EP2144585A2

EP2144585A2 - Vehicle with variable geometry for users with deambulation problems

Info

Publication number: EP2144585A2
Application number: EP08736310A
Authority: EP
Inventors: Arrigo Arletti; Mario Ramari
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-19
Filing date: 2008-04-17
Publication date: 2010-01-20
Also published as: WO2008128950A2; ITMI20070809A1; WO2008128950A3

Abstract

The present invention relates to a vehicle (1) with variable geometry for users (3) with deambulation problems. The vehicle according to the invention essentially comprises a frame (4) which supports a seat (5) for a user. The seat is connected to the frame (4) in an oscillating way so as to maintain a degree of freedom of oscillation about an axis of reference (R) substantially orthogonal to the direction of travel (D) of the vehicle. The seat is also connected to the frame so that the centre of mass thereof is located in a position between said axis of reference (R) and a supporting surface (M) on which the vehicle rests preferably through crawler movement means (18).

Description

VEHICLE WITH VARIABLE GEOMETRY FOR USERS WITH DEAMBULATION

PROBLEMS DESCRIPTION

The present invention relates to a vehicle to be used to transport users with deambulation problems. In particular, the present invention relates to a vehicle with "variable geometry", where this expression intends to indicate the fact that it is provided with one or more reciprocally movable parts, for example for the purpose of allowing architectural barriers, such as a kerb or a flight of stairs, to be overcome.

The use of vehicles to transport persons with deambulation problems, such as wheelchairs for the disabled and/or the elderly, is widely known. These vehicles generally comprise a frame with which there is associated a seat intended to support a person. In their most classic form, these vehicles are moved through a manual thrust that is exerted directly by the user seated on the vehicle or by an accompanying person. In recent years however, the majority of vehicles are motorized, i.e. provided with movement means comprising wheels or crawler assemblies operated by one or more electric motors. In particular, the crawler assemblies allow the vehicle, through the driving action exerted by the crawler belts, to overcome in a relatively easy manner complex obstacles such as an ascending or descending flight of stairs.

In almost all conventional vehicles, motorized or not, the seat is associated rigidly with the frame so as to rapidly follow the movements thereof. In other words, if the vehicle travels over a sloping surface, frame and seat slope in the same way according to the slope of this surface. It has been observed that this operating condition proves particularly disadvantageous for at least two reasons. Firstly, the position of the centre of gravity of the vehicle is sensitive to any movements of the user who, by moving on the seat, for example tilting the body with respect to the seat, contributes significantly toward moving the centre of gravity of the vehicle-user system. During travel of the vehicle on particularly steep surfaces, this condition can be dangerous as it can cause the vehicle to tip over.

Secondly, again in the hypothesis in which the vehicle is travelling over a particularly sloping surface, the rigidity of the frame-seat connection causes the user to experience an unpleasant feeling of tipping over, regardless of whether or not this actually occurs. Therefore, it is observed that in conventional vehicles the rigid connection between the seat and the frame does not allow acceptable travelling conditions during travel of the vehicle on sloping surfaces, both from the point of view of safety and from the point of view of user comfort. To overcome complex architectural barriers, such as flights of stairs, conventional vehicles, also those that are motorized, often make use of auxiliary lifting and transport devices which physically move the vehicle along the stair in descent or ascent according to requirements.

An example of these auxiliary lifting and transport devices is illustrated in the American patent US 4432426 which describes an auxiliary device provided with two crawler units which are shaped so as to allow an easy approach to the flight of stairs. The vehicle is placed operatively on a supporting surface provided on the auxiliary device so that the user has his or her back to the stair. The vehicle is then tilted toward the stair so as to maintain the centre of gravity in a position which prevents tipping over during travel of the device along the stair.

The European patent EP 0839 705 describes an auxiliary lifting device conceptually similar to the one described above. In particular, in this solution the auxiliary device is provided with a "lift platform" which is tilted with respect to the crawler units so as to maintain the vehicle in a horizontal position during movement of the device along the stair. In this case, a constant position of the vehicle-user system is maintained during travel of the auxiliary device along the flight of stairs, so as to prevent it from tipping over.

The use of auxiliary lift devices is disadvantageous for various reasons, the first of which can be identified in the fact that these auxiliary devices present decidedly limited functional versatility, being in the majority of cases functional to the flight of stairs that they require to serve and also create considerable problems of overall dimensions after use. Obviously, these auxiliary lift devices are somewhat disadvantageous also from an economic point of view, as their cost is added to the costs to be sustained for the vehicle.

The American patent US 4564080 describes a vehicle with variable geometry provided with two movement wheels that allow the vehicle to travel on a horizontal surface or in any case on a surface without obstacles. The vehicle is also provided with two lateral crawler assemblies which remain raised during travel of the vehicle on the level. In the presence of an obstacle, such as a stair to be ascended, the crawler assemblies are lowered through an articulated mechanism that simultaneously raises the movement wheels off the supporting surface. Advance of the vehicle on the stair is implemented through the crawler assemblies which by gripping the edges of the steps drive the vehicle up or down the stairs. Besides varying the support of the vehicle on the surface, the articulated mechanism causes tilting of the seat toward the stairs in order to move the centre of gravity of the seat-user system toward the rear part of the vehicle so as to prevent the vehicle from tipping over. The solution described above is accompanied by several drawbacks, the first of which being represented by the fact that the vehicle must always be oriented in the same manner to tackle a stair, regardless of the fact that this must be ascended or descended. In fact, according to the patent in question, to ascend a stair the vehicle must be oriented so that the user has his or her back to the stair. In other words, the vehicle cannot face the stairs being ascended. In fact, if the entry to the stairs were frontal the vehicle would inevitably tip over as the vertical line passing through the centre of gravity of the user-seat system would fall outside the support provided by the crawler means. This operating limit represents a serious drawback as it obliges the user to perform a series of manoeuvres aimed at positioning the vehicle correctly before ascending the stair. In practice, when the vehicle requires to ascend a stair, the user must rotate the vehicle by half a turn before starting to ascend the stair in reverse. It is apparent that this method of ascending represents per se a considerable drawback, added to which is the difficulty of manoeuvring in those cases in which the space available on the top landing is limited.

