WO2017208200A1

WO2017208200A1 - Threshold conqueror for wheelchairs

Info

Publication number: WO2017208200A1
Application number: PCT/IB2017/053273
Authority: WO
Inventors: Ludo Debergh
Original assignee: Ludo Debergh
Priority date: 2016-06-03
Filing date: 2017-06-02
Publication date: 2017-12-07
Also published as: BE1024258A1; BE1024258B1

Abstract

What has been described, is a rolling lifting system with the aim of being a tool for wheelchair users to lift a wheelchair, mounted on the rolling lifting system, to be able to overcome an obstacle threshold on their path. This obstacle threshold can occur in an ascending as well as a descending line. This means to say that the path surface behind the obstacle threshold can be lower as well as higher than the path surface on which the wheelchair user finds himself with his wheelchair, before having to overcome the threshold obstacle.

Description

Threshold conqueror for wheelchairs

FIELD OF THE INVENTION

The current invention pertains fitting a rolling lifting system under a wheelchair with which the wheelchair user can autonomously overcome an obstacle threshold with his wheelchair by means of the lifting system such as, for example, a threshold when entering a home through the front door. More particularly, the invention pertains to a equipping a wheelchair with a rolling lifting system in order to get an improved autonomous wheelchair with which the wheelchair user, in case of an obstacle, for example, a threshold, occurring on his or her path, for example, a walkway, with which the level of his path is interrupted by the obstacle appearing and lies 15 cm higher than the rest, can then continue unhindered and autonomously on his path with the improved wheelchair without having to call in external help to allow for his wheelchair accessibility and to facilitate overcoming similar obstacle thresholds in his path. BACKGROUND TO THE INVENTION

It is well-known that the existing versions of wheelchairs cannot overcome such obstacles without using access opportunities such as drive-up ramps or by calling in external help from people who must help the wheelchair user overcome the obstacle. The various versions of the traditionally manually- operated wheelchairs are well-known They are usually metal frames in the form of a chair equipped at the rear with two fixed drive wheels that have a standard diameter of, for example, 60 cm and fitted with handles, which enables the driver to turn the drive wheels with his hand to let the wheelchair move forward and backward. At the front, the chair is equipped with two pivoting wheels of, for example, standard 12 cm, which rotate 360° around their vertical axles so that the driver can move the wheelchair to the left or to the right.

In this way, several inventions describe various methods of assembling wheelchairs with the different methods for implementation, to move a wheelchair forward and to offer the wheelchair user a comfortable sitting position, etc. However, the applicants have noticed that none of the existing versions of the existing inventions of traditional wheelchairs, have a wheelchair equipped with a system to overcome an obstacle in terms of a level difference because of, for example, a threshold. This invention seeks to solve the problem of autonomous accessibility of existing or new standard wheelchairs to such obstacle thresholds in quite a simple manner

SUMMARY OF THE INVENTION

The current method provides a lifting system that can even be added or fitted to an existing or new wheelchair to lift the wheelchair so that it can continue its way by means of three additional support wheels. This facilitates moving the wheelchair in two ways. On the one hand, the wheelchair fitted with the lifting system, according to the invention, can move just as any other normal wheelchair equipped with its four normal standard wheels that find themselves on a single level of the path. In this position, the lifting system is in a rest position with the support wheels retracted. On the other hand, the wheelchair fitted with the lifting system, according to the invention, can move with the aid of the additional support wheels, in particular its three additional support wheels of which a least one additional support wheel is located at the front of the wheelchair that will move on the higher level of the path and which can be before or after the obstacle threshold, all of this depending whether the obstacle threshold is descending or ascending on the path to be followed by the wheelchair user with his wheelchair fitted with a lifting system according to the invention.

