The present invention relates to an improved trailer and an articulated vehicle provided with such a trailer .

As known, the term trailer today identifies a vehicle intended to be coupled to a tractor vehicle for the transport of goods .

In general, the trailers are divided into two categories, depending on whether they have or not both front and rear wheels .

The trailers equipped only with rear wheels are known in the sector with the specific term of "semi- trailers" .

It is hereby specified that for the purposes of the present application, are identified with the term trailer only the trailers as such or those equipped with both front and rear wheels .

Usually the structure of the trailer includes a platform supporting the goods, underneath of which are bound single or twin wheels.

Usually trailers pick up from the tractor vehicle the electric current necessary to any electrical equipment such as air conditioners, indicator lights, etc.

US7338335 describes an articulated vehicle equipped with a tractor vehicle and with a semi-trailer.

Such a semi-trailer is equipped with power accumulators, of the solar panels type, connected to batteries integrated in the tractor vehicle. If necessary, these batteries provide power to the wheels both of the tractor vehicle, and of the semi-trailer to reduce fuel consumption.

FR2854122 describes another example of an articulated vehicle equipped with a tractor vehicle and a semitrailer .

Such articulated vehicle is provided with a control unit of the tractor vehicle motor drive and the secondary motor drives attached to the wheels of the semi-trailer in the case wherein, according to preset parameters, extra power is required compared to the single motor drive of the tractor vehicle.

Both embodiments described in FR2854122 and US7338335 have the common drawback of not allowing movement of the trailer in the absence of a tractor vehicle or an inoperative tractor vehicle.

Beyond the fact that these documents show only semitrailers, even when these semi-trailers were equipped with front wheels, they would not be able to move independently when uncoupled from the tractor vehicle because either the control, according to FR2854122, and/or the power supply, according to US7338335, of the motor drives of the wheels of these trailers are integrated on the related tractor vehicles.

Once failing the tractor vehicle, inevitably fails the power supply, according to US7338335 or the control according to FR2854122 of the trailer wheels which, although motorised, they could not be activated and controlled .

Currently, are also known trailers provided with steering wheels to reduce the turning radius, and the wear of the tires, and of motor drives acting directly on the wheels of the trailer thereof.

Examples of such trailers are described in patent applications IT2006PD00213 and IT2009TO0089 , where they respectively provide hydraulic steering cylinders and hydraulic motor drives for activating the wheels. This last embodiment has the advantage of having a further traction acting on the trailer wheels, a useful configuration in emergencies, such as for example the presence of snow on the road surface.

However also this embodiment has the same drawback highlighted previously for the non-motorised tractor vehicles since the hydraulic circuits provided to operate correctly must be necessarily connected to the motor drive and the hydraulic system of the tractor vehicle .

In other words, even these trailers equipped with hydraulic motors to be moved, expressly require the presence of a tractor vehicle from which to take power. Object of the present invention is that of producing a trailer able to solve the above mentioned drawbacks of the prior art in an extremely simple, economical and particularly functional manner.

Another object is that of producing a trailer equipped with a motor drive for activating at least the rear wheels entirely independently, both in power supply and in activation, with respect to the tractor vehicle and therefore able to move the trailer even in the absence of the tractor vehicle thereof or to move directly the articulated vehicle, which integrates it under inoperative tractor vehicle conditions.

These objects according to the present invention are achieved by producing an articulated vehicle and a trailer as set forth in the independent claims.

Further characteristics of the invention are highlighted by the dependent claims.

The characteristics and advantages of an articulated vehicle and a trailer according to the present invention will become more apparent from the following by way of example and non- limiting description, with reference to the attached schematic drawings wherein:

- Figure 1 is a perspective view of a trailer according to the present invention;

- Figure 2 is a bottom view of a first embodiment of a trailer according to the present invention;

- Figure 3 is a bottom view of a second embodiment of a trailer according to the present invention;

Figure 4 shows a perspective view of a motorised wheel of the trailer of Figure 2;

- Figure 5 shows a perspective view of a motorised wheel of the trailer of Figure 3;

- Figure 6 shows the power supply and the movement of the wheels of the trailer according to the present invention; and

- Figure 7 is a side view of an articulated vehicle according to the present invention.

With reference to the figures, it is shown with 10 an embodiment of a trailer according to the present invention and with 100 an articulated vehicle equipped with a tractor vehicle 10 ¹ and of such a trailer 10.

The trailer 10, as all the trailers of the known type, is of the selectively type attachable to a tractor vehicle 10' provided with a main motor drive.

The description of the means and the devices for the connection and uncoupling of the trailer from the tractor vehicle will not be detailed, nor shown because they are of the known type . This trailer 10 includes a platform 11 for supporting goods to be transported, at least one pair of rear wheels 12, 13 and at least one front axle 30 equipped with front wheels 12 ' , 13 ¹ .

The presence of both front and rear wheels actually makes the trailer of the same movable type in absence of a tractor vehicle 10'.

However, to make such a possibility concrete, namely to move the trailer even in absence of a tractor vehicle, according to the invention at least one rear wheel 12, 13 is equipped with a motor drive power supplied by batteries 15 directly integrated in the trailer 10 and activated independently with respect to the tractor vehicle .

In other words, both the power supply, and the activation of the motor drive of the rear wheels 12, 13 are independent with respect to the tractor vehicle. This macro difference distinguishes the present invention from the prior art US7338335 and in particular from FR2854122 where, even by assuming that the described semi-trailers were equipped with front wheels, the batteries and the control of the trailer wheels are integrated into the tractor vehicle and not in the trailer thereof.

