The invention concerns a vehicle with front-wheel drive, in particular a bicycle, a motorcycle or a delivery tricar. It is a known fact that vehicles, such as bicycles, motor- cycles and delivery tricars consist of a frame bearing at its front end a wheel which is connected through a fork revolving by means of a steering, which is connected to the frame in correspondence with a steering column. Attached to the rear end of the frame there are two wheels, in the case of a delivery tricar or a single wheel in the case of bicycles or motorcycles, which are driven by a propelling device. The propelling device is an endothermic motor in the case of motorcycles and for delivery tricars or it consists of a pair of pedal cranks with pedals in the case of bicycles. The vehicles of the just described type have in common the • characteristic that the rear wheels or wheel are the dri- ving wheels, while no vehicle of this type is known, where the front wheel is a driving wheel. It is, therefore, the purpose of the present invention to disclose a vehicle wherein the front wheel becomes the driving wheel by means of a propelling device, which drives it through transmission means. The just described purpose is reached by means of a vehicle which, in accordance with the main claim comprises a frame associated with: - a front wheel coupled with a fork, the latter being connected with the steering column of the frame and atta- ched to the steering; - at least one rear wheel connected with the rear end of the frame; - a propelling device associated with the frame for the generation of power, and is characterized in that the front wheel is made motive a gear-wheelwork associated with the vehicle frame in corre-

spondence with the steering column, said gear-wheelwork presenting an ingoing shaft which is rigidly attached to the steering column and is connected through driving means with the propelling device, which drives it into rotateion and at least one outgoing shaft, rigidly attached to the fork and connected through more driving means with the front wheel, which it drives. A front-wheel driven vehicle presents undoubtedly some advantages according to the type of vehicle and its use. If the vehicle is a delivery tricar with two or more rear driving wheels, the possibility of having also a front- drive wheel means to obtain an all-wheel driven vehicle offering on rough, muddy or yielding grounds, in general, a larger degree of safety than offered by analogous vehicles with rear-wheel drive only. Moreover, advantegeously and always in the case of a deli- very tricar, the fact of making the front wheel a driving wheel permits also to render the rear wheels idle, thereby eliminating the differential, if there is an interest in achieving that, so that it becomes less costly to manufac- ture the vehicle. On the other hand, if the vehicle is a bicycle or a motor - cycle , the all-wheel drive also offers an undoubtable advantage of driving safety and an improved grip on the ground . More specifically, the all-wheel drive in motorcycles can advantageously be useful in the curves and during competi- tions, when the maximum grip on the ground is required in order to always guarantee the maximum transmission of power and/or torque. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific example, while indicating a preferred embodiment of the invention, are given by way

of illustration only, since various changes and odifica- tions within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description and from the drawings, wherein: -Fig. 1 represents the vehicle with the front-wheel drive being the object of the present invention; - Fig. 2 shows in an axonometric view the detail of the gear-wheelwork for the driving of the front wheel; - Fig. 3 shows a longitudinal cross-section of the gear- wheelwork of Fig. 2. It will be specifically pointed out that the following description refers to a specific two-wheel vehicle, a bicycle in this case, wherein both wheels are driving whels. It is, however, understood that the two-wheel vehi- cle could also be a motorcycle or even a delivery tricar wherein both the front wheel and the rear wheels are dri- ving wheels. The same description in general can also apply for vehicles wherein the front wheel only is a driving wheel. As can be observed in Fig. 1 the two-wheel drive vehicle according to the invention, in this case a bicycle, indica- ted as a whole with 1, comprises a frame, indicated as a whole with 2, with which a pair of wheels is associated. The front wheel 3 is coupled with the front fork 4, which is connected with the steering column 5 of the frame and is attached through a tie-rod 18, visible in Fig. 3, to the steering, in this case a handle bar 6, while the rear wheel 7 is attached to the rear fork 8, which is part of the frame 2 and is an integral part thereof. The rear wheel 7 is a driving wheel thanks to a propelling device, indicated as a whole with 9, which in the specific case of the bicycle referred to in the description consists of a pair of pedal cranks 10, which are driven into rota- tion by the pedals 11, said pedal crank being arranged at the opposite sides of and coaxial with a chain wheel 12.