In this position, the support wheels are extended from the lifting system. In both cases, the two rear standard drive wheels of the wheelchair will be used to move the wheelchair, on the one hand, in the normal state directly in contact with the ground and, on the other hand, in a lifted state via the contact and mutual friction between the standard drive wheels and both rear support wheels that are then in contact with the ground. The present invention therefore provides for a rolling lifting system for a wheelchair, with the lifting system comprising of the following elements: a frame (1 1 ) formed with profiles fitted with several hinge points, two rear support wheels (3), and one front support wheel (1 ). A special feature of the lifting system is that the frame (1 1 ) comprises a crossbar (6). In addition, the frame (1 1 ) comprises recesses (15) for moving the crossbar (6) forward and backward. The frame (1 1 ) comprises two recesses (15) for moving the crossbar (6) forward and backward. The lifting system in this invention is particularly characterised by the presence of two rear support wheels (3) a front support wheel (1 ), where the front (1 ) and rear (3) support wheel are suspended from the crossbar (6) of the frame (1 1 ) with the aid of a wheel carrier (2,4) and a pull and push rod (5, 16). In this embodiment, every front support wheel (1 ) is suspended from the crossbar (6) of the frame (1 1 ) with the aid of a wheel carrier (2) and a pull and push rod (5). Every rear support wheel (3) is suspended from the crossbar (6) of the frame (1 1 ) with the aid of a wheel carrier (4) and a pull and push rod (16).

In particular, every pull and push rod (5, 16) is hingedly connected to the respective wheel carrier (2, 4) and the crossbar (6) with connection points. By moving the crossbar (6) forward or backward, respectively, in the recesses (15) provided in the frame, the support wheels are extended or retracted respectively. The lifting system according to the invention will therefore be fitted with operating elements for moving this crossbar in the recesses provided. These mainly pertain to manual operating elements, such as a handle with mechanical or hydraulic transmission; or electrical operating elements with an electric motor that operates the crossbar (6) directly or via mechanical or hydraulic transmission.

In a specific embodiment, the operating elements for the rolling lifting system, according to the current invention, comprise an extendable piston (7), which is hingedly connected to the crossbar (6). In a further embodiment, the extendable piston (7) is connected in the middle of the crossbar (6). Because of the presence of this extendable piston (7), the crossbar (6) can move forward and backward in the provided recesses (15). In a specific preferred embodiment of the present invention, the extendable piston (7) is operated by a hydraulic pump. This hydraulic pump can be operated manually or driven electrically

As already indicated above, the rolling lifting system according to the present invention is characterised by the presence of pull and push rods (5, 16). In a further preferred embodiment, one end of the pull and push rod (16) of the two rear support wheels (3) is hingedly connected to a hinge point (17) on the wheel carriers (4) of these rear support wheels (3). In a further preferred embodiment, one end of the pull and push rod (5) of the front support wheel (1 ) is hingedly connected to a hinge point (17) on the wheel carrier (2) of one or two of the front support wheels (1 ).

The present invention therefore provides for a lifting system that can come into operation if the wheelchair moves forward and ends up with its front standard wheels against the threshold of an obstacle. In this case, the level of the path to be followed with the wheelchair behind the obstacle threshold is higher than the level of the path covered by the wheelchair prior to the obstacle threshold. The wheelchair user can extend his three support wheels (two rear support wheels and one front support wheel) to overcome this obstacle threshold. In this invention, it is assumed that the wheelchair discussed in this embodiment has two standard drive wheels with a diameter of approximately 60cm and two pivoting standard front wheels of approximately 12cm in diameter. However, any other dimension of the standard wheels is possible when this is in proportion to each other and the wheelchair.

