WO2024005654A2

WO2024005654A2 - An improved wheelchair and improved seating device

Info

Publication number: WO2024005654A2
Application number: PCT/NZ2023/050064
Authority: WO
Inventors: Marcus William THOMPSON
Original assignee: Whanauka Limited
Priority date: 2022-06-29
Filing date: 2023-06-29
Publication date: 2024-01-04
Also published as: WO2024005654A3

Abstract

Aspects of the present invention provide a wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel so as to form an acute angle with a surface on which the wheelchair is traveling.

Description

PCT SPECIFICATION

An Improved Wheelchair and Improved Seating Device

Technical Field

This invention relates to an improved wheelchair. In particular, the invention relates to a wheelchair with improved control.

This invention also relates to improvements in seating devices, such as chairs.

Background art

Wheelchairs are well known. A common configuration of wheelchair has two wheels located at the sides of the chair and mounted on a chassis. The chassis also mounts a seat for the rider. The wheelchair is typically controlled by the rider applying forward and reverse torques to the wheels to steer the chair. This configuration of wheelchair has shortcomings in rider control of the chair.

Conventional wheelchairs may also have a shortcoming in requiring a rider to exercise balance and other faculties involved in motion only to a limited degree.

Similarly, conventional seating devices may engage the rider to exercise balance and other faculties only to a limited degree.

It would be of advantage to have improvements in the field of wheelchairs which provide for improved control, or at least to provide the public with a useful choice.

It would also be of advantage to have improvements in the field of chairs which engage the muscular-skeletal system of the person sitting on the chair.

Disclosure of Invention

The wheelchair may comprise a seat platform operable to support a rider.

The wheelchair of any one of the preceding paragraphs comprising a mid-chassis to which the seat platform is connected. The wheelchair of any one of the preceding paragraphs wherein the seat platform may be connected to the mid-chassis by linkages that allow the seat platform to tilt relative to the midchassis.

The wheelchair of any one of the preceding paragraphs wherein the first and second drive wheels are operable to raise or lower relative to each other in response to a shift in weight of the rider at the seat platform, and the first and second drive wheel are able to move relative to the mid-chassis in response to as shift of weight of the rider at the seat platform.

The wheelchair of any one of the preceding paragraphs comprising support-wheel mounts for first and second support wheels for the wheelchair located on first and second sides of the wheelchair respectively.

The wheelchair of any one of the preceding paragraphs wherein the support-wheel mounts may be provided on support linkage assemblies operable to move mounts for the support wheels as mounts for drive wheels on respective first and second sides of the wheelchair move.

According to an aspect of the invention there is provided a wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel so as to form an acute angle with a surface on which the wheelchair is traveling.

According to an aspect of the invention there is provided a wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel such that the first wheel exerts a turning effect on the wheelchair, said turning effect operable to turn the wheelchair in a radius centred beside the wheelchair. The radius may be centred on the first side of the wheelchair.

According to an aspect of the invention there is provided a wheelchair having a first drive wheel on a first side of the wheelchair, having a second drive wheel on a second side of the wheelchair, having a first support wheel on the first side of the of the wheelchair and having a second support wheel on the second side of the wheelchair, wherein a support wheel comprises a wheel which is separated from a drive wheel to provide support against the wheelchair tipping forward or backward, wherein a support wheel is mounted so as to follow a mounting axis and wherein the wheelchair is operable to arrange the mounting axis to lean towards the first side of the wheel chair when the first drive wheel on the first side is raised relative to the second drive wheel on the second side.

The support wheel following a mounting axis that is leaned towards the first side may exert a turning effect towards the first side.

The mounting axis of a support wheel may be substantially vertical when the wheelchair is not in a leaned configuration. Said tipping may be in a forward direction relative to a direction of travel of the wheelchair.

Said tipping may be in a forward direction relative to a direction of travel of the wheelchair.

According to an aspect of the invention there is provided a wheelchair having a rider platform operable to support a rider, the rider platform being operable to move so as to allow the rider to roll relative to the rest of the wheelchair.

According to an aspect of the invention there is provided a wheelchair having a rider platform operable to support a rider, the rider platform being operable to move so as to allow the rider to pitch relative to the rest of the wheelchair.

According to an aspect of the invention there is provided a wheelchair having a rider platform operable to support a rider, the rider platform being operable to move so as to allow the rider to yaw relative to the rest of the wheelchair.

According to an aspect there is provided a wheelchair having a rider platform operable to support a rider wherein the platform is operable to move in an arc aligned longitudinally with a direction of travel of the wheelchair and being concave upwards.

According to an aspect there is provided a wheelchair having a rider platform operable to support a rider wherein the platform is operable to move in an arc aligned transversely with a direction of travel of the wheelchair and being concave upwards.

According to an aspect there is provided a wheelchair having a rider platform operable to support a rider wherein the platform is operable to pivot on a vertical axis. The vertical axis on which the rider platform pivots may be located within area defined by the rider platform.

According to an aspect of the invention there is provided a wheelchair having: a first drive wheel on a first side of the wheelchair; a a second drive wheel on a second side of the wheelchair, said second side distal the first side, a rider-supporting platform operable to support a rider of the wheelchair; a rider-supporting assembly on which the rider-supporting platform is mounted; a mid-chassis to which the rider-supporting chassis is mounted; a first swing-arm extending substantially longitudinally to a direction of travel of the wheelchair, wherein the first swing arm is mounted so as to pivot at a point substantially at the first side of the wheelchair, said point separated from the hub of the first wheel; a second swing-arm extending substantially longitudinally to a direction of travel of the wheelchair, wherein the second swing arm is mounted so as to pivot at a point substantially at the second side of the wheelchair, said point separated from the hub of the first wheel; wherein the first and second wheel hubs are able to move upward and downward relative to the mid-chassis.

The first and second swing-arms may be mounted so as to pivot at respective pivot points that cause the first and second drive wheels to move upward or downward relatively to the other as weight of the rider is shifted relatively towards one of the first or second sides of the wheelchair.

The rider-supporting platform is able to move to affect one or more of pitching, rolling or yawing relative to the mid-chassis.

The rider-supporting platform may be able to move relative to the mid-chassis to facilitate the rider shifting weight rider. The first and second drive wheels may be operable to raise or lower relative to each other in response to a shift in weight of the rider, and the first and second drive wheel are able to move relative to the mid-chassis in response to as shift of weight of the

The rider-supporting platform may be movable to facilitate the rider controlling shifts in their weight.

The rider-supporting platform may be movable to facilitate the rider controlling shifts in their weight to initiate a turn.

The rider-supporting platform may be movable to facilitate the rider controlling shifts in their weight to end a turn.

The rider-supporting platform may be movable to facilitate the rider balancing during dynamic turning actions of the wheelchair.

According to one aspect the invention provides a wheelchair having a platform for the rider wherein the platform is able to tilt laterally with respect to a direction of forward travel of the wheelchair in response to the rider of the wheelchair leaning.

Said transfer of weight of the rider may cause one of the first and second wheels to move relatively upwards or downwards relative to the other of the first and second wheels on an opposite side of the wheelchair.

The wheelchair may comprise a means to distribute weight between the first and second wheels located at opposite sides of the wheelchair.

The means to distribute weight may comprise a torsion element.

The means to distribute weight may comprise a crossbar which mounted at a pivot located between the first and second wheels on opposite sides of the wheelchair.

The wheelchair may comprise first and second wheel-mounting linkages which mount first and second wheel respectively and allow the first wheel to move upward relative to the second wheel. The wheel-mounting linkages may comprise said swing arms. The wheelchair may comprise first and second swing arms which allow first wheel move upward relative to the second wheel.

The wheelchair may comprise a support linkage which mounts support wheels wherein the support linkage moves the support wheel of a first side or a support wheel of a second side with the respective first or second wheel.

The wheelchair may comprise a rider-supporting platform which is operable to tilt with respect to a mid-chassis.

Another aspect of the invention provides a wheelchair comprising a rider-supporting platform mounted on a mid-chassis, and a wheel-mounting platform operable to mount first and second wheels on opposite sides of the wheelchair, wherein the rider supporting platform is operable to tilt relative to the mid-chassis and wherein the height of a first wheels is operable to raise relative to the second wheel to allow the mid-chassis to tilt relative to a surface on which the wheelchair is riding.

The wheelchair of claim may comprise a weight distribution means operable to distribute weight between the first and second wheels.

The weight distribution means may comprise a torsion element.

The weight distribution means may comprise a crossbar mounted at a pivot mount located between the first and second wheels wherein the pivot may be rigidly connected to the midchassis to transfer weight from the mid-frame to the crossbar.

The wheelchair may comprise a support assembly operable to mount support wheels which support the wheelchair against titling longitudinally wherein the support assemblies are operable to raise a support wheel on the side of the wheelchair of the first wheel with the first wheel and are operable to raise a support wheel on the side of the wheelchair of the second wheel with the second wheel.

According to one aspect the invention provides a wheelchair having a platform for the rider wherein the platform is able to tilt laterally with respect to a direction of forward travel of the wheelchair.

