WO2019138209A1

WO2019138209A1 - Lifting apparatus for a wheeled mobility assistance device and a wheeled mobility assistance device

Info

Publication number: WO2019138209A1
Application number: PCT/GB2018/053777
Authority: WO
Inventors: Jeffrey RODBARD
Original assignee: Roma Medical Aids Limited; Rodbard Critical Power Engineering Limited
Priority date: 2018-01-15
Filing date: 2018-12-28
Publication date: 2019-07-18
Also published as: GB201800624D0; GB2570293A

Abstract

A lifting apparatus is provided for the powered lifting of a wheeled mobility assistance device, such as, for example, a wheelchair from one surface to another surface at a different elevation. This will enable the users of wheelchairs to move over changes in height between surfaces in a controlled manner without the need to additional human assistance of high levels of upper body strength.

Description

LIFTING APPARATUS FOR A WHEELED MOBILITY ASSISTANCE DEVICE AND A WHEELED MOBILITY ASSISTANCE DEVICE

FIELD

The invention relates to a lifting apparatus for a wheeled mobility assistance device and a wheeled mobility assistance device. In particular, hut not exclusively, the invention relates to a lifting apparatus which enables a wheeled mobility assistance device to move between surfaces of different elevations without requiring the user to seek additional help or rely on upper body strength.

BACKGROUND

Often, when a person suffers from a disability which reduces their mobility, they can be reliant on a wheelchair for mobility. Whilst the assistance these appliances provide is not in question, the cumbersome nature of these appliances means that it can be difficult to navigate certain aspects of life.

One example of such a difficulty is climbing or descending kerbs. Whilst some wheelchair users do possess the upper body strength and general dextrousness required to navigate such obstacles, many wheelchair users will find this difficult without additional help from another human being - which diminishes their sense of independence.

Aspects and embodiments were conceived with the foregoing in mind.

SUMMARY

Aspects are described in relation to a wheeled mobility assistance device. Examples of wheeled mobility assistance devices include wheelchairs and mobility scooters.

A wheeled mobility assistance device which may be used in conjunction with aspects of this invention is a wheelchair of a type that use rear wheels that are larger compared to a set of front wheels. 9

Viewed from a first aspect, there is provided a lifting apparatus for enabling a wheeled mobility assistance device to move from a first surface at a first elevation to a second surface at a second elevation, the lifting apparatus configured to respectively raise and lower the wheeled mobility assistance device between the surfaces to enable the wheeled mobility assistance device to be used on the second surface

A lifting apparatus in accordance with the first aspect raises and lowers a wheeled mobility assistance device between surfaces at differing elevations without any requirement for additional help from a second person or any upper body strength on the part of the user. This enables the user of the wheeled mobility assistance device to maintain their independence for longer even if their condition means that they suffer severe degradation of their upper body.

The lifting apparatus may be powered by a suitable battery which runs the control modules needed for the powered lifting and lowering of the wheelchair when it is coupled to the wheeled mobility assistance device.

The lifting apparatus may comprise a first device for lifting and lowering a first portion of the wheeled mobility assistance device and a second device for lifting and lowering a second portion of the wheeled mobili ty assistance device.

The first device may be configured, in a first mode, to draw the first portion of the wheeled mobility assistance device onto the second surface and configured, in a second mode, to low_'er the first portion onto the second surface and further wherein the second device is configured, in a first mode, to raise the second portion of the wheeled mobility assistance device to a position level with the first portion and configured, in a second mode, to lower the second portion onto the second surface.

The first device may comprise a lever to apply leverage to the first portion of the wheeled mobility assistance device and the second device may comprises a lifting mechanism to raise and lower the second portion of the wheeled mobility assistance device. The lever may comprise a pair of arms which may he moved relative to a rotating axle to apply leverage to one of the first or second surfaces.

The lifting mechanism may comprise a pair of wheels at one end to facilitate motion of the wheeled mobility assistance device.

The lifting apparatus may be configured to respectively raise and lower the wheeled mobility assistance device between surfaces responsive to a trigger event which may be a user input or the detection of a boundary between the first and second surfaces by a sensor, which may be a proximity sensor.

The boundary may be a kerb face or a kerb edge.

A lifting apparatus for a wheeled mobility assistance device may be configured to determine a change in elevation between a first surface at a first elevation on which the wheeled mobility assistance device is positioned and a second surface at a second elevation on which the user desires to position the wheeled mobility assistance device; and move the wheeled mobility assistance device from the first surface to the second surface.

The lifting apparatus may be coupled to the wheeled mobility assistance device using any suitable means.

Embodiments enable a wheeled mobility assistance device to be moved from a surface at a first elevation to another surface at a second elevation. There may be a height difference between the first elevation and the second elevation which provides an obstacle to the user of the wheeled mobility assistance device. Embodiments in accordance with the first aspect mean that the wheeled mobility assistance device is automatically moved from one surface to a higher or lower surface by the lifting apparatus without the need for another person or considerable upper body strength on the part of the user of the wheeled mobility assistance device. If we consider the example of a wheelchair, an lifting apparatus in accordance with the first aspect will enable a wheelchair to climb or descend a step or kerb by enabling the attachment of additional items to be fitted to the wheelchair which facilitate powered lifting or controlled descent of the front or rear of the wheelchair as is desired by the user. The powered lifting and/controlled descent of the front or rear of the wheelchair may be automatically coordinated by a control module or by two discrete sensor arrangements. When the wheelchair is on a flat surface neither of these functional items are in contact with the ground, so that the wheelchair is fully controllable by the user by rotation of the main wheels by hand in the normal manner.