Typical for the present invention is the presence of a front support wheel (1 ). The support wheel that is located at the front in the middle of the lifting system, is suspended from one end of the wheel carrier (2), in this invention, referred to as lever (2), with the other end hingedly connected to a horizontal axle of a fixed pre-determined attachment point (12) at the front of the frame of the lifting system. The lever is provided with an attachment point (13) to which a pull and push rod (5) is hingedly connected at the one end and with the other end (of the pull and push rod) hingedly connected to a pre-determined attachment point (18) to the crossbar (6) that can move forward or backward in the provided slides (15) to the left and right of in the frame (1 1 ) of the lifting system. The two support wheels at the rear (3) are suspended from one end of the wheel carriers (4) in this invention: called end-carriages, which, at their other ends, are hingedly attached to the pre-determined attachment points (10) at the back of the frame (1 1 ) of the lifting system. The end-carriers are provided with pre-determined attachment points (17) to which the pull and push rods (16) are, at one end, hingedly connected and with their other ends, hingedly connected to both pre-determined attachment points (14) at the end of the same crossbar (6). The presence of this crossbar (6) is typical of the current invention and helps with the retraction and extension of the front and rear support wheels. By moving the crossbar (6) forward and backward (6) in the slides (15) provided in the frame of the lifting system, the pull and push rods (5, 16) will automatically move along to let the support wheels retract or extend. In the embodiment shown in the figures, the support wheels can be retracted or extended by the wheelchair user by means of a hydraulic pump. This pump can be both manually and electrically operated. The pump causes a hydraulic piston (7) to be pushed out of or retracted into its associated cylinder. This hydraulic piston (7) is hingedly connected to the crossbar (6) that can slide forward or backward in the two slides provided to the left and right in the frame of the lifting system, and to which the pull and push rods (5, 16) of the support wheel carriers are hingedly connected at one end. If the hydraulic piston (7) is pushed out, the crossbar (6) will be pushed forward in its slides and this will, in turn, push out the pull and push rod (5) of the front support wheel (2) by which the lever with the front support wheel (2) will extend until this front support wheel comes into contact with the upper path behind the obstacle threshold. At the same time, the pull and push rods (16) of the two rear support wheels (3) are also pushed forward by the crossbar (6), which, in turn, will let the wheel carriers (4) with which the rear support wheels (3) are extended until they come into contact with the path located before the obstacle threshold. In a further embodiment of the present invention, the attachment points (10) provided on the frame (1 1 ) to which the two wheel carriers (4) of the two rear support wheels (3) are hingedly connected, are selected as such that the circumference radius that defines the axles of the two rear support wheels when extending, are selected as such that they will touch the rear drive wheels of the wheelchair at the appropriate time and retract further under the standard running wheels of the wheelchair to be able to lift the wheelchair at the back until the desired height is reached.

In a preferred embodiment, the two rear support wheels (3) of the rolling lift system has a diameter of a quarter of the diameter of the rear standard wheel. In a specific embodiment where the rear standard wheel has a diameter of approximately 60cm, the two rear support wheels have a diameter of at least 27cm. The two rear support wheels (3), in every embodiment of the present invention, have the aim of lifting the wheelchair at the back by retracting the support wheels under the standard drive wheels of the wheelchair by means of the lifting system. By this, an obstacle threshold with a height of, for example, 18cm can be overcome. In this specific embodiment, it is necessary that the vertical axles of the two rear support wheels with the diameter of at least 27cm, will remain standing at least 25cm before the vertical axles of the standard drive wheels of the wheelchair with a diameter of 60cm in the highest possible lifted position of the wheelchair. In every embodiment of the present invention, the three support wheels are therefore being collapsed simultaneously and this will lift the wheelchair up until the desired height is reached so that the underside of the four standard wheels of the wheelchair end up on the upper path behind the obstacle threshold. The wheelchair user will subsequently move the wheelchair forward with its standard drive wheels via the rear support wheels (3) to up against the obstacle threshold (indicated with c) in figure 6)) and the drive wheels find themselves on the first position so that they can get into touch with the upper path level behind the obstacle threshold. According to the present invention, this means that the vertical axles of the drive wheels of the wheelchair, at that moment, find themselves at least 10cm behind the obstacle threshold and the wheelchair user can lower his wheelchair by means of the lifting system until he makes contact with the upper path behind the obstacle threshold with his four standard wheels, and can subsequently fully collapse the lifting system and the autonomous wheelchair has overcome the obstacle threshold and can move further just as a normal wheelchair.