Another drawback related to the preceding solution and to the other conceptually similar known solutions is identified in the considerable longitudinal dimensions that accompanies the vehicle. In fact, the length of the vehicle and in particular of the supporting frame is related to the need to provide the vehicle with at least two supporting points during descending and ascending a flight of stairs. In other words, the useful length of the crawler belt and consequently of the frame must present a value greater than or at least equal to a minimum value equal to the distance between the edges of two consecutive steps in order to allow this operating condition. However, it must observed that currently this actual value imposed on the length of the vehicle limits the manoeuvrability thereof. In fact, this value only actually appears functionally useful when the vehicle is ascending or descending a stair. For example, if the vehicle requires to ascend two flights of stairs separated by a landing, if the dimensions of this landing are relatively small, the manoeuvrability of the vehicle could be unfavourably compromised. There is thus the evident need to provide alternative technical solutions to those described above which allow an architectural barrier to be approached frontally and also allow excellent manoeuvrability of the vehicle in small spaces.

On the basis of this consideration, the main object of the present invention is to provide a vehicle that allows the aforesaid drawbacks to be overcome. Within the scope of this aim, a first object of the present invention is to provide a vehicle that is capable of travelling over relatively sloping surfaces in total safety.

A second object of the present invention is to provide a vehicle that is capable of independently overcoming complex architectural barriers, such as ascending or descending stairs without recourse to auxiliary driving and/or lifting devices.

Yet another object of the present invention is to provide a vehicle that allows an architectural barrier to be overcome frontally without the user requiring to perform preliminary manoeuvres aimed at orienting the user according to a different direction from the normal direction of advance.

Another object of the present invention is to provide a vehicle that requires limited manoeuvring spaces or that presents limited longitudinal dimensions, while simultaneously ensuring high longitudinal and transverse stability of the vehicle, above all while overcoming said complex architectural barriers.

Another object of the present invention is to provide a vehicle that is reliable, easy to manufacture and at competitive costs.

This aim, these and other objects that will be more apparent below are achieved through a vehicle with variable geometry according to the claims in claim 1 and in the dependent claims.

The oscillating connection of the seat to the frame advantageously allows the user to maintain a constant position during travel of the vehicle. In fact, rotation of the frame, for example due to the change in slope of the surface on which the vehicle is resting, does not affect the seat due to the oscillating connection between the two parts. This contributes toward preventing the feeling of tipping that the user can experience if the vehicle is subjected to changes in slope or, for example, in the case in which it is ascending or descending a flight of stairs.

Another innovative aspect of the present invention is represented by the use of second movement means which advantageously allow the position of the axis of rotation of the seat to be moved with respect to the frame between predetermined positions. In this way the centre of gravity of the user-seat system and consequently of the vehicle can be moved toward the front part or toward the rear part of the vehicle according to requirements. In particular, the centre of gravity can advantageously be moved toward the front part of the vehicle when, for example, the vehicle is ascending a stair or toward the rear part when the vehicle is descending a stair. Moving the centre of gravity forward and rearward according to the obstacle to be overcome in fact allows the vehicle always to approach the obstacle facing forward according to one of the objects of the present invention.

Another aspect of the present invention is represented by the use of one or more front crawler extensions and of one or more rear crawler extensions, which are associated rotatingly with the frame. The use of these extensions advantageously allows the longitudinal dimensions of the vehicle to be limited while simultaneously ensuring the vehicle has an adequate supporting length during ascending and descent of the stair. According to the invention, the extensions take a position of minimum dimensions during normal travel of the vehicle, while they take one or more operating positions during ascent or descent of the stairs in order to provide further supporting points for the vehicle. In other words, the crawler extensions temporarily increase the useful supporting length of the vehicle in order to increase the manoeuvrability thereof, this being an advantageous characteristic above all in the presence of limited manoeuvring spaces.

Further advantages of the invention will be more apparent from the description of preferred, but not exclusive, embodiments of the vehicle with variable geometry according to the present invention illustrated by way of non-limiting example in the accompanying drawings, wherein:

Fig. 1 is a schematic view of a vehicle with variable geometry according to the present invention in a position travelling along a substantially horizontal surface;

Fig. 2 is a schematic view of the vehicle with variable geometry shown in Fig. 1 in a position descending (solid line) and ascending (dashed line) a sloping surface;

Fig. 3 is a view relative to positions taken by the seat of the vehicle of Figs. 1 and 2 with respect to frame of this vehicle;

Figs. 4, 5 and 6 show a possible embodiment of movement means of the seat with respect to the frame of a vehicle with variable geometry according to the present invention;

Fig. 7 is a view showing a vehicle according to the present invention provided with a pair of front crawler extensions;

Fig. 8 is a first view relative to a vehicle according to the present invention provided with a pair of front crawler extensions and with a pair of rear crawler extensions;

Fig. 9 is a second view relative to the vehicle shown in Fig. 8;

Figs. 9A and 9B are views relative to two possible operating configurations taken by the vehicle shown in Fig. 9;

Figs. 10, 1OA and 1OB are views relative to a possible embodiment of front crawler extensions of a vehicle according to the present invention;

Figs. 11, HA and HB are views relative to a possible embodiment of rear crawler extensions of a vehicle according to the present invention;

Fig. 12 is a partial sectional view of the vehicle shown in Figs. 8 and 9;

Fig. 13 is a further plan view of the vehicle shown in Fig. 12; Figs. 14 to 17 show a series of operating configurations taken by the vehicle shown in Figs. 12 and 13 while overcoming an architectural barrier composed of a single step in ascent;