On the other hand, the problem of being able to move the semi-trailer even in absence of the tractor vehicle is not even cited in these documents, which only wish to provide a solution concerning the problem of having a greater start to the articulated vehicle or when the latter is under emergencies.

The present invention aims instead of solving another problem, or better still, offers all the qualities of the vehicles described in FR2854122 and US7338335 with, in addition, the ability of being able to move the trailer even in absence of a tractor vehicle or with inoperative tractor vehicle.

Since the faced problems are therefore different, it is deemed that FR2854122 and US7338335 are completely unrelated to the spirit and purpose of the present invention .

In other words, a skilled person in the sector, by analysing FR2854122 and US7338335, would never reach the solution proposed by the present invention because these documents relate expressly only to semi-trailers and because they do not mention at all to the problem of being able to move the load in absence of a tractor vehicle.

As further confirmation of this, FR2854122 expressly provides for the presence of an electronic interface between the tractor vehicle and the trailer power supply.

Therefore, in an extremely advantageous manner, according to the invention, on the one hand the trailer can be moved even when unhooked from the tractor vehicle, for example in manoeuvres for loading/unloading of goods, and on the other hand the articulated vehicle that incorporates such a trailer can be pushed into movement simultaneously by the motor drive of the main tractor vehicle and by the secondary motor drive of the trailer, or by only one between the main motor drive of the tractor vehicle and the secondary motor drive of the trailer.

Figure 7 shows how the rear wheels are powered by the batteries 15, line F of the power flow is shown schematically, and how the front axle 30 is revolving, rotation R, around a central vertical pin 31 is shown schematically.

In particular, this vertical pin 31 is of the movable type between a lowered position, wherein the front wheels 12 ' , 13 ¹ touch the ground for the independent movement of the trailer 10 even in absence of the tractor vehicle 10 ' , and a raised position to allow coupling of the trailer 10 with the tractor vehicle 10 ¹ .

Of course, depending on the requirements, embodiments can be provided wherein some wheels are motorised and others are idle, or they are all motorised.

Associated with the wheels, braking devices can naturally be provided, preferably independent for each wheel .

According to the shown embodiments , the motor drive of the trailer wheels comprises at least one electric motor 14 powered by at least one battery 15 located below the platform 11.

According to two different embodiments, the motor- driven wheel shown in the figure is not steering, while that in Figure 5 is equipped also with a steering motor drive .

As for the traction motor drive, also the steering motor drive of the trailer 10 wheels is operable in an independent manner with respect to the provided motor drive in the tractor vehicle and comprises an electric motor 16 connected to the aforementioned battery 15.

Finally, concerning the solutions shown related to the trailer 10 motorised wheels, solutions that represent some of the possible embodiments of the invention, they provide a pneumatic suspension 17, a damper 18 and a direct attachment upper frame 19, 20 to the platform 11 or an intermediate chassis.

In the embodiment wherein the motorised wheels are also controlled in steering, Figure 5, this upper frame 20 includes a disk 21 on the circumference of which is mounted a revolving bearing 22.

This bearing 22 is engaged with a toothed wheel 23 which is driven by the electric motor 16 and/or by a reducer 24 located downstream of the motor 16 thereof.

The possibility of the steering motorised activation of the trailer wheels allows performing manoeuvres otherwise problematic, such as a reversing manoeuvre. This manoeuvre may advantageously be operated from the tractor vehicle cab, or even in another remote location, away from the tractor vehicle, by means of a joystick control device, even of the wireless type, of the motor drives associated to the trailer wheels.

This joystick device is nothing but an example of one of many possible embodiments of the control means of traction and steering of the trailer wheels independent from traction and steering means of the tractor vehicle wheels .

Contrary to what is provided in FR2854122, the present invention provides precisely control means of traction and steering means of the trailer wheels independent from the control of the tractor vehicle wheels.

It is quite easy to understand the function of the trailer object of the invention, both when associated to a tractor vehicle and when disconnected from the latter .

As described, the trailer according to the present invention comprises motor drives acting on the wheels thereof entirely independent, both in power supply and in drive, in relation to the tractor vehicle.

In this way, it is possible to move the trailer in absence of a tractor vehicle, or the motor drive of the trailer can supply additional traction or alternative to that supplied from the tractor vehicle.

An additional traction may be useful in emergencies, such as for example in the presence of snow.

An alternative traction to the motor drive may be useful, besides reducing fuel consumption, to move the articulated vehicle into areas inside of which is prohibited the use of endothermic engines which cause pollution, or in case of failures to the motor drive of the tractor vehicle.

Furthermore, in the embodiment wherein the trailer wheels are of the steering type, that is, controlled in steering, and on the one hand is reduced the steering angle and the consumption of the tread, and on the other hand, more importantly, the trailer can steer even in absence of a tractor vehicle or with tractor vehicle with inoperative motor drive.

It is thus seen that a trailer according to the present invention achieves the purposes outlined previously.

Differently from the known documents US7338335 and FR2854122, in fact, the present invention has solved the problem of making the trailer moved even in absence of the tractor vehicle.

The trailer of the present invention thus conceived is susceptible of several modifications and variations, all falling within the same inventive concept; in addition, all details can be replaced by technically equivalent elements. In practice, the materials used, as well as their dimensions, may be of any type depending on the technical requirements.