Conversely, when the level of the path to be followed behind the obstacle threshold to be overcome would be lower that the level of the path already covered before the obstacle threshold, the autonomous wheelchair user must overcome the obstacle threshold be reversing his wheelchair and must proceed as follows. He reverses with his wheelchair until the vertical axle of the drive wheels is located approximately 10cm before the obstacle threshold, puts the handbrake on the drive wheels and lets the three support wheels of the lifting system fully fold down by means of the hydraulic cylinder and pump until the rear support wheels make contact with the lower path behind the obstacle threshold and make sufficient frictional contact with the standard drive wheels of the of the wheelchair. At the same time, the front support wheel will touch the path before the obstacle threshold to be overcome. In this position, the wheelchair is fully lifted and the wheelchair can reverse further with the aid of its drive wheels supported by the rear support wheels and creating sufficient friction with the rear support wheels to, in doing so, overcome the obstacle threshold in an autonomous manner until its two standard front wheels find themselves past the obstacle threshold. To this end, it is still supported by the front support wheel that is still on the upper path before the obstacle threshold and supported by the rear support wheels that are still on the lower path behind the obstacle threshold. The wheelchair user can then collapse the lifting system and the wheelchair will touch the lower path behind the obstacle threshold with its four standard wheels. The lifting system can then be fully collapsed into its starting position, referred to as the rest position, and the autonomous wheelchair user can continue the path to be followed.

The present invention provides for a lifting system for making it autonomously accessible for wheelchair users to overcome obstacle thresholds with a wheelchair. The diameters of the three support wheels of the lifting system to lift the wheelchair are, on the one hand, dependent on the diameters of the standard front and rear wheels of the wheelchair in question and, on the other hand, dependent on the desired height level that must be overcome. The lifting system according to the present invention can be applied to and installed on every existing or new type of manually operated wheelchair and can be operated both manually and electrically be means of a battery and electric pump.

The inventor also found that the lifting system can also be applied to electric wheelchairs provided that the support wheels are adjusted or otherwise operated electrically so that friction contact with the standard wheels of the wheelchair becomes superfluous

The inventor further thought of having two support wheels at the front of the lifting system folded out to provide more stability to the wheelchair while it is lifted and supported by its support wheels. However, this method implies that the two front support wheels could be a considerable inconvenience in terms of the comfortable sitting position of the wheelchair user! Hence, it is preferable to only install one support wheel at the front and it has been found that the stability of the wheelchair remains safe enough as, in the end, only one meter must be covered with the aid the support wheels to be able to overcome an obstacle threshold

The inventor also found that different combinations, that means to say, different operating elements, are possible to let the lifting system operate and lift the wheelchair; this can, as is described in the present invention, be done by means of a manually-operated oil pump, an electric oil pump operated with a battery, but also with a mechanical system, for example, with gears and transmissions that can make a spur gear, attached hingedly to the crossbar, move forward and backward and let the crossbar move forward and backward in its slides.

The frame of the rolling lifting system according to the current invention can be formed from any material whatsoever that is sufficiently strong to fulfil the function as described in this invention. The frame is preferably a metal frame, a plastic frame or a frame made of composite, particularly a metal frame. The rolling lifting system according to the current invention can be formed with profiles from another material that is sufficiently strong to fulfil the function as described in this invention. The rolling lifting system can preferably be formed with metal profiles, plastic profiles or composite profiles; in particular with metal profiles.

The front and rear support wheels of the rolling lifting system of the present invention are also manufactured from any material that is sufficiently strong to fulfil the function of these support wheels. The front and rear support wheels are preferably manufactured from a range of metal types, plastic or composite materials.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows, in perspective view, a schematic representation of the collapsed lifting system for a wheelchair in a specific embodiment according to the present invention. Figure 2 shows, in perspective view, a schematic representation of the extended lifting system for a wheelchair in a specific embodiment according to the present invention.

Figure 3 shows, in perspective view, a schematic representation of the collapsed lifting system mounted on a wheelchair in a specific embodiment according to the present invention.

Figure 4 shows, in perspective view, a schematic representation of the extended lifting system mounted on a wheelchair in a specific embodiment according to the present invention.

Figure 5 shows a side view of a wheelchair with an extended lifting system in the position ready for overcoming an obstacle threshold in a specific embodiment according to the present invention.