Figs. 18 to 21 show a series of operating configurations taken by the vehicle shown in Figs. 12 and 13 while overcoming an architectural barrier composed of a single step in descent;

Figs. 22 to 32 show a series of operating configurations taken by the vehicle shown in Figs. 12 and 13 during descent of a flight of stairs;

Figs. 33 to 42 show a series of operating configurations taken by the vehicle shown in Figs. 12 and 13 during ascent of a flight of stairs;

With reference to the aforesaid figures, in particular to Fig. 1, the vehicle 1 with variable geometry according to the invention comprises a frame 4 which supports a seat 5 intended for a user 3. The frame 4 is provided inferiorly with first movement means 8 which allow movement of the vehicle 1 along a direction of travel indicated in the figures with the reference D. The vehicle 1 according to the invention is characterized in that the seat 5 is connected to the frame 4 in an oscillating way so as to retain a degree of freedom of oscillation about a substantially horizontal axis of rotation (reference R). The expression "connected in an oscillating way" is intended as a connection according to which the seat 5 can oscillate with respect to the frame 4 or can maintain a same position while the frame 4 moves following the slope of the surface being travelled along, this latter being intended as the surface (ground, road, etc.) on which the vehicle is resting and travels. This advantage is evident by observing Fig. 2, which shows the vehicle of Fig. 1 while it is travelling over a downward sloping surface (frame 4 and travelling surface M with a solid line) and an upward sloping surface (frame 4 and travelling surface M with a dashed line). In fact, it can be seen that the seat maintains the same position during upward and downward sloping travel while the frame 4 moves following the slope of the travelling surface M. The oscillating connection consequently allows the user to maintain a constant and stable position during travel of the vehicle preventing the user from experiencing the feeling of tipping that occurs with the use of conventional vehicles due to the rigid connection between seat and frame.

The vehicle 1 according to the invention is also characterized in that the seat 5 is connected in an oscillating way to the frame 4 so that its centre of mass G is placed in a position between the axis of reference R and the travelling surface M on which the vehicle 1 is resting through the first movement means 8. This technical characteristic, which compares the seat-user unit to a compound pendulum in stable equilibrium, amplifies the effect of stability provided by the oscillating connection making travel along sloping surfaces comfortable and safe. As will be described in detail below, this oscillating connection, cooperating with crawler movement means, will allow the vehicle to easily overcome even complex architectural barriers such as flights of stairs.

According to an advantageous embodiment, the vehicle 1 can be provided with a locking system that temporarily locks the seat 5 to the frame 4 preventing mutual oscillation between the two parts. In this way, a user can easily sit down on/get up from seat 5 without it starting to oscillate due to the oscillating connection. Once in the seated position, for example, the user can release the system to make use of the advantages deriving from the oscillating seat during travel of the vehicle 1. For this purpose, the vehicle could also be provided with safety belts for obvious and advantageous reasons.

With reference to Fig. 1 , the seat 5 is connected in an oscillating way to the frame 4 at two side members 4B substantially parallel with each other. The structure of each side member, at least in the essential form thereof, is composed of a front upright 4C and a rear upright 4E mutually connected through a longitudinal element 4D that supports the seat 5. The two side members 4B are mutually disposed at a distance that allows positioning of the seat 5 and define at respective lower portions, a front axle 15 and a rear axle 16 to which said first movement means 8 are keyed. In particular, these axles extend transverse to the two side members and respectively define a front axis 15A and a rear axis 16A for rotation of the first movement means 8 (see Fig. 3). In particular these front and rear axes are substantially parallel to each other and mutually positioned so that the axis of rotation R of the seat 5 with respect to the frame 4 is in an intermediate position of reference (indicated with N in Fig. 2) between these axes. Preferably, but not exclusively, the axis of rotation R is placed in a position corresponding to the centre line of the distance between the front axis 15A and the rear axis 16A defined by the respective axles.

According to a preferred embodiment of the invention, the vehicle 1 advantageously comprises second movement means 9 which have the function of performing a controlled movement of the seat 5 with respect to the frame 4, i.e. a variation of the position of the axis of mutual rotation R (see Figs. 4 and 5). This movement is preferably implemented along a direction of movement S substantially orthogonal to this axis of rotation R, i.e. to the front 15A and rear 16A axes of rotation. With particular reference to Fig. 3, the second movement means 9 allow a movement of the axis of rotation R between the intermediate position of reference and a first operating position (shown in Fig. 3 with a solid line and indicated with the reference A).

According to a preferred embodiment of the invention, the second movement means 9 also allow movement of the axis of reference R along the direction of movement S between the intermediate reference position N and a second operating position (shown in Fig. 3 with a dashed line and with the reference B) which can be considered substantially opposite the position A with respect to the intermediate position N. The use of these second movement means 9 advantageously allow the position of the centre of gravity of the seat-user system to be moved in a controlled manner with respect to the vehicle. In particular, passage from the intermediate position N to the first operating position A in fact represents a forward movement of the centre of gravity G toward the front part of the vehicle 1 (in particular toward the front axle 15), while passage from the intermediate position N to the second operating position B in fact represents a rearward movement of the centre of gravity G toward the rear part of the vehicle (in particular toward the rear axle 16).

Again according to a preferred embodiment of the invention, the first operating position A is determined so that its projection, calculated along a direction substantially orthogonal to the direction of movement S, passes through the front axis 15A identified by the front axle 15, while the second operating position B is determined so that its projection, calculated in the same manner, passes through the rear axis 16A defined by the corresponding rear axle 16.

As will be more apparent during the description, the possibility of moving the position of the centre of gravity forward or rearward allows the vehicle 1 to enter a flight of stairs always facing the front regardless of the fact that the flight is to be ascended or descended.

Figs. 4, 5 and 6 shows a first possible embodiment of the second movement means 9 according to the present invention which comprise at least a first element 21 associated with the frame 4, at one of the side members 4B, and a second element 22 connected in an oscillating way to the seat 5. The first 21 and the second 22 element are reciprocally coupled through a screw-nut screw coupling so that the second element 22 is able to translate with respect to the first element 21 to move the axis of mutual rotation R along the direction of movement S.

