WO2010109466A1

WO2010109466A1 - Wheelchair

Info

Publication number: WO2010109466A1
Application number: PCT/IL2010/000250
Authority: WO
Inventors: Avishay Novoplanski
Original assignee: Galileo Mobility Instruments Ltd
Current assignee: Galileo Mobility Instruments Ltd
Priority date: 2009-03-24
Filing date: 2010-03-24
Publication date: 2010-09-30
Anticipated expiration: 2011-09-24

Abstract

A movable platform (10), such as a wheelchair, is presented. The platform comprises a mobility assembly (12), a carrier assembly (11), and a coupling system (14) for adjustably coupling the carrier assembly to the mobility assembly. The coupling system (14) comprises a guiding member (16) having an axis and mounted for pivotal movement about the mobility assembly (12), and a slider (18) attached to the carrier assembly (11) and mounted on said guiding member (16) for a linear movement along said axis of the guiding member (16). The attachment between the slider and the carrier assembly provides for pivotal relative displacement between them. This pivotal movement of the guiding member with respect to the mobility assembly together with the sliding movement of the carrier assembly along the guiding member allow multiple relative positions of the carrier assembly including raising and lowering of the carrier assembly.

Description

WHEELCHAIR

FIELD OF THE INVENTION

This invention is generally in the field of movable platforms such as wheelchairs, and relates to a wheelchair (or generally platform), which may be powered or not, and is capable of adjusting multiple positions of a patient.

BACKGROUND

Wheelchairs enabling multiple positions of a patient are generally of two types: powered (either fully- or semi-automatic) and manual. Various mechanisms have been developed for moving a seat surface up and down and for rotating with respect to the ground plane. Powered wheelchairs typically utilize electric motors for implement such movements.

Various examples of the wheelchairs and mechanisms used therein are described for example in the following patent publications: US 5,730,236; US 4,747,611; US 5,601,302; US 4,613,151; US 2007/0067905; US 2006/0255640; US7,316,441; US 3,882,949; US 4,962,941.

GENERAL DESCRIPTION

There is a need in the art in a simple and effective mechanism enabling shift of a movable platform in between various positions if its carrier assembly. The present solves this problem by providing a novel configuration of a movable platform equipped with mobility assembly. According to a broad aspect of the invention, there is provided a movable platform comprising:

- a mobility assembly,

- a carrier assembly, and - a coupling system for adjustably coupling the carrier assembly to the mobility assembly, said coupling system comprising a guiding member having an axis and mounted for pivotal movement about the mobility assembly, a slider attached to the carrier assembly and mounted on said guiding member for a linear movement along said axis, the attachment between the slider and the carrier assembly providing for pivotal relative displacement between them, the pivotal movement of the guiding member with respect to the mobility assembly and the sliding movement of the carrier assembly along the guiding member allowing multiple relative positions of the carrier assembly including raising and lowering of the carrier assembly. The platform may be configured as a wheelchair, in which case the carrier assembly comprises a seat surface and a back support surface, which are preferably pivotal one with respect to the other. The carrier assembly may also include a leg support unit, e.g. pivotally coupled to the seat surface.

The coupling system is preferably configured and operable for adjusting a relative position of the center of mass (center of gravity) of the carrier assembly while carrying a patient during said movements. In some embodiments, the coupling system comprises a housing containing a driving mechanism configured and operable for effecting these movements and possibly also some electronic controller(s). For simplicity and with no limitations, such housing will be referred to hereinafter as "control box". The control box may be attached to the guiding member and be pivotal, together with the guiding member, about the mobility assembly. The control box and the guiding member may be mounted such that a pivotal axis thereof coincides with a rotational axis of the mobility assembly, or is spaced-apart from and parallel to a rotational axis of the mobility assembly. In some embodiments, the guiding member is a variable length, e.g. has a telescopic mechanism allowing for extending and shortening a path of the linear movement of the slider.

The multiple positions achievable by the wheelchair of the invention comprise inter alia a position of the back support substantially parallel to the seat surface, including substantially vertical and horizontal positions of the seat surface and back support.

In some embodiments, the platform is a powered one (fully automatic or semi-automatic), in which case the driving mechanism of the control box preferably comprises a hydraulic drive.

In some embodiments of the invention, the mobility assembly is configured to enable the platform movement along a tilted surface. To this end, the mobility assembly has an appropriate mechanism for adjusting the platform orientation to move up or down along the tilted surface, e.g. that defined by a stairway. This may for example utilize a mechanism disclosed in US 7,334,850 and US 6,422,576 both assigned to the assignee of the present application and incorporated herein by reference.