Figure 6 shows a side view of a wheelchair with an extended lifting system in the position after the obstacle threshold has been overcome, ready to collapse the lifting system, in a specific embodiment according to the present invention. Figure 7 shows a side view of a wheelchair with a collapsed lifting system in the position after the obstacle threshold has been overcome, a position in which the wheelchair is ready to continue the path to be followed as a normal wheelchair, in a specific embodiment according to the present invention. Figure 8 shows, in perspective view, a schematic representation of how a wheelchair is placed on a lifting system, in a specific embodiment according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in certain embodiments and with reference to specific drawings, but the invention is not limited thereto, but only by the claims. The drawings are only schematic and not restrictive. In the drawings, some of the elements may seem exaggerated and not be drawn on scale for illustrative purposes. The dimensions, even relative, in the drawings therefore do not necessarily correspond with how the invention is applied in practice.

In addition, the terms first, second, third and the like, in the description and the claims are used to distinguish between similar elements and not necessarily to describe sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention may occur in orders other than described and illustrated herein.

In addition, the terms lifting system, raising system, standard drive wheel, standard wheel, and the like, in the description and in the claims, are used for descriptive purposes and not necessarily to indicate relative positions. The terms used as such are interchangeable under appropriate circumstances and the embodiments of the invention may occur in orders other than described and illustrated herein.

The term "include", as used in the claims, may not be construed as being restrictive to the elements listed in context with it. This does not exclude the occurrence of further elements or steps. It must be regarded as prescriptive of the presence of the features, numbers, steps or components referred to, but does not exclude the presence or addition of one or more other features, numbers, steps or components, or groups thereof. Accordingly, the scope of "an object including means A, B and C" may not be restricted to an object only consisting of means A, B and C. That means to say the A, B and C are the only elements of interest for the object relating to the present invention.

In this document, the terms parts and components are used interchangeably and as full synonyms. In this document, the terms wheelchair user and wheelchair driver are used interchangeably and as full synonyms.

In this document, the terms folding out and extending are used interchangeably and as full synonyms.

In this document, the terms collapsing and retracting are used interchangeably and as full synonyms.

In this document, the terms lifting system and device are used interchangeably and as full synonyms.

According to the inventors, the present invention is perfectly suited as additional tool for a wheelchair, with which a wheelchair user can independently use his wheelchair that is accessible to overcome obstacles, such as thresholds, access steps etc., which may occur on his path.

So, in a specific embodiment, the present invention, uses a randomly-existing standard wheelchair that is equipped with a lifting system as described in this invention. In another embodiment, the present invention can also be integrated when manufacturing a new wheelchair. When the lifting system is installed in an existing wheelchair, the chassis of the existing wheelchair is, in so doing, placed on a new lifting system and, in this way, is integrated in the existing wheelchair chassis and afterwards, together, form a single unit. The lifting system includes various components such as pull rods, axles, 3 support wheels, hinged lever and end-carriers, hydraulic double-acting cylinder with manually or electrically operated hydraulic pump, push rods and bearings. In their dimensions and diameters, all these parts are dependent on the existing wheelchair type or a new wheelchair type that can be equipped with the new lifting system. All these parts can be made from different material types, such as: steel, aluminium, titanium, composite plastic etc.

The front support wheel is attached to a hinged lever around its associated axle and can be made as collapsible or otherwise so that it can be stored below the seat of the wheelchair to be less troublesome when using the wheelchair and for the wheelchair user for getting on to the wheelchair. Just like the front support wheel, the rear support wheels can be made as collapsible, so that these support wheels, when not being used, can be stored more compactly in the wheelchair frame resulting in the wheelchair user requiring a smaller area for manoeuvring with the wheelchair. This will also result in less space being taken up when storing the wheelchair. The hydraulic double-acting cylinder with associated hydraulic pump can be operated manually or otherwise electrically. As a variant, the movements of the lifting system can be performed by means of electric power and gear transmission, an electrically operated lifting system is simple to carry out in an electrically operated wheelchair as current is available, but it could be unfavourable in case of a manual wheelchair as this requires a power source such as, for example, a battery that needs to provide power to these motors. Electric operation of the lifting system is an advantage for wheelchair users who cannot operate the manually-operated hydraulic system because of their disability, but an electric system requires additional maintenance and attention when storing the wheelchair, including charging the battery

In this embodiment, the support wheels of the lifting system are executed in plastic but may just as well be executed as variant in aluminium or a combination of pneumatic tyres. However, in doing so, the inventors experienced that the stability of the wheelchair with this variant of pneumatic tyres very adversely affects the stability of the wheelchair, which could endanger the safety of the wheelchair user, hence the preference for opting for solid plastic wheels.