According to a preferred embodiment of the invention, the first element 21 is composed of a threaded bar 26 associated with a side member of the frame 4 and more precisely with the longitudinal element 4D of the same frame. The second element 22 instead comprises a bush 27 with internal thread from which there extends a first connecting bracket 31 coupled in an oscillating way, for example through a pin joint 44, to a second connection bracket 32 associated at one side with the seat 5. The bush 27 is coupled kinematically to the threaded bar 26 which is operatively connected to an auxiliary motor 29. This motor rotates the threaded bar 26 causing translation of the bush 27 according to the principle of the worm screw.

Fig. 5 is a schematic view illustrating a preferred embodiment of the invention according to which the second movement means 9 comprise a first pair of elements 21 predisposed on the two side members 4B of the frame 4 and at least a second pair of elements 22 connected in an oscillating way at opposite sides of the seat 5. Each element of the first pair of elements 21 is coupled to a corresponding element 22 of the second pair of elements 22 through a screw-nut screw coupling analogously to the indications above. As illustrated, the first pair of elements 21 is formed of a pair of threaded bars 26 which are predisposed along the longitudinal supporting element 4D of each side member 4B. Each threaded bar 26 is preferably operated by an auxiliary motor 29 which allows rotation thereof about the longitudinal axis. As is apparent in Fig. 4, the connecting brackets 31 and 32 are connected so as to define the axis of mutual rotation R between the seat and the frame 4 which in substance represents the axis of suspension of the "pendulum" in stable equilibrium formed by these two elements.

The vehicle according to the invention preferably comprises motor means 50 operatively connected to the first movement means 8 to provide the driving force required for travel of the vehicle. The motor means 50 are preferably electrically powered and for this reason the vehicle 1 is preferably also provided with electrical power supply means 55 such as conventional rechargeable electric batteries. As can be seen for example in Fig. 7, these power supply means 55 can advantageously be associated with the lower part of the seat 5 so that their weight contributes toward improving the stability of travel as permitted by the operating principle of the oscillating connection described above.

With reference 7 and 8 and according to a preferred embodiment of the invention, the first movement means 8 comprise a crawler assembly operated through the motor means 50 and associated with the frame 4 at the front axle 15 and the rear axle 16 indicated above. The use of a crawler assembly is to be considered preferable as it prevents the vehicle 1 from slipping above all during travel over uneven ground or in any case while overcoming architectural barriers (such as stairs or steps).

Figs. 12 and 13 respectively show a sectional view and a plan view of a vehicle 1 according to the present invention and allow a preferred embodiment of the crawler assembly according to the invention to be observed. In particular, this assembly comprises a pair of crawler units 35B operatively connected to the front axle 15 and to the rear axle 16 of the frame 4 each on one side member 4B of the frame 4. Each of these crawler units 35B comprises a front wheel 36 keyed to the front axle 15 and a rear wheel 37 keyed to the rear axle 16. Each unit comprises a crawler belt 38 which is operatively placed in such a way as to surround the front wheel 36 and the rear wheel 37. Each crawler unit 35B is also preferably provided with a tensioning element 39 associated with the frame 4 to maintain the crawler belt 38 tensioned during travel of the vehicle 1.

The front wheel 36 and the rear wheel 37 are connected to corresponding axles 15 and 16 so as to be located in a position between the two side members 4B of the frame 4. In this way the transverse dimensions of the assembly 35 is contained inside a volume (the one defined by the side members of the frame) required in any case for the structural stability of the vehicle.

As mentioned above, the use of the crawler assembly 35 is particularly advantageous as it allows the vehicle 1 to have a greater stability while overcoming uneven ground or obstacles due to the large supporting surface or due to the crawling and friction action generated by this crawler belt appropriately shaped for this purpose. During normal travel of the vehicle 1, the large supporting surface can needlessly reduce the travelling speed thereof. This could cause an undesirable functional limit, above all when the vehicle 1 is travelling over ground in good condition and/or with no obstacles and barriers and/or when changes in direction are to be made.

For this reason the vehicle 1 is preferably provided with one or more auxiliary wheels 14 associated with the frame 4, for example on the front axle 15 as shown in the sectional views in Figs. 12 and 13. The pivoting front auxiliary wheels 14, through a relative drive 14B (see Fig. 12) take an operating position thereof in which they maintain the vehicle raised at the front providing a relative supporting point and decreasing the contact surface of the crawler units 35B with the ground. In this way, travel of the vehicle is implemented with greater fluidity and easier manoeuvres. Once they have been withdrawn, for example in the presence of uneven ground or an obstacle, the vehicle 1 is supported fully by the crawler units 35B. Analogously, auxiliary rear wheels (not shown in the figures) can also be provided on the rear axle 16 of the vehicle for the purpose of facilitating parking of the vehicle after use thereof.

In order to allow the user to control the vehicle 1 directly, this latter can comprise a control unit 100 which controls at least the first motor means 50, in charge of activating the first movement means 8, and the second movement means 9 in charge of varying the position of the axis of mutual rotation R. The control unit 100 can advantageously also control the drive 14B in charge of activating the auxiliary wheels 14 and the front 70 and rear 80 crawler extensions described in greater detail below.

With reference to Figure 7, the vehicle 1 according to the present invention preferably comprises at least a front crawler extension 70 connected rotatingly to the frame 4 in proximity of the front axle 15. The front crawler extension 70 has the function of helping to overcome difficult architectural barriers such as kerbs and ascending and descending stairs. According to a preferred embodiment of the invention, shown in the figures, the vehicle 1 comprises a pair of crawler extensions 70 which are mounted rotatingly on opposite sides of the frame 4 preferably so as to be coaxial to the front axis 15A defined by the corresponding front axle 15. In particular, both crawler extensions are operatively connected on the outer side of one of the two side members 4B of the frame 4 (see plan view of the vehicle in Fig. 3).