Preferably, the coupling system is operable for adjusting a relative position of the center of mass of the carrier (seat) assembly in accordance with an orientation of the tilted surface. This can be implemented using a sensing system for sensing the mobility assembly orientation with respect to the tilted surface, for example utilizing one or more inertial optical, infra red, acoustic (ultra sonic),mechanical (e.g. a sensor operable to detect a shift of balance of the main wheel caused by the mobility assembly interaction with the tilted surface), or other sensors. BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. IA is schematic illustration of an example of a movable platform according to the invention;

Fig. IB exemplifies the movable platform of Fig. 1 modified into a wheelchair;

Figs. 2A and 2B show the wheelchair of the present invention in upright sitting position where the slider assembly is in, respectively, a vertical position and an intermediate position (between horizontal and vertical positions);

Figs. 3A to 3C show three examples of the wheelchair while being adjusted for movement along a tilted surface or staircase;

Figs. 4A and 4B show the wheelchair operation to bring the carrier assembly to the uppermost and lowermost positions respectively;

Figs. 5A and 5B exemplify the wheelchair in its standing and laying positions of the carrier assembly; and

Fig. 6 exemplifies more specifically the powered configuration of the wheelchair using a coupling system having a control box (containing a power pack and control unit) controlling the above movements of the carrier assembly.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is made to Fig. IA which is a schematic illustration of a side view of a movable platform 10 according to an example of the present invention. In the present example, the platform is configured as a wheel chair, but it should be understood that the invention is not limited to this specific application. The movable platform 10 includes a carrier assembly 11, a mobility assembly 12, and a coupling system 14. The mobility assembly 12 may be of any suitable type including for example a track device, legged (e.g. walking) device, wheel assembly or any combination of such devices. In the example of Fig. IA, the mobility assembly 12 includes wheel assembly comprising two main wheels (only one such main wheel Wl being seen is the figure) and two auxiliary wheels (only one of them W2 is shown) mounted on a frame F. The two main wheels are configured to revolve about their symmetry (revolution) axes: axis Xl is the revolution axis of main wheel Wl and is preferably the common revolution axis for both of the main wheels. In some other embodiments of the present invention, the wheel assembly 12 may comprise less than four wheels.

The frame F is pivotally connected to the coupling system 14 through a pivot Pl providing for a rotation of the coupling system 14 with respect to the frame F about an axis that is substantially parallel to the main wheels' revolution axes Xl. In some embodiments, the pivot Pl is mounted on the main wheel revolution axis Xl. However, such a configuration is not essential and it is possible and in some cases preferable that the pivot Pl is spaced apart from the revolution axis Xl. This might optimize adjustment of the center of mass (balance) of the wheelchair at its various positions as these are exemplified below. In some cases separation between the pivot Pl and wheel revolution axis Xl is adjustable manually or motorized mechanically.

The carrier assembly 11 is pivotally attached to the coupling system 14 via a pivot P2. The coupling system 14 includes a slider assembly 17 having a guiding member (e.g. guiding rail) 16 and a slider 18 mounted thereon for linear movement (e.g. sliding) along the axis of the guiding rail. Also optionally provided in the coupling system is a load L (shown in the figure by dashed lines), which has a housing containing a driving mechanism and/or power pack and/or control electronics.

Rail 16 is mounted for pivotal movement with respect to the mobility assembly 12. In the present example, this is implemented by mounting the rail 16 on the pivot connection Pl. Slider 18 is mounted on pivot connection P2 providing pivotal movement of the carrier assembly 11 relative to the rail (generally, to the coupling system 14). It should be understood that the rail 16 and the slider 18 can be mounted directly on their respective pivot connection or indirectly (e.g. through an intermediary connecting frame attached to the respective pivot connection). The slider assembly 17 provides for a linear displacement between slider 18 along the rail 16 and accordingly between the carrier assembly 11 and the mobility assembly 12. Carrier and mobility assemblies 11 and 12 are connected (directly or indirectly) to the slider assembly through pivot connections P2 and Pl. For example, one part (slider 18 or rail 16) of the slider assembly 17 is connected to the carrier assembly through a pivot connection and the other part is connected to mobility assembly. In this connection it should be noted that in some embodiments of the present invention, rail 16 is connected to carrier assembly 11 and slider 18 is connected to mobility assembly 12.

The carrier assembly 11 is pivotally attached to the coupling system 14 via a pivot P2.