The lifting apparatus uses two devices positioned to control the height of the front of the wheelchair. One of the device comprises a centrally mounted support wheel or wheels mounted in front of the front wheels and which can he made to move downwards when required during climb or descent of a step thus preventing excessive forward tilt of the wheelchair. The second device comprises of a high-friction pad or stop also mounted centrally under the wheelchair but slightly behind the front self-steering wheels, and at a height that brings it close to the ground in normal operation. During the operation of descending a step or kerb this device is used to prevent the wheelchair toppling forwards if the front wheels are driven over the edge of the step.

The height of the rear of the wheelchair when climbing or descending from a step or kerb is controlled by a third device, this comprises of a pair of electrically driven articulated arms mounted on a horizontal shaft that is parallel to the axis of the rear wheel s but pivoted at a point rearward of it. These arms are mounted on the shaft radially and in parallel such that one arm can control the height of the left side of the wheelchair, and the other the right side.

The default position of the arms for normal use of the wheelchair on a fiat surface is to project downwards and rearwards with the ends near to the floor, so that they can act as a safeguard against the wheelchair tipping rearwards. Each aim may be in at least two sections. There is a section fixed radially to the horizontal shaft mentioned is of a length slightly less than the radius of the rear wheels of the wheelchair. At the extremity of this section is pivotally attached a second section which can extend the total reach of the arm beyond the length of the first section, but can also fold round to an acute angle to the first section, so that the total length of the arm is then reduced to that of the fi rst section. For each of the lifting arms, a spring holds the second section at a pre-set maximum obtuse angle to the first section by means of a mechanical stop fitted to the pivot point of the outer section.

When the user desires to mount a step, the wheelchair may be reversed up to the step with the pair of arms in the default position. For safety reasons, if the wheelchai r is already leaning backwards more than a pre-set angle at the point, then tilt sensing switch within the wheelchair will prevent the arms from being raised at all to avoid the risk of the chair tipping rearwards. Provided the wheelchair is not tilting rearwards more than the pre-set angle, the shaft carrying the arms can then be driven around to raise the arms, and as they do the articulated section of each arm touches the top, also known as the riser, of the step, and folds round temporarily to allow this movement to continue until they are raised sufficiently for the ends of the anus to clear the top of the step, where they will then articulate back to their maximum length due to the action of the fitted springs. To climb the step, the shaft is the power driven in the opposite direction to cause the arms to move the downwards to contact the top surface of the step, and as this movement is continued the rear of the wheelchair is caused to rise. This will cause the wheelchair to begin to tip slightly forwards, and a forward tilt sensing switch in the wheelchair is operated, which is used to operate the front support device downwards until it reaches the ground and so lifts the front of the wheelchair to maintain it in an approximately level configuration. This lifting operation of the front and rear of the wheelchair can then continue with the wheelchair held approximately level throughout until the rear wheels are fully over the step, and at this point the lifting arms will fold to a shorter length and thus deposit the main wheels on the top surface of the step. The operator can then reverse the wheelchair manually as far as possible until the front caster wheels are also over the step, and at this point the front lifting device can then be retracted and the lifting arms returned to the default position. If the user desires to descend a step, the wheelchair may be directed toward the step in a forward direction. If the front caster wheels go over the edge of the step the front of the wheelchair drops slightly but is arrested by a stop pad which is mounted under the wheelchair and just behind the front wheels. Of course, the user may prevent the wheels from passing over the edge manually. This stop pad has a switch mounted within it, so that as it is pressed down onto the edge by the weight of the front of the wheelchair, it operates the front lifting device which continues downward travel until it reaches the bottom level of the step, and will then raise the front of the wheelchair to an approximately level configuration in a similar manner as used for the climbing operation already described. The stop pad is lifted clear of the step at this point, so that the wheelchair can now be moved forward by the operator, as it is supported by the rear wheels as normal and at the front by the wheels of the front lifting device on the lower level. When the wheels go over the nose of the step, further downward movement of the rear of the wheelchair is arrested by the two arms resting on the top of the step. The slight tilting of the wheelchair in the rearward direction as a result of the two arms resting on the top of the step will operate a rearward tilt switch which retracts the forward lifting device sufficiently to lower the front of the wheelchair to restore an approximately level configuration. The operator can then cause the lifting arms to 1 ower the rear of the wheelchair in a controlled manner, during which the front lifting device will retract further to maintain the wheelchair in an approximately level configuration throughout. When the wheelchair is fully descended, it remains only to raise the front lifting device fully, and return the lifting arms to the default position of acting as safety stops.

The lifting apparatus may be further configured to determine the user desire to position the wheeled mobility assistance device on the second surface responsive to the detection of a trigger event by a sensor.

The trigger event may be the proximity of a barrier between the first surface and the second surface. The barrier may be a kerb or a step.

The trigger event may be a user input which may be input on a control panel which is operatively coupled to the lifting apparatus. Such a trigger event may be the tipping of the wheeled mobility assistance device in a first or second direction. The trigger event may be detected by a sensor which generates a signal which is transmitted to a control module which is used to initiate a sequence of operations which enable the movement of the wheeled mobility assistance device to the second surface.

The lifting apparatus may comprise a control module operatively coupled to a first control arrangement coupled to a first set of wheels on the wheeled mobility assistance device. The control module may additionally be operatively coupled to a second control arrangement operatively coupled to a second set of wheels on the wheeled mobility assistance device.