The lifting system as described in this invention can be applied on both the existing and to new models of wheelchairs. The height differences that must be overcome with the system are limited to the height level that the wheelchair can and may achieve with this lifting system, without impairing the stability of the wheelchair and the safety of the wheelchair user.

The invention is now further illustrated by the following drawings.

Figure 1 shows a perspective image of how a lifting mechanism for a wheelchair according to the present invention would look schematically in its rest position, when the three support wheels (1 , 3) do not touch the ground. The lifting mechanism consists of a frame F that is formed with profiles (1 1 ) and provided with hinge points (10, 12) and in which two recesses or slides (15) have been provided for moving forward and backward the crossbar (6) that, in turn, has hinge points (14 and 18) to which the two push and pull rods (16) and the push and pull rod (5) are hingedly connected to one end. The wheel carriers (4) of the rear support wheels (3) with, in this embodiment, a diameter of, for example, 28cm, are hingedly suspended from two pre-determined points (10) of the frame F and these wheel carriers are each provided with pre-determined hinge points (17) to which the two push and pull rods (16) are attached to one end.

The lever (2) that is the wheel carrier of the front support wheel (1 ) with, in this embodiment, a diameter of, for example 12cm, is hingedly connected at the front and in the middle of the frame F at a predetermined point (12). This lever (2) is provided with a pre-determined hinge point (13) to which the push and pull rod (5) is attached to one end. A double- acting hydraulic extendable piston (7) is connected hingedly in attachment point (7) to a crossbar (6) and where this crossbar can move forward and backward in recesses, slides (15) of frame F and to which the push and pull rod (5) is attached in hinge point (18). The two push and pull rods (16) are also hingedly connected at their ends to the crossbar (6) at pre-determined points (14). In this embodiment, an oil tank (8) has been fitted on the frame F with a manually- operated pump that can be operated by the wheelchair user with the handle (9). In this figure, the support wheels are in the position in which the wheelchair stands on the ground with its four standard wheels with the three support wheels retracted and in a rest position.

Figure 2, shows the same embodiment as described in figure 1 , but with the three support wheels in their operational position. In this position, the front support wheel (1 ) and the two rear support wheels (3) are extended and are in their operational position. This happens by the wheelchair user operating the handle (9) and by which the pump of the oil tank (8) generates oil pressure. In this way, the hydraulic cylinder (7) extends by which the crossbar (6) is moved forward via the recesses (15) in the frame F and which, in turn, extends the push rod (5) and pull rods (16) together with the wheel carriers (2 and 4), push the three support wheels (1 and 3) until they touch the ground (path) and come into their operational position. In this position, the wheelchair will be fully lifted from the ground up to a certain height to facilitate overcoming an obstacle threshold.

Figure 3, in perspective, shows an overall picture of a wheelchair equipped with the lifting system described in this invention in rest position in which the three support wheels (3 and 1 ) have been collapsed and retracted and the wheelchair can move forward just a normal wheelchair on its four standard wheels.

Figure 4, in perspective, shows an overall picture of a wheelchair equipped with the lifting system described in this invention in operational state where the wheelchair is lifted because the two rear support wheels (3) are extended and located below the rear large standard wheels B of the wheelchair and can generate enough friction with these rear standard wheels B so that they drive each other as they rotate and these support wheels (3) make contact with the path 20) before the obstacle threshold to be overcome (C). Simultaneously with extending the two rear support wheels (3), the front support wheel (1 ) is sufficiently unfolded and extend until it is supported by the path (21 ) behind the obstacle threshold C, which the wheelchair must overcome. This happens by means of the manually-operated pump (8) and handle (9) operated by the wheelchair user, as described in the method in figure 2, and, accordingly, the rear support wheels (3) becoming the temporary drive wheels of the wheelchair via their contact and friction with the large standard drive wheels (B) of the wheelchair and their contact with the path. The lifted wheelchair is now in its autonomous support-drive position and is supported by the three support wheels of the lifting system so that the wheelchair user can autonomously overcome the obstacle threshold (C) with his wheelchair. After the wheelchair would have overcome the obstacle threshold (C), the three support wheels (1 and 3) are again collapsed into the rest position by means of the double-action hydraulic cylinder and associated manual pump and the wheelchair can continue further behind the obstacle (C) just as a normal wheelchair on its four standard wheels (A and B).