According to one aspect the invention provides a wheelchair having a central chassis able to support the weight of a rider wherein the central chassis is able to tilt laterally with respect to a direction of forward travel of the wheelchair.

According to another aspect the invention provides a wheelchair having a platform for the rider wherein the platform is able to tilt laterally, with respect to a direction of forward travel of the wheelchair, in response to a torque applied by the rider of the wheelchair.

According to another aspect the invention provides a wheelchair having a platform for the rider wherein the platform is able to tilt laterally, with respect to a direction of forward travel of the wheelchair, in response to a shift in weight of the rider of the wheelchair. According to another aspect the invention provides a wheelchair having a platform for the rider wherein the platform is able to tilt laterally, with respect to a direction of forward travel of the wheelchair, in response to the rider of the wheelchair leaning. The leaning may be in towards the centre of a turn. The leaning may be upwards with respect to a sloped surface the wheelchair may be traversing.

According to one aspect of the present invention there is provided a wheelchair for a wheelchair rider, the wheelchair comprising: first and second wheel arms each pivotally mounted so as to allow the alignment of the first arm to move relative to the second arm through a range of relative alignment; first and second wheel mounts provided on first and second arms respectively to mount respective first and second wheels with central axes of first and second wheels able to move in an arc about the point of pivotal mounting of the respective first or second arm.

The wheelchair may comprise a support for the weight of the rider.

The support may be able to transfer a torque relative to first and second axes about which the first and/or second wheel arms are pivotally mounted.

The support may be able to transfer weight of the rider relatively to the first and second wheel arms and respective first and second wheels mounted thereon.

The first and second wheel arms may be arranged such that each of the first and second axes at which a first or second arm respectively is mounted is separated from an axis of the respective first or second wheel in a direction of travel of the respective wheel. In one example, the axis of the first or second wheel follows the axis of the pivotal mount on the first or second arm relative to a forward direction of movement of the wheelchair. In another example, the axis of the first or second wheel leads the axis of the pivotal mount on the first or second arm relative to a forward direction of movement of the wheelchair.

The first and second wheel arms may be arranged such that each of the first and second axes at which a first or second arm respectively is mounted is separated from respective mounts on the respective arm for the respective first or second wheel in a direction of travel of the respective wheel.

The first and second wheel arms may be arranged at an angle away from vertical in an axis parallel to a plane of a respective mounted wheel.

Said torque which is able to be applied by the support for the rider may move the first wheel arm away from relative alignment with the second wheel arm.

The first and second wheel arms may be pivotally mounted at a common axis. This may allow each of the first and second wheels to move orbital ly about a substantially common axis. This may allow the position of each of the first and second wheels to move relatively forward or aft of the other of the first or second wheels. This may allow the position of each of the first and second wheels to move relatively upwards or downwards of the other of the first or second wheels.

Alternatively, the first and second arms may be mounted so as to have a common axis when substantially no torque is applied at the support.

Said torque and/or said transfer of weight of the rider may cause one of the first and second wheels to move relatively upwards or downwards relative to the other of the first and second wheels. Movement of one of the first and second wheels relative to a surface on which both wheels are supported may allow the support to lean towards the surface. This may be in a direction of said torque applied at the support. This may be in a direction of said transfer of weight at the support.

Embodiments of the present invention provide a wheelchair with a support for a rider and wheels mounted on arms which are mounted pivotally with respect to the support so that a torque applied to the support causes a first wheel to move upwards relative to a second wheel so to cause the support to lean relative to a surface supporting the wheels.

The arms may be pivotally mounted at axes which are transverse to a direction of travel of the wheelchair. The wheel mounts provided on the arms may provide axes of rotation of the wheels which are transverse to a direction of travel of the wheelchair.

The wheelchair may comprise a biasing means able to bias the first arm relatively towards alignment with the second arm.

The biasing means may comprise a resilient element which deforms as the first arm is moved relatively out of alignment with the second arm.

The biasing means may comprise a torsion element. The torsion element may act to return the first and second arms into relative alignment so as to resist a torque and/or transfer of the weight of the rider applied at the support.

The support may comprise an axle and a mount for a platform for the rider.

The mount may be operable to allow the platform to lean relative to the support.

The wheelchair may comprise pivotal mounts for the first and second arms.

The pivotal mounts may be formed integrally with the biasing element.

The wheelchair may comprise a central chassis which provides a mount for the support and mounts for the first and second arms.

The mount for the support may comprise a bore which is able to receive a rod on which a platform for the rider is mounted. The mount for the support may be operable to allow the support to tilt relative to the pivotal mount for the first wheel arm and/or the pivotal mount for the second wheel arm. The mount for the support may comprise a stop to limit the degree of said tilt of the support.

The mounts for the first and second wheel arms may each comprise a bore for an axle which provides the pivotal mount for the wheel arm.

The central chassis may comprise first and second chassis arms to support respective first and second pivotal mounts for respective first and second wheel arms.

The wheelchair may comprise a biasing means able to bias a central axis of the first wheel relatively towards alignment with a central axis of the second wheel. This may act to right the platform for the rider.

The biasing means may comprise a first resilient element connecting the first chassis arm to a part of the chassis proximate the mount for said bore for said rod on which a platform for the rider is mounted.

The biasing means may comprise a second resilient element connecting the first chassis arm to a part of the chassis proximate the mount for said bore for said rod on which a platform for the rider is mounted.

Said first and second resilient elements may be formed integrally with each other.

The wheelchair may comprise a bracing wheel assembly arranged to brace the support against rotation forward and/or aft relative to the direction of movement of the wheelchair.

The bracing wheel assembly may comprise bracing chassis connecting a cross bar the support for the rider, wherein the cross bar mounts bracing wheels.

The bracing wheel assembly may be operable to allow the cross bar to rotate transversely to the direction of travel of the wheelchair to allow the bracing wheels mounted on the cross bar to maintain contact with a surface on which the wheelchair is supported when the first wheel is raised relative to the second wheel.

The bracing assembly may comprise a biasing element able to bias the cross bar towards a position relative to the support for the rider which is parallel with the support for the rider.

The bracing wheel assembly may comprise a torsion element able to provide a restoring torque to align the first wheel arm with the second wheel arm.

The bracing wheel assembly may comprise a torsion element able to provide a restoring torque towards a position parallel with the cross bar of the bracing assembly.

According to one aspect of the invention there is provided a wheelchair the wheelchair comprising a platform to support a rider, a right linkage assembly which provides a right wheel mount to mount a right wheel, and a left linkage assembly which provides a left wheel mount to mount a left wheel wherein one of the right and left wheel mounts are able to move upward relative to the other.

A wheel-supporting linkage assembly may be operable to allow the wheel to move in a plane substantially parallel to a plane in which the wheel rotates.

The wheelchair may comprise drive wheels mounted on the wheel-mounting linkages.

A wheel-supporting linkage assembly may be operable to allow one of the right or left wheels to move upward relative to the other.

The wheelchair may comprise a crossbar connecting the right wheel-supporting linkage assembly and the left wheel supporting linkage assembly.

The crossbar may be rigid and mounted on a pivot to mechanically couple the right and left wheel-mounting linkage assemblies.

The wheelchair may comprise a mid-chassis to which a platform for the rider is connected.

A pivot mount at which the crossbar is mounted may be connected rigidly to the mid-frame. This may allow the pivot mount to act as a fulcrum for the crossbar. The pivotally mounted crossbar may distribute weight between the wheel mounts. The weight thus distributed might be distributed substantially evenly between the two wheel-mounting linkage assemblies. The pivotally mounted crossbar may limit a range of movement of one of the wheel mounts relative to the other.

The pivot mount may be connected to the mid chassis.

The pivot mount may be provided on the mid chassis.

The pivot at which the crossbar is mounted may be located between the right and left wheelmounting linkage assemblies. The crossbar may be operable to share the weight of the rider onto right and left wheel-mounting linkage assemblies. The crossbar may be operable to match the weight of the rider borne by each of the right and left wheel-mounting linkage assemblies.

In one example the wheelchair is situated on a slope which rises transversely to a direction of movement of the wheelchair. In this scenario a wheel-mounting linkage assembly mounting a wheel on an upper side of the slope, a right wheel-mounting linkage assembly for example, is located upwards relative to the other wheel-mounting linkage assembly. The mounted wheel on the upper side is similarly located above the wheel on the other side. In this scenario one exemplary embodiment has substantially equal weight on each wheel-mounting linkage assembly and mounted wheel due to the pivotally mounted crossbar distributing weight of the wheelchair and rider between the wheel-mounting linkage assemblies and mounted wheels. However, the relative position of the right wheel above the left wheel allows the mid-chassis to remain in a horizontal orientation, tilted up towards the slope. A linkage assembly may comprise a swing arm operable to swing in a plane substantially parallel to a plane in which the wheel mounted on the respective linkage assembly rotates. This may allow a wheel mount provided by one of the right and left wheel-mounting linkage assemblies to move upwards relatively to the other. This may allow a wheel mount provided by one of the right and left wheel-mounting linkage assemblies to move upwards relatively to the other.