Operatively coupled means that the respective sensor arrangement can transmit signals to the control module and can receive signals transmitted from the control module. The transmission of signals between the control module and the respective sensor arrangements can be implemented by any suitable transmission means or transmission protocol.

The lifting apparatus may be operable in at least one of a plurality of modes.

In a first mode, the lifting apparatus may be configured to determine that the second surface is higher than the first surface and further configured to move the wheeled mobility assistance device from the first surface to the second surface to enable the user to travel in the wheeled mobility assistance device on the second surface.

The effect of this is that the lifting apparatus determines that the user wants to move to a higher surface and moves the wheeled mobility assistance device to the higher surface responsive to that determination.

Moving the wheeled mobility assistance device onto the second surface may comprise: moving a first support mechanis into contact with the second surface to lift a first part of the wheeled mobility assistance device to a height equal to the height of the second surface; deploying a second support mechanism to lift a second part of the wheeled mobility assistance device to a height substantially level with the height of the second surface; using the second support mechanism to move the wheeled mobility assistance device into position onto the second surface.

The second support mechanism may be used in combination with the first support mechanism to move the wheeled mobility assistance device into position on the second surface.

A height substantially level with the height of the second surface may be determined by a tilt sensor which may determine that the wheeled mobility assistance device is at a zero angle relative to the horizontal axis as the second part of the wheeled mobility assistance device is horizontally aligned with the first part of the wheeled mobility assistance device. Substantially means that some tolerance is allowed in that the wheeled mobility assistance device may be described as being at a height substantial ly level with the height of the second surface if the incline of the wheeled mobility assistance device is of a magnitude of less than 5 degrees.

The second support mechanism may comprise wheels arranged at the end of an arm to enable the second support mechanism to move the wheeled mobility assistance device into position on the second surface.

The determination that the second surface may be higher than the first surface may be terminated if the lifting apparatus detects that the wheeled mobility assistance device is tilting by more than a pre-set angle. The lifting apparatus may be configured to determine that the second surface is lower than the first surface and may be further configured to move the wheeled mobility assistance device from the first surface to the second surface to enable the user to travel in the wheeled mobility assistance device on the second surface.

The lifting apparatus may be configured to detect the wheeled mobility assistance device is in a tipping position to determine that the second surface is lower than the first surface; and responsive to the determination that the second surface is lower than the first surface, the lifting apparatus may be configured to lower the wheeled mobility assistance device onto the second surface.

Lowering the wheeled mobility assistance device onto the second surface may comprise: detecting a si gnal i ndi cati ve of a tilt of the wheel ed mobil ity assistance device toward the second surface; deploying a first support mechanism into contact with the second surface to support a first portion of the wheeled mobility assistance device on the second surface; moving a second portion of the wheeled mobility assistance device towards the second surface using the first support mechanism; deploying a second support mechanism to arrest the downward movem ent of the second portion of the wheeled mobility assistance device toward the second surface.

The lifting apparatus may comprise coupling mechanisms configured to enable the lifting apparatus to be attached to and detached from the wheeled mobility assistance device.

Viewed from a second aspect, there is provided a wheeled mobility assistance device configured to determine a change in elevation between a first surface at a first elevation on which the wheeled mobility assistance device is positioned and a second surface at a second elevation on which the user desires to position the wheeled mobility assistance device and further configured to move from the first suit ace to the second surface responsive to the determination of a change in elevation between the first surface and the second surface.

A wheeled mobility assistance device in accordance with the second aspect can move between surfaces at difference elevations without the need for an additional human assistant and without requiring the user of the wheeled mobility assistance device to use their own body strength or call upon the goodwill of others or the use of an assistant.

The wheeled mobility assistance device may be further configured to determine the user desire to position the wheeled mobility assistance device on the second surface responsive to the detection of a trigger event by a sensor.

Such a sensory may be a proximity sensor, which may be a capacitive proximity sensor.

In using a trigger event the wheeled mobility assistance device can initiate the process of moving between surfaces at different elevations responsive to an event w_'hich indicates that such movement is desirable. This means that the user does not need to provide input which again reduces the onus on the user, wdio may not have use of their limbs to provide such user input.

The wheeled mobility assistance device may be operated in at least one of a plurality of modes including a first and a second mode.

In the first mode, the wheeled mobility assistance device may be configured to determine that the second surface is higher than the first surface and further configured to move the wheeled mobility assistance device from the first surface to the second surface to enable the user to travel in the wheeled mobility assistance device on the second surface.

Moving the wheeled mobility assistance device onto the second surface may comprise: moving a first support mechanis into contact with the second surface to lift a first part of the wheeled mobility assistance device to a height equal to the height of the second surface; deploying a second support mechanism to lift a second part of the wheeled mobility assistance device to a height substantially level with the height of the second surface to provide a level configuration of the wheeled mobility assistance device; using the second support mechanism to move the wheeled mobility assistance device into position onto the second surface.

The second support mechani sm may comprise wheels arranged at the end of an arm to enable the second support mechanism to move the wheeled mobility assistance device into position on the second surface.

The determination that the second surface is higher than the first surface may be terminated if the wheeled mobility assistance device detects that the wheeled mobility assistance device is tilting by more than a pre-set angle. This means that if the wheeled mobility assistance device is tilting in an unsafe way, the wheeled mobility assistance device does not continue with the process of moving between the first surface and the second surface.

In the second mode, the wheeled mobility assistance device may be configured to determine that the second surface is lower than the first surface and further configured to move the wheeled mobility assistance device from the first surface to the second surface to enable the user to travel in the wheeled mobility assistance device on the second surface. This means that the wheeled mobility assistance device can be lowered onto a lower surface.