The coupling system 14 includes a slider assembly 17 having a guiding rail 16 and a slider 18 mounted thereon for linear movement (e.g. sliding) along the axis of the guiding rail. Rail 16 is mounted for pivotal movement with respect to the mobility assembly 12. In the present example, this is implemented by mounting the rail 16 on the pivot connection Pl. Slider 18 is mounted on pivot connection P2 providing pivotal movement of the carrier assembly 11 relative to the rail (generally, to the coupling system 14). It should be understood that the rail 16 and the slider 18 can be mounted directly on their respective pivot connection or indirectly (e.g. through an intermediary connecting frame attached to the respective pivot connection). The slider assembly 17 provides for a linear displacement between slider 18 along the rail 16 and accordingly between the carrier assembly 11 and the mobility assembly 12. Carrier and mobility assemblies 11 and 12 are connected (directly or indirectly) to the slider assembly through pivot connections P2 and Pl. For example, one part (slider 18 or rail 16) of the slider assembly 17 is connected to the carrier assembly through a pivot connection and the other part is connected to mobility assembly. In this connection it should be noted that in some embodiments of the present invention, rail 16 is connected to carrier assembly 11 and slider 18 is connected to mobility assembly 12.

The mobility assembly 12 and the carrier assembly 11 are thus interconnected with one another through the coupling system 14 which enables relative movements of three degrees of freedom between them: rotational movements about pivot connections Pl and P2 and a linear movement along the axis of the slider assembly. These relative movements enable multiple positions of the carrier assembly 11 with respect to the mobility assembly 12 and with respect to the ground plane G.

It should be noted that the above movements can be executed automatic or semi-automatic using a powered design of the movable platform or manually. The platform utilizing the invention may be of any suitable kind, e.g. the so- called "walk behind" design (controlled by handles 31), robotic system, etc.

Referring to Fig. IB, there is illustrated a wheelchair configured constituting a movable platform, which in this example is configured generally similar to the platform exemplified with respect to Fig. IA. To facilitate understanding, the same reference numbers are used for identifying components that are common in all the examples of the invention.

In the example of Fig. IB, the carrier assembly 11 is designed for supporting a patient in a manner allowing his multiple positions. Carrier assembly thus has a seat HA and a back support HB. It should be noted that carrier assembly of Fig. IA can be detached from the slider assembly and replaced by seat-and-back support assembly of Fig. IB, or alternatively, carrier assembly of Fig. IA can present the seat HA of Fig. IB and the back support HB can be appropriately attached thereto. Thus, carrier assembly 11 is pivotally attached to the coupling system 14 via a pivot P2, which in the present example is optionally located on seat HA. Seat HA and back support HB are in turn pivotally connected to one another through a pivot connection P3. In some embodiments of the invention, the pivot axis of the pivot connection P3 coincides with the pivot axis of the pivot connection P2.

The carrier assembly 11 may further include leg support(s) HC which may be rigidly or pivotally connected to the seat HA. In this example the leg support HC is pivotally connected to the seat HA by a pivot connection P4 which provides various positions of the legs with respect to the seat (e.g. about

90° angle as shown in the figure, a straight 180° position etc).

It should be understood that pivots P3 and P4 provide for a variety of the carrier assembly 11 positions: upright sitting (an angle of about 90° degrees between the seat HA and the back support HB and an angle of about 90° degrees between the seat HA and the leg support HC), a laying/standing position (an angle of about 180° between the seat HA and the back support HB and an angle of about 180° between the seat HA and the leg support HC), and intermediate positions.

Similar to the example of Fig. IA, the coupling system 14 includes a slider assembly 17 formed by a guiding rail 16 and a slider 18 mounted for linear movement along the axis of the guiding rail. Rail 16 is mounted for pivotal movement with respect to the mobility assembly 12, e.g. by mounting the rail 16 on the pivot connection Pl. Slider 18 is mounted on pivot connection P2 providing pivotal movement of the seat assembly H relative to coupling system 14.

The mobility assembly 12 and the seat assembly H are interconnected with one another through the coupling system 14 which enables relative movements of three degrees of freedom between them. For example, the wheelchair might be configured for an upright sitting position, while the slider assembly (the rail 16) is in the horizontal (or near horizontal) position (as shown for example in Fig. 1) or is in a substantially vertical position as shown in Fig. 2A. Moreover, the transition between vertical and horizontal positions of the slider assembly 17 can be achieved while maintaining the upright sitting position of the carrier assembly 11, as shown in Fig. 2B illustrating an intermediate state between horizontal and vertical positions of the slider assembly.