A swing arm swinging in a plane substantially parallel to a plane in which the wheel mounted on the respective linkage assembly rotates may cause the wheel mount of one of the right or left wheel-mounting linkages to move upwards and forward relative to the wheel mount of the other wheel-mounting linkage assemblies.

In alternative embodiments a swing arm swinging in a plane substantially parallel to a plane in which the wheel mounted on the respective linkage assembly rotates may cause the wheel mount of one of the right or left wheel-mounting linkages to move upwards and rearward, with respect to a forward direction of movement of the wheelchair, relative to the wheel mount of the other wheel-mounting linkage assemblies.

The wheelchair may comprise a rider-support assembly operable to support the weight of a rider. The rider-support assembly may comprise a seat platform to support an attached seat for a rider.

The seat platform may be operable to tilt laterally to a direction of forward travel of the wheelchair.

The seat platform may be operable to tilt side to side relative to a direction of forward travel of the wheelchair.

The seat platform may be operable to tilt longitudinally to a direction of forward travel of the wheelchair.

The seat platform may be operable to tilt forward and backward relative to a direction of forward travel of the wheelchair.

The seat platform may be supported by double ended rods. The rods may be arranged in a rectangular pattern.

The rods may be operable to allow the seat platform to move through a concave arc. The rods may be operable to allow the seat platform to move through a concave arc such that a neutral position of the seat platform is at the nadir of the arc.

The rods may be arranged to allow movement which can occur in two planes separately.

The rods may be arranged to allow movement which can occur in two planes concurrently.

The rods may be arranged to allow movement which can occur in two planes separately or concurrently. The rider support assembly may comprise biasing elements to provide stability in the neutral position. The rider support assembly may comprise compression springs to provide stability in the neutral position.

The rider support assembly may comprise biasing means to provide extra help to return from an out-of-vertical position to the neutral position. The rider support assembly may comprise compression springs to provide extra help to return from an out-of-vertical position to the neutral position.

The degree of bias and/or force of spring and/or range of extension of rod assemblies under force of a rider and/or the range of movement pf the seat platform under force of the rider may be selected and/or tuned. The tuning may be by section of a spring rate.

The compression springs may be further operable to act as end stops in their solid state avoiding a collision of the seat pan with the rear wheels in the lateral direction and for the seat pan to tilt back.

The wheelchair may comprise support-wheel mounts for right and left support wheels for the wheelchair. The support-wheel mounts may be provided on support linkage assemblies operable to move mounts for the support wheels as mounts for drive wheels move. In one example a mounted drive wheel on a first side of the wheelchair moves upward and forward relative to a drive wheel mounted on an opposite, second side of the wheelchair and a support on the first side is moved upward and forward relative to a support wheel on the opposite, second side of the wheelchair. The mounted drive wheel on a first side of the wheelchair may be referred to herein as the first wheel. The mounted drive wheel on a second side of the wheelchair may be referred to herein as the second wheel.

In this example the support linkages maintain the position of the mount for a support wheel relative to a mount for a drive wheel. In this example distribution of weight between drive wheels and support wheels on the same side is substantially maintained.

The support linkage assemblies may be arranged maintain the position of the mount for a support wheel relative to a mount for a drive wheel.

The support linkage may be mounted on the mid-chassis. The mid-chassis may provide a pivot mount for the support linkages.

The mid-chassis may support a footrest platform.

The mid chassis may support a seat platform operable to support a rider. The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt relative to the mid-chassis.

The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt laterally to a direction of movement of the wheelchair, said tilting relative to the mid-chassis. The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt sidewards to a direction of movement of the wheelchair, said tilting relative to the mid-chassis.

The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt laterally to a direction of movement of the wheelchair, said tilting relative to the mid-chassis.

The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt forward or backward to a direction of movement of the wheelchair, said tilting relative to the mid-chassis.

The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt longitudinally to a direction of movement of the wheelchair, said tilting relative to the mid-chassis.

The seat platform for the rider may be connected to the mid-chassis by linkages that allow the seat platform to tilt relative to pivotal mount for the crossbar.

In one aspect the invention provides a wheelchair having a rider platform which is operable to be articulated and a wheel-mounting assembly which is operable to be articulated wherein the rider platform can be articulated independently of the wheel-mounting assembly.

The rider platform may be articulated to tilt.

The wheelchair may comprise a mid-chassis to mount the rider platform.

The rider platform may be articulated to tilt relative to the mid-chassis. This may allow a rider to shift their weight relative to the mid-chassis. This may allow a rider to apply a torque to the midchassis.

The wheel-mounting assembly may be operable to be articulated to allow a wheel mount on a first side of the wheelchair to be raised relative to a mount on a second chair.

The wheel-mounting assembly may comprise a force-distribution means to distribute force between wheel mounts on first and second sides of the wheelchair.

The force-distribution means may be operable to substantially evenly distribute weight to wheel mounts on first and second sides of the wheelchair as a wheel mount on a first side moves over a range of height relative to another wheel mount on a second side of the wheelchair.

The wheel-mounting assembly may be operable to move a wheel mount on a first side of the wheelchair relatively upward or downward relatively to a wheel mount on a second side of the wheelchair to maintain a substantially even weight on each of said wheel mounts. The wheel-mounting assembly may be operable to move a wheel mount on a first side of the wheelchair relatively upward or downward relatively to a wheel mount on a second side of the wheelchair in response to a shift of weight of the rider relative to the mid-chassis.

The wheel-mounting assembly may be operable to move a wheel mount on a first side of the wheelchair relatively upward or downward relatively to a wheel mount on a second side of the wheelchair in response to a torque applied by the rider to the mid-chassis. The applied torque may be transverse to a direction of travel of the wheelchair.

The force-distribution means may be a crossbar. The crossbar of the force-distributing means may be pivotally mounted on the mid-chassis.

In one example, a rider shifts weight transversely to a direction of movement of the wheelchair to place more weight on a first side of the mid-chassis, causing the wheel mount, and mounted wheel, on the first side to move upwards relatively to the wheel mount on the second side of the wheelchair. This upward movement may be caused by the pivotally mounted crossbar distributing weight evenly between the wheel mounts on the first and second sides of the wheelchair. This may be in a dynamic situation, such as when the wheelchair is cornering.

In another example, the wheelchair moves on a sloped with a wheel on a first side of the wheelchair resting on an elevated part of the surface compared to a part of the surface on which a wheel of the second side rests. The force distribution means, which in this example is a crossbar pivotally mounted to the mid-chassis causes the wheel mount, and mounted wheel, on the first side to move upwards relatively to the wheel mount, and mounted wheel, on the second side of the wheelchair.

According to another aspect of the invention there is provided a seating device having: a first platform adapted to support an occupant of the seat, the seating platform being mounted on; a second platform, and a first support assembly operable to support the first platform and mount the first platform on the second platform, the first support assembly operable to allow the first platform to move relative to the second platform with a first components of movement comprising an arc.

The first support assembly may be further operable to allow the first platform to move relative to the second platform with a second component of movement comprising an arc.

The first and second components of movement may be transverse to each other.

One or more of the first and second components of movement may be concave upward from the chair in use. The first support assembly may comprise a set of connection rods arranged to extend from the second platform to the first platform so as to form a truncated pyramid.

The set of connection rods may have lengths selected to define the movement allowed of the first platform relative to the second platform.

The seating device may also have: a third platform, and a second support assembly operable to mount the second platform on the third platform and operable to allow the second platform to rotate about an axis located between the second platform and the first platform.

The axis located between the second platform and the first platform may be arranged at an incline with respect to the third platform. The third platform may be provided by a base which is supported by a surface on which the seating device rests.

The second support assembly may comprise a base, an axle mounted by the base and a support for the second platform, wherein the supports the second platform.

In further embodiments any one or more of the platforms of any paragraph above may be substituted with a chassis.

In various embodiments a platform is any structure capable of supporting anther platform as described herein and/or enabling connection of any assemblies, such as mounting assemblies or support assemblies, or mechanisms described and illustrated herein.

As used herein ‘linkage assembly’ is any assembly of mechanically linked elements, such as an assembly of rigid elements pivotally connected to other elements.

As used herein ‘a’ is used in the inclusive sense and a phrase involving ‘a’ given feature does not exclude ‘another’ given feature.

As used herein the term ‘comprise’ is used in the inclusive sense as ‘including’ and not in the sense of ‘consisting of.’

