Tapper
Original assignee: Gibbs Technologies Ltd
Current assignee: Gibbs Technologies Ltd
Priority date: 2006-06-06
Filing date: 2006-06-06
Publication date: 2007-12-12
Also published as: EP2029375A1; GB0611139D0; CN101500826A; WO2007141515A1; TW200824932A

Abstract

Amphibious vehicle 110 has a bow 113 and a stem 119. Land propulsion means comprises at least two retractable tracked drives 122. A marine drive may comprise a jet drive (not shown). The tracks 122 are retractable above the water line (fig. 9) for marine travel. The vehicle may plane, and may have a vee type hull 111. The tracks may be full length (figs. 1, 13, 14); dual tracks (fig. 5); or "half tracks" (fig. 4). Wheels 124, 126 may be provided for land travel, and may be retractable. The tracks may retract vertically, or by rotation about a longitudinal axis (fig. 11). Mudguards may be provided (52, fig. 12). Track retraction guides may be provided (14, fig. 2); a vehicle roof (not shown) may be attached to said guides. Hydraulic rams used to retract the land propulsion means may also provide vehicle suspension.

Description

AI4PHIBIOUS VEHICLE The present invention relates to an amphibious

vehicle; and in particular to an amphibious vehicle which is at least partly supported and driven by a tracked drive.

Placement of axles in a conventional off-road vehicle is a compromise between breakover angle on the one hand; and approach and departure angles on the other hand. Figure 15 illustrates these angles for a vehicle 500. A front wheel 503 is mounted on a front axle, and a rear wheel 504 is mounted on a rear axle. The axles have to be inset from the outer ends 505,506 of the vehicle to give an acceptable breakover angle 507; but this limits mobility by reducing the approach angle 501 and departure angle 502. It is also conventional to inset axles from bumpers to build in crushable space for impact absorption. However, where mobility off road is the prime concern, the fitment of tracks between front and rear axles makes breakover angle 507 an irrelevant concept. The vehicle will not ground on its sills between the axles, because the tracks are there to support it. This allows the front and rear axles to be pushed out towards the bumpers, maximizing approach and departure angles 501,502.

Tracked vehicles have many advantages off road, but are limited on road. They are slow (maximum recommended speed may be only 40mph or 64km/h); are often noisy; may use a lot of fuel; and may also break up hard road surfaces. In an age where relations between military forces and civilians are often fraught, any modification to military vehicles which makes their passage along public roads less conspicuous, and less likely to induce hostility, is a major advantage.

Wheeled vehicles may be adapted for use off road by providing balloon tyres and elongated suspension travel in both bump and rebound modes. However, these modifications may limit speed, economy, and ease of handling on road.

Provision of tracks allows tyres and suspension to be tuned more to road use, and may avoid use of balloon tyres which have speed limits on road.

Document US 5,752,862 describes an amphibious vehicle which has tracked drives. The vehicle on water can get up onto the plane and travel as a planing vehicle. The amphibious vehicle described has the problem that the tracked drives extend below the hull, which increases drag and can prevent the vehicle from turning reliably.

According to the present invention, there is provided an amphibious vehicle according to the attached claims.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic side elevation of a first embodiment of an amphibious vehicle according to the present invention; Figure 2 is a schematic cut-away front elevation view of the amphibious vehicle according to the present invention in a first state; Figure 3 is a schematic cut-away front elevation view of the amphibious vehicle according to the present invention in a second state; Figure 4 is a schematic side view of a second embodiment of an amphibious vehicle according to the present invention; Figure 5 is a schematic side elevation view of a third embodiment of the amphibious vehicle according to the present invention; Figure 6 is a schematic side elevation view of a fourth embodiment of the amphibious vehicle in a first state; Figure 7 is a schematic side elevation view of the fourth embodiment of the amphibious vehicle in a second state; Figure 8 is a schematic side elevation view of a fourth embodiment of the amphibious vehicle in a third state; Figure 9 is a schematic side elevation view of the fourth embodiment of the amphibious vehicle in a fourth state; Figure 10 is a schematic cut-away front view of a further embodiment of the amphibious vehicle in a first state; Figure 11 is a schematic cut-away front view of the amphibious vehicle of Figure 10 in a second state; Figure 12 is a schematic cut-away front view of a yet further embodiment of the amphibious vehicle of the present invention; Figure 13 is a perspective view of the amphibious vehicle of the present invention in use; Figure 14 is a further perspective view of the amphibious vehicle of the present invention in use; and Figure 15 is a schematic side elevation view of a prior art vehicle.