Figs. 10, 1OA and 1OB are relative to a possible embodiment of the front extensions 70 which comprise a rearward wheel 71 keyed to a supporting structure 73 so that the centre of the rearward wheel 71 also defines a keying point 7 IB for the structure to the frame 4 of the vehicle 1. The supporting structure 73 extends symmetrically from the first keying point 7 IB to a second keying point 72B to which a forward wheel 72 is keyed. The extension 70 is then completed by a crawler belt 77 wound between the two wheels 71 and 72.

With reference to Fig. 9A, in the situation, for example, in which the vehicle 1 is about to ascend a stair, the front crawler extensions 70 are rotated from a withdrawn position to an operating position in which each crawler extension 70 is in contact with the first step S 1 of the stair. Reaching of the operating position provides the vehicle 1 with a first contact point with the stair favouring approach thereto. In other words, the use of the front crawler extensions 70 favours detachment of the vehicle 1 from the supporting surface PP preceding the stair, favouring alignment of this vehicle with the line of the steps T of the stair. Once the crawler belts of the crawler units 35B are in contact with the edge Sl of the first step Gl, the crawler extensions 70 can be withdrawn again leaving the task of moving the vehicle on the stairs solely to the crawler units 35B. Alternatively, the front extensions 70 can be aligned with the crawler belts of the crawler units 35B in order to increase the useful supporting length of the vehicle with the edges of the steps of the stair. In this case, the use of front crawler extensions 70 allows a considerable reduction in the longitudinal length of the vehicle 1.

With reference to Fig. 9B, when the vehicle 1 is on the last step GU it has to ascend, the front crawler extensions 70 can take a second operating position in order to provide the vehicle 1 with a supporting point on the landing PU at the top of the stairs. In this way detachment of the vehicle 1 from the stairs take place smoothly, without rapid movements caused by the change in slope. As can be seen in Figs. 9A and 9B, the front extensions 70 substantially make passage of the vehicle 1 from a substantially horizontal configuration, characteristic of the landing PP/PU at the bottom and/or at the top of a stair, to a sloping configuration, characteristic of the slope (line T) of the stair, and vice versa, continuous.

According to a preferred embodiment of the invention, the vehicle 1 comprises at least a rear crawler extension 80, which is associated with the frame 4 in a rotating manner in a position close to the rear axle 16. As for the front crawler extension 70, the rear crawler extension 80 also has the function of favouring travel of the vehicle 1 while overcoming complex obstacles. Also in this case, the vehicle 1 preferably comprises a pair of rear crawler extensions 80 which are mounted in a rotating manner on the two longitudinal side members 4B of the frame 4 in particular in proximity to the rear axle 16.

Figs. 11, 1 IA and 1 IB show a preferred embodiment of the rear crawler extensions 80 which comprise a first wheel 81 which is keyed to the rear axle 16 at a first keying point 8 IB. The rear extensions 80 also comprise a structure 83 which extends so as to take a substantially cam configuration. The rear extensions 80 are then completed by a rear crawler belt 88 operatively positioned so as to surround the first 81 and the second 82 wheel and so as also to surround a curved portion 84 of said structure 83. Figs. HA and HB are two views of the cam extension shown in Fig. 11 which is provided with a series of rollers 87 positioned along the curved section 84 of the structure 83 in order to favour movement of the rear crawler belt 88 mounted on this cam.

In accordance with the description above, the front 70 and rear 80 crawler extensions preferably take a withdrawn position during normal travel of the vehicle 1, this being intended as a travel on a flat surface with no obstacles. While ascending or descending a stair, at least one of the two extensions 70, 80 is positioned so that the respective crawler belt 77, 88 is substantially aligned with the crawler belt of the crawler units 35B according to the direction of travel of the vehicle (defined by the slope of the stair). This condition advantageously allows the length of the vehicle to be temporarily increased so as to reach at least a length according to which the vehicle 1 is in contact with the stair at the edges of two subsequent steps.

In other words, the presence of the front extensions 70 and/or of the rear extensions 80 allows the longitudinal dimensions of the vehicle 1 to be limited so as to allow it to move without difficulty even is small spaces, as, for example, the landings between two flights of stairs can be. Once the stairs have been ascended or descended, the extensions 70, 80 advantageously take a withdrawn position so that these extensions substantially do not project beyond the length of the side members 4B of the frame 4.

The front 70 and rear 80 crawler extensions are respectively operated through first 91 and second 92 drive means (Fig. 13) which have the function of rotating the extensions between a neutral position and one or more operating positions as a function of the architectural barrier to be overcome or in general of the function that they are required to perform. With reference to Figs. 7 and 13, the first drive means 91 in fact rotate the front extensions 70 about the front axis 15 A, while the second movement means 92 allow rotation of the rear extensions 80 about the rear axis 16 A. In particular, the rear extensions 80 rotate describing, in part or in full, a circumference C according to which raising of the rear of the vehicle 1 is determined. As described in detail below, this raising advantageously allows a step, such as a kerb, to be overcome and favours alignment of the vehicle on the stair during descent thereof or also exiting of the vehicle from the stair during ascent or during descent of a stair.

Both the drive means 91, 92 can be controlled by the user through the control unit 100 defined above. In particular, according to an embodiment, operation of the front 70 and rear 80 extensions, just as of the first 8 and second 9 movement means, takes place according to pre-established programs selectable by the user as a function of requirements. The control unit 100 can, for example, be provided with a "stair ascent program", "a stair descent program", a single step (kerb) ascent and/or descent program and a "vehicle park program". According to the program selected by the user, the control unit 100 controls a sequence of movements to the different motorized parts forming the vehicle 1 so that the latter is put in the best conditions to overcome the obstacle.