Bringing the slider assembly to the horizontal or intermediate (between vertical and horizontal) positions enables to utilize the linear displacement movement of the seat assembly slider to shift the horizontal position of the carrier assembly 11 towards a front side FS or a rear side RS of the wheelchair 10. By this, a change in the position of the center of mass of the wheelchair 10 (occupied or not) with respect to the wheels is effected. It is a specific requirement to control the position of the wheelchair center of mass (Center of Gravity) in a case when the wheelchair is moving along or positioned on a tilted surface (e.g. maintaining the position of the seat assembly 11 substantially above a base B of the wheelchair constituted by the contact points between the wheels and the ground G). This may be achieved by utilizing the slider assembly to shift the seat assembly 11 towards the rear side RS when the chair is in a descent direction or towards the front side FS when the chair is an ascent direction of a slope.

Fig. 3A shows how the slider assembly is positioned to shift the carrier assembly 11 towards the rear side RS of the wheelchair 10 when the wheelchair 10 is in a descent direction of a slope Sl (tilted surface). The slider assembly may be configured for varying the length of the slider path along the rail. In this example, a telescopic slider assembly 17 is used, allowing extension of the rail, shown in the figure in dashed lines. Also, as shown in the figure, slider 18 is capable of extraction beyond the length of the guiding rail 16 thereby providing extended range of linear movement of the slider assembly 17. Fig. 3B shows the slider assembly position when shifting the carrier assembly 11 towards the front side FS when the wheelchair 10 is in an ascent direction of a slope S2.

Fig. 3C shows more specifically an example where ascending slope S2 is constituted by a non-planar path (a stairway) and accordingly the mobility assembly 12 is of the type capable of traversing such non-planar surface. In the present example, the mobility assembly 12 utilizes a traction system configured for upstairs/downstairs movement. Such traction system is disclosed for example in US 7,334,850 and US 6,422,576 both assigned to the assignee of the present application and incorporated herein by reference. A traction system for a vehicle has a support frame that defines a circular track belt support that is revolvable about an axis at its center, a flexible track belt; and a track belt stretching assembly comprising one or more track belt stretching rollers. The traction system includes a flexible traction belt which is held on a support track forming a substantially circular, wheel-like traction surface, and which can change to a stretching state in which rollers engage the belt and stretch it from its circular state to a stretched state to define one or more other traction configurations of the system.

Thus, the mobility assembly of the wheelchair (platform) may include rollers associated with the main wheel and may be operable for selective controllable shifting between a normally circular shape of the main wheel and non-circular shapes thereof. The mobility assembly, when with the non-circular shape of the main wheel, allow the wheelchair movement along a tilted surface.

Reference is made to Fig. 4A, showing that by placing the slider assembly in a vertical or intermediate position the linear displacement movement of the carrier assembly can be utilized in order to adjust the height of the carrier assembly with respect to the mobility assembly and accordingly with respect to the ground plane. This enables an elevated position of the carrier assembly, where the slider assembly is extended upwards while maintaining the carrier assembly vertically above the mobility assembly 12 thus maintaining a required position of the wheelchair (e.g. control the position of the center of mass).

As indicated above, in order to achieve greater range of positions of the carrier assembly with respect to the mobility assembly 12, the slider assembly may utilize a telescopic mechanism thus extending the length of the rail and accordingly increasing the possible path of the seat assembly in its linear movement. In Fig. 4A, the rail 16 has two joints 16A and 16B that are shown in their extracted state providing for about twice the linear displacement that can be provided by a non telescopic slider assembly and rail of the same length. Fig. 4B shows the wheel chair 10 in its lowermost position while the slider assembly is substantially vertical and the carrier assembly 11 is lowered to enable a patient sitting on the chair to reach the floor. Also here, a stable position of the wheelchair 10 is maintained by keeping the center of mass of the wheelchair 10 (occupied or not) above the base of the wheelchair 10. In order to enable even more lowering the seat, the legs support HC may be rotated to be positioned with an angle of 180 with respect to the seat HA.

Figs. 5A and 5B illustrate the standing and laying positions of the wheelchair 10 respectively. In both positions, as described above, angles of about 180 degrees are maintained between the seat HA and both the legs and back support (HC and HB) of the carrier assembly 11. In Fig. 5A, a standing position is achieved by rotating the slider assembly 17 to a substantially vertical direction. The slider 18 linear displacement can be also adjusted to locate the leg supports adjacent to the ground. In Fig. 5B, the laying position is similar to the standing position shown in Fig. 5A but the slider assembly is rotated to a substantially horizontal direction and the linear displacement of the slider is adjusted to maintain the wheelchair's center of mass above its base.