Brief description of the drawings

Example embodiments of the invention are now discussed with reference to the drawings in which:

Figure 1 shows a rear elevation view of a wheelchair according to an embodiment of the invention; Figure 2 shows a front elevation view of a wheelchair of an alternative embodiment to Figure 1 ;

Figure 3 shows a side elevation view of the wheelchair of the embodiment of Figure 2 with first and second wheels removed to reveal detail;

Figure 4 shows a front elevation view of the wheelchair of the same embodiment as Figure 2 with the wheel arms and wheels configured to traverse a slope;

Figure 5 shows a side elevation view with the wheelchair of the embodiment of Figure 2 in a leaned configuration;

Figure 6 shows a front elevation view of the wheelchair of the same embodiment as Figure 2;

Figure 7 shows a side elevation view of the wheelchair of the same embodiment with first and second wheels removed;

Figure 8 shows a front elevation view of a wheelchair according to the same embodiment;

Figure 9 shows a side elevation view of a wheelchair also of the same embodiment;

Figure 10 shows a plan view of a central chassis of a wheelchair according to the same embodiment again;

Figure 11 shows a close-up side elevation view illustrating the central chassis;

Figures 12 and 13 show central chassis assemblies according to alternative embodiments of the invention;

Figure 14 shows front elevation view a wheelchair according to a further embodiment;

Figure 15 shows a rear view of a wheelchair according to the embodiment of Figure 14;

Figure 16 shows a side view of a wheelchair according to the same embodiments as Figure 14;

Figure 17 shows a perspective view of a wheelchair according to the embodiment of Figure 14;

Figure 18 shows a rear elevation view of a wheelchair of the embodiment of Figures 14 to 18 with the right wheels raised;

Figure 19 shows a side elevation of a wheel of the embodiment of Figures 14 to 18 with the right wheel raised as would occur when a rider leans towards the right;

Figure 20 shows a perspective view of a wheelchair according to the embodiment of Figure 14 ;

Figure 21 shows a perspective view of a rider-support platform and support assembly of a wheelchair according to the embodiment of Figure 14; and

Figure 22 shows an alternative view of the rider-support platform and assembly of Figure 21 ; Figure 23 shows a front view of a wheelchair according to another embodiment of the invention;

Figure 24 shows a rear perspective view of a wheelchair according to the embodiment of Figure 23;

Figure 25 shows a side view of a wheelchair according to the embodiment of Figure 23;

Figure 26 shows a perspective view of a wheelchair according to the embodiment of Figure 23;

Figure 27 shows a rear view of a wheelchair according to the embodiment of Figure 23;

Figure 28 shows a side view of a wheelchair according to the embodiment of Figure 23;

Figure 29 shows a perspective view of a wheelchair according the embodiment of Figure 23;

Figure 30 shows a perspective view of a rider platform of the embodiment of Figure 23 ;

Figure 31 a perspective view of a rider platform of the embodiment of Figure 23 ;; and

Figure 32 shows a side view of a further embodiment;

Figures 33 to 43 show views of the embodiment of Figure 32 showing how the wheelchair is controlled;

Figure 44 show a side views of a seating device according to a further embodiment of the present invention in various configurations;

Figure 45 shows the seating device of figure 44 with a seating platform in a pitched-back configuration;

Figure 46 shows the seating device of figures 44 and 45 with a seating platform in a pitched- forward configuration;

Figure 47 shows a front view of the seating device of figures 44 to 46 with the seating device in a neutral configuration;

Figure 48 shows a front view of the seating device of figures 44 to 47 with the seating device in a translated, lowered and rolled configuration; and

Figure 49 shows a front view of the seating device of figures 44 to 48 with the seating device in another translated, lowered and rolled configuration; and

Figure 50 shows a front view of the seating device of Figures 44 to 49 in an alternative configuration. Best modes for carrying out the Invention

Figure 1 shows a top view of a wheelchair 1 according to a preferred embodiment of the invention.

Figure 2 shows a rear elevation view of a wheelchair 1 of the same embodiment as Figure 1 .

The wheelchair 1 has a seat 2 to provide a support for the weight of the wheelchair rider (not shown). The wheelchair has a first drive wheel 3 located on a first side of the wheelchair. A second drive wheel is located on a second side of the wheelchair. The first and second sides are distal each other. The first drive wheel 3 and a second wheel 4 are mounted on respective first wheel arm 5 and second wheel arm 6 to support the wheel arms above a surface (not shown) on which the wheelchair travels. In this embodiment the wheelchair 1 has a forward direction of travel 7 into the page as shown. The first and second wheel arms are pivotally mounted to a central chassis 8 which supports the seat 2. The pivots 5a and 6a for each arm is located between the respective wheel and a front end of the wheelchair. The reader will appreciate this as allowing substantially as large a range of movement of the wheel upwards or downwards as possible for a given length of arm.

A bracing assembly 9 has bracing wheels 10 and 11 mounted on a cross bar 12. The wheels are castor wheels which trail their respective mounts 10a on the cross bar 12 in the direction of forward travel. The cross bar is separated from the axis of the first and second wheels by a distance to brace the seat against rotation forward in the direction of travel 7 of the wheelchair 1 . The cross bar 12 with mounted wheels 10 and 11 also provides lateral bracing for the seat against rotation lateral or transverse to the direction of travel 7.

The central chassis 8 is mounts a support chassis 13 for the seat 2. The central chassis 8 also provides first and second bores for pivotal mounting of the first wheel arm 5 and for second wheel arm 6 about first wheel arm pivot axis 5a and second wheel arm pivot axis 6a. In this embodiment the first and second wheel arm pivot axes are common to each other or aligned.

The first wheel arm 5 has a wheel mount 14 for the first wheel 3 with a first wheel axis at a central axle (not shown). The second wheel arm 6 has a wheel mount 15 for the second wheel 4 with a second wheel axis at a central axle (not shown) of the wheel. When the wheel arms are aligned with each other, the first wheel axis and the second wheel axis are common to each other or aligned. Here a wheel axis refers to the central axis of a wheel, such as where an axle would be located. As the wheel arms are able to pivot at the axis of the bores of the central chassis, the first wheel axis is able to move upwards and backward into the page, as shown in Figure 2, relative to the second wheel axis. As the wheel arm defines an arc about the pivot axis of the wheel arm for the wheel axis, the first wheel axis will also move backwards relative to the second wheel axis. This will be up the page as shown in Figure 1 . As the wheel arm moves in an arc it may be recognised by the reader as a swing arm.

Figure 3 shows a side elevation of the wheelchair with first and second wheels removed to reveal detail. Figure 3 shows the seat 2 mounted to the support chassis by a rod 16 which is located aft of and above the pivot mount 17 for the first wheel arm 3. As shown in Figure 3 the wheel arm has an elbow 18 with the wheel mount 14 located aft of the main part of the arm as shown.

Figure 3 shows the bracing assembly extending down and forward from the platform for the seat. The castor wheels 10 and 11 are shown trailing their mounts 19 and 20 on the cross bar 12.

Figure 4shows a rear elevation of the wheelchair 1 of the same embodiment as Figures 1 to 3 with the wheel arms and wheels configured to traverse a sloped surface 21 with the seat substantially horizontally aligned.

Figure 5 shows a side elevation with the wheelchair 1 in a leaned configuration with the seat 2 tilted towards a centre of a turn, for example. The first wheel arm 5 is pivoted relative to the second wheel arm 6 to swing rearward to cause the second wheel mount 14 to move on an arc rearward and upward relative to the first wheel mount 14. This causes the bottom, load bearing edge 22 of the second wheel 5 to move upwards to lean the chair and to allow the seat and platform supporting the seat to tilt towards the second wheel 5.

The movement of the second wheel arm relative to the first can be initiated by a torque applied by the seat, such as by a shift of weight of the rider. This may be initiated by the rider leaning inwards toward the centre of a turn. This may be initiated also by the rider leaning upwards towards a vertical orientation when the wheelchair is traversing a sloped surface.

Torsion elements of the wheelchair provide a restoring torque to the first wheel arm relative to the second wheel arm. In this embodiment torsion elements are arranged to provide restoring torque acting to align to return the first and second arms towards relative alignment. The reader will appreciate the torsion elements as distributing weight of the rider between the arms and first and second wheels mounted on respective arms. The reader will appreciate the torsion elements as distributing force of the rider between the arms and first and second wheels mounted on respective arms. The reader will appreciate the torsion elements as transferring force between the arms and first and second wheels mounted on respective arms. The arms might be considered to be coupled to distribute the weight of the rider and part of the wheelchair between the assemblies mounting the first and second wheels.

Figure 6 shows a elevation of the wheelchair of the same preferred embodiment as Figure 2. As shown, he support chassis is pivotally mounted to the central-chassis 8 which has a stop (not shown) to limit the degree of pivoting of the support chassis 13. The pivoting support chassis allows the seat to tilt as the rider leans to transfer weight or apply a torque against the action of the torsion element to pivot the first arm relative to the second arm to allow the seat to tilt further. Figure 7 shows a side elevation of the wheelchair of the same embodiment with first and second wheels removed to illustrate the first and second wheel arms having moved partially through a range or relative alignment such as would occur when the wheelchair leans as illustrated in Figure 6. Figure 8 shows an elevation of a wheelchair according to the same embodiment.

Figure 9 shows a side elevation of a wheelchair also of the same embodiment.

Figure 10 shows a plan view of a central chassis 8 of a wheelchair according to the same embodiment again. Figure 10 shows the support chassis 13 which allows the seat to tilt laterally with respect to the mid-chassis 8. Figure 11 shows a close-up side elevation illustrating the central chassis 8.

