GB2038252A

GB2038252A - Improvements in and relating to amphibious tracked vehicles

Info

Publication number: GB2038252A
Application number: GB7914090A
Authority: GB
Original assignee: GUNDERSEN E
Current assignee: GUNDERSEN E
Priority date: 1978-12-18
Filing date: 1979-04-23
Publication date: 1980-07-23

Abstract

A tracked vehicle is described typically for carrying personnel and equipment over difficult terrain ranging from ordinary road surfaces and the like through to snow. The vehicle may even be adapted to float on water and suitable propeller drive is provided to that end. The vehicle includes a smooth flat underside (12) with caterpillar tracks (such as 54) mounted on opposite sides of the vehicle, the track being formed from segments (72) into which teeth of inverted T cross-section are fitted, the teeth being designated by reference numerals 76 and 78. The caterpillar tracks pass round solid rubber wheels and the whole of the tracks are adjustable vertically relative to the rest of the vehicle to allow for deeper or shallower grip to be obtained. A canopy is provided over the vehicle. Weight distribution within the vehicle is arranged so that the central gravity is slightly to the rear of centre. A trailer having a skid or road wheels is provided where appropriate. <IMAGE>

Description

SPECIFICATION Improvements in and relating to tracked vehicles Field ofinvention This invention concerns tracked vehicles particularly vehicles suitable for carrying personnel and equipment over difficult terrain ranging from ordinary road surfaces and the like through to snow.

Background to invention It is known to provide vehicles with tracks instead of ordinary discrete wheel drive for negotiating uneven and unstable terrain. It is also known to provide tracked vehicles for use on snow and it is an object of the present invention to provide an improved all-purpose vehicle which is adapted to ride over snow, swamps, marshes, sand etc.

The invention According to the present invention a tracked vehicle includes a smooth underside which is adapted to skim over terrain such as snow and the like having at least one and preferably two track drives mounted thereon so as to extend below the level of the underside of the vehicle to engage in the material forming the surface over which the vehicle is moving to provide a forward tractive force.

To assist in manoeuvring, separate drive is provided for the two tracks. This may be from a single engine with a differential drive to two drive sprockets associated with the two different tracks one on one side and the other on the other side of a vehicle with provision for braking one or other of the two tracks.

Alternatively two infinitely variable gear boxes may be provided for supplying drive from the single engine unit to the two tracks independently.

Alternatively two separate engine units may be provided one for driving the one track and the other for driving the other.

According to a preferred feature of the invention the depth of the track is adjustable.

The adjustment of the track depth may be achieved manually or through manually controlled hydraulic rams or the like.

Alternatively means may be provided for automatically lowering the tracks relative to the underside of the vehicle to achieve the designed thrust onto the surface over which the vehicle is moving. To this end the automatic means includes a thrust sensing mechanism and a feedback network to initiate appropriate operation of the means for moving the track in a downward or upward direction so that just the right depth below the underside surface of the vehicle is achieved to produce the desired and designed thrust.

According to another preferred feature of the invention the track segments are formed from aluminium alloy with replaceable teeth located thereon. Preferably the teeth are formed from steel or an alloy or rubber or plastics material and preferably the teeth are rapidly and easily replaceable to allow the tracks to be adjusted to vary the performance and wear characteristics of the track in advance of a change in terrain or change of surface over which the vehicle is to run.

In addition to varying the teeth so as to change the tooth material from one kind of material to another, the replaceability of the teeth allows teeth of different size to be inserted into the tracks. Thus teeth which extend only by a small distance from the track surface and are formed from hard material would be used on sand, marshes etc. but on snow and similar materials teeth of softer material and which extend by a larger amount from the surface of the track may be used.

According to another preferred feature of the invention the entire craft may be formed from an aluminium alloy or alternatively partly from glass reinforced plastics materials. For example the shell of the vehicle may be formed from glass reinforced plastics material and an inner sub-frame from an aluminium alloy to give the.required degree of strength.

According to another feature of the invention, a canopy may be provided formed in one or more sections and adapted to be removable from the vehicle. Such a canopy will allow protection for equipment or personnel on board the vehicle.

In view of the environment in which a vehicle such as this can be used, high quality seals are required between the axles and the body shell through which they protrude to prevent the ingress of moisture, dirt, etc. to allow the craft to float on water as and when required.

When floating on water sufficient thrust will normally be obtainable from the caterpillar drives but large teeth specially for use in water are preferably provided.