The wheeled mobility assistance device may be configured to detect the wheeled mobility assistance device is in a tipping position to determine that the second surface is lower than the first surface; and responsive to the determination that the second surface is lower than the first surface, the lifting apparatus is configured to lower the wheeled mobility assistance device onto the second surface.

Lowering the wheeled mobility assistance device onto the second surface may comprise: detecting a signal indicative of the tilt of the wheeled mobility assistance device toward the second surface; deploying a first support mechanism into contact with the second surface to support a first portion of the wheeled mobility assistance device on the second surface; moving a second portion of the wheeled mobility assistance device towards the second surface using the first support mechanism; deploying a second support mechanism to arrest the downward movement of a second portion of the wheeled mobility assistance device toward the second surface.

The use of a lifting apparatus in accordance with the first aspect or a wheeled mobility assistance device in accordance with the second aspect means that the wheeled mobility assistance device can be used to automatically move between surfaces at different elevations without the input of an additional human assistant.

DESCRIPTION

An embodiment in accordance with the first and second aspects will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a schematic illustration of a wheelchair in accordance with the embodiment; Figure 2 is a schematic illustration of a lifting apparatus for a wheelchair in accordance with the embodiment;

Figure 3 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the wheelchair is reversing toward a kerb;

Figure 3a is a schematic illustration of an arm comprising substantially perpendicular bent portions in accordance with an embodiment;

Figure 4 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the lifting apparatus is in an obstacle ascent mode;

Figure 5 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the lifting apparatus is in an obstacle ascent mode;

Figure 6 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the Sifting apparatus has been used to lever the wheelchair onto a surface at a higher elevation;

Figure 7 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the Sifting apparatus is in an obstacle ascent mode;

Figure 8 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the wheelchair is now on the surface of higher elevation;

Figure 9 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the wheelchair is approaching the boundary between a surface at a higher elevation and a surface at a lower elevation; Figure 10 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the wheelchair is being operated in an obstacle descent mode;

Figure 11 is a schematic illustration of a wheelchair comprising an lifting apparatus in accordance with the embodiment when the rear of the wheelchair is being moved downwards onto a surface of lower elevation; and

Figure 12 is a schematic illustration of a wheelchair comprising a lifting apparatus in accordance with the embodiment when the Sifting apparatus has been used to lower the wheelchair onto a surface of a lower elevation.

We now describe, with reference to Figure 1, a wheelchair 100 in accordance with the embodiment.

Wheelchair 100 comprises a set of handles 102, a set of front wheels 104 and a set of rear wheels 106. Wheelchair 100 further comprises a seat portion 108 w'here a user 110 (not shown in Figure 1) is supported when they are using the wheelchair 100. The wheelchair 100 may be driven manually by an assistant (not shown) to the user directing the wheelchair 100 using the handles 102.

The set of rear wheels 106 is larger in diameter than the set of front wheels 104. The set of front wheels 104 provide good longitudinal stability to the wheelchair 100.

The set of front wheels 104 typically need to be positioned closely to the set of rear wheels 106 The close proximity of the set of front heels 104 to the set of rear heels 106 makes the wheelchair liable to pitch forward or backwards dangerously when attempting to climb or descend an obstacle such as a kerb or step.

The wheelchair 100 is used to transport the user 1 10 across all manner of terrain, some more easily than others. 3

For users of wheelchairs, independence can come at a premium, as their reasons for being confined to a wheelchair may mean that certain aspects of life are difficult to navigate by themselves. Additionally, reduced upper body strength due to age-related muscle degeneration or other forms of muscular degeneration may also erode the user’s independence. This means that intervention from additional human beings can be necessary in order to enable to say, navigate kerbs at roadsides or other similar obstacles where a change in elevation is present.

Additionally, users of wheelchairs who do not typically require additional help may choose to navigate kerbs using wheelchairs without the help of others, which may put them in danger of toppling out of the wheelchair 100 by introducing the instability inherent in a situation where they navigate a kerb themselves. These individuals may also need to call upon the goodwill of others to provide them with assistance which again erodes away at their sense of independence.

We now describe, with reference to Figure 2, a lifting apparatus 200 in accordance with the embodiment.

The lifting apparatus 200 comprises a control module 202 which is operatively coupled to a first control arrangement 204 and a second control arrangement 206. Each of the control module 202, the first control arrangement and the second control arrangement is powered by a suitable power source. For example, they may each be coupled to a suitable battery. The battery_' may be the battery used for the wheelchair or it may be a battery configured specifically for the lifting apparatus.

As will be understood from what follows, the control module 202 coordinates the operation of the first control arrangement 204 and the second control arrangement 206. However, it will be understood that the first control arrangement 204 and the second control arrangement 206 may alternatively comprise components which enable them to jointly implement the functionality provided by control module 202 if control module 202 were to be omitted.

The first control arrangement 204 forms a device which controls the electronically powered lifting and lowering of the front of the wheelchair 100 and the second control arrangement 206 forms a device which electronically controls the lifting and lowering of the rear of the wheelchair 100.

The operative coupling between the first control arrangement 204 and the control module 202 and the second control arrangement 206 and the control module 202 can be implemented using a co-axial cable implementing a standard data bus which will allow the respective first control arrangement 204 and second control arrangement 206 and the control module 202 to exchange data during use of the lifting apparatus 200.