Figure 5 shows a side view of a wheelchair equipped with a lifting system of which the two rear support wheels (3) are sufficiently unfolded and extend and supported by the path before the obstacle threshold (C) and the support wheels (3) are in contact and can generate sufficient friction with the rear standard drive wheels (B) of the wheelchair. The front support wheel 1 is sufficiently extended and supported by the path behind the obstacle threshold (C). In this position, the wheelchair is still located before the obstacle threshold (C) with its four standard wheels (A and B) and is ready to bridge the obstacle threshold (C) autonomously with the aid of its three support wheels (1 and 3) by means of its standard drive wheels (B), operated by the wheelchair user, which will drive the rear support wheels (3) and will let the wheelchair move forward until the vertical axle (D) of the two standard drive wheels (B) of the wheelchair are located approximately 10cm behind the obstacle threshold (C) and the rear support wheels (3) have driven up against the obstacle threshold (C). Subsequently, the wheelchair can be lowered onto its four standard wheels (A and B) by retracting the three support wheels (1 and 3) of the lifting system, until the four standard wheels (A and B) come into contact with the path behind the obstacle threshold (C).

The inventors have also found that, in a further embodiment, the hydraulic pump and the support wheels can be powered by means of a battery, electric motors and all kinds of components so that friction with the standard drive wheels of the wheelchair is superfluous, but this results in an expensive to extremely expensive construction that is of little or no interest to wheelchair users with limited financial resources. However, such embodiment could be of interest for providing electric wheelchairs with the lifting system described in this invention that is powered electrically instead of manually- operated, so that such wheelchairs could also overcome obstacle thresholds Such wheelchairs will be extremely expensive and will only be intended for wheelchair users who have the financial resources to purchase such wheelchairs.

Figure 6, shows a side view of a wheelchair equipped with a lifting system according to this invention of which the support wheels 1 and 3 have been folded out and extended and have moved across the obstacle threshold C by means of its support wheels 1 and 3 until it is up against the obstacle threshold with its two support wheels.

Figure 7, shows a side view of a wheelchair that has overcome the obstacle threshold C and the wheelchair user has collapsed the support wheels 1 and 3 and has brought his lifting system back to the rest position. The wheelchair user is now ready to continue with his wheelchair as normal wheelchair on its four standard wheels A and B on the path behind the obstacle threshold C.

Figure 8, in perspective, shows how a wheelchair can be mounted on a lifting system as described in this invention by means of four bolts and wing nuts M.

Claims

1. A rolling lifting system for a wheelchair wherein the lifting system comprises the following elements:

- a frame (1 1 ) that is formed with profiles provided with several hinge points, - two rear support wheels (3), and

- a front support wheel (1 ),

wherein:

- the frame (1 1 ) comprises a crossbar (6),

- the frame (1 1 ) comprises two recesses for moving the crossbar (6) forward and backward.

- each rear support wheel (3) and front support wheel (1 ) is suspended from the crossbar (6) of the frame (1 1 ) with the aid of a wheel carrier (2, 4) and a pull and push rod (5, 16);

wherein every pull and push rod is hingedly connected to the wheel carrier (2, 4) and the crossbar (6) with connection points.

2. The rolling lifting system according to claim 1 , comprises an extendable piston (7), which is hingedly connected to the crossbar (6); more particularly to the middle of the crossbar (6), with which it can move forward and backward in the recesses that are provided.

3. The rolling lifting system according to claim 2 wherein the extendable piston is operated with a hydraulic pump.

4. The rolling lifting system according to anyone of the preceding claims, wherein one end of the pull and push rod (16) of the two rear support wheels (3) is hingedly connected to a hinge point (17) on the wheel carriers (4) of these rear support wheels (3).