For this purpose, according to a preferred embodiment of the invention, the vehicle 1 comprises sensor means SD, SI operatively connected to the control unit 100. More in detail, the vehicle 1 preferably comprises distance sensor means (SD) and tilt sensor means (SI). The former can be provided in order to detect the presence of obstacles during travel of the vehicle and can, for example, be of the optical type. In a possible mode of use thereof, the distance sensor means SD can advantageously be positioned in the front part of the vehicle 1 , for example on the front upright 4 A of the frame 4. The tilt sensor means SI can instead by used in order to calculate the inclination of the vehicle while overcoming obstacles. These means can advantageously be positioned in any part of the vehicle 1.

To show some characteristics aspects of the invention, including two possible functions of these sensor means SD, there is described below the behaviour of the vehicle 1 when encountering different obstacles. In particular, there is firstly described a first possible behaviour of the vehicle 1 while ascending and descending a step. Subsequently there is described the behaviour of the vehicle 1 while ascending and descending a flight of stairs.

Figs. 14 to 17 show a series of possible configurations taken by the vehicle 1 to overcome a step obstacle such as a common kerb. In this hypothesis, the vehicle 1 takes a sequence of configurations that have the purpose of allowing the vehicle to pass from a lower surface PI to an upper surface PS.

As shown in Fig. 14, the front extensions 70 rotate in the direction of the obstacle, in the example outward (direction of the arrow O), while the rear extensions 80 rotate inward (arrow OA) raising the rear of the vehicle 1 to a height preferably greater than or equal to the upper surface PS of the step. Subsequent advance of the vehicle 1, which maintains the position of the seat 5 unchanged, is aided by the front extensions 70 which in substance allow the vehicle 1 to carry the entire front part thereof to the level of the upper surface PS. As shown in Fig. 16, having reached this condition, the vehicle 1 can translate to the level of the upper surface PS due to the rear extensions 80 which maintain it raised at the rear.

With reference to Fig. 17, once the vehicle 1 is completely on the upper surface PS then the rear extensions 80 can be withdrawn. The front extensions 70 can be withdrawn simultaneously to the rear extensions 80 or alternatively can already take the position of minimum dimensions as soon as the crawler units 35B of the vehicle rest on the upper surface PS of the step.

Figs. 18 to 21 show the vehicle 1 again in the presence of a step obstacle, but in the hypothesis in which the vehicle 1 requires to move from the upper surface PS to the lower surface PI of the step. During travel of the vehicle 1 on the surface PS, the sensor means SD detect the presence of the step, stopping travel of the vehicle 1 in the position shown in Fig. 18 and if the difference in level detected is below a safety value ΔHmax, the front extensions 70 rotate toward the lower surface PI of the step so as to provide, on this surface PI, a supporting point for the vehicle 1. The rear extensions 80 instead rotate in the opposite direction to that of the front extensions 70 as shown in Fig. 19. Subsequent advance of the vehicle 1 is implemented substantially at the level of the upper surface PS due to the action of the front extensions 70 which hold the vehicle raised at the front. This condition is maintained until the vehicle 1 reaches the condition shown in Fig. 20 in which the entire vehicle 1 is in a condition of complete projection with respect to the step. Subsequent descent of the vehicle 1 is implemented by making use of the previously tilted rear extensions 80 which gradually accompany the rear part of the vehicle 1 toward the lower surface PI providing a constant contact point. Once the vehicle 1 is completely on the lower surface PI (Fig. 21) then the front 70 and rear 80 extensions are withdrawn to the position of minimum dimensions.

Figs. 22 to 32 show the different possible configurations taken by the vehicle 1 while descending a stair formed of a plurality of steps. In the description below, it is assumed, for the sake of completeness, that the vehicle 1 is provided with sensor means SD always active and thus capable of automatically detecting the presence of an obstacle, in the case in hand the steps of the stair to be overcome. Figs. 22 and 23 show two different approaches to the stair by the vehicle. In detail, in Fig. 22 the vehicle 1 is shown travelling on the crawler belts, while in Fig. 23 it is shown with combined crawler belt-auxiliary wheel travel 14. In front of the stair to be descended the user can activate the sequence of controls that allow the vehicle 1 to enter the stair, align itself therewith and leave it after having travelled down all the steps. Figure 22 shows the vehicle entering the stair in the condition with the "descent program" activated. Vice versa, Fig. 23 shows the same vehicle in the condition with the "descent program" not activated. In any condition, the sensor means SD detect the difference in level and temporarily block the vehicle 1. After having verified that the difference in level ΔH detected by the sensor means SD is below a safety value ΔHmax, the control unit 100 controls the second movement means 9 to move the axis of rotation R from the intermediate position to the first position of reference indicated above. In other words, the control unit controls a rearward movement of the centre of gravity of the seat 5 toward the rear part of the vehicle (see Fig. 24). Once the axis of rotation R has occupied the second position of reference then the vehicle 1 is made to advance until the sensor means SD detect a difference in level greater than ΔHmax. In this condition the vehicle 1 stops and the front extensions 70 are rotated from the position 1 (position of minimum dimensions) to the position 4 (see rotations diagram indicated with EA) in which these extensions move towards the edge S 1 of the first step (see Fig. 25). It must be underlined that in this condition the line of the centre of gravity r(G) of the system formed by the user and the vehicle is fully within the surface PP preceding the stair due to the rearward movement of the centre of gravity.

The rear extension 80 subsequently rotate according to the rotation way of the front extension 70. In particular they rotate from the position 1 (position of minimum dimensions) to the position 3 indicated in the rotations diagram with reference E. P.. During the rotation from the position 0 to the position 3 (in the rotations diagram E. P.) the cam shape of the rear extension 80 causes the raising of the rear part of the vehicle 1. Such as raising, during a first phase, rotates the vehicle around to the edge SO until the front extension 70 contact the edge Sl and during a second phase rotates the vehicle 1, around to Sl, raising it from the edge SO (see fig 26). The next alignment of the front extension to the central crawler 35B (rotations from the position 4 to the position 3 in the rotations diagram E.A.) causes a lowering of the front part of the vehicle 1 and the movement of the line r(G) from the plane PP to the plane of the first step. Finally the return of the rear extension 80 (rotation from the position 3 to the position 1 in E. P.) leans the vehicle on the edges SO and Sl in a position which is perfectly aligned to the direction T of the stair (the direction T being defined by the line which along the edges of the steps).