The control module 202 is arranged to be coupled to the wheelchair 100 in any suitable way. For example, the control module 202 may comprise screw-holes which enable it to be screwed into place on the wheelchair 100 Additionally, the control module 202 may comprise a Velcro pad which enables the control module 202 to be put into place on the wheelchair 100.

The first control arrangement 204 is configured to be coupled to the wheelchair 100 in a suitable position such as, for example, near to the set of front wheels 104. The coupling between the wheelchair 100 and the first control arrangement 204 can be implemented in any suitable way such as, for example, by screw's or by a Velcro pad.

The second control arrangement 206 is configured to be coupled to the wheelchair 100 in a suitable position such as, for example, near to the set of rear wheels 106. The coupling between the wheelchair 100 and the second control arrangement 206 can be implemented in any suitable way such as, for example, by screw's or by a Velcro pad. The second control arrangement 206 comprises first and second arms 212 which move between at least three positions relative to an axle 228. The three positions are upper, lower and intermediate positions. The first and second arms 212 are illustrated in Figure 3.

The first and second arms 212 are generally bent in shape to enable them to grip surfaces effectively. The bend may be more profound in shape in that a first section 212a may be substantially perpendicular in shape to second section 212b. This arrangement is shown in Figure 3 a.

The operation of the fi rst control arrangement 204 and the second control arrangement 206 will now be described by way of an illustrative example describing the lifting apparatus 200 being used to enable the wheelchair 100 to both ascend and descend a kerb 300.

This example is described with reference to Figures 3 to 12.

Firstly, we will describe, with reference to Figures 3 to 8, the use of the lifting apparatu s 200 to ascend a kerb 300.

During use of a wheelchair 100 comprising the lifting apparatus 200, the user may encounter a kerb 300 which may be in front of a shop from which the user may want to visit to buy goods or the user may want to ascend the kerb 300 to access a leisure facility such as a public house, restaurant or a sports centre.

In order to ascend the kerb 300, the user moves the wheelchair 100 toward the kerb 300 in a backward direction (indicated by an arrow) either using an electronic controller positioned on the wheelchair 100 which can receive an input to indicate the desire to move the wheelchair 100 backwards or using their arms to move the rear set of wheels 106 in a backward direction. The first and second steel arms 212 are in their intermediate position, which is the default position occupied by the arms 212. If the user wishes to ascend the kerb 300, they may provide a user input to the electronic controller positioned on the wheelchair 100 which initiates an obstacle ascent mode in the lifting apparatus 200. Responsive to receiving this input, the control module 202 switches to an obstacle ascent mode.

The movement of the first and second steel arms 212 may be driven by an electric motor comprising an actuator such as an D3M3 actuator. The first and second steel arms 212 may also be coupled to a torsional spring which stores and releases energy based on the movement of the arms between their respective positions.

The second control arrangement 206 may comprise a proximity sensor 208 which is arranged to detect an obstacle such as a kerb 300. The proximity sensor 208 is oriented such that its signal transmits outwardly from the rear of the wheelchair 100.

An example proximity sensor 208 detects the kerb 300 by detecting a change in capacitance due to the difference in dielectric constant between the concrete which is typically used to make a kerb and air. Responsive to detecting the difference in dielectric constant due to the presence of a concrete kerb 300, the proximity sensor 208 then transmits an obstacle ascent signal to a control sub-module 210 which forms part of the second control arrangement 206. This causes the second control arrangement to transmit the obstacle ascent signal to the control module 202. The proximity sensor 208 may detect the kerb 300 and initiate the obstacle ascent mode without the input of the user.

The obstacle ascent signal is a signal which indicates to the control sub-module 210 that the lifting apparatus 200 is to be operated in a mode in vvhi ch the lifting apparatus 200 is used to enable the wheelchair 100 to climb the kerb 300 Responsive to receiving the obstacle ascent signal, the control sub-module 210 transmits a signal to the control module 202 to indicate that the lifting apparatus 100 is being used in the obstacle ascent mode. in the obstacle ascent mode, the control module 202 will then switch on a tilt sensor 214. The tilt sensor 214 in this embodiment is part of the control module 202 but in the absence of the control module 202 the tilt sensor 214 m ay be part of the first control arrangement 204 or the second control arrangement 206. The tilt sensor 214 determines the angle of the wheel chair relative to the horizontal axis. That is to say, when the wheelchair 100 is in the horizontal position, the tilt sensor 214 will return a value of zero to indicate a zero tilt of the wheelchair 100.

An example of a tilt sensor 214 is a gyroscope which generates a signal indicative of the the orientation of the wheelchair 100 relative to the ground.

The control sub-module 210 then provides a first drive signal to turn an axle 228 about which a set of first and second steel arms 212 rotate. The first drive signal moves the set of first and second arms 212 from a lower position to an upper position in which they protrude outwards beyond the rear of the wheelchair 100 to engage the uppermost surface of the kerb 300. This is described in reference to Figure 4.

In embodiments where the torsional spring is used the movement to the upper position may cause the torsional spring to contract to store the energy generated by the movement of the arms to their upper position.

If the tilt sensor 214 determines that the wheelchair 100 is tilting by more than a pre-set angle the obstacle ascent mode is terminated.

The user may adjust the height of the upper position of the arms using a control panel which is operatively coupled to the control module 202 either by using standard electronics or a wireless transmission link. Such a control panel may be mounted to the wheelchair 100

Responsive to user input, the control sub-module 210 transmits a second drive signal to the set of first and second arms 212 to move them towards their lower position. This will cause the first and second arms 212 to push downwards on the surface 304. The drive signal may- cause the torsional spring to be released which will release the energy fro the torsional spring. The energy released by the torsional spring may be used to drive the arms 212 toward their lower position. If the proximity sensor 208 is being used, the proximity sensor 208 can be configured to detect that the rear of the wheelchair 200 is only a small, i.e. of the order of less than 5 millimetres, distance away from the kerbside 310, this will lead to the movement of the first and second arms 212 toward their lower position to cause them to push downwards on the surface 304.

