The present invention concerns equipment for floating a vehicle, such as a tractor, said equipment comprising first containers and second containers associated with the tyres of the vehicle, and third containers associated with the bodywork of the vehicle. More particularly, the present invention concerns equipment for transform¬ ing a standard vehicle into a floating vehicle.

Amphibian vehicles are conventionally constructed by using separate floats in connection with the vehicle, to achieve a sufficient force of buoyancy. For example a cross-country vehicle can be equipped with elongated pontoons attached to the sides. Another way to bring about an amphibian vehicle is to construct a water- craft that can also restrictedly move on dry land. Amphibian vehicles constructed according to any of these two known arts face difficulties when moving on swamps and alluvious lands. A vehicle equipped with floats is unwieldy in both elements and a vehicle primarily constructed for use on water is in significant danger to sink if, for example, its sealed constructions fail in the course of time. Changing over from water to dry land or vice versa requires ramps or other constructions of the type when using this kind of solutions.

Amphibian vehicles are needed, for example, for military purposes, in tasks relat- ing to environmental care, on ice roads, in peat bogs, in forest work and on various building sites in areas with limited bearing capacity. Construction machine combi¬ nations require, in addition of having assured unsinkability, sufficient load bearing capacity and sufficiently powerful construction machinery for accomplishing each work task, as well as sufficient movability in all circumstances.

The purpose of the present invention is to provide equipment for transforming a standard vehicle, such as an agricultural tractor, into an amphibian vehicle. The equipment can be easily installed and fairly quickly removed when required. The equipment does not span beyond the overall dimensions of the vehicle, and ground clearance remains unchanged, whereby the driving and operating charac- teristics of the vehicle remain on dry land as well. Characteristics of agricultural tractors of standard type have evolved to suit difficult cross-country conditions, and such tractors can be used to efficiently accomplish tasks in, for example, agricul¬ tural and forest work. The power to weight ratio of these tractors is advantageous, so they can be advantageously transformed floatable by means of the equipment according to the present invention.

A modern tractor has different box-type spaces and spaces that can be easily shaped into boxes. Bodyworks are hollow, and the vehicle has different contain- ers and free spaces into which structures providing buoyancy can be placed. Pro¬ viding a tractor with amphibian equipment requires accurate charting of existing and potential sources of buoyancy. In addition to box-type structures mentioned above, the existing sources of buoyancy include, for example, stock tyres and eventual twin-tyre arrangements. Tyre volumes in high-power tractors are consid- erably large, so they have a lot of buoyancy potential as such. By sealing the spaces within and between the tyres, thus forming boxes, the buoyancy can be significantly increased.

When analyzing sources of buoyancy, stability of the vehicle in partial and com¬ plete situations of displacement must be considered. The effect of possible asym- metrically placed containers, such as fuel tanks, when getting empty, must be taken into account for example by arranging an additional, balancing fuel tank into the vehicle. The goal is to keep the buoyant forces balanced, regardless of the driving mode. The centre of gravity of the vehicle remains stable with respect to the buoyant forces, and therefore sufficient stability is reached when the vehicle is carried by its displacement.

Tyres of the trailer can be equipped with similar sealing means, and the trailer it¬ self can be equipped with floats, which can also function as a part of bodyworks. Connecting apparatus of the vehicle and trailer is equipped with active balancing elements to stabilize the combination vehicle in different driving and load condi- tions.

The combination vehicle moves driven by the tyres of the tractor also in the dis¬ placement situation. In windy conditions and in moving water, the combination can be equipped with a turning propeller apparatus or with a corresponding propulsive device.

The present invention provides solutions to the abovementioned problems and eliminates drawbacks associated with the solutions of prior art, as well as provides equipment for transforming a standard type vehicle into an amphibian vehicle. These advantageous features are achieved by means of the equipment according to the invention, characterized by what is stated in the claims. The equipment in accordance with the invention comprises containers placed in spaces within and between the tyres of the vehicle, balancing box-type structures, box-type structures simultaneously providing buoyancy and acting as bodywork, and active balancing means associated with the vehicle and the trailer. The con- tainers in the tyres act simultaneously as coupling means for eventual twin tyres. The coupling means are advantageously attached with fast couplings. Alterna¬ tively, the containers in the tyres can be implemented separately, whereby they are placed into a normal twin tyre construction with suitable coupling means. The balancing containers, suitably chosen for right volume, are located in places de- termined by means of a displacement analysis, to the front, back and sides of the tractor. The balancing means comprise a transversal beam, having actuators in its ends for providing an active balancing force. The trailer is balanced with respect to turning about its longitudinal axis by means of the actuators, which also as effect on the weight distribution of the combination as a whole.

The invention will be described in more detail in the following by means of exam¬ ples of some advantageous embodiments, with reference to the enclosed draw¬ ings.

Figure 1 is a cross-sectional view of some equipment in accordance with the invention, installed in and between the tyres of the vehicle, to provide buoyancy.

