Wheelchair curb-climbing and curb-descending system

A wheelchair curb-climbing and curb-descending system for aiding a wheelchair to negotiate a curb. The system includes a wheelchair attachment mechanism; a pair of front arms adapted to extend to lift a front portion of wheelchair and to retract back to lower the front portion of the wheelchair; a pair of rear arms adapted to extend to lift a rear portion of wheelchair and to retract back to lower the rear portion of the wheelchair. The system further includes an arm extending mechanism for extending/retracting the arms; a rotatable lifting-arm wheel at free ends of each arm; a wheel motor for rotating the arm wheels; an operation control unit; and a leveling mechanism for ensuring the seat of the wheelchair remains substantially level to the ground during operation of the system.

FIELD OF THE INVENTION

The present invention relates to equipment for aiding the handicapped, in particular, wheelchairs and accessories.

BACKGROUND OF THE INVENTION

Wheelchairs are commonly used by people with ambulatory problems. A common issue with wheelchairs is that they do not easily roll or otherwise progress up and down step-like or elevated structures, such as sidewalk curbs; and if they do, it is typically via a complex mechanism and/or a mechanism that causes the user to be tilted, which can be uncomfortable or even dangerous to the user, as well as expensive.

SUMMARY OF THE INVENTION

The present invention relates to a wheelchair curb-climbing and curb-descending system adapted to raise a wheelchair to, and lower a wheelchair from, (hereinafter in the description and claims: “negotiate” or a derivative thereof) a step-like elevated structure or surface such as a sidewalk curb (hereinafter in the specification and claims: “curb” or any derivative thereof). As the present system is particularly suited for use with motorized wheelchairs, the present system will be described in this context. However the present wheelchair curb-climbing and curb-descending system, mutatis mutandis, is not limited to motorized wheelchairs.

The term “curb” and its derivatives will be used herein the description and claims to indicate any relatively isolated obstacle of a curb-like nature, such as a sidewalk curb, a single stair, a step-up/down as may be found at a building or store entry-way, and so on. The term “curb” and its derivatives herein are not intended to include obstacles such as a flight of stairs.

In accordance with embodiments of one aspect of the present invention there is provided a wheelchair curb-climbing and curb-descending system for aiding a wheelchair to negotiate a curb. The system includes a wheelchair attachment mechanism for securing the system to the wheelchair; a pair of front arms, each front arm adapted and controllable to extend, or be positioned, forward and downward so as to lift a front portion of wheelchair and to retract back so as to lower the front portion of the wheelchair upon deployment of the system; a pair of rear arms, each rear arm adapted and controllable to extend, or be positioned, rearward and downward so as to lift a rear portion of wheelchair and to retract back so as to lower the rear portion of the wheelchair upon deployment of the system. The system further includes an arm extending mechanism having an arm extension and retraction motor associated with each of the front arms and with each of the rear arms for extending or positioning, and retracting the arms; a rotatable lifting-arm wheel disposed at the free ends of each front arm and each rear arm; a wheel motor associated with, and adapted for rotating, at least one of the arm wheels; an operation control unit adapted to actuate and control operation of the system; and a leveling mechanism operably connected to the arms for ensuring the seat of the wheelchair remains substantially level to the ground during operation of the system.

It is a particular feature of the present wheelchair curb-climbing and curb-descending system that it is adapted to negotiate a step-like elevated structure such as a sidewalk curb, essentially without tilting the user.

Additional particular features of the present system include that it is relatively lightweight, for example on the order of 40 kg; allows overcoming a curb of about 20 cm, within a reasonably quick period, for example approximately 10 seconds; and does not increase the existing footprint of the wheelchair so as not to interfere with maneuvering of the wheelchair or entry into doorways or the like.

The following detailed description of embodiments of the invention refers to the accompanying drawings referred to above. Dimensions of components and features shown in the figures are chosen for convenience or clarity of presentation and are not necessarily shown to scale. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the invention are described below. In the interest of clarity, not all features/components of an actual implementation are necessarily described.

FIGS. 1-6also show a first embodiment and including optional modifications thereof, of the present wheelchair curb-climbing and curb-descending system for use with a wheelchair. Without limitation, the system is particularly suited for use with a motorized wheelchair and will be described in that context. The wheelchair typically comprises a chair100, including a seat102and a chair support shaft104; a base106; a set of drive wheels108; a set of front casters or wheels110; a set of rear stabilizing wheels112; footrest(s)114; a propulsion power source (such as one or more batteries) and motor116; arm rests120and a operation control unit122for the user to control the movement of the wheelchair.

In some embodiments, the curb-climbing and curb-descending system comprises a pair of lifting-arm housings10, one housing on each side of the wheelchair. Arm housings10are made of a sturdy material, such as aluminum and in some preferred embodiments, are arcuate, as shown. The system includes a wheelchair attachment mechanism11(including in some embodiments a generally transversely oriented connector rod52and associated fasteners,FIG. 6) that typically connects the system to the wheelchair for example via an attachment between the system (e.g. arm housings10) and chair support shaft104, though the system could be attached in other ways and means, for example to base106, etc.