Additional thrust may be obtained by using two or more outboard motors attached to the rear of the craft or a flexible drive may be provided from the main engine or engines to one or more drive units mounted or demountable on the stern of the vehicle for driving propellers carried thereby.

To facilitate manoeuvring in water, the vehicle may be provided to advantage with a demountable rudder assembly.

According to another preferred feature of the invention the engine and any other fixed heavy equipment, fuel tanks etc. are located on the vehicle so that the centre of gravity of the vehicle is approximately halfway between the front and the rear and preferably slightly to the rear of centre rather than forward of centre so as to lift the front of the craft.

To facilitate the stopping of the craft particularly on an inclined surface under ice and snow conditions, a land anchor is conveniently provided attached to a chain or hawser. Alternatively a land anchor assembly may be mounted on board the vehicle so as to protrude through the floor of the vehicle and ram means or the like is provided within the vehicle to force the land anchor assembly in a generally downward and forward direction so as to arrest the forward motion of the vehicle in the event of an emergency. Conveniently two such land anchor assemblies are provided one pointing towards the rear and one pointing towards the front so that any tendency of the vehicle to run away in a rearward direction could also be arrested.

According to a particularly preferred feature of the invention the underside of the vehicle is provided with a plurality of apertures and means is provided on board the vehicle for storing antifreeze or a similar low freezing temperature liquid and means is provided for applying the liquid in a controlled quantity of the underside of the vehicle through the apertures so that the underside of the vehicle can be un-frozen in the event that the vehicle becomes iced up.

According to an alternative solution to this prefer red aspect of the invention, the underside of the vehicle may have incorporated therein or associated therewith one or more heating coils or a heat exchanger unit to which hot water is supplied from an appropriate source of hot water on board the vehicle for the same purpose i.e. to de-ice the vehicle in the event that the vehicle becomes snowbound and icebound.

The heating coil may be heated electrically from an electrical current from a generating or alternating set driven by the main power unit or an auxiliary unit on board the vehicle. The heat exchanger may comprise a pipe through which water or a similar liquid may be forced, the liquid having first of all been heated typically as a result of having passed through the cooling circuits of the engine which drives the vehicle.

In order to prevent personnel and/or equipment on board the vehicle from becoming affected by the cold which would otherwise strike up through the floor of the vehicle, the latter preferably includes a thermal insulating panel on which equipment and/or personnel can stand.

As is well known from motor vehicle technology, heater means may be provided to warm the interior of the vehicle.

Preferably ballast is provided either in the form of auxiliary equipment or in the form of expendable weights etc. to allow the craft to be trimmed depending on the load it is carrying and to allow the front of the vehicle to always be lighter than the rear ofthe vehicle to prevent digging in to snow and soft ground.

A vehicle incorporating one or more features of the invention may be used in the following typical applications: (a) as an Army vehicle to carry troops and equip ment in any conditions, (b) as a rescue vehicle to recover personnel, anim als and equipment stranded in adverse weather conditions particularly deep snow, (c) as a general purpose farming vehicle which at the same time can be used as a rescue craft for rescuing cattle and other livestock stranded in the snow and other difficult weather conditions.

According to a particularly preferred feature of the invention the caterpillar tracks are supported by wheels made of solid rubber.

According to another feature of the invention, one or more trailers may be provided for towing behind a vehicle embodying the invention and in order to allow the pair of vehicles to be general purpose vehicles, whilst the trailer is provided with a smooth underside or with sledge runners depending on the normal application, means is also provided on board the trailer having road wheels attached thereto which are pivotable from an inboard position to an outboard position in which the wheels extend below the underside surface of the trailer to allow the latter to be trailed over ordinary roads and hard terrain.

Preferably mechanical means is provided for lowering or raising the wheels which is itself operable from the towing vehicle.

According to another preferred feature of the invention, the teeth which form the drive transmitting elements within the caterpillar tracks are engaged in and retained in transversely extending slots formed in the segments of the caterpillar track. Pins or other locking means may be provided for retaining the teeth segments in position.

The invention will now be described by way of example with reference to the accompanying drawing.

In the drawing Figure 1 is a side elevation of a motorised caterpillar drive rescue craft embodying the invention and shown towing a sledge which forms a subsidiary vehicle which may or may not be used with the main vehicle, Figure 2 is a plan view of the vehicle and trailer assembly shown in Figure 1, Figure 3 is a side elevation on an enlarged scale of a segment of the vehicle track and Figure 4 is an edge view as viewed in the direction of the arrow A in Figure 3.