That is to say, the set of first and second arms 212 are moved downwards from an upper position where they are above the top of the kerb 300 towards the top of the kerb 300 so that the first and second arms 212 push downwards on the top of the kerb 300.

The pushing of the first and second arms towards the top of the kerb 300 means that the wheelchair 100 causes the rear part of the wheelchair 100 to be partial ly lifted from the surface 302 on which it is currently positioned in that the force applied by the kerb 300 on the first and second arms will translate into a force which will cause the rear set of wheels 106 to be lifted from the surface 302 on which they are currently positioned to a position where the bottom of the set of rear wheels 106 is level with the top of the kerb 300, i.e. level with the surface 304 on which the user would like the wheelchair 100 to be. This is described with reference to Figure 5

That is to say, the pushing of the first and second amis 212 towards the top of the kerb 300 enables a levering effect on the rear of the wheelchair 100 to lift that part of the wheel chair 100 from surface 302.

This will of course cause the wheelchair 100 to be tilted. The tilt sensor 214 determines the amount of tilt generated by the levering of the wheelchair 100 caused by the movement of the first and second arms 212. When the tilt sensor 214 determines that the wheelchair 100 is tilted at a pre-set angle, which will typically be approximately 25 degrees, the tilt sensor 214 transmits a signal to the first control arrangement 204 to indicate that the lifting apparatus 200 is being operated in an obstacle ascent mode.

Responsive to receiving the signal from the tilt sensor 214, the control sub-module 216 transmits a drive signal to a telescopic arm 218. The telescopic arm 218 comprise an arm section which is comprised of concentric sections with a stop axle 220 at the end which is aligned with a pair of wheels which are coupled to first and second ends of the stop axle 220.

Responsive to receiving the drive signal from the control sub-module 216, the telescopic arm 218 is arranged to telescopically extend from a housing 224 toward the surface 302. The action of the telescopic arm 218 to cause it to extend from the housing 224 toward the surface 302 causes the set of wheels 222 to be brought into contact with the surface 302 The action of the set of wheels 222 on the surface 302 will cause the front end of the wheelchair 100 to be lifted from the surface 302 as illustrated in Figure 5.

When the tilt sensor 214 detects that the wheelchair 100 is tilted at a zero angle, i.e. the front of the wheelchair is level with the rear of the wheelchair, the tilt sensor 214 transmits a stop signal to the first control arrangement 204. Responsive to receiving the stop signal, the first control arrangement 204 transmits a terminate signal to the telescopic arm 218 which halts the telescopic extension of the telescopic arm 218 and holds the telescopic arm 218 at its current position, i.e. maintaining the wheelchair 100 in a level configuration as illustrated in Figure 5.

That is to say, the movement of the telescopic arm 218 levels the wheelchair 100 so that the wheelchair 100 is no longer tilted.

The arms 212 will then continue to move downwards which will be translated into movement of the rear part of the wheelchair 100 as the arms will continue to lower the rear part of the wheelchair 100 toward the surface 304 which will result in the rearward movement of the wheelchair 100 onto the surface 304.

Of course, as the telescopic arm 218 has wheels 222 at its end and the telescopic arm 218 causes the front part of the wheelchair 100 to be lifted from the surface 302, the point of contact between the front part of the wheelchair 100 and the surface 302 will be the wheels 222. The wheels 222 will cause the front part of the wheelchair 100 to move backwards toward the surface 304 as the rear of the wheelchair 100 is moved backwards by the ievering effect of the arms 212 The direction of movement of the wheels 222 and the rear set of wheels 106 is described by the directional arrows in Figure 6.

The movement of the wheelchair 100 toward the surface 304 and the continued movement of the arms 212 towards the lower position will result, inevitably, in the rearward movement of the wheelchair 100 onto the surface 304. This is illustrated in Figure 6

That is to say, the combined action of the movement of the arms 212 and the contact between the wheels 222 and the surface 304 will lever the wheelchair 100 onto the surface 304 fro the surface 302 and cause the wheelchair 100 to be dragged onto the surface 304 This will bring the rear wheels 106 into contact with the surface 304 and the wheels 222 will continue moving to push the front end of the wheelchair 100 toward the surface 304.

Upon contact with the surface 304 the natural momentum of the movement of the rear wheels 106 onto the surface 304 will cause the rear wheels 106 to roll on the surface 304 which will, in turn, cause the wheels 222 to roll in the same direction as the rear wheels 106 which will cause the front part of the wheelchair 100 to move toward the surface 304 Alternatively, the user may use their own strength to roll the rear wiieels 106 backwards to move them along the surface 304 which will cause the wheels 222 to roll in the same direction as the rear wheels 106.

The continued movement of the first and second arms 212 will cause the first and second arms 212 to move into a position within the profile of the wheelchair 100 so that they do not interfere with the motion of the wheelchair 100.

When the user realises that the front part of the wheelchair 100 is above the top of the kerb 300 they can then provide a further user input to indicate that the telescopic arm 218 should be retracted. This position is described with reference to Figure 7. The first control arrangement 204 then transmits an arm retract signal to the control sub-module 226.