Each arm housing10has a pair of arm receiving tunnels12, one tunnel configured to house a correspondingly shaped frontward/downward extendable wheelchair lifting and lowering arm14(herein-after in the specification and claims also/interchangeably referred to as “front arms”14, regardless of the method of their operation) and the other tunnel configured to house a correspondingly shaped rearward/downward extendable wheelchair lifting and lowering arm16(herein-after in the specification and claims also referred to as “rear arms”16, regardless of the method of their operation). At the free ends of each lifting arm16are wheelchair lifting-arm wheels18, rotatable via a wheel motor20as part of an arm extending mechanism. For such purpose, in some embodiments, each wheel motor20of the arm extending mechanism has an associated gear wheel22(FIG. 5); and each lifting/lowering arm (front arms14and rear arms16) has a toothed portion or toothed rail24(FIG. 5) corresponding to its respective gear wheel. In some modifications, the arm extending mechanism includes friction rollers (not shown) or a pulley device (not shown) rather than gear wheels.

For smooth operation during extension and retraction, each lifting/lowering arm14and16also typically has a roller or pair of rollers26for interfacing with the inner surface of tunnels12of housing10. A lifting-arm extension and retraction motor28is associated with each of lifting/lowering arms14and16, for extending and retracting the arms.

In some preferred embodiments, a rear (or front) pair of lifting-arm wheels18are connected by an axle30so that both of the pair of wheels will be rotatable by wheel motor20. In some embodiments, each wheel18has an associated motor such as wheel motor20. In some embodiments, each pair of wheels, connected by an axle such as axle30, has an associated motor such as wheel motor20.

In some embodiments, the curb climbing and curb-descending system further includes a leveling mechanism32(FIG. 6) including one or more level or inclinometer sensors34operably engaged with wheel motor(s)20to control the relative extension of arms14and16so as to ensure that seat102(i.e. the user) is maintained level to the ground during lifting and descent of the wheelchair.

In some embodiments, the curb climbing and curb-descending system includes one or more sensors36(e.g. a pressure/contact sensor,FIG. 6) to detect when wheels18interface with the ground so as to control the relative extension of arms14and16so as to ensure that seat102(i.e. the user) is maintained level to the ground during lifting and lowering of the wheelchair.

In some embodiments, the relative extension of arms14and16are controllable by the user, for example via operation control unit122, which is typically used in any event to actuate the curb climbing and curb-descending system. While the exact amount of lifting of the wheelchair is clearly a function of the dimensions and/or design of the system, it is envisioned that an ascent and descent of about twenty centimeters is sufficient to negotiate most typical curbs and the like. Furthermore, although there is no theoretic time limit on the operation, the system as presented can be designed to reasonably complete an ascent or descent in about ten seconds or so.

In reference to operation,FIG. 7Ashows the approach to a curb to be climbed;FIG. 7Bshows the curb-climbing and curb-descending system being deployed;FIG. 7Cshows the system after it has lifted the wheelchair to the level of the curb;FIG. 7Dshows the system advancing the wheelchair onto the curb; andFIG. 7Eshows the wheelchair after it has completed the curb climbing.FIG. 7Fshows the approach to a curb to be descended;FIG. 7Gshows the system being deployed for the descent;FIG. 7Hshows the system advancing the wheelchair off the curb; andFIG. 7Ishows the wheelchair after it has completed the curb descent.

To operate the system, the user uses operation control unit122to actuate the system when adjacent a curb or the like that the user needs help to ascend or descend. Taking an ascent for example, when frontward/downward extendable wheelchair lifting/lowering arms14are above the curb, the system is actuated and lifting-arm extension and retraction motors28are operated to extend arms14and16. Depending on the exact nature of the aforementioned sensors, the extension of arms14and arms16are controlled so that seat102(i.e. the user) is kept level to the ground whereby the seat/user is not tilted, which provides stability to the operation as well as comfort to the user. The absolute extent of the extension of the arms is typically controlled (and the system designed accordingly) so that the arms raise the wheelchair approximately twenty centimeters whereby most curbs can be negotiate.

After wheels18of arms14and16engage the ground, wheel motor20operates to rotate at least one of wheels18to thereby propel the wheelchair forward. When all of the (standard) wheels108,110and112are above the curb surface, arms14and16are retracted, typically by the user.

A descent is generally similar. When the user is on a curb but adjacent a step off, the user actuates the system and arms14and16are extended by motors28. Sensors34ensure that seat102remains substantially parallel to the ground and wheel(s)18are rotated as mentioned above. When all of the (standard) wheels108,110and112have cleared the curb surface, arms14and16are retracted, typically by the user. In some embodiments, the system may include a further sensor to let the user know when to actuate retraction of arms14and16, or such control can be automatic.

Generally analogously toFIGS. 7A-7I,FIGS. 8A-8Hshow the operation of another embodiment, including optional modifications thereof, of the present wheelchair curb-climbing and curb-descending system. In these embodiments, there is no housing10for housing arms14and16and the arms are typically attached to base106, or other appropriate component, rather than to a housing such as housing10. Front motors28aassociated with frontward/downward extendable wheelchair lifting/lowering front arms14are adapted to move a first segment14aof each arm14so as to move a second segment14b, pivotably connected to the first segment at a pivot or axis50, of each arm14in order to lower wheels18when ascending a curb and in order to raise wheels18when descending a curb. In some embodiments, second segment14bof arms14is attached to the wheelchair, for example to base106via attachment member54; although in other embodiments, depending upon the structure and design, arms14, in particular second segments14b, are directly attached to the wheelchair.

Rear motors28bare associated with rear arms16and are adapted to pivot arms16downward (upon ascent) and upward (upon descent). In some embodiments, rear arms16are attached to the wheelchair at wheels112.

It should be understood that the above description is merely exemplary and that there are various embodiments of the present invention that may be devised, mutatis mutandis, and that the features described in the above-described embodiments, and those not described herein, may be used separately or in any suitable combination; and the invention can be devised in accordance with embodiments not necessarily described above.