The central chassis has a first bore in a tube 24 to mount an axle (not shown) to mount the first wheel arm and a second bore to mount an axle to mount the second wheel arm.

The seat-mounting chassis 13 has a bore to pivotally mount the seat-bearing chassis so as to allow the seat to tilt laterally. The seat bearing chassis provides a stem for the seat to be supported by the central chassis to act as a support for the rider while allowing the rider’s weight to be transferred laterally. The set-bearing chassis has bearing points which engage the central chassis to apply a torque to the central chassis and thereby to the wheel arms to cause them to rotate relatively to raise one wheel relative to the other and trail the raised wheel relative to the other wheel.

Figure 11 shows a side elevation of the same embodiments with parts removed.

Figures 12 and 13 show central chassis assemblies according to alternative embodiments of the invention.

In various alternative embodiments the bracing assembly may be arranged to extend down and away from the rear of the seat.

In various alternative embodiments the wheel arms may be aligned in a vertical position.

In various alternative embodiments the wheel arms may be aligned in an orientation where they extend down and forward from the pivot mounts.

In alternative embodiments the first and second wheel arm pivot axes are common to each other, or aligned, when the weight of the rider is centred but are able to move relative to each other into distinct axes as the weight is shifted to control the chair into a leaned or tilted configuration.

In alternative embodiments the wheels are mounted on extensible arms which allow the wheels to move out of relative alignment to put the chair into a leaned configuration by way of the arms relatively extending or retracting.

In various embodiments the seat is able to move relative to the mid-chassis. This movement may be tilting movement. In various embodiments also the mid-chassis is able to move relative to the surface on which the wheelchair is travelling. The mid-chassis may be able to move relative to a surface defined by the bottom edges of the drive wheels or relative to the central axes of the drive wheels. Embodiments of the invention provide a wheelchair with improved response to force components occurring laterally with respect to a surface on which the wheelchair rides.

Figure 14 shows a wheelchair 101 according to a further embodiment of the present invention. The wheelchair is shown from a front view. Forward travel of the wheelchair will typically be in the direction 7 shown out of the page in Figure 14. The wheelchair has a rider platform assembly 102 to support a rider. A seat (not shown) may be attached to the rider platform assembly 102. The rider platform assembly 102 is connected to and mounted by a mid-chassis of the wheelchair. A wheel-mounting assembly 104 is connected to the mid-chassis 108 to mount the mid-chassis on the wheels, or the wheels on the mid-chassis. The wheel-mounting assembly 104 has a first, right-hand wheel-mounting linkage 105 and a second, left wheel-mounting linkage 106. The wheel-mounting linkages provide first, right wheel mount 107 on a first side of the wheelchair and second, left wheel mount 108 on a second side of the wheelchair distal the first side. A first, right drive wheel 109 is mounted to the right wheel mount linkage assembly

105. A second, left drive wheel 110 is mounted to the left wheel-mounting linkage assembly

106.

A force, distributing means, in the form of a crossbar 111 connects to the right wheel-mounting linkage assembly 106 and to the second wheel-mounting linkage assembly 106. The crossbar 111 is pivotally mounted at a pivot mount 112 which is connected to the mid-chassis 103. In this example the crossbar acts to evenly distribute the upward force transmitted by each wheelmounting linkage assembly 105 and 106, and mounted wheel 109 and 110, to the mid-chassis 103. In this example a pivot mount 112 for the crossbar 111 is located between the wheelmounting linkage assemblies 105 and 105. In this example, the pivot 112 is located half way between the linkage assemblies. The reader may appreciate the crossbar as distributing weight between the wheel-mounting linkage assemblies and mounted first and second wheels. The reader may appreciate the pivotally mounted crossbar as transferring force between the linkage assemblies and mounted first and second wheels.

Figure 16 shows the wheelchair 101 from a side view. The wheel-mounting linkage 105 is shown having a swing-arm 121 mounted at a swing-arm pivot 122 to a swing-arm mounting bar 123 connected to the mid-chassis 108. The swing-arm 121 is able to swing, or pivot to allow the wheel mount and drive wheel 109 to move upward and forward. In this embodiment the movement is in an arc. The crossbar 111 is also shown in Figure 16.

Also shown in Figure 16 is a first, right support-wheel mounting assembly 131 which mounts a support wheel 132 The support wheel supports the wheelchair against falling forward in the direction of travel. In this example the support wheel is separated from the drive wheel in the direction of travel and, in this example, forward of the drive wheel.

The support-wheel linkage assembly 131 is operable to move the support wheel 132 upward. In this example the support-wheel is moved upwards with the location relative to the respective drive wheel maintained. In this example the support wheel linkage assembly moves the support wheel in synch with the drive wheel, and the mount for the drive wheel. A cam included in the wheel-mounting linkage 105 and support-actuation bar 139 actuate the support linkage 131 as the wheel mount 107 and mounted wheel 109 move.

Figure 19 shows the wheelchair 101 from a side view. The wheelchair 101 is in a configuration in which wheels on the right side are raised relative to wheels on the left side. This may occur when the wheelchair 101 traverses a sloped surface. This may also occur when the wheelchair 101 is leaned in towards a centre of a turn. This may be to maintain the balance of the wheelchair and rider under a centripetal force which causes the turn.

Shown in Figure 20 are linkage bars 139 which lift the vertical bar 135 as the wheel mount 107 is raised. A rod 141 connects to opposite vertical bars 136 and 156 which are mounted on the mid-chassis 103. Also shown in Figure 17 is a rider foot platform mounted on the mid-chassis 103.

Figures 21 and 22 show the rider-supporting assembly 161. The assembly 161 has a ridersupporting platform 102, or pan, which supports a seat (not shown) for a rider which is attached to the platform 102.

The platform 102 is connected to mounting bars 162a and 162b which are mounted to the midchassis 108.

The platform 102 is connected to bars 162a and 162b by double-ended rod ends 167 to 169, which are mounted by brackets, such as 172, and pins 173. The double-ended rods 168 to 171 are arranged in a rectangular pattern connecting the support bars 162 a and 162b and the seat pan 102. The rod ends allow the seat pan to move through a concave arc. In this example the neutral position is the nadir. In this embodiment this movement can occur in two planes separately or concurrently.

The platform is supported on support bars 162 and 163 by enclosed springs 164 to 167.

The four, enclosed springs, or encased compression springs provide stability in the neutral position and provide a biasing force to return from an out-of-vertical position to the neutral position. The reader will recognise this as biasing the pan 102 from a leaned position relative to mid-chassis 108 to a position perpendicular to a plane formed by the support bars 162a and 162b. A secondary function of the compression springs is that they act as end stops in their solid state avoiding a collision of the seat pan with the rear wheels in the lateral direction and for the seat pan to tilt backward and forward excessively. The reader will appreciate that the seatplatform support assembly 102 is able to move relative to the mid-chassis. The reader will appreciate that the wheels of the right and left side of the wheelchair are able to move relatively to each other. The reader will also appreciate that movement of the rider platform relative to the mid-chassis can be independent of the movement of wheels on right and left sides relative to each other.

Figures 23 to 31 show the wheelchair of the same embodiment in various views from various angles to further illustrate the wheelchair. Operation of the wheelchair is illustrated below.

In one example use of various embodiments, a rider in a wheelchair with forward momentum swings their hips transversely to the forward direction of travel. This causes a shift in weight which causes the crossbar to lift one drive wheel relative to the drive wheel on the other side. This in turn causes the wheelchair to initiate a turn. The rider may apply braking to a wheel to assist the turn. The wheelchair makes a turn with, in this example, both the mid-chassis leaned in towards the centre of the turn and the rider-supporting platform leaning in towards the centre of the turn. In this example the rider then swings their hips the opposite way to shift weight away from the centre of the turn. The crossbar then causes the drive wheel at the inside of the turn to lower relative to the drive wheel on the opposite side towards a position where they are at the same height. This causes the wheelchair to track in a straight line, ending the turn.

The reader will appreciate that in some embodiments, movement of the rider platform as described and illustrated herein allows the rider to shift weight with respect to the mid-chassis. The reader will appreciate that, in various embodiments, the right and left wheel-mounting linkage assemblies being able to allow the wheel mounts to move upwards relatively to each other and being connected to the crossbar to distribute weight between the drive-wheel mounts , the drive wheels are able to move relatively to each other to allow the mid-chassis to lean with respect to the surface. The reader will appreciate that, in various embodiments, the movement of right and left wheels relatively to each other occurs in response to the rider shifting weight.

When the wheelchair traverses a slope in a straight line, the uphill facing rear wheel and uphill facing caster will move up and forward relative to the downhill facing rear wheel and caster. This allows the occupant to remain seated vertically.

The rear wheel motion is achieved by means of two swing arms, or arms for mounting drive wheels, linked together by a pivoting crossbar, or crossbeam.