Figure 1 shows an amphibious vehicle 10 having a main vehicle structure in the form of a hull 11. The vehicle has a front (bow) 13 and a rear (stern) 19. The vehicle is propelled on land by means of a tracked drive 12 extending longitudinally along each side of the hull 11. Each tracked drive 12 is a single track on one side of the vehicle. The tracked drives 12 comprise one or more driven wheels 15 and one or more non- driven wheels 16. The tracked drive 12 further comprises a track 18 in the form of an endless ioop supported by the wheels 15,16, in a conventional tracked drive arrangement. The vehicle 10 is shown standing on ground 520.

The tracked drives 12 extend along substantially the whole length of the vehicle 10. The vehicle 10 may be steered by independently operating the tracked drive 12 on each side of the hull. The tracks 18 may have a width of approximately 300mm.

The hull 11 is a vee type hull as shown in Figure 2.

The vehicle 10 additionally has a marine propulsion means for travelling on water. This is preferably in the form of at least one jet drive (not shown) . The jet drive is able to generate sufficient force to allow the vehicle 10 to plane on water.

Figure 2 shows a front view of the amphibious vehicle 10. Each tracked drive 12 has at least one guide element located in one or more slides 14. The slides 14 extend substantially vertically adjacent the hull 11, and allow the tracked drives 12 to be raised or lowered substantially vertically. The slides 14 may be in the form of tubes. The slides 14 are arranged in pairs across the width of the vehicle 10. Pairs of slides 14 may be attached to each other across the width of the vehicle 10 by attachment elements (not shown) Hydraulic rams (not shown) are connected to the tracked drives 12, and are operable to raise or lower the tracked drives 12 in the slides 14. The tracked drives 12 can be raised until they are above the waterline of the vehicle 10.

This allows the vehicle 10 to plane on water without interference or drag from the tracked drives. The tracked drives 12 are raisable above the level of any rudder. All protraction operations are inverse to the retraction operations described.

The hydraulic rams may additionally provide for suspension springing of the vehicle 10. The hydraulic rams may additionally provide suspension damping for the vehicle, as known from Wa 01/74612 which is incorporated herein by reference.

A cover or roof (not shown) may be supported by the slides 14. The cover or roof may be attached to the attachment elements. The cover may provide physical protection for occupants of the vehicle in a military conflict, for example providing protection from enemy fire.

Figure 3 shows the amphibious vehicle of Figure 2 in which the tracked drives 12 have been raised upwardly. The tracked drives 12 are raised above the level of the waterline 510 of the vehicle 10.

Figure 4 shows a second embodiment of the amphibious vehicle 20. The vehicle has a front (bow) 23 and a rear (stern) 29. The amphibious vehicle 20 is provided with half tracks 22 adjacent the rear of the vehicle. One half track 22 is located on each side of the hull 21. The half tracks 22 function similarly to the tracked drives 12 of Figure 1, and extend over part of the length of the vehicle 20.

A pair of road wheels 24 are located adjacent the front of the vehicle 20. The half tracks 22 may be raised vertically upwardly along slides as described with reference to Figure 2 and 3. The road wheels 24 may be raised in slides, or by any other means for retracting wheels.

Figure 5 shows an amphibious vehicle 30 having four sets of tracks. A front tracked drive 32 and a rear tracked drive 33 are provided on each side of a hull 31. The vehicle 32 may be steered by independently driving the tracks on each side.