Fig. 6 illustrates a powered wheelchair 10 according to the present invention. The powered wheelchair includes an energy source unit 22 (which in the present example uses a battery pack), and a driving system 24. The latter is connected to the energy source and includes one or more actuation units 26 (a single electric motor is used as the actuation unit 26 in the present example). According to some embodiments, the driving system is configured for driving at least one of the main wheels of the wheelchair 10, for example by utilizing a transmission system 28 such as a gear and/or differential units. Alternatively or additionally, the driving system 24 is adapted for actuating relative motions between the various elements of the wheelchair which are associated with at least some of the pivot connections Pl, P2, P3, P4 and the slider assembly.

Preferably, the actuation of relative motions between the various elements of the wheelchair associated with the pivot connections Pl, P2, P3, P4 and with the slider assembly 17 is achieved by utilizing a hydraulic actuation system

(being a part of the driving system 24). The hydraulic actuation system includes hydraulic a pumping system 30 and hydraulic actuation elements Al, A2, A3, A4 and A5. Thus, in this example, the hydraulic pumping system 30 is connected to the actuation unit 26 through the transmission system 28.

It should be understood that in the present example the transmission system 28 is configured to enable using the single actuation unit 26 for driving the wheels of the wheelchair and for driving the hydraulic pumping system 30 either simultaneously or at different times. It should also be understood the according to other embodiments of the present invention more than one, dedicated, actuation units can be used, such that at least one actuation unit is dedicated for actuation of at least one of the wheels of the wheelchair 10 and another one is dedicated for actuation of the hydraulic pumping system 30. In such configurations where multiple, dedicated, actuation units are used, a transmission system 28 might not be required or a much simpler transmission system can be used.

The hydraulic pumping system 30 is connected through pressure cables to the hydraulic actuation elements Al, A2, A3, A4 and A5 which are associated respectively with the pivot connections Pl, P2, P3, P4 and the slider assembly. This enables adjusting various positions of the wheelchair 10 as described above. In some embodiments of the present invention, all or some of the actuation elements Al, A2, A3, A4 and A5 have electric actuators (electric motors) connected to the battery pack 22 and residing respectively in the vicinity of the pivot connection and/or slider assembly which are thereby actuated (directly or through proper transmission assemblies). In the case that no hydraulic actuators are used (e.g. all the actuation elements Al, A2, A3, A4 and A5 are electric or some of the actuation elements are electric and the other motions of the wheel chair are not powered), the hydraulic pumping system 30 may no longer be required and thus does not form a part of the driving system 24. The energy source unit 22 and optionally also parts of the driving system

24 such as the actuation unit 26, the hydraulic pump 30 and the transmission system 28 are accommodated within a control box 20. Hence, the total mass of the control box 20 is of a considerable value with respect to the mass of the wheelchair itself and with respect to the mass of a patient sitting thereon. This enables to utilize the control box mass in order to provide improved balancing of the wheelchair when in its various positions. To this end, the control box is displaceable with respect to the mobility assembly. In the present example, the control box is attached to the coupling system thus being an integral part thereof, and is rotatable together with the guiding rail. Turning back to Figs. 5A and 5B for example, a control box 20 is shown there being attached to the coupling system 14 such that the slider assembly 17 is located in between the control box 20 and the seat assembly 11 (which is pivotally connected to the slider assembly). In the position of the wheelchair 10 shown in Fig. 5B, the control box 20 is located relatively low near the base of the wheelchair thereby lowering the total center of mass of the wheelchair 10 and providing an improved stability of the chair in this position. In other positions of the wheelchair, such as the elevated position, the lowest position and the standing position of the seat assembly, shown in Figs. 4A, 4B and 5A respectively, it may be preferable to maintain the center of mass of the wheelchair substantially vertically above the base of the wheelchair to thereby provide for improved stability of the wheelchair. To this end, when in this positions, the massive control box 20, which is attached to one side of the slider assembly, counter acts the mass of the seat assembly (when occupied with a patient or not) which is connected through the pivot connection P2 to the opposite side of the slider assembly. The location of the control box in these positions, as exemplified in Fig. 5B for the chair's lowest position, enables to shift the center of mass of the wheelchair towards a vertical position substantially above the center of the base of the chair to provide an optimal balancing/stability to the chair. It should be noted that the mass of the control box might be further adjusted (e.g. by adding weights or redistributing the parts of the wheelchair that are accommodated therein) according to a patient weight in order to provide an optimally balanced wheelchair adapted for specific patient.