Motion upward, downwards of the support wheels of some embodiments, which may be castor wheels, is driven by the motion of the rear wheels, where the right rear wheel moves the left caster, and the left rear wheel moves the right caster. The linkage mechanism crosses over from one side to the other under the seat via the lateral internal and external tubes.

The drive wheels of various of the embodiments illustrated above have a weight-bearing, or road-contact, rim and a drive or control rim adapted to be actuated by a rider. The drive or control rim can also be braked by the rider. For example, the rider may grip one or other of the control rims to break one or other of the wheels or to brake or drive both with a differential of braking or driving to affect a turn of the wheel chair. The wheelchairs of the embodiments described herein therefore have a combination of an ability to lean the central chassis or midchassis and an ability to selectively brake or drive wheels to affect a turn. The wheelchairs of these embodiments therefore allow the rider to balance the lean of the chair with the instantaneous radius of a turn. The reader will appreciate that balancing in a turn creates a positive neurological effect in a rider. This benefit will be familiar to the reader acquainted with skiing or riding a bicycle for example. The wheelchairs of various embodiments illustrated herein further have an ability to allow the rider to lean the rider-support platform or seat independently. These embodiments allow a rider to balance the leaning, titling or similar of the rider-supporting platform or seat with either or both of the turning of the wheelchair and the leaning of the central-chassis providing further opportunities for the same or similar neurological benefit.

In various embodiments features of the wheelchair are provided on alternative vehicles. Various embodiments provide any combination of the features described and illustrated on any vehicle known as suitable to the reader including mobility scooters, road vehicles, air vehicles and sea vehicles.

In alternative embodiments the force-distributing means is a pneumatic mechanism operable to provide equal upward force to each wheel-mounting linkage assembly.

In various additional embodiments elements, bars, linkages or part described as mounted are attached and/or connected by any attachments known as suitable to the reader.

In various additional embodiments elements, bars, linkages or part described as attached and/or connected are mounted by any mounts known as suitable to the reader.

In alternative embodiments the support wheels are located behind the drive wheels or follow the drive wheels.

In various embodiments the central chassis is a mid-chassis, or vice versa. The reader will recognise that in some embodiments the central chassis and/or mid-chassis support assemblies provide mounts for an assembly to mount the central-chassis on drive wheels and also provide mounts the platform that supports the rider. In various embodiments a tilt or lean of the rider platform can be independent of the relative height of the drive wheels or first and second wheels. In various embodiments the tilt of the rider platform controls the relative height of the first and second wheels. In other embodiments the drive wheels may be substituted with passive wheels and other wheels, such as the support wheels for example, may drive the wheelchair.

Various additional embodiments have any combination of the individual features described and illustrated herein with reference to specific embodiments. For example, one embodiment comprises the features of the embodiment illustrated with reference to Figure 14 but includes biasing means to bas the swing-arms at each side of the chair into alignment with each other. This may bias the arms towards putting the wheels at the same height. This may assist the rider right the wheelchair.

The rider-support assembly as described herein, such as with reference to Figure 18, allows the rider to swing their hips in an arc transversely to the direction of travel. The rider-support assembly as described herein, such as with reference to Figure 18, allows the rider to swing their hips in an arc longitudinally with the direction of travel. In further alternative embodiments provide a wheelchair with the height of the drive wheels fixed relative to each other with the rider-support assembly as described herein, such as with reference to Figure 18.

In further alternative embodiments provide a vehicle with the height of the wheels fixed relative to each other with the rider-support assembly as described herein, such as with reference to Figure 18.

In various additional embodiments various wheels, mounts for the wheel and/or linkages providing mounts for wheels are operable to turn as given wheels, or given other wheels, are raised or lowered relative to others. This may cause or assist the wheelchair to turn as the central chassis or mid-chassis leans.

In various embodiments the tracking of the wheels may be adjustable to tune the steering of the wheelchair, or other vehicle.

Figure 32 shows a side view of a wheelchair 200 of another embodiment of the present invention. Figure 32 gives a close-up view of an assembly 200 for a support wheel 209. The assembly 200 has an actuation post 203 on a first side of the wheelchair which is actuated via a cross-linkage (not shown) by a linkage (not shown) on an opposite, second side of the wheelchair to move the support wheel 209 up and forward as the first drive wheel 204 moves upward. In this embodiment the drive wheel 204 moves forward as it moves upward.

Figure 32 shows a fork blade which mounts the support wheel 209 at an axle 206. The fork blade 205 is mounted at a pivot 207 which has a substantially vertical axis as shown. The fork blade 205 has a backward rake so that the support wheel 209 follows the axis of the pivot 206. The reader may recognise the fork blade 205 as a castor wheel assembly.

Figure 33 shows a front view of the wheelchair 200 of the embodiment of Figure 32. As shown in Figure 33 the drive wheel 204 on the first side of the wheelchair is raised relative to drive wheel 208 on the second side of the wheelchair so the mid-chassis 208 is tilted downward relative to a surface to the first side to a degree and tilted upwards from the surface at the second side. In the example shown the wheelchair is tilted to a degree that the wheel 204 is leaned past the vertical towards the surface (not shown) on which the wheelchair is travelling.

As shown in Figure 33 the actuation post 203 is leaned towards the first side and towards the surface (not shown) on which the wheelchair travels. As shown the fork blade 205 has swung on pivot 207 so that the support wheel 209 is directed to roll towards the first side of the wheelchair. The support wheel therefore exerts a turning effect, in addition to the turning effect of the drive wheel 203, towards the first side of the wheelchair. The reader will appreciate that drive wheel 204 forms an acute angle with the surface on which the wheelchair is travelling. This is an acute angle towards a centre of a turn. The reader will appreciate that in any instance the centre of a turn can be defined, this is even if the turn does not have a constant radius over time. The turning effects of each, or either, of the drive wheel 203 and the support wheel 209 act to turn the wheelchair to the first side of the wheelchair. Therefore, actuation of the drive wheels to raise the first drive wheel upward relative to the second drive wheel causes a second turning effect to be exerted by the support wheel 209.

Figure 34 shows front view of a wheelchair of the same embodiment of Figures 32 and 33. Figure 34 shows the first drive wheel 204 leaned during a turn. The line 210 extending from a central axis of the drive wheel. The line 211 represents the plane of the surface on which the wheelchair is travelling. A distance from the intersect 212 of lines 210 and 211 to the wheel 204 represents the radius of a turn made by the wheelchair. In this embodiment the turn is affected by the raising of first wheel 204 relative to the second wheel 213. The wheel 204 leaned towards the centre of the turn, represented by intersection 212, exerts a second turning effect towards the centre of the turn. Therefore, the effect of raising the first wheel relative to the second turn is to cause the turning effect applied by the drive wheel 204.

Figure 35 shows a front view of a rider platform 220 which is able to support a rider of the wheelchair. The rider platform of this particular embodiment supports a seat 221. The rider platform 220 is supported by the mid-chassis by an assembly of springs and rods. The assembly has rods 223a to 223d, of which 223a and 3d are visible in Figure 35, as a front view. The rods are connected to the mid-chassis and the rider support. The rods are mounted to be angled from outer positions to inward positions. The rods are extensible with a selected range of extension.

Springs 222a to 222d are also connected to the mid-chassis 209 and also the rider support 220.

The assembly of springs and rods mounts the rider platform 220 to the mid-chassis 209 while allowing movement in three ways. In a first way the platform is able to move with a component being an arc arranged longitudinally with a direction of forward travel of the wheelchair, or approximately parallel with the drive wheels. In this embodiment the arc is concave upwards. This may be recognised as moving to allow the rider to change pitch. In a second way the platform is able to move with a component being an arc arranged transverse to the forward direction of travel of the wheelchair. This arc may be arranged to be concave upwards, or away from the mid-chassis. This may be recognised as allowing the rider to roll. In the third way the platform may be able to pivot about an internal part of the platform. This may be recognised as allowing the rider to yaw.

Figures 36 to 38 show front views of a wheelchair of the embodiment shown in Figures 33 to 35. Figures 26 to 23 show an axis 224 to represent a central axis of the rider’s body.

Figure 28 illustrates three alternative states of roll of a rider. Axis 224a depicts the rider in a neutral state of roll, or upright. Axis 224b depicts the rider in a state of rolling to the second side of the wheelchair. This would transfer weight to the second side of the wheelchair. This would tend to move the drive wheel on the second side upwards relative to the drive wheel on the first side. If the wheels were in a neutral position, at equal heights, and the wheelchair was moving the axis 224b would tend to initiate a turn to the second side. The turn would be affected in this embodiment by turning effects of the support wheels and the drive wheels as described herein. Axis 224c depicts the rider in a state of rolling to the first side of the wheelchair.

If the wheels were in a configuration with the drive wheel on the first side being higher than the drive wheel on the second side, such as when the wheelchair is in a turn, the axis 224b would tend to cause the turn to cease and/or a following turn to be initiated. This may be recognised as an example of controlling a turn of the wheelchair.

The reader will appreciate that, separately to moving their central axis, the rider may articulate their hips to allow then to balance with respect to a turn, for example, while controlling the turn.