Figure 6 shows a further embodiment of an amphibious vehicle 110. The vehicle has a front (bow) 113 and a rear (stern) 119. The vehicle 110 has a front pair of wheels 124 and a rear pair of wheels 126. A pair of tracked drives 122 is located between the front and rear wheels 124,126, on either side of the vehicle. The front and rear wheels 124,126 and the tracked drives 122 can be independently raised or lowered on slides 114 as described with respect to Figures 2 and 3. Figure 6 shows the front and rear wheels 124, 126 and the tracked drives 122 in a lowered position, extending below the hull ill. The vehicle 110 is shown standing on ground 520.

This arrangement is advantageous off-road, where the tracks can engage the terrain surface even over rugged terrain. The wheels allow for improved steering, particularly on hard surfaces.

Figure 7 shows the amphibious vehicle 110 in which the front and rear wheels 124,126 have been raised on the slides 114. The tracked drives 122 are in the lowered position, and are able to propel the amphibious vehicle on land. This arrangement is advantageous for off-road travel, since tracks are more able to negotiate rugged terrain than wheels, particularly as they offer very low ground pressure.

Figure 8 shows the amphibious vehicle of Figure 6 in which the tracked drives 122 have been raised on the slides 114. The front and rear wheels 124, 126 remain lowered to drive and steer the vehicle 110. This state is advantageous on roads, where the wheels 124, 126 allow relatively fast, quiet travel and allow smooth steering of the amphibious vehicle 110.

Figure 9 shows the front and rear wheels 124,126 raised. The tracked drives 122 are also raised. This allows the amphibious vehicle 110 to travel on water, where it is propelled by a jet drive. The wheels 124,126 and tracked drives 122 are raised above the waterline 510, allowing the vehicle to plane on the water without interference from the wheels 124,126 or tracked drives 122.

All of the front wheels and rear wheels 124 and 126 may be driven. Alternatively, only the front wheels 124 or the rear wheels 126 may be driven. The front wheels, rear wheels, or all road wheels may be used to steer the vehicle on land. At least one tracked drive may also be driven, stopped or reversed in order to steer the vehicle.

Figure 10 shows an alternative means for raising and lowering the tracked drives. This may be used on any of the previously described embodiments. The tracked drives 212 are mounted on support members 230. The support members 230 extend vertically downwardly from the main structure when the tracked drives 212 are in the lowered position.

As shown in Figure 11, the support members 230 are pivotally attached to the main structure, so that the tracked drives 212 can swing laterally outwardly in an arc.

The tracked drives 212 rotate about one or more axes extending substantially longitudinally along the vehicle.

The support members 230 can pivot to a horizontal orientation in order to lift the tracked drives 212 away from the hull 211 and above the waterline 510 of the vehicle 210. The retracted position is thus substantially perpendicular to the protracted position. In the retracted position the tracked drives 212 may act as fenders for the amphibious vehicle when on the water.

Wheels may also be raised or lowered by rotation in an arc as described above.

As shown in Figure 12, mudguards 52 or spray guards 52 may be provided over the tracked drives 12. The mudguards 52 may be rigidly attached to the hull 11, such that the mudguards 52 do not move when the tracked drives 12 are raised and lowered. Alternatively, the mudguards 52 may be attached to the tracked drives and/or slides such that the mudguards 52 are raised and lowered with the tracked drives 12 to stay a constant distance from the tracks 18.

Figure 13 shows the vehicle 10 in use planing on water.

Figure 14 shows the vehicle 10 in use on land, with the tracked drives lowered.

The wheels and/or tracked drives of any of the embodiments may be powered by a mechanical transmission.

Alternatively, the wheels and/or tracked drives may be powered by an electric transmission or a hydraulic transmission. Alternatively, the wheels and/or tracked drives may be powered by a transmission comprising mechanical and hydraulic elements. The hydraulic elements may be hydraulic wheel motors.

The wheels and/or tracked drives of any of the embodiments may be lowered on water; either to limit speed in crowded spaces e.g. harbours or marinas; in readiness for landing; or in areas such as swamps, where depth of water is unpredictable and constantly changing. Furthermore, heavy marine growth in swamps may choke up a water jet intake.