Responsive to receiving the arm retract signal, the control sub-module 226 transmits an undo drive signal to the telescopic arm 218 which results in the telescopic arm 218 being retracted into the housing 224 and within the profile of the wheelchair 100. The retraction of the telescopic arm 218 to a position within the profile of the wheelchair 100 means that it will not prevent an obstacle to the progress of the front wheels 104 towards the surface 304. This is illustrated in Figure 8.

The first control arrangement 204 may comprises a proximity sensor 226 arranged to determine when the front part of the wheelchair 100 is above the top of the kerb 300 which will indicate that the front wheels 104 are on the surface 304 or that they are close to being in contact with surface 304.

The proximity sensor 226 is configured similarly to the proximity sensor 208 which forms part of the second control arrangement 206 in that it determines a change in capacitance which would be due to the proximity of the kerb 300. The proximity sensor 226 is oriented to emit its signal towards the surface underneath the wheel chair 100.

When the front part of the wheelchair 100 is in a position where it is above the surface 304, the proximity sensor 226 detects that the front wheels 104 are about to be in contact with the surface 304 or are on the surface 304, as illustrated in Figure 6.

Responsive to detecting that the front wheels 104 are about to be in contact with the surface 304 the proximity sensor 226 transmits an arm retract signal to the control sub- module 226 which causes the telescopic arm 218 to be retracted into the housing 224.

That is to say, when the front wheels 104 and the rear wheels 106 are both on the surface 304, the set of arms 212 and the telescopic arm 218 are moved back out of the way of the operation of the wheelchair 100 so that the wheelchair 100 can move freely on the surface 304 The set of arms 212 may then be moved back to their default position as is shown in Figure 8.

Therefore, in the obstacle ascent mode, the lifting apparatus enables the wheelchair 100 to be lifted over a kerb 300 onto a surface 304 which is at a higher elevation. We will now describe the operation of the l ifting apparatus 200 to enable a wheelchair 100 to be lifted over the edge of a kerb 300 onto a surface which is at a lower elevation. This is described with reference to Figures 9 to 12.

If the user of the wheelchair 100 wishes to descend a kerb 300 the user of the wheelchair 100 may push the wheelchair 100 over the edge of the kerb 300 such that the set of front wheels 104 will initially drop over the kerb 300.

Upon dropping over the kerb 300, a stop-pad 232 positioned adjacent the set of front wheels 104 connected to the first control arrangement 204 comes into contact with the kerb 300. The contact between the kerb 300 and the stop-pad 232 triggers a switch which generates an obstacle descent signal which is transmitted to control sub-module 216. The obstacle descent signal may also be triggered by a user input on a controller coupled to the wheelchair.

The lifting apparatus 200 is arranged such that the stop-pad 232 is positioned so that it cannot be superficially triggered by routine movement of the wheelchair 100. That is to say, the lifting apparatus 200 is configured in such a way that the stop-pad 232 positioned above the level of the set of front wheel s 104 so that only movement of the set of front wheels 104 down a kerb 300 can trigger the transmission of the obstacle descent signal.

Responsive to receiving the obstacle descent signal, the control sub-module 216 switches to an obstacle descent mode. The control sub-module then transmits a signal to the control module 202 to indicate that the lifting apparatus 200 is in an obstacle descent mode.

Upon switching to an obstacle descent mode, the control sub-module 216 transmits a drive signal to the telescopic arm 1 18 which leads to the telescopic arm 118 extending telescopically from the housing 224 towards the surface 302 until the telescopic arm 1 18 meets the surface 302 when the wheels 222 hit the surface 302. The telescopic arm 118 continues to extend toward the surface 302 causing the front part of the wheelchair 100 to be lifted clear of the kerb 300 until the tilt sensor 214 detects that the wheelchair 100 is at zero tilt, i.e. the front and rear of the wheelchair are level. This is shown in Figure 10 This means that the lifting apparatus 200, at this stage, enables the wheelchair 100 to be supported on both of the surfaces 302 and 304.

The movement of the telescopic arm 118 will cause the front part of the wheelchair 100 to be lifted clear of the kerb 300 and the stop-pad 232 to be lifted clear of the kerb 300.

As the set of rear wheels 106 are moved over the edge of the kerb the rear part of the wheelchair 100 will move downwards under the force of gravity. The combined movement of the set of rear wheels 106 and the relative position of the end of the arms means that the end of the arms 112 remain in contact with the surface 304 to partially arrest the pace of the descent of the rear wheels 106 toward the surface 304 until the rear wheels 106 come into contact with the surface 304. This will, in turn, cause the aims 1 12 to continue to move upwards toward their uppermost position. The momentum generated by the movement of the set of rear wheels 106 will result in the movement of the wheels 222 on the surface 302 in the forward direction which will result in movement of the wheelchair 100 in the forward direction.

As the set of rear wheels 106 move downwards under the force of gravity toward the surface 304, the telescopic arm 118 is withdrawn back into its housing 224 to enable the compl ete downward motion of the wheelchair 100 toward the surface 304 in a relatively level orientation. This is shown in Figure 11

The withdrawal of the telescopic arm 118 into the housing 224 and the downward movement of the rear wheels 106 due to the sweeping motion of the arms 112 toward the surface 304 wall bring the wheelchair 100 into contact with the surface 304 - meaning that the kerb 300 will have been navigated and the wheelchair 100 will have been moved, under the action of the lifting apparatus 200, over the edge of the kerb 300. This is shown in Figure 12 That is to say, the operation of the lifting apparatus 200 in the obstacle descent mode enables the wheelchair 100 to descend the kerb 300 between the surface 304 and the surface 302.