Figure 2 is a side view of an amphibian vehicle realized by means of the equip¬ ment in accordance with the invention, floated by displacement.

Figure 3 shows the trailer of the vehicle of Fig. 2, as a section along the line A-A.

Figure 4 shows the trailer of the vehicle of Fig. 2, seen from the drawbar side.

Figures from 1 to 4 illustrate the equipment for floating the vehicle 1 and the trailer 9, and the transforming of a standard vehicle to an amphibian vehicle by means of said equipment. The equipment comprises first containers 4 within the twin tyres 3, 6 attached to disc wheels 2, and second containers 5, placed between the tyres 3, 6, with coupling means. The equipment also comprises balancing third containers 7 associated with the tractor and floating boxes 8 associated with the trailer and active balancing means 10 between the vehicle 1 and the trailer 9, as well as pro¬ pulsion means 12, if necessary.

A disc wheel 2 is attached to the hub of axle 1a with conventional coupling means 2a, the first container 4 being attached thereto with coupling means 2b. The first container 4 is preferably cylindrical, and it is accurately fitted within the tyres 3 and 6. The tyre 6 is attached to the first container 4 with coupling means 4a. The cou¬ pling means 2b, 4a are preferably fast couplings. Preferably, an annular second container 5, is arranged between the tyres 3 and 6 before installation of the outer tyre 6, said container being attached ultimately when more pressure is added to the tyres 3 and 6. The second containers 5 can be replaced with tyres 3 and 6 having as much more volume as the volume of the second containers 5. The first container 4 can also be realized as a separate construction within the tyres 3 and 6 connected to the twin tyres.

The balancing third containers 7a, 7b, 7c are make-specific by form, and their vol¬ ume and disposition are determined according to the balancing and buoyant force analysis.

The floating boxes 8 are arranged in the space defined by dimensions and ground clearance of the trailer 9. They can act simultaneously as bodywork, whereby a more lightly constructed trailer can be chosen for the combination with an amphib¬ ian application.

The active balancing means 10 comprise a transversal beam 10a having actuators 10b attached to its ends. The longitudinal balancing means 10c is attached be¬ tween the trailer bar and the tractor mainly parallel with the longitudinal axis of the combination.

The propulsion means 12, such as a turning propeller apparatus, can be placed to the front, back and sides of the tractor. In an advantageous embodiment the transmission of the propeller apparatus is hydrostatic and the turning is achieved by means of hydraulic cylinders. The transmission of the propulsion means 12 can also be realized mechanically, for example, by means of output shafts.

In an advantageous embodiment, the containers 4, 5 and 7 and/or boxes 8 can be filled with a pressurized medium having low density, to make them stronger against external pressure and can therefore be made with a smaller wall thick¬ ness. Alternatively, the containers can be filled with lightweight material, such as non-wetting polystyrene. When necessary, the open space of the trailer 9 can be sealed with sealing means 11 , to gain additional bearing capacity.

The equipment in accordance with the present invention functions as follows. The parallel tyres 3, 6 of the combination are equipped with first and second containers 4, 5 and the balancing third containers 7 are selected and placed within the body of the vehicle, to places determined by the balancing and buoyant force analysis. The floating boxes 8 are connected to the trailer and the active balancing equip¬ ment 10 is coupled between the trailer 9 and the vehicle 1. The combination func¬ tions on dry land in the normal way, since the ground clearance and the outer di- mensions of the vehicle remain unchanged. When driven to a surface with less bearing capacity, there is no risk of sinking, since the floating containers and boxes are perfectly sealed. When the surface further fails, the combination be¬ comes carried by displacement completely, whereby progressive movement is effected by the drive wheel tyres 6, 3 of the combination. Moving and steering purely in water can be enhanced by means of the propulsive apparatus 12. Bank¬ ing of the trailer with respect to the longitudinal axis thereof with different loads is adjusted with active balancing elements 10a, 10b, advantageously attached to suitable arms 1b, such as the lifting arms of the tractor. The mutual weight distribu¬ tion of the trailer 9 and the tractor 1 can be controlled by means of an actuator 10c, that can be, for example, a hydraulic cylinder. One end of the actuator 10c is attached to the trailer drawbar 1d and the other end to the tractor. The centre of gravity of the combination can be moved to the desired direction by lifting and low¬ ering the trailer by means of the actuator 10c.

The figures and the associated description are meant only for illustration of the present invention. The equipment can vary with respect to its details within the enclosed claims and the inventive idea disclosed by the description of the inven¬ tion. It will be clear for those skilled in the art that the technical solutions of the equipment can vary depending on the purpose of use. For example a car can be equipped with balancing and floating containers mounted within the construction, and it can also be equipped with propulsion means. The embodiments of the in¬ vention can vary depending on the operating conditions and the needs of the cus¬ tomer, as well as the solutions of manufacturing to be taken into use in connection with the production.