Although it is envisaged that a vehicle according to the invention should be able to reverse on water, the shape of a typical planing hull, with a tapered bow and cut-off -10 -stern, indicates that there will be a forward direction of travel in which the vehicle can travel considerably faster than in reverse, due to the very different hydrodynamic resistance encountered in each direction. In general, an amphibious vehicle will have similar proportions to a road vehicle or boat, being approximately 1.5-5 times, preferably 2.5-4 times, longer than it is wide. The practical and legislative limits on width of road vehicles are a major influence here; as are the hydrodynamic characteristics of the hull. The conventional direction of travel of an amphibious vehicle is along its length.

Where the claims refer to a "main structure" of the vehicle, this should be regarded as the hull for marine use; and as the body for land use.

Any of the embodiments described may be operated from a "forward control" driving position at the front of the vehicle, and preferably in front of the engine. With such a vehicle, there is very little bodywork forward of the windscreen -possibly just a bumper. Such a driving position offers excellent visibility on both land and water. The obvious drawbacks are visibility to hostile fire in military applications; and lack of crushable structure forward of the driver in case of collision.

A jet drive has been described as providing drive for the vehicle on water. Alternatively, a marine outdrive or propeller or propellers may be used. Providing a marine outdrive improves ease of conversion from a dedicated road vehicle. Alternatively, the vehicle may have two or more jet drives for propulsion on water.

-11 -The tracked drives and wheels have been described as being driven for driving the vehicle on land. Alternatively, the wheels may be driven and the tracked drives are not driven. Alternatively, the tracked drives are driven and the wheels are not driven.

Hydraulic rams have been described as raising or lowering the tracked drives. Alternatively, the tracked drives may be moved by threaded drives, hydraulic motors or other suitable means. Alternatively, the tracked drives may be raised and lowered by pneumatic rams or other pressurised air actuating means. The pneumatic rams may additionally provide for suspension springing of the vehicle. The pneumatic rams may additionally provide suspension damping for the vehicle.

Pivoted link arms or other linkages may be used between the actuating means and tracked drives and/or wheels as required.

The tracked drives have been described as mounted on either side of the hull. Alternatively, a single tracked drive may be provided, extending longitudinally under the centreline of the hull. Alternatively, three tracked drives may be provided, one on each side of the hull and one under the centreline of the hull. The tracked drives may be located either on the sides of the hull as shown, or partially or fully mounted underneath the hull.

A pair of front wheels and a pair of rear wheels have been described. Alternatively, the vehicle may have a pair -12 -of front wheels and a single, central, rear wheel.

Alternatively, the vehicle may have a pair of rear wheels and a single, central, front wheel. Alternatively, the vehicle may have additional or fewer wheels or tracked S drives than any of the particular embodiments shown. For example, the vehicle may have two pairs of front wheels at the front of the vehicle, and a pair of half tracks at the rear of the vehicle. Alternatively, the vehicle may have one pair of front wheels and a single, centrally mounted, tracked drive at the rear of the vehicle. Alternatively, the vehicle may have a pair of tracked drives at the rear, and a single, central, wheel at the front of the vehicle.

Claims

-13 -

CLAIMS

1. An amphibious vehicle for use on land and on water, comprising a main vehicle structure, land propulsion S means, and water propulsion means, where the land propulsion means include at least two tracked drives, characterised in that the tracked drives may be retracted above the vehicle waterline for use of the vehicle on water.

2. An amphibious vehicle according to claim 1, which is adapted to plane over water, and has a vee type hull.

3. An amphibious vehicle according to claim 1 or claim 2, where the marine propulsion means is a water jet.

4. An amphibious vehicle according to any one of claims 1 to 3, where the tracked drives extend substantially along the full length of the vehicle.

5. An amphibious vehicle according to any one of claims 1 to 3, where the tracked drives are provided towards the rear of the vehicle, and wheels are provided towards the front of the vehicle.