5. The rolling lifting system according to anyone of the preceding claims, wherein one end of the pull and push rod (5) of the front rear support wheel (1 ) is hingedly connected to a hinge point (17) on the wheel carrier (2) of the one or two front support wheels (1 ).

6. The rolling lifting system according to anyone of the preceding claims, wherein the connection points provided on the frame (1 1 ) to which the two wheel carriers (4) of the two rear support wheels (3) are hingedly connected, are selected as such that the circumference radius that will touch the axles of the two rear support wheels and can be retracted further under the standard running wheels of the wheelchair to be able to lift the wheelchair at the back until the desired height is reached.

7. The rolling lifting system according to anyone of the preceding claims wherein the rolling lifting system is combined with an existing wheelchair.

8. The rolling lifting system according to anyone of the claims 1 to 6 wherein the rolling lifting system is integrated in a wheelchair during manufacture of the wheelchair.

9. A wheelchair comprising a rolling lifting system according to anyone of the preceding claims.

10. The wheelchair according to claim 9 wherein the wheelchair is operated manually or electrically.

1 1. A method for autonomously overcoming an obstacle threshold by using a rolling lifting system according to anyone of the preceding claims 1 to 8, or a wheelchair according to claim 9 or 10, wherein the crossbar (6) moves forward in the provided recesses (1 1 ), the rear and front support wheels extend until they touch the path, the rear support wheels are collapsed under the rear standard wheels of the wheelchair and the front support wheel (1 ) is extended behind the obstacle threshold and wherein the rolling lifting system or wheelchair is lifted up to the desired height of the path surface behind the obstacle threshold.

12. Method for autonomously overcoming an obstacle threshold according to claim 1 1 , wherein the wheelchair is lifted at the front when the front support wheel is extended.

13. Method according to one of the preceding claims 1 1 or 12, wherein the rear support wheels and the front support wheel can make a retraction and extension movement by means of the pull and push rods (16, 5), the crossbar (6) and the hydraulic piston (7), and wherein these retraction and extension movements are always carried out simultaneously.

14. A method according to one of the claims 1 1 to 13, wherein the rear support wheels and the front support wheel are simultaneously extended by means of a hydraulic pump which causes the hydraulic cylinder (7) to extend to, in turn, let a crossbar, to which the pull and push rods are attached, move forward to simultaneously extend the rear and front support wheels to lift the wheelchair to the desired height until the wheelchair is supported by its three support wheels, on the one hand, with its front support wheel on the path surface behind the obstacle threshold and, on the other hand, with the two rear support wheels on the path before the obstacle threshold.

15. A method according to claim 14 wherein the rear support wheels and the front support wheel are simultaneously extended to lift the wheelchair to the desired height and to also have sufficient friction generated between both rear support wheels and the standard drive wheels of the wheelchair, as such that it becomes accessible, in an autonomous manner, for the wheelchair user to, with the standard drive wheels of his wheelchair, via the support wheels, move forward with his wheelchair to overcome an obstacle threshold on his path and that it becomes accessible for the wheelchair to follow an upper path located behind the obstacle threshold.

16. Method according to claim 15 wherein the wheelchair user releases the handbrake and autonomously moves his wheelchair forward by means of his support wheels until the vertical axle of his rear standard drive wheels are at least 10cm behind his rear support wheels up against the obstacle threshold.

17. A method according to claim 16 wherein the wheelchair user activates the handbrake of his wheelchair and then collapses his three support wheels simultaneously by means of the manually-operated hydraulic system, as such that his wheelchair is supported by its four standard wheels on the upper path that is located behind the obstacle threshold and the wheelchair user can autonomously move his wheelchair on this upper level in a normal manner.

18. A method for overcoming an obstacle threshold in a descending line using a rolling lifting system according to anyone of the claims 1 to 8 or a wheelchair according to claim 10, wherein the obstacle will be overcome by driving the wheelchair in reverse until the vertical axle of the standard drive wheels are located at a distance of at least 10cm from the obstacle threshold.