Figure 40 shows a front view of a wheelchair of the same embodiment as Figure 33 to 36. Depicted is arcuate arrows 225a and 225b to represent the upwardly convex arcuate component of movement that allows a rider to roll.

Figure 41 depicts arcuate arrows 226a and 226b depicting the upwardly convex component of movement of the rider platform 220 which allows the rider to pitch with respect to the wheelchair. The ability to pitch can allow the rider to shift their weight forward and backward in control and drive actions for the wheelchair. For example, the rider may pitch forward to brace themselves to drive the wheels.

Figure 42 shows a plan view of a wheelchair of the same embodiment as Figures 23 to 29. Depicted is arcuate arrows 227a and 227b to represent yaw movement by the rider platform. The ability to yaw is a component of control of the wheelchair, and specifically a turn, by the rider. In one example the rider can yaw into a turn. In another example the rider may yaw outwardly with respect to a turn. An example use of the embodiments of Figures 23 to 32 will now be given to illustrate the operation of the wheelchair according to the present embodiment.

A rider might commence movements as shown in Figure 29 in a straight line out of the pages as shown. The rider may align the central axis of their weight as depicted by axis 224a. The rider may then align the central axis of their weight as depicted by axis 224b to initiate a turn. Referring now to the embodiment described above as an analogue the wheel 109/204 is mounted at an axle 137 which is mounted via a bar 105 to pivot at bar 102. This arrangement lets the distance between the wheel 109/204 and the rider platform 102/220 to reduce, or be compresses, and the first drive wheel to raise relative to the second drive wheel as the rider rolls to the first side as depicted by axis 224b. This induces the turning effect of the support wheel and/or the turning effect of the drive wheels as described herein and the wheelchair initiates a turn under the influence of the rider’s roll.

During the turn the rider can adjust the central axis of their weight to ‘ride’ the turn. This may be to align the central axis 224 with the vector sum of gravity and centripetal acceleration. This may be to roll upwards within the turn. The rider may also exert forces through their hips.

The rider may then align their central axis as depicted by 224b. If this is sufficiently ‘rolled over’ the first wheel may be caused to fall relative to the second drive wheel and the turn may cease. With enough roll a turn in an opposite curve may be initiated. The rider may control the wheelchair with the roll in combination with pitch and yaw, each providing a different degree of freedom of control of the wheelchair. Therefore, embodiments of the invention provide a wheelchair which is operable to lean and/or turn where the lean and/or turn are initiated and/or ceased by the rider exerting control on a rider platform by shifting their weight and/or the alignment and orientation of their mass. The control may be enabled by a rider platform that provides one or more modes of movement relative to a central chassis which mounts linkages to drive wheels and/or support wheels.

In alternative embodiments control exerted by a rider via a rider support controls only support wheels to exert a turning effect on the wheelchair.

In alternative embodiments control exerted by a rider via rider-support controls only drive wheels to exert a turning effect on the wheelchair.

In various embodiments the terms joining, connecting and mounting may be used interchanged. In various embodiments the central axis of the rider, as illustrated by 224 for example, represents the central axis of the weight or mass of a rider, or the upper body of a rider. In various examples the central axis 224 may be changed, shifted or adjusted by a rider changing, shifting or adjusting alignment of their head relative to their upper body or spine, for example. In various other examples the central axis might be changed, shifted or adjusted by the rider changing, shifting or adjusting their whole upper body and head with head in alignment with their upper body. In various other examples the central axis might be changed, shifted or adjusted by the rider changing, shifting or adjusting alignment of their hips.

Figure 44 shows, side view of a chair 1 according to a first embodiment of the invention. The chair will be recognised as an example of a seat or an example of seating device.

As shown the chair has a seat pan 2. The seat pan is a platform to support an occupant (not shown) of the set, such as a person sitting in the chair. In this embodiment the seat pan is integrated with a platform to support the seat pan. In other embodiments the seat pan may be mounted on a platform. The seating platform may be recognised as a first chassis or first platform.

In Figure 44 the seat pan 2 is shown in a level position or configuration.

Figure 45 shows a side view of the seating device of Figure 44 with the seat pan in a rearward- tilted, or backward-tilted, position or configuration.

Figure 46 shows a side view of the same seating device with the seat pan in a forward-tilted, or front-ward-tilted, position or configuration.

The chair has a mid-chassis 3 which supports the seat pan via a seat-support mechanism, or seat-support assembly 4. The mid-chassis may be recognised as an interface plate, interface platform, second platform or second chassis. The chair 1 as shown has a lower chassis, or base, 5 with legs 6 to support the chair on a surface. As shown in Figure 1 a base mechanism or base assembly 7 supports the mid-chassis above the base 5.

The seat-support mechanism has, in this embodiment, 4 rod ends or conrods 8a to 8d. These rod-ends may be recognised as mobile connectors which join the seat platform to the midchassis 3. The rod-ends 8 form a truncated pyramid in this particular embodiment. Here a truncated to eliminate the apex. The pyramid of this embodiment has the narrower end, towards a virtual apex, directed upwards. Other embodiments may have a virtual apex directed downwards. The seat-support assembly allows the seat platform to move with a component of movement that form an arcs in the plane of the page as shown in Figure 1 . The seat-support assembly allows the set platform to move with a component forming an arc into the page as shown in Figure 1. Here a component is a, typically though not necessarily, orthogonal trajectory. Complex movements enabled by the seat-support assembly may comprise movement in any combination of these components. These components of movement of the seat-platform relative to the mid-chassis may be described as pitch and roll. The arcs are typically concave upwards. The seat-support assembly also allows the seat-platform to yaw relative to the mid-chassis. This is by allowing the seat platform to pivot about an axis, typically but not necessarily, within the area of the seat platform. This axis is typically, though not necessarily substantially upright. For example, the seat-support mechanism may allow the seat to pivot in the plane of the mid-chassis.

The base assembly 7 has an axle 9. In this embodiment the axle 9 is arranged at an angle to the mid-chassis and mounted by a mount 10. The angle may represent an axle inclined with respect to the base. In alternative embodiments the axle may be arranged level, at other angles or at angles with alternative alignment, as seen in plan view, to that shown here.

The seat-support assembly of this embodiment has biasing elements, such as springs (not shown). Alternative embodiments may have no biasing elements.

The base assembly of this embodiment has biasing elements, such as springs (not shown). Alternative embodiments may have no biasing elements.

Figure 47 shows a front view of the chair of Figure 1 . Visible in the front view are rods 8a and 8b. The mount 10 for the axle 9 are visible also.

The primary motion of the seat pan is defined by the range of movement from the seat-support mechanism A, which is composed of 4 rod end joints set in a pyramid pattern between platform A1 (seat pan) and A2 (mechanism interface plate). The seat-support mechanism A has a sprung resistance that in conjunction with the rod ends keeps the surfaces of A1 and A2 of the seat-platform and mid-chassis separate relative to the parameters of weight of user, force applied and strength of resistance and stored energy.

A secondary motion of the seat pan and interface 3 with the seat base 5 (B1), of this embodiment , is defined by the mechanism B which is a single pivot point of rigid connection between the surfaces of A2 and B1 placed on the central axis running front to back of the chair, with the swing of the pivot running perpendicular - across the chair. The axis of the pivot is angled with either a front or rear bias that creates a side-to-side tilt of the interface platform 3 with an additional rotational action of the interface 3 A2 relative to the base 5 B1 in line with a central balance point. The base-assembly, or mechanism B has a sprung resistance that is tuneable relative to parameters of weight of the user, force applied, strength of resistance and stored energy.

The action of the seat design is that the seat pan 1 and therefore the pelvis of the occupant (not shown) can tilt and rise on any direction around 360 degrees on a horizontal plane when the interface 3 A2 is in neutral (horizontal on all axis) or when the interface A2 is not horizontal then the relative tilt and rise of A1 will be to the surface plane of A2. When one point of the A1 seat pan tilts the opposite point (perpendicular on a horizontal plane) will rise, the seat pan will also travel a relative distance in the direction of the rise in horizontal terms thus creating an arc of movement. The seat-support mechanism can also move in a limited rotational manner around the horizontal centre of the seat platform 1 and interface 3, or surfaces A1 and A2 as shown. This will be recognised as yawing.

Referring again to Figure 1 , this figure shows the seat-support mechanism A and basemechanism B set in a neutral position that positions the dynamic surfaces of A1 and A2 parallel with B1.

Referring to Figure 45 the rear 2 rod end joints of the seat-support mechanism A is shown in a forward tilt, or pitch, with the front 2 rod end joints 8 of the seat-support mechanism A is shown in a forward action rise resulting in forward travel of the seat pan A1 and relative rear tilt angle attitude to A2 and B1 . Mechanism B is in the neutral position with A2 in a parallel attitude to B1 .

Referring to Figure 46, this figure shows front two rod end 8 joints of the seat-support mechanism A in a rear tilt, or pitch, configuration with the rear two rod end joints 8 of the seatsupport mechanism A in a rear action rise resulting in rear travel of the seat pan A1 and relative rear tilt angle attitude to A2 and B1 .