6. An amphibious vehicle according to any one of claims 1 to 3, where a first pair of tracked drives are provided towards the rear of the vehicle, and a second pair of tracked drives are provided towards the front of the vehicle.

-14 - 7. An amphibious vehicle according to any one of the above claims, where the land propulsion means are powered by a mechanical transmission.

8.An amphibious vehicle according to any one of claims 1 to 6, where the land propulsion means are powered by an electric transmission.

9. An amphibious vehicle according to any one of claims 1 to 6, where the land propulsion means are powered by a hydraulic transmission.

10. An amphibious vehicle according to any one of claims 1 to 6, where the land propulsion means are powered by a transmission comprising mechanical and hydraulic elements.

11. An amphibious vehicle according to claim 10, where the hydraulic elements comprise hydraulic wheel motors.

12. An amphibious vehicle according to any one of the above claims, where the tracked drives are retractable substantially vertically.

13. An amphibious vehicle according to any one of claims 1 to 11, where the tracked drives are retractable about one or more axes running fore and aft along the vehicle, so that each tracked drive retracts in an arc about said axes.

14. An amphibious vehicle according to claim 13, where the retracted positions of the tracked drives are -15 -substantially perpendicular to their protracted positions.

15. An amphibious vehicle according to any one of the above claims, where the tracked drives are retracted by means of threaded drives.

16. An amphibious vehicle according to any one of claims 1 to 13, where the tracked drives are retracted by means of hydraulic rams or pneumatic rams.

17. An amphibious vehicle according to claim 15, where the hydraulic rams or pneumatic rams also provide vehicle suspension springing.

18. An amphibious vehicle according to claim 15 or claim 16, where the hydraulic rams or pneumatic rams also provide vehicle suspension damping.

19. An amphibious vehicle according to any one of the above claims, where the tracked drives have guide elements which locate in tubes attached to the main vehicle structure which guide the retraction of the tracked drives.

20. An amphibious vehicle according to claim 19, where the tubes are attached to each other in pairs across the width of the vehicle by attachment elements.

21. An amphibious vehicle according to any one of claims 1 to 18, where the tracked drives have guide elements which locate in slides attached to the main -16 -vehicle structure which guide the retraction of the tracked drives.

22. An amphibious vehicle according to claim 19, where the slides are attached to each other in pairs across the width of the vehicle by attachment elements.

23. An amphibious vehicle according to claim 20 or claim 22, where a vehicle cover or roof is attached to the attachment elements.

24. An amphibious vehicle according to any one of the above claims, where the tracked drives have mudguards fitted above the tracks.

25. An amphibious vehicle according to claim 24, where the mudguards are attached to the tracked drives, so that they are retractable therewith.

26. An amphibious vehicle according to any one of the above claims, where the vehicle is provided with a "forward control" driving position.

27. An amphibious vehicle according to claim 1 or claim 2, where road wheels are provided in front of and behind the tracked drives.

28. An amphibious vehicle according to claim 27, where the tracked drives can be retracted on land.

29. An amphibious vehicle according to claim 27, where the road wheels can be retracted on land.

-17 - 30. An amphibious vehicle according to claim 4 or claim 27, where all road wheels are driven.

31. An amphibious vehicle according to claim 4 or claim 27, where at least two road wheels can be used to steer the vehicle.

32. An amphibious vehicle according to any one of the above claims, where at least one tracked drive may be stopped in order to steer the vehicle.

33. An amphibious vehicle according to any one of the above claims, where at least one tracked drive may be reversed in order to steer the vehicle.

34. An amphibious vehicle comprising a main vehicle structure, land propulsion means, and marine propulsion means, wherein the land propulsion means includes at least one tracked drive and at least one wheel; characterised in that: the at least one tracked drive and at least one wheel may be retracted above the vehicle waterline for use of the vehicle on water.

35. An amphibious vehicle substantially as hereinbefore described or as shown in any one or more of the accompanying Figures 1 to 14.

729274; AR}IB, VSP