As shown in figure 28, the vehicle once aligned with the direction T of the stair continues its moving until the surface PU following the last step of the same stair. The descent of the vehicle 1 from the last steps is advantageously performed by using the rear extensions 80 which provide actually a rear support point for the vehicle 1 especially during the moving on the last step as clearly evident from figures 29 and 30. Once the vehicle 1 is completely on the landing PU following the stair then the front 70 and rear 80 extensions are withdrawn so as to take the position of minimum dimensions. The axis of rotation R of the seat with respect to the centre of gravity is returned to the intermediate position through the second movement means 9 and the vehicle 1 is in the condition of normal travel (see Fig. 32).

In the case in which the space at the bottom of the stair is particularly small, the front extensions 70 can be withdrawn, by an indication of the tilt sensor SI, before the vehicle 1 rests completely on the landing PU at the bottom of the stair.

Figs, from 33 to 42 show the different configurations taken by the vehicle 1 during ascent of a stair formed of a plurality of steps. In the presence of a stair to be ascended the user can activate the sequence of controls that allow the vehicle 1 to enter the stair, align itself therewith and exit therefrom after having ascended all the steps. Fig. 34 shows the vehicle in the condition of entering the stair with the "ascent program" activated. As shown in Fig. 34, entry to the stair is preceded by a rotation of the front extensions 70 from the position 1 of minimum dimensions to the position 2 indicated in the relative rotations diagram EA. The rear extensions 80 are instead rotated from the position 0 of minimum dimensions to a position (indicated with 2 in the rotations diagram E.P.) so that the extension is substantially aligned with the crawler belt 37 of the crawler units 35B.

With reference to Fig. 35, the vehicle 1 ascends the first step of the stair Gl making use of the front crawler extensions 70 which provide the first supporting point (edge Sl) of the vehicle 1 on the stair. After exceeding the first step, the control unit 100 controls the second movement means 9 to advance the point of rotation of the seat 5 with respect to the frame 4 toward the front part of the vehicle 1. This causes a movement of the centre of gravity of the user-seat system toward the stair. As clearly shown in Fig. 36, the vehicle 1 ascends the stair aligning itself with the direction T thereof. Alignment of the rear extensions 80 with the crawler belts of the crawler units 35B allows the vehicle 1 to simultaneously rest on a plurality of edges so as to make ascent of the stair extremely stable and rapid.

Upon reaching the last step of the stair (see Fig. 37), the sensor means SD detect the absence of further steps and block the vehicle 1. As shown in Fig. 38, the front extensions 70 rotate from the position 2 to the position 4 (see rotations diagram EA) in which their ends move towards the surface PU at the top of the stair. The rear extensions 80 rotate in the same direction of the front extensions 70, from the position 2 (see rotations diagram E. P.) in substance travelling through a angle of 180° as can be seen by observing Fig. 39. Due to the particular cam configuration, the rear extensions 80 causes a raising of the rear part of the vehicle which, during a first phase of rotation, leaning the front extension 70 on the surface and, during a second phase of rotation, raises the vehicle 1 from the edge SO moving consequently the line r(G) towards the plane (see figure 39). A subsequent advance takes the vehicle 1 on the surface at the top of the stairs (Fig. 40). It can be seen therefore that in this phase of exiting the stair the front 70 and rear 80 extensions can cooperate to vary the alignment of the vehicle from an ascending configuration to one of travelling on the level without any stress for the user.

Once the vehicle 1 is resting completely on the surface at the top of the stair, then the front 70 and rear 80 extensions take the configuration of minimum dimensions, while the seat 5 is returned to the intermediate position by means of the second movement means 9 and the vehicle is located on the surface at the top of the stair in conditions of normal travel (see figure 42).

The technical solutions adopted for the vehicle allow the proposed aims and objects to be fully achieved. In particular, the vehicle allows the user to overcome particularly sloping surfaces, and complex architectural barriers, in complete safety and without any stress for the user. For example, it allows ascent and descent of flights of stairs facing the front without requiring preliminary manoeuvres to orient the vehicle. The use of retractable front and rear extensions allows the longitudinal dimensions of the vehicle to be reduced significantly, to the full advantage of manoeuvrability thereof in small spaces on the one hand and of transverse stability on the other.

The vehicle thus conceived is susceptible to numerous modifications and variants, all falling within the scope of the inventive concept; moreover all details can be substituted with others technically equivalent.

In practice, the materials used and the dimensions and contingent shapes can be any according to requirements and to the state of the art.

Claims

1. Vehicle (1) with variable geometry comprising a frame (4) which supports a seat (5) for a user (3), said vehicle (1) comprising first movement (8) associated with said frame (4) to allow movement thereof along a direction of travel (7), characterized in that said seat (5) is connected to said frame (4) in an oscillating way so as to maintain a degree of freedom of oscillation about an axis of reference (R) substantially orthogonal to the direction of travel of said vehicle, said seat (5) being connected to said frame (4) so that the centre of mass (G) is located in a position between said axis of reference (R) and a supporting surface (M) on which said vehicle (1) rests through said movement means (8).

2. Vehicle (1) according to claim 1, characterized in that said seat (5) is connected on opposite sides to two side members (4B) of the frame substantially parallel to each other which define, in proximity of respective lower portions, a front axle (15) and a rear axle (16) to which there are keyed said first movement means (8), said front axle (15) and said rear axle (16) respectively defining a front axis (15A) and a rear axis (16A) for rotation of said first movement means (8), said front and rear axes being substantially parallel to said axis of rotation (R) and being mutually positioned so that said axis of rotation (R) is located in an intermediate position between them.