Detailed description of drawings Referring to Figures 1 and 2, a tracked rescue craft comprises a motorised vehicle generally designated 10 having a snub-nosed front end and a smooth flat underside 12 which merges at least on the underside in a smooth curve with the snub-nosed end. The rear of the vehicle is inclined and a towing bracket extends therefrom at 14. Side panels such as 16 complete the assembly and form a generally open box structure within which the drive unit and other equipment can be mounted as will hereinafter be described.

The vehicle includes a cab 18 towards the forward end of the vehicle which includes the driving position and some or all of the controls for manoeuvring and driving the vehicle.

To the rear of the cab the cockpit-like arrangement provides good storage room for personnel and/or equipment and in situations where large volumes of equipment or large number of people or livestock are to be transported one or more trailers can be attached to the vehicle such as the trailer sledge 20 also shown in Figure 1. This is attached by a rigid towing bar 22 to the towing bracket 14 and the underside of the towing sledge is formed with sledge runners of which one is shown at 24. Apart from the underside, the trailer includes two sides of which one is shown at 26 and the rear may be left open or a rear gate may be provided (not shown).

On opposite sides of the unit are mounted road wheels 28 and 30 and each is mounted on an axle 32 and 34 respectively each of which is carried at the end of a swinging arm which is rotatable aboutan axis designated by reference numeral 36 on the one hand and 38 on the other hand.

Each of the swinging arms designated 40 and 42 respectively is movable from a position in which the wheels 28 and 30 are raised well clear of the underside of the vehicle (as shown in Figure 1) to a position in which the stub axles 32 and 34 are received in grooves (of which one is shown at 44) in bracket assemblies mounted on opposite sides of the sledge trailer one of which is shown at 46.

In this lowered position the wheels extend below the underside of the trailer sledge and below the sledge runners 24 so that in that position the unit becomes a conventional trailer adapted to be run along a tar macadam surface or the like.

A mechanical linkage (not shown) between a mechanical screw assembly generally designated 48 mounted at the front of the trailer sledge allows the angular position of the swinging arms 40 and 42 to be adjusted remotely and preferably from the rear of the towing vehicle. Alternatively the towing bar 22 provides a platform on which an operator can stand to adjust the screw assembly 48 and so raise or lower the wheels 28 and 30.

In order to facilitate the movement of the vehicle over certain terrain, particularly soft terrain and snow, the main weight carried by the towing vehicle at least is arranged to be rear of centre and to this end all of the fixed heavy items of equipment are located in a well and covered by a suitable lid designated 50 (see Figure 2) which is positioned slightly rear of centre. In this way even when the vehicle is adversely loaded with personnel or equipment all at the forward end of the vehicle, the chances are that the vehicle will still have a centre of gravity position which is rear of centre.

The track drive is similar on both sides ofthe vehicle and is located under an overhanging side section designated by reference numeral 52 in Figure 1. A similar overhanging section (not shown) is provided on the opposite side of the vehicle which is not visible in Figure 1.

Since the two drives are similar reference will only be made to the one shown in Figure 1.

The tracked drive comprises a plurality of segments each of which is similar to the segment as shown in Figure 3 each of which are pivotally joined together so as to form an endless chain generally designated 54. This passes around two main supporting wheels 56 and 58 which whilst rotatable are not driven. At the forward end the chain passes around a driving sprocket 60 and a tensioning mechanism generally designated 62 supports the chain where it extends on the underside of the vehicle between the two main supporting wheels 56 and 58. The unit 62 includes a movable plate generally designated 64 having pivotable rollers or wheels 66,68,70 carried thereon.The unit 62 is movable under the action of hydraulic rams orthe like (not shown) or by means of mechanical linkage in an upward or downward direction so as to exert a force on the endless chain caterpillar drive and tension this as well as support it in contact with the ground.

This movement of the unsupported endless chain between the two wheels 56 and 58 may be sufficient in some applications to provide for all the up and down movement of the caterpillar drive that is required. However alternatively and preferably the whole caterpillar drive with the exception of the driving sprocket 60 is mounted on a sub-frame which is itself movable relative to the remainder of the vehicle so that the whole of the drive can be moved in an up or down direction from a position in which the teeth of the caterpillar drive almost touch the underside of the overhanging section 52 to a lowered position corresponding to that shown in Figure 1.