Through chain 13 the chain wheel 12 drives a pinion gear 14 co-axially attached to hub 15 of the rear wheel 7. Positioned co-axially to the chain wheel 12 there is anot- her chain wheel 16 which through other driving means - in this case again a chain 17 - transmits the rotation of the propelling device 9 to a gear-wheelwork, indicated as a whole with 20, being associated with frame 2 of the vehicle in correspondence with the steering column 5, said gear wheelwork 20 being visible in better detail in the Figs. 2 and 3. When chain 17 engages a cogged wheel 21 positioned at the end of an ingoing shaft 22, it drives a bevel pinion 23 belonging to the gear-wheelwork 20. Said bevel pinion 23, as can be observed in. Fig. 3, belongs to an upper set of four bevel pinions, indicated as a whole with 24, to which another bevel pinion 25 also belongs. Said bevel pinions • constitute a pair of crown pinions 23 and 25 facing each other, their bevelled surfaces converging and being co- axial. These crown pinions in turn engage a pair of side pinions 26 and 28, also being co-axial with each ^" other. It can be observed that, while the crown pinions 23 and 25 present their pivots, 27 and 29 respectively, matching within seats obtained in the steering column 5 of the frame through the interposition of the ball bearings _, 57 and 59, the side pinions 26 and 28 are co-axially arranged with tie-rod 18 which permanently connects the front fork 4 with the handle-bar 6. Below the upper set of four bevel pinions 24 there is a lower set of four bevel pinions, indicated as a whole with 34. In the same way as the previously described set, this set consists of a pair of crown pinions, 33 and 35 respec- tively, which engage corresponding side pinions, 36 and 38 respectively. In this case, too, the crown pinions present their pivots, 37 and 39, matching withing seats obtained in fork 4 and supported by ball bearings 70 and 69, while the

side pinions are co-axial in this case, too, with the tie- rod 18 joining fork 4 with handle-bar 6. It will be observed that the crown pinion 35 is connected with shaft 32, which supports at its end a cogged wheel 31 engaging driving means 47, for instance a chain, which is better visible in Fig. 1, which engages a corresponding pinion 48, attached co-axially with hub 49 of the front wheel 3. The two sets of four pinions, the upper 24 and lower 34 respectively, are kinematically connected, since, through connecting means, for instance the pegs 50, the side pinion 28 of the upper set 24 is connected with its corresponding side pinion 36 in the lower set 34 in correspondence with their flat mutual surfaces 51 which are matched with each other. When the ingoing cogged wheel 21 is driven in direction 91 by chain 17, the bevel pinions of the gear-wheelwork 20 drive the outgoing cogged wheel 31, which rotates in direc- tion 71, which is the same as direction 91 followed by the ingoing cogged wheel 21. The wheelwork 20, because of the way it is built, acts in the substance as a differential. In fact the cogged wheel 31 besides performing a rotational movement around its own axis 61 can also accomplish, at the same time, a revolving movement around the vertical axis 52, said movement being impressed upon it when, by moving the handle-bar 6, fork 4, with which said outgoing cogged wheel 31 is rigidly connected through its shaft 32, is caused to rotate in direction 53. It is easy to understand that this fact is crucial in order to permit the transmission of the movement from the propel- ling device 9, consisting in this case of the pedals 11, to the front wheel 3, thereby allowing the steering of the bicycle. In fact, when chain 17 tramsmits the rotation from the pedals 11 to the ingoing cogged wheel 21, for instance with direction 91, the latter drives the wheelwork 20 and

causes the outgoing cogged wheel 31 to rotate in direction 72, which is the same as direction 91. The cogged wheel 31 through chain 47 and pinion 48 insures in turn the drive of the front wheel 3. When the cyclist steers, the outgoing cogged wheel 31 follows in its rotation fork 4 of the front wheel 3 which is associated with it, the rotation occurring, for instan- ce, in the direction of arrow 53 represented in Fig. 3, while maintaining the co-planarity of the cogged wheel 31 with pinion 48 and permitting thereby the continuation of the transmission of the movement through chain 47 which, by always operating on the same plane, is in no way influenced by the rotation induced by the handle-bar 6 on fork 4. In fact the cogged wheel 31 not only can rotate around its own axis 61, it can also accomplish at the same time a revol- ving movement around the vertical axis 52 which is impres- sed on it when, by rotating the handle-bar 6, fork 4, with which said outgoing cogged wheel 31 is rigidly connected through its shaft 32, is caused to rotate in the direction of arrow 53. On the basis of what has been described it can be under- stood how the vehicle described, a bicycle in the example, according to the teachings of the invention permits to obtain a vehicle with both driving wheels, said driving wheels being driven by the single driving unit associated with the frame. In a different embodiment it is possible to make the front wheel the single driving wheel. In this case it suffices to eliminate chain 13 transmitting the motion to the rear wheel 7. As has already been said, the vehicle can indifferently be a motorcycle of any type, rather than a bicycle, or even a delivery tricar. In these cases, too, the rear wheel can be a driving wheel or not. Possible changes in the shape, dimensions, number of cogs

and means for the transmission of the movement between the cogged wheels, which can be belts or other means, such as for instance couplings through endless screws, helicoidal wheels or others, instead of chains, are all to be conside- red to fall within the spirit and scope of the present invention.