As shown in Figure 46, the base mechanism B is in the neutral position with A2 in a parallel attitude to B1.

Figure 47 shows a front view with seat-support mechanism A and base-mechanism B in a neutral position setting the surfaces of A1 , A2 and B2 all parallel, or the seat platform, interface platform and base all parallel.

Fig. 48 shows left 2 rod ends of the seat-support mechanism A set on an inward action tilt and the right two rod ends 8 of mechanism A1 on a right to left axis with linear travel horizontally right relative to A2.

The base mechanism B in a left right action tilt set causing the surface A2 to tilt right relative to B1. The action direction of A and B are in an opposition set allowing for variable force control of each other. Figure 49 shows the right two rod ends 8a and 8d of the seat-support mechanism A set on an inward action tilt and the left two rod ends 8b and 8c of mechanism A set on an outward action rise tilting A1 on a left to right axis with linear travel horizontally left relative to A2.

Figure 50 shows the seating device in a configuration in which the seat platform is tilted one way relative to the second platform and the second platform is titled in an opposite way relative to the third platform.

Mechanism B in a right left action tilt set causing the surface A2 to tilt left relative to B1 . The action direction of A and B are in an opposition set allowing for variable force control of each other.

Embodiments of the invention provide a chair which promotes either passive, person generated or power generated movement of the seat pan, with sprung tension - resistance and rebound, in a primary and secondary motion set that interact to create force control for the seated person in a live transition between a range of seating attitudes.

Embodiments of the invention provide a seating device which allows movement of the chair with

Embodiments of the present invention comprise only one of the seat-support assembly and base assembly.

In alternative embodiments the swing arms are substituted with any linkage, assembly or mechanism known as suitable to the reader to allow a first drive wheel on a first side of the wheelchair to raise or lower relative to a second wheel on the second side of the wheelchair. Example linkages, assemblies or mechanisms include a parallelogram linkage, assembly or mechanism.

In various embodiments the terms linkage, assembly or mechanism can be interchanged.

In the preceding description and the following claims, the word “comprise” or equivalent variations thereof is used in an inclusive sense to specify the presence of the stated feature or features. This term does not preclude the presence or addition of further features in various embodiments.

In various embodiments any one of the following may be any other of the following: ridersupporting platform, seat platform, rider platform or platform for a rider.

In various embodiments the mid-chassis is a central chassis.

In various embodiments a linkage is an assembly.

In various embodiments a bar is an element. In various embodiments support wheels move upward or downward relatively to each other with drive wheels on respective same sides of the wheel chair to allow the mid-chassis and/or rider platform to tilt relative to the surface on which the wheelchair is travelling.

In various embodiments the wheelchair ‘travelling’ refers to the wheelchair traveling when in use.

In various embodiments joining, connecting and mounting may be interchanged and/or substituted for each other.

In various embodiments a leaned configuration for the wheel chair refers to the mid-chassis tilted relative to the surface on which the wheelchair is travelling and/or the seat platform tilted relative to either said surface or relative to the mid-chassis.

In various embodiments a main wheel is substituted for a drive wheel.

In various embodiments a larger wheel, compared to a support wheel, is substituted for a drive wheel.

In the preceding description and the following claims, the word “a” is used in an inclusive sense such that “a” does not exclude “another”.

The reader will appreciate that the seating device allows pitching, rolling or yawing of the seat pan.

Additional embodiments of the invention “a” device, element, chassis or other component or part is substituted with “first” device, element, chassis or other component or part and any additional devices, elements, chassis’ or other components or parts is substituted for “second”, “third” etc.

It is to be understood that the present invention is not limited to the embodiments described herein and further and additional embodiments within the spirit and scope of the invention will be apparent to the skilled reader from the examples illustrated with reference to the drawings. In particular, the invention may reside in any combination of features described herein, or may reside in alternative embodiments or combinations of these features with known equivalents to given features. Modifications and variations of the example embodiments of the invention discussed above will be apparent to those skilled in the art and may be made without departure of the scope of the invention as defined in the appended claims.

Claims

What we claim is:

1 . A wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel so as to form an acute angle with a surface on which the wheelchair is traveling.

2. The wheelchair of claim 1 comprising a seat platform operable to support a rider.

3. The wheelchair of any one of the preceding claims comprising a mid-chassis to which the seat platform is connected.

4. The wheelchair of any one of the preceding claims wherein the seat platform is connected to the mid-chassis by linkages that allow the seat platform to tilt relative to the midchassis.

5. The wheelchair of any one of the preceding claims wherein the first and second drive wheels are operable to raise or lower relative to each other in response to a shift in weight of the rider at the seat platform, and the first and second drive wheel are able to move relative to the mid-chassis in response to as shift of weight of the rider at the seat platform.

6. The wheelchair of any one of the preceding claims comprising support-wheel mounts for first and second support wheels for the wheelchair located on first and second sides of the wheelchair respectively.

7. The wheelchair of claim 7 wherein the support-wheel mounts may be provided on support linkage assemblies operable to move mounts for the support wheels as mounts for drive wheels on respective first and second sides of the wheelchair move.

8. A wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel such that the first wheel exerts a turning effect on the wheelchair, said turning effect operable to turn the wheelchair in a radius centred beside the wheelchair. The radius may be centred on the first side of the wheelchair.

9. A wheelchair having a first drive wheel on a first side of the wheelchair, having a second drive wheel on a second side of the wheelchair, having a first support wheel on the first side of the of the wheelchair and having a second support wheel on the second side of the wheelchair, wherein a support wheel comprises a wheel which is separated from a drive wheel to provide support against the wheelchair tipping forward or backward, wherein a support wheel is mounted so as to follow a mounting axis and wherein the wheelchair is operable to arrange the mounting axis to lean towards the first side of the wheel chair when the first drive wheel on the first side is raised relative to the second drive wheel on the second side.

10. The wheelchair of any one of the preceding claims wherein a support wheel following a mounting axis that is leaned towards the first side exerts a turning effect towards the first side.

11. The wheelchair of any one of the preceding claims wherein a mounting axis of a support wheel is substantially vertical when the wheelchair is not in a leaned configuration.

12. The wheelchair of any one of the preceding claims wherein said tipping may be in a forward direction relative to a direction of travel of the wheelchair.

13. The wheelchair of any one of the preceding claims wherein said tipping may be in a forward direction relative to a direction of travel of the wheelchair.

14. A seating device having: a first platform adapted to support an occupant of the seat, the seating platform being mounted on; a second platform, and a first support assembly operable to support the first platform and mount the first platform on the second platform, the first support assembly operable to allow the first platform to move relative to the second platform with a first components of movement comprising an arc.

15. The seating device of claim 14 wherein the first support assembly is further operable to allow the first platform to move relative to the second platform with a second component of movement comprising an arc.

16. The seating device of any one of claims 14 to 15 wherein the first and second components of movement are transverse to each other.

17. The seating device of any one of claims 15 to 16 wherein the first and second components of movement are transverse to each other.

18. The seating device of any one of claims 14 to 17 wherein one or more of the first and second components of movement are concave upward from the chair in use.

19. The seating device of any one of claims 14 to 18 wherein the first support assembly comprises a set of connection rods arranged to extend from the second platform to the first platform so as to form a truncated pyramid.

20. The seating device of any one of claims 14 to 19 wherein the set of connection rods have lengths selected to define the movement allowed of the first platform relative to the second platform.

21. The seating device of any one of claims 14 to 20 also having: a third platform, and a second support assembly operable to mount the second platform on the third platform and operable to allow the second platform to rotate about an axis located between the second platform and the first platform.

22. The seating device of any one of claims 14 to 21 wherein the axis is located between the second platform and the first platform may be arranged at an incline with respect to the third platform. The third platform may be provided by a base which is supported by a surface on which the seating device rests.

23. The seating device of any one of claims 14 to 22 wherein the second support assembly comprises a base, an axle mounted by the base and a support for the second platform, wherein the supports the second platform.

24. A wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel so as to form an acute angle with a surface on which the wheelchair is traveling.

25. According a wheelchair having a first drive wheel on a first side of the wheelchair and having a second drive wheel on a second side of the wheel chair, said second side distal the first side, wherein the wheelchair is operable to raise the first wheel relative to the second wheel so as to lean the first drive wheel such that the first wheel exerts a turning effect on the wheelchair, said turning effect operable to turn the wheelchair in a radius centred beside the wheelchair. The radius may be centred on the first side of the wheelchair.

26 A wheelchair having a first drive wheel on a first side of the wheelchair, having a second drive wheel on a second side of the wheelchair, having a first support wheel on the first side of the of the wheelchair and having a second support wheel on the second side of the wheelchair, wherein a support wheel comprises a wheel which is separated from a drive wheel to provide support against the wheelchair tipping forward or backward, wherein a support wheel is mounted so as to follow a mounting axis and wherein the wheelchair is operable to arrange the mounting axis to lean towards the first side of the wheel chair when the first drive wheel on the first side is raised relative to the second drive wheel on the second side.