3. Vehicle (1) according to claim 1 or 2, characterized in that it comprises second movement means (9) associated with said frame (4) to allow a controlled movement of said seat (5) with respect to said frame (4).

4. Vehicle (1) according to claim 3, characterized in that said second movement means (9) are such as to allow a movement of said axis of reference (R) along a direction of movement (S) substantially orthogonal to the same axis of rotation (R), said second movement means (9) allowing a movement of said axis of reference (R) between said intermediate position of reference (N) and a first position of reference (A).

5. Vehicle (1) according to claim 4, characterized in that said second movement means (9) allow a movement of said axis of reference (R) along said direction of movement (S) between said intermediate position of reference (N) and a second position of reference (B) substantially opposite said first position of reference (A) with respect to said intermediate position (N).

6. Vehicle (1) according to claim 5, characterized in that said first position (A) is determined so that the projection thereof, calculated along a direction substantially orthogonal to said direction of movement (S), passes through the front axis defined by said front axle (15), said second operating position (B) being determined so that the projection thereof, calculated along a direction substantially orthogonal to said direction of movement (S), passes through the rear axis defined by said rear axle.

7. Vehicle (1) according to one or more of claims 1 to 5, characterized in that said second movement means (9) comprise at least a first element (21) associated with said frame (4) and a second element (22) connected in an oscillating way to said seat (5), said first (21) and said second (22) element being reciprocally coupled through a screw-nut screw coupling so that said second element (22) can translate with respect to said first element (21) along said direction of movement (S).

8. Vehicle (1) according to claim 7, characterized in that said first element (21) comprises a threaded bar (26) associated with said frame (4) while said second element (22) comprises a threaded bush (27) coupled to said threaded bar (26), said second movement means (9) comprising an auxiliary motor (29) operatively connected to said threaded bar (26) to allow the rotation following which said bush (27) translates along said direction of movement (S).

9. Vehicle (1) according to claim 8, characterized in that said movement means (9) comprise a first pair of elements (21) predisposed on opposite sides of said frame (4) and at least a second pair of elements (22) each connected in an oscillating way to a side member of said seat (5), each element of said second pair of elements (22) coupling to a corresponding element of said first pair of elements (21) through a screw-nut screw coupling so as to allow translation of each element (22) of said second pair with respect to the corresponding element of said first pair (21) along said direction of movement (S).

10. Vehicle (1) according to claim 9, characterized in that each element of said first pair of elements (21) comprises a threaded bar (26) operatively connected to an auxiliary motor (29) which allows rotation thereof, each element of said second pair of elements (22) comprising a bush (27) each coupled kinematically to one of said threaded bars (26), each element of said second pair of elements (22) comprising a first connection bracket (31) coupled through a rotation pin to a corresponding second connection bracket (32) associated with a side member of said seat (5).

11. Vehicle (1) according to one or more of claims 1 to 10, characterized in that it comprises motor means (50) operatively connected to said first movement means (8) to allow movement thereof, said vehicle (1) comprising electrical power supply means (55) to allow operation of said motor means (50), said electrical power supply means (55) being associated with said seat (5).

12. Vehicle (1) according to claim 10, characterized in that said first movement means (8) comprise a crawler assembly operated by said motor means (50) and associated with said frame (4) at said front axle (15) and said rear axle (16).

13. Vehicle (1) according to claim 11, characterized in that said crawler assembly comprises a pair of crawler units (35B) operatively connected to said front axle (15) and to said rear axle (16) on said side members (4B) of said frame (4), said crawler units (35B) being connected to said axles (15, 16) so as to occupy a position between said side members (4B) of said frame (4).

14. Vehicle (1) according to claims 12 and 13, characterized in that it comprises one or more pivoting auxiliary wheels (14) associated with the frame (4) at said front axle (15), said auxiliary wheels (14) taking at least an operating position in which the vehicle 1 is supported at the front on these auxiliary wheels.

15. Vehicle (1) according to one or more of claims 12 to 14, characterized in that it comprises one or more rear auxiliary wheels to facilitate parking of said vehicle.

16. Vehicle (1) according to one or more of claims 1 to 13, characterized in that it comprises at least a front extension (70) connected rotatingly to said frame (4).

17. Vehicle (1) according to claim 16, characterized in that it comprises a pair of front crawler extensions (70) mounted rotatingly on opposite sides of said frame (4), each front crawler extension (70) being mounted coaxially to said front axle (15) so as to be located on the outside of a corresponding side member of said frame (4).

18. Vehicle (1) according to one or more of claims 1 to 17, characterized in that it comprises at least a rear extension (80) connected rotatingly to said frame (4) in a position in proximity of said rear axle (16).

19. Vehicle (1) according to claim 18, characterized in that it comprises a pair of rear crawler extensions (80) mounted rotatingly on opposite sides of said frame (4), each rear extension being mounted coaxially to said rear axle so as to be located on the outside of a corresponding side member of said frame (4).

20. Vehicle (1) according to claim 19, characterized in that each of said rear crawler extensions (80) presents a structure that extends eccentrically with respect to the keying point of said extension to said frame (4) to give a substantially cam configuration such as to cause raising/lowering of the vehicle during rotation about said rear axis (16A) defined by said rear axle (16).

21. Vehicle (1) according to one or more of claims 16 to 21, characterized in that it comprises a control unit (100) which controls at least the first motor means (50), in charge of activating the first movement means (8), and the second movement means (9), in charge of varying the position of the axis of mutual rotation (R) between said frame (4) and said seat (5), the front (70) and the rear (80) crawler extensions.

22. Vehicle (1) according to one or more of claims 16 to 21, characterized in that it comprises sensor means (SI, SD) operatively connected to said control means (100) to detect the presence of obstacles during travel of said vehicle (1) and/or to calculate the inclination of said vehicle (1).