The present invention relates to the field of the two-wheel vehicles, in particular to bicycles. More specifically this invention concerns a device for changing the riding position as a function of the slope of the road in case both of paved roads and unpaved roads.

The bicycle is a widespread means of locomotion and recreation and has been improved over the years. The innovations and improvements, however, have not modified the basic structure, i.e. a two-wheel means driven by leg muscle strength.

Bicycles adapted to dirt roads and rough terrain have been recently made, while the use of variable-ratio drive systems and highly effective brakes has permitted the use of bicycles on impassable hills and prohibitive downhills as is the case with the so called "mountain bikes".

Heretofore, the now possible use of the bicycle under such prohibitive conditions has evidenced a problem intrinsic in the medium that is the rigidity of its geometrical shape and its consequent sensitivity to the slope and characteristics of the road.

The bicycle in fact does not offer the cyclist any particular driving difficulty both on flat and regular terrain. Under such conditions the position of the whole bicycle-cyclist is sufficiently stable; the centre of gravity of such whole is well centered with respect to the two supports, i.e. the contact points

between wheels and ground; and the weight of the cyclist is uniformly distributed on the two wheels.

The situation is different when going down a steep incline: the effect of a pronounced slope is to bring the vertical line through the centre of gravity and that through the point of contact between front wheel and ground dangerously" close together . Under such conditions _r the load resting on the back wheel is lower than that on the front wheel so that the back wheel loses its adherence to the ground; moreover in this case the effective brake is only that of the front wheel, and abrupt use of it can cause the bicycle to overturn. The cyclist tries to face this situation by stretching the arms as far as possible and moving the body back until his stomach brushes against the saddle.

Conversely, in the case of a steep hill the vertical line through the centre of gravity and that through the point of contact between back wheel and ground near each other. Under such conditions, the load resting on the front wheel is lower than that on the back wheel so that poor adherence of the front wheel makes steering very hard. The strong pressure exerted on the pedals to the slope is transmitted to the gears integral with the back wheel so that the bicycle tends to rotate about the hub of the back wheel with the danger of overturning. Under such conditions, the cyclist moves the weight of his body forward and rides standing on the pedals.

A simple device ^" so called "Hite-Rite" has been proposed to try to face these problems and consists of a spring inserted under pressure between the saddle and the

frame so as to raise the saddle. According to whether the cyclist rests on the saddle with all his weight or rides standing on the pedals, he will release the stopping device of the saddle tube and make such tube slide inside the saddle column so as to modify his position on the bicycle, and then he .will block the saddle again. Although this device is a first attempt to make the riding position variable, it is very little used because of the limited extension of the saddle tube and other problems such as the increase of the distance between handlebar and saddle upon raising of the latter.

The present invention seeks to overcome in a functional and effective way the problem mentioned above by means of a device of simple mechanical design and reliable operation which can be provided both upon manufacturing the bicycles and under the form of a kit ready for assembling and installing on already existing bicycles. According to the invention a device is provided to make both handlebar and saddle movable with respect to the frame of the bicycle, the two movements being correlated to each other so that the raising of the saddle corresponds to the lowering of the handlebar and viceversa. In addition the cyclist can control such movements by blocking and releasing the device so as to modify at will his riding position whenever he likes it. The paths of saddle and handlebar can also be different.

This invention will now be described with reference to the annexed drawings which show by way of an

illustrative non-limitative example a preferred embodiment of the invention. In the drawings:

Fig. 1 shows schematically the device in the oleodynamic embodiment;

Fig. 2 shows a merely mechanical embodiment;

Fig. 3 shows the angular position of the sleeve supporting the saddle with respect to the vertical in conventional bicycles;

Fig. 4 shows a positive angular position of the sleeve supporting the saddle with respect to the vertical;

Figs. 5 and 6 show the equilibrium of the weights in a conventional bicycle in a descent and in a hill, respectively;

Figs. 7 and 8 are views similar to Figs. 5 and 6 which show the riding position and the equilibrium of the weight of a bicycle provided with the device according to the invention;

Fig. 9 show an embodiment provided with a shock absorber;

Fig. 10 shows an embodiment which provides at the same time different paths of the two sleeves relative to the saddle and the handlebar; - -

Fig. 11 shows the device of the invention applied to the

already existing bicycles.

With reference to Fig. 1 both sleeve 10 supporting the saddle and stem 11 of the handlebar can slide in their respective housings; chamber 12 and chamber 13 of the frame are completely filled with oil and the passage of oil from one chamber to the other is subjected to the opening of gate valve or cock 14. When facing a hill, the cyclist turns the cock 14 and causes the handlebar to lower and the saddle to raise by standing on the pedals and pressing the handlebar until the desired position is reached. When turning cock 14 off, the whole assembly is blocked in its position because of the incompressibility of the oil until it is operated again.