According to some other embodiments of the present invention, the massive control box 20 is fixed to the mobility assembly 12 to increase the mass of the mobility assembly thus enabling it to remain stable at the various positions of the wheelchair. This may also provide for a lower center of mass of the wheelchair.

Considering the example of Fig. 3C, where the wheelchair enables appropriate adjustment of the carrier assembly position for moving up and down along the stairway, the wheelchair is preferably equipped with a sensing system (not shown) for sensing the mobility assembly orientation with respect to the tilted surface. Such sensing system may include one or more optical, and/or ultrasonic, and/or mechanical, and/or inertial, and/or other sensors. The mechanical sensor may be operable to detect a shift of balance of the main wheel caused by the mobility assembly interaction with the tilted surface. Hence, such seat shifting and control mechanism with an appropriate sensor acts as a stabilizer mechanism to allow climb and descent stairs and or slopes.

Claims

CLAIMS:

1. A movable platform comprising:

- a mobility assembly,

- a carrier assembly, and - a coupling system for adjustably coupling the carrier assembly to the mobility assembly, said coupling system comprising a guiding member having an axis and mounted for pivotal movement about the mobility assembly, a slider attached to the carrier assembly and mounted on said guiding member for a linear movement along said axis of the guiding member, the attachment between the slider and the carrier assembly providing for pivotal relative displacement between them, the pivotal movement of the guiding member with respect to the mobility assembly and the sliding movement of the carrier assembly along the guiding member allowing multiple relative positions of the carrier assembly including raising and lowering of the carrier assembly.

2. The platform of Claim I₅ being configured as a wheelchair, said carrier assembly comprising a seat surface and a back support surface.

3. The platform of Claim 2, wherein said seat surface and said back support surface are pivotal one with respect to the other.

4. The platform of any one of Claims 1 to 3, wherein said coupling system is configured and operable for adjusting a relative position of the center of mass of the carrier assembly while carrying a patient during said movements.

5. The platform of any one of Claims 2 to 4, wherein said carrier assembly comprises a leg support unit pivotally coupled to said seat surface.

6. The platform of any one of the preceding Claims, wherein said coupling system comprises a housing containing at least one of the following: a driving mechanism, a power pack and a controlling electronics, configured and operable for effecting said movements.

7. The platform of Claim 6, wherein said housing is attached to said guiding member and is pivotal, together with the guiding member, about the mobility assembly.

8. The platform of Claim 7, wherein the housing and the guiding member are mounted such that a pivotal axis thereof coincides with a rotational axis of the mobility assembly.

9. The platform of Claim 7, wherein the housing and the guiding member are mounted such that a pivotal axis thereof is spaced-apart from and parallel to a rotational axis of the mobility assembly.

10. The platform of any one of the preceding Claims, wherein the guiding member has a variable length.

11. The platform of Claim 10, wherein the guiding member has a telescopic mechanism allowing for extending and shortening a path of said sliding movement.

12. The platform of any one of Claims 2 to 11, wherein said multiple positions comprise a position of the back support substantially parallel to the seat surface, including substantially vertical and horizontal positions of the seat surface and back support.

13. The platform of any one of Claims 6 to 12, wherein said driving mechanism comprises a hydraulic drive.

14. The platform of any one of the preceding Claims, wherein the mobility assembly comprises a main wheel defining a rotational axis of the mobility assembly, and one or more rollers, the mobility assembly being configured and operable for selective controllable shifting between a normally circular shape of a circumference defined by the main wheel and various non-circular shapes thereof, the mobility assembly when with the non-circular circumference of the main wheel allowing the platform movement along a tilted surface.

15. The platform of Claim 14, wherein said coupling system is operable for adjusting a relative position of the center of mass of the carrier assembly in accordance with an orientation of said tilted surface.

16. The platform of Claim 14 or 15, comprising a sensing system for sensing the mobility assembly orientation with respect to said tilted surface.

17. The platform of Claim 16, wherein said sensing system comprises at least one of the following sensors: optical, mechanical, acoustic sensors.

18. The platform of Claim 17, wherein the mechanical sensor is operable to detect a shift of balance of the main wheel caused by the mobility assembly interaction with the tilted surface.