Each of the segments of the drive comprises a plate generally designated 72 having a slot formed therein which in cross-section is T-shaped so as to define a restricted parallel-sided aperture 74 through which the stem of a T cross-section tooth can extend.

Such a stem is shown at 76 in Figure 3. The remainder of the tooth is in the form of a transverse head section generally designated 78 and this is retained within the slot in the segment 72 by means of the overhanging sections of the plate 72 which define the parallel-sided aperture 74 through which the stem 76 extends.

An end view of the segment taken in the direction of the arrow A is shown in Figure 4.

Although not shown one or more canopy sections may be provided adapted to be extended over the open trailer section of the vehicle 10. Similarly although not shown, canopy means may be provided for the trailer sledge unit.

Claims

CLAIMS 1. A tracked vehicle which includes a smooth underside which is adapted to skim overterrain such as snow and the like having at least one caterpillar track mounted thereon so as to extend below the level of the underside of the vehicle to engage in the material forming the surface over which the vehicle is moving to provide a forward tractive force. 2. Atracked vehicle as claimed in claim 1 having two caterpillar tracks in which a separate drive is provided for each of the two tracks. 3. A tracked vehicle as claimed in claim 2 having a single engine with a differential drive to two drive sprockets associated with the two different tracks one on one side and the other on the other side of a vehicle, with provision for braking one or other of the two tracks. 4. Atracked vehicle as claimed in claim 2 having two infinitely variable gear boxes for supplying drive from a single engine unit to the two tracks independently. 5. Atracked vehicle as claimed in claim 1 in which there are two caterpillar tracks and two separte engine units are provided one for driving the one track and the other for driving the other. 6. A tracked vehicle as claimed in any of claims 1 to 5 in which the depth of the or each track is adjustable. 7. Atracked vehicle as claimed in claim 6 in which the adjustment of the track depth is achieved manually or through a manually controlled drive such as hydraulic rams. 8. A tracked vehicle as claimed in claim 6 further comprising means for automatically lowering the track or tracks relative to the underside of the vehicle to achieve the designed thrust onto the surface over which the vehicle is to move. 9. Atracked vehicle as claimed in claim 8 in which the automatic means includes a thrust sensing mechanism and a feedback network to initiate appropriate operation of the means for moving the track in a downward or upward direction so that just the right depth below the underside surface of the vehicle is achieved to produce the desired thrust. 10. Atracked vehicle as claimed in any of the preceding claims in which the segments of each caterpillar track are formed from aluminium alloy with replaceable teeth located thereon. 11. Atracked vehicle as claimed in claim 10 in which the teeth are formed from steel or an alloy or rubber or plastics material. 12. Atracked vehicle as claimed in claim 10 in which different sets of teeth are provided for fitting into the track segments, to allow for different surface conditions. 13. Atracked vehicle as claimed in claim 12 in which one of the sets of teeth extend further from the surface of the segments than do the others of the sets. 14. Atracked vehicle as claimed in any of the previous claims in which the entire craft is formed from an aluminium alloy or partly from such an alloy and partly from glass reinforced plastics materials. 15. A tracked vehicle as claimed in claim 14 in which the shell of the vehicle is formed from glass reinforced plastics material and an inner subframe from an aluminium alloy. 16. Atracked vehicle as claimed in any of the preceding claims in which a canopy is provided, formed in one or more sections, which is removable from the vehicle, and serves to protect equipment and/or personnel on board. 17. Atracked vehicle as claimed in any of the preceding claims seals are provided between the axles and the body shell through which they protrude to prevent the ingress of moisture and dirt, and to allow the craft to float on water as and when required. 18. Atracked vehicle as claimed in claim 17 having mounted thereon two or more outboard motors for propelling the vehicle through water or a flexible drive is provided on the main engine or engines to one or more drive units mounted at, or demountable on, the stern of the vehicle, for driving propellers carried thereby. 19. Atracked vehicle as claimed in claim 18 further comprising a demountable rudder assembly. 20. A tracked vehicle as claimed in any of the preceding claims in which the engine or engines and any other fixed heavy equipment and fuel tanks, are located on the vehicle so that the centre of gravity of the vehicle is approximately halfway between the front and the rear, and slightly to the rear of centre. 21. A tracked vehicle as claimed in any of the preceding claims further comprising a land anchor either attached to a chain or hawser mounted on board the vehicle so as to protrude through the floor of the vehicle with ram means within the vehicle to force the land anchor assembly in a generally downward and forward direction so as to arrest a forward motion of the vehicle in the event of an emergency. 22. A tracked vehicle as claimed in claim 21 further comprising a second land anchor assembly pointing towards the rear so that any tendency of the vehicle to run away in a rearward direction can also be arrested. 23. Atracked vehicle as claimed in any of the preceding claims in which the underside of the vehicle is provided with a plurality a of apertures and means is provided on board the vehicle for storing antifreeze or a similar low freezing temperature liquid and means is provided for applying the liquid in a controlled quantity to the underside of the vehicle through the apertures so that the underside of the vehicle can be un-frozen in the event that the vehicle becomes iced up. 24. A tracked vehicle as claimed in any of claims 1 to 22 in which the underside of the vehicle has incorporated therein or associated therewith one or more heating coils (or a heat exchanger unit to which is supplied from an appropriate source of hot water on board the vehicle) to de-ice the vehicle in the event that the vehicle becomes snowboard or icebound. 25. A tracked vehicle as claimed in any of claims 1 to 22 in which the heating coil is heated electrically by electric current from a generating or alternating set driven by the main power unit or an auxiliary unit on board the vehicie. 26. A tracked vehicle as claimed in claim 24 in which the heat exchanger comprises a pipe through which water or a similar liquid is forced, the liquid having first of all been heated as a result of having passed through the cooling circuits of the engine which drives the vehicle. 27. Atracked vehicle as claimed in any of the preceding claims which further comprises a thermal insulating panel on which equipment and/or personnel can stand. 25. A tracked vehicle as claimed in any of the preceding claims in which ballast is provided either in the form of auxiliary equipment or in the form of expendable weights to allow the craft to be trimmed depending on the load it is carrying and to allow the front of the vehicle to always be lighter than the rear of the vehicle to prevent digging in to snow and soft ground. 29. A tracked vehicle as claimed in any of the preceding claims in which the cs'ierpillar tracks are supported by wheels made o, solid rubber. 30. Atracked vehicle as lcmc-d in claim 10 in WhiCil the teeth which form the drove transmitting elements within the caterpillartracics are engaged in and retained in transversely extending slots formed in the segments of the caterpillar tack and pins or other locking means are provided for retaining the teeth segments in position. 31. A tracked vehicle as claimed in claim 1 constructed arranged and adapted to operate substantially as herein described with reference to the accompanying drawings. New claims or amendments to claims filed on 23.11.79 Superseded claims:- 1 to 31 New or amended claims:- 1 to 33 CLAIMS