When facing a downhill, the cyclist carries out opposite actions: opening cock 14, pressing the saddle so as to cause it to lower, raising the handlebar, closing the cock, and blocking the assembly. The decisive advantage of such system is that of maintaining the position of the cyclist with respect to the horizontal unchanged and optimum by compensating the variations of the position of the cyclist to the bicycle. Such positive effect can be enhanced by providing a construction expedient in the design of the frame.

In the known frames the sleeve supporting the saddle is housed inside a column which tipically is inclined by some degrees backwards to the vertical, as can be seen in Figure 3. This produces the opposite- effect to the adjustment of the height of the saddle. As

already seen, such height should be increased when facing a hill and viceversa; with the design of the present state of art, however, the raising of the saddle causes also the cyclist to move back, whereas a forward movement would be necessary.

When going.downhill, the opposite situation occurs, i.e. an undesirable ^' forward movement of the saddle when it is lowered.

To avoid this inconvenience, an arrangement can be provided in order to increase the efficiency of the device according to the invention. The frame should be designed so as to allow the sleeve 10 supporting the saddle to slide along a direction forming a positive (instead of negative) angle with the vertical. This can be achieved by constructing sleeve 10 so as to be introduced in a tubular column 21 in line with the back fork 22 (see Fig. 4). If necessary, it can be made in a split form to increase the sliding range allowed in the two vertical sleeves. The same split can also be made in the stem supporting the handlebar.

The invention allows the object of maintaining an optimum riding position on the bicycle to be achieved by the positive angle of the sleeve supporting the saddle even in case of variation of the characteristics of the road.

A mechanical embodiment is shown in Fig. 2. In this case an oscillating arm 15 pivoted at the frame supports at one end the saddle 16 and at the other end a collar 17 in which the sleeve 18 of the handlebar can rotate without sliding and can slide without rotating in

a suitable casing 19 integral with the fore fork. A mechanical blocking and releasing device formed of a manual control lever 20 which can be provided on the handlebar allows the riding position to be varied and fixed at will.

The effectiveness and the validity of the device according to the invention can easily be appreciated by comparing Figures 5 and 6 with Figures 7 and 8, respectively. In such figures the centre of gravity G of the whole cyclist-bicycle is vertically projected to the ground, while A and B are the vertical passing through the points of contact between wheels and ground.

In the opposite conditions of steep hill and descent it is evident that the riding position on a conventional bicycle can become unbalanced and dangerous, while the described device under such extreme conditions can allow the cyclist to assume a well balanced and safe riding position as the vertical through the centre of gravity G is generally centered with respect to A and B. The use of a bicycle in competitions on rough roads made it necessary to absorb or dampen the intolerable effects that the high speed and the rough ground cause to the cyclist. To this purpose suspensions for both wheels have been provided, and in other cases the mount of the handlebar or the support of the saddle have been fitted with springs always at the cost of considerable construction complexity.

The present invention allows the same effect to be easily and effectively achieved. With reference to the oleodynamic embodiment, for example, the springing effect

can be provided by a simple construction arrangement relative to the sleeves supporting the saddle and the handlebar which can slide in the respective columns, as shown in Fig. 9. Sleeve 23 includes a chamber 24 closed by an air-tight sliding plunger 25. Such chamber 24 is filled with compressed air through valve 26, and spring 27 opposes the sliding of the plunger outwards. As a result, the saddle (or the handlebar) mounted on such sleeve is protected from impacts and jumps by a compressed air cushion between the saddle or the handlebar and the frame.

The spring suspension can be adjusted to be harder or softer by suitably regulating the amount of air let into chamber 24 through the above-mentioned valve 26. It should be noted that the movements of the saddle and the handlebar made at the same time but in opposite directions should not be necessarily the same. The ratio between the two travels can be determined on the ground of particular design criteria and very easily put into practice. With reference to the oleodynamic embodiment, for example, such ratio (see Fig. 10) is inversely proportional to the ratio between the surfaces SI and S2 of the sections of the two sleeves 10 and 11, so that the two travels X and Y are regulated by the known proportion Y:X=S2:S1.

Conversely, in the mechanical embodiment, the travels of saddle and handlebar are only proportional to the distance of such elements from the fulcrum of their motions. In any case the travel of one element can be as much as possible reduced to zero, and the travel of the other element can be increased accordingly.

In Fig. 11 there is shown the oleodynamic embodiment consisting of a kit which can be applied to a conventional, already existing bicycle.

As can be seen in Fig. 11, the existing sleeve supporting the saddle and the sleeve supporting the handlebar are replaced by two different elements 10 and 11, respectively, which are manufactured according to the above-mentioned criteria and connected to each other by a hose 28 in which the described blocking and releasing device 14 is provided.

In the preceding description reference has been made to the bicycles but it is evident that the described device can also be applied to other two-wheels vehicles such as motor-cycles, scooters and the like.

The present invention has been illustrated and described according to a preferred embodiment thereof but it should be understood that construction modifications can be made by those skilled in the art without departing from the scope of the present industrial invention.