It will be understood that a wheelchair 100 comprising the lifting apparatus 200 described above enables a user of a wheelchair to negotiate a kerb or a step without assistance from another person or the use of a ramp.

As will be evident from the embodiment described above, the use of the lifting apparatus 200 provides two drive lifting apparatus, one respectively coupled to the front and rear of the wheelchair 100 which is convenient for users that do not have sufficient strength to operate the wheelchair 100 mechanically in a way which will enable the safe and stable navigation of a kerb.

In accordance with the described embodiment, the lifting apparatus enables the wheelchair 100 to be used to climb or descend a step or a kerb using additional sensor arrangements which are fitted to the wheelchair 100. The additional arrangements provide powered lifting and controlled descent of the wheelchair 100. The powered lifting and controlled descent may be coordinated by a central component which communicates with the respective additional arrangements or by communication between the respective arrangements.

These sensor arrangements do not interfere with the wheelchair during its normal operation.

The lifting apparatus in accordance with the embodiment electronically raises and lowers a wheelchair between surfaces at different elevations without the need for considerable upper body strength on the part of the wheelchair user or the requirem ent for additional assistance from another person. The lifting apparatus enables this whilst maintaining stability of the wheelchair. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be capable of designing many alternative embodim ents without departing from the scope of the invention as defined by the appended claims. In the claims, any reference signs placed in parentheses shall not be construed as limiting the claims. The word "comprising" and "comprises", and the like, does not exclude the presence of elements or steps other than those listed in any claim or the specification as a whole. In the present specification,‘'comprises” means“includes or consists of’ and“comprising” means“including or consisting of’. The singular reference of an element does not exclude the plural reference of such elements and vice-versa. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim enumerating several means, several of these means may be embodied by one and the same ite of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to ad vantage.

Claims

1. Lifting apparatus for raising and lowering a wheeled mobility assistance device comprising a seat on which to support a user to move from a first surface at a first elevation to a second surface at a second elevation, the lifting apparatus comprising a lifting apparatus to enable the respective raising and lowering of the wheeled mobility assistance device between the surfaces to enable the wheeled mobility- assistance device to be used on the second surface.

2. Lifting apparatus according to Claim l, wherein the lifting arrangement comprises a first device for lifting and lowering a front part of the wheeled mobility assistance device and a second device for lifting and lowering a rear part of the wheeled mobility assistance device

3. Lifting apparatus according to Claim 2 wherein the first device is arranged to be coupled to a front part of the wheeled mobility assistance device and the second device is arranged to be coupled to a rear part of the wheeled mobility assistance device.

4. Lifting apparatus according to Claim 2, wherein the first device is configured, in a first mode, to draw the rear part of the wheeled mobility assistance device onto the second surface and configured, in a second mode, to lower the rear part onto the second surface and further wherein the second device is configured, in a first mode, to raise the front part of the wheeled mobility assistance device to a position level with the rear part and configured, in a second mode, to lov/er the front part onto the second surface.

5. Lifting apparatus according to Claim 2 or Claim 3, wherein the first device

comprises a levering arrangement to apply leverage to the rear part of the wheeled mobility assistance device and wherein the second device comprises a lifting mechanism to raise and lower the front part of the wheeled mobility assistance device.

6. Lifting apparatus according to Claim 4 wherein the lever comprises a pair of arms.

7. Lifting apparatus according to Claim 4 wherein the lifting mechanism comprises a pair of wheels at one end to facilitate motion of the wheeled mobility assistance device.

8. Lifting apparatus according to any preceding claim wherein the first device is

arranged to engage the second surface and to lift the rear of the wheeled mobility assistance device by applying a downward force onto the second surface to lift the rear of the wheeled mobility assistance device to a position level with the second surface and further wherein the second device is arranged, responsive to the first device lifting the wheeled mobility assistance device to a position level with the second surface, to lift the front of the wheeled mobility assistance device to a positi on substantially level with the rear of the wheeled m obility assistance device.

9. Lifting apparatus according to any of Claims 1 to 7 wherein the second device is arranged to receive a signal indicative of the wheeled mobility assistance device travelling toward the second surface and, responsive to receiving that signal, the second device is arranged to engage the second surface and to support the front part of the wheeled mobility assistance device on the second surface and further wherein the first device is arranged to lower the rear part of the wheeled mobility assistance device onto the second surface in a position substantially level with the front part of the wheeled mobility assistance device.

10. Lifting apparatus according to Claim 9 wherein the signal is received from a stop pad which has contacted a boundary between the first and second surfaces to indicate that the wheeled mobility assistance device is about to progress across the boundary onto the second surface.

11. Lifting apparatus according to any preceding claim wherein the lifting apparatus is configured to respectively raise and lower the wheeled mobility assistance device between surfaces responsive to a trigger event.

12. Lifting apparatus according to Claim 1 1 wherein the trigger event is user input.

13. Lifting apparatus according to Claim 11 wherein the trigger event is the detection of a boundary between the first and second surfaces by a sensor.

14. Lifting apparatus according to Claim 13 wherein the sensor is a proximity sensor.

15. Lifting apparatus according to any of Claims 13 or 14 wherein the boundary is a kerb face.

16. Lifting apparatus according to any of Claims 13 or 14 wherein the boundary is a kerb edge.

17. A wheeled mobility assistance device comprising a lifting apparatus in accordance with any of Claims 1 to 16.

18. A wheeled mobility assistance device according to Claim 17 wherein the wheeled mobility assistance device is a wheelchair.