1. A tracked vehicle which includes a smooth underside which is adapted to skim over terrain such as snow and the like having at least one caterpillar track mounted thereon so as to extend below the level of the underside ofthe vehicle to engage in the material forming the surface over which the vehicle is moving to provide a forward tractive force, wherein the segments of the caterpillar track or tracks are formed with replaceable teeth located thereon.

2. A tracked vehicle as claimed in claim 1 in which the teeth are formed from steel or an alloy or rubber or plastics material.

3. A tracked vehicle as claimed in claim 1 or claim 2 in which different sets of teeth are provided for fitting into the track segments, to allow for different surface conditions.

4. A tracked vehicle as claimed in claim 3 in which one of the sets of teeth extend further from the surface of the segments than do the others of the sets.

5. Atracked vehicle as claimed in any of claims 1 to 4 in which the teeth are engaged and retained in transversely extending slots formed in the segments of the caterpillar track or tracks.

6. Atracked vehicle as claimed in claim 5, in which pins or other locking means are provided for retaining the teeth segments in position.

7. A tracked vehicle as claimed in claim 5 or claim 6, in which the teeth each have a T-shaped cross-section of which the crosspiece engages in the transversely extending slot in each caterpillar segment and the stem projects outwardly through an opening in the segment for driving engagement with the material forming the surface over which the vehicle is moving.

8. Atracked vehicle as claimed in any of claims 1 to 7 in which the caterpillar segments are formed of aluminium alloy.

9. A tracked vehicle as claimed in any of claims 1 to 8 having two caterpillar tracks in which a separate drive is provided for each of the two tracks.

10. Atracked vehicle as claimed in claim 9 having a single engine with a differential drive to two drive sprockets associated with the two different tracks one on one side and the other on the other side of a vehicle, with provision for braking one or other of the two tracks.

11. Atracked vehicle as claimed in claim 9 having two infinitely variable gear boxes for supplying drive from a single engine unit to the two tracks independently.

12. A tracked vehicle as claimed in any of claims 1 to 8 in which there are two caterpillar tracks and two separate engine units are provided one for driving the one track and the other for driving the other.

13. Atracked vehicle as claimed in any of claims 1 to 12 in which the depth of the or each track is adjustable.

14. Atracked vehicle as claimed in claim 13 in which the adjustment of the track depth is achieved manually or through a manually controlled drive such as hydraulic rams.

15. Atracked vehicle as claimed in claim 13 further comprising means for automatically lowering the track or tracks relative to the underside of the vehicle to achieve the designed thrust onto the surface over which the vehicle is to move.

16. A tracked vehicle as claimed in claim 15 in which the automatic means includes a thrust sensing mechanism and a feedback network to initiate appropriate operation of the means for moving the track in a downward or upward direction so that just the right depth below the underside surface of the vehicle is achieved to produce the desired thrust.

17. Atracked vehicle as claimed in any of the previous claims in which the entire craft is formed from an aluminium alloy or partly from such an alloy and partly from glass reinforced plastics materials.

18. Atracked vehicle as claimed in claim 17 in which the shell of the vehicle is formed from glass reinforced plastics material and an innersubframe from an aluminium alloy.

19. A tracked vehicle as claimed in any of the preceding claims in which a canopy is provided, formed in one or more sections, which is removable from the vehicle, and serves to protect equipment and/or personnel on board.

20. A tracked vehicle as claimed in any of the preceding claims wherein seals are provided between the axles and the body shell through which they protrude to prevent the ingress of moisture and dirt, and to allow the craft to float on water as and when required.

21. A tracked vehicle as claimed in claim 20 having mounted thereon two or more outboard motors for propelling the vehicle through water or a flexible drive is provided from the main engine or engines to one or more drive units mounted at, or demountable on, the stern of the vehicle, for driving propellers carried thereby.

22. Atracked vehicle as claimed in claim 21 further comprising a demountable rudder assembly.

23. Atracked vehicle as claimed in any of the preceding claims in which the engine or engines and any other fixed heavy equipment and fuel tanks, are located on the vehicle so that the centre of gravity of the vehicle is approximately halfway between the front and the rear, and slightly to the rear of centre.

24. A tracked vehicle as claimed in any of the preceding claims further comprising a land anchor either attached to a chain or hawser mounted on board the vehicle so as to protrude through the floor of the vehicle with ram means within the vehicle to force the land anchor assembly in a generally downward and forward direction so as to arrest a forward motion of the vehicle in the event of an emergency.

25. Atracked vehicle as claimed in claim 24 further comprising a second land anchor assembly pointing towards the rear so that any tendency of the vehicle to run away in a rearward direction can also be arrested.

26. Atracked vehicle as claimed in any of the preceding claims in which the underside of the vehicle is provided with a plurality of apertures and means is provided on board the vehicle for storing antifreeze our a similar low freezing temperature liquid and means is provided for applying the liquid in a controlled quantity to the underside of the vehicle through the apertures so that the underside of the vehicle can be un-frozen in the event that the vehicle becomes iced up.

27. Atracked vehicle as claimed in any of claims 1 to 25 in which the underside of the vehicle has incorporated therein or associated therewith one or more heating coils (or a heat exchanger unit to which hot water is supplied from an appropriate source of hot water on board the vehicle) to de-ice the vehicle in the event that the vehicle becomes snow-bound or icebound.

28. Atracked vehicle as claimed in claim 27 in which the heating coil is heated electrically by electric current from a generating or alternating set driven by the main power unit or an auxiliary unit on board the vehicle.

29. A tracked vehicle as claimed in claim 27 in which the heat exchanger comprises a pipe through which water or a similar liquid is forced, the liquid having first of all been heated as a result of having passed through the cooling circuits of the engine which drives the vehicle.

30. Atracked vehicle as claimed in any of the preceding claims which further comprises a thermal insulating panel on which equipment and/or personnel can stand.

31. Atracked vehicle as claimed in any of the preceding claims in which ballast is provided either in the form of auxiliary equipment or in the form of expendable weights to allow the craft to be trimmed depending on the load it is carrying and to allow the front of the vehicle to always be lighter than the rear of the vehicle to prevent digging in to snow and soft ground.

32. Atracked vehicle as claimed in any of the preceding claims in which the caterpillar track or tracks are supported by wheels made of solid rubber.

33. Atracked vehicle as claimed in claim 1 constructed arranged and adapted to operate substantially as herein described with reference to the accompanying drawings.