NO345178B1

NO345178B1 - Self-leveling wheelchair

Info

Publication number: NO345178B1
Application number: NO20190030A
Authority: NO
Inventors: Harald Myrhaug; Hallvard Dahle
Original assignee: Hallvard Dahle; Harald Myrhaug
Priority date: 2019-01-09
Filing date: 2019-01-09
Publication date: 2020-10-26
Also published as: NO20190030A1

Description

The present invention is concerning a self-levelling wheelchair, as appears from the preamble of claim 1.

Background

The present invention is concerning a vehicle of the type wheelchair for transporting a physically handicapped or disabled person indoor as well as outdoor. However, traditional wheelchairs have limitations with respect to the condition of the ground upon which the wheelchair is moving, such as a level sidewalk versus kerbs, stairs and terrain in forest and mountain. Accordingly, physically disabled persons therefore have limited space to move. During winter season when the ground often is covered by snow and ice, physically disabled persons often stay indoor more or less during the whole season.

Several attempts have been done to overcome these limitations. US Patent 9,073,399 B1 discloses a wheelchar having a seat assembly that can be rotated and elevated by actuators connected to the seat and base assembly by ball joints, allowing four degrees of movement. The assembly simplifies movement upon a surface sloping downwardly or upwardly.

US Patent 6,325,167 B1 belt-driven wheelchair where the chair is provided with a mechanism that keeps the seat in a horizontal position, thus maintaining comfort for the user when moving uphill or downhill.

WO 2008/051946 A2 and EP 0829247 A2 both describe a wheelchair with seat stabilization. The seat is mounted on two linear actuators and supported rotary in a fixed third location. The seat can be adjusted horizontally both in the lateral and longitudinal directions.

WO 2016057104 describes a wheelchair having a base assembly with a drive wheel and one or two casters at each side(s) of the drive wheel viewed in the driving direction. A seat with a backrest is arranged upon the base assembly. An actuator assembly, expandable and retractable and controlled by a computer, are arranged to adjust the position of the seat with respect to the base assembly.

KR 20130057648 describes a wheelchar system having a control system that enables adjustment of tilt angle and elevation of a support frame connected to a chair body via actuators.

Object

An object of the present invention is to provide a wheel chair that can be used in terrain, such as forest and mountain, as well as stairs and other uneven surfaces. Another object is to provide a wheelchair that prevents the seat from moving forward when hitting the kerb or a similar obstacle on the ground.

The invention

The objects above are achieved by a self-leveled wheelchar in accordance with the characterizing art of claim 1. Additional advantageous features appear from the dependent claims.

The invention concerns a self-levelling wheelchair comprising a seat, a drive comprising a motor, wheels or belts, a drive control device available to a driver located on the seat, a platform attached at the upper side of the drive and exhibiting a substantially horizontal plane, and linear actuators connecting the seat to the platform in a controllable manner. A tilt sensor and the actuators are arranged to tilt the seat in a desired angle of inclination with respect to the platform, wherein the wheelchair exhibits a longitudinal axis (300) in a driving direction.

In accordance with the invention, the wheelchair comprises:

a first actuator pair comprising a first actuator and a second actuator arranged at a mutual distance along a first horizontal axis and connected pivotal to the platform by respective lower connectors, said lower connectors arranged to allow the respective actuators to move in a plane perpendicular to the plane of the platform about mutually parallel respective first and second pivotal axis and, extending in parallel with the plane of the platform, wherein the first and second actuators are attached to the seat by an articulated upper connector, arranged allow tilting of the seat in any position in three dimensions with respect to the platform, and

a second actuator pair comprising a third actuator and a fourth actuator arranged at a mutual distance along a second horizontal axis and connected pivotal to the platform by respective lower connectors, said lower connectors arranged to allow the respective actuators to move in a plane perpendicular to the plane of the platform about mutually parallel respective third and fourth pivotal axis and, extending in parallel with the plane of the platform, wherein the third and fourth actuators are attached to the seat by an articulated upper connector, arranged allow tilting of the seat in any position in three dimensions with respect to the platform, wherein

said first horizontal axis is extending perpendicular to the second horizontal axis and at an angle with the longitudinal axis of the wheelchair, and wherein

said first and second pivotal axis are extending perpendicular to said third and fourth pivotal axis.

The first and second horizontal axis are advantageously extending at an angle of about degrees with the longitudinal axis of the wheelchair.

In one embodiment, the lower connector is a hinge connector in form of a fork-shaped bracket provided with a pivotal pin defining said pivotal axis.

In one embodiment, the upper connector is realized in the form of a ball-and-socket joint.

The seat levelling can be realized in the form of a controller in communication with the tilt sensor, the actuators, and with a user control device at the seat, arranged to sense angle of inclination with respect to the horizontal level of earth and adjust individual actuators to keep the seat in the horizontal level of earth. The tilt sensor is located at the drive or at the platform, whereas the controller can be located anywhere in the wheelchair.

A particularly useful effect of the invention is that wheelchair users now can enter unlevel terrain i the nature with a belt-driven self-levelled wheelchair according to the invention.

In an alternative embodiment, the actuators can be controlled to change the elevation of the seat. This is particularly desireable for example when the user is checking out in a shop, or when conversating with standing people.

Drawings

The invention is described in further details below with reference to drawings, where

Fig.1 is a schematic side view of a wheelchair,

Fig.2 is a perspective view of a platform and lower part of a stabilized seat,

Fig.3 is a scmatic sectioned top view of a part of the platform in Fig.2,

Fig.4 is a side view of a seat supporting actuator with a ball joint connection,

Fig.5 is a perspective view of the seat supporting actuator of Fig.4 with an articulated connection, Fig.6 is a front view of the wheelchair located in a laterally stabilized position, and

Fig. 7 is a side view of the wheel chair located in a stabilized position in terrain sloping in the driving direction.

Now with reference to Fig.1, a wheelchair is illustrated in a schematic side view and indicated with reference number 100. The wheelchair comprises a seat 101 supported by a platform 102 via four elongate axially length adjustable actuators 104 of which only two out of four actuators are shown here. The platform 102 is mounted on top of a drive 103, here illustrated in the form of a belt drive. The drive can be realized in numerous embodiments know from the prior art, and is therefore not described in further details here. The actuators 104 are connected to the underside of the seat of the wheelchair by respective upper connectors, one actuator located adjacent to a respective corner of the seat, thus forming a rectangular or square distribution as described below. The actuators are controlled by a controller 114 (Fig. 2) including a gyro sensor. The controller is arranged to transmit individual control signals to individual actuators by respective wired or wireless signal connectors (not illustrated). Hence, the controller is arranged to adjust the longitudinal extension of the controllers 104 in the respective controller pairs.

Reference is now made to Figs.2-5. Figure 2 illustrates the platform 102 in perspective view from above. A first actuator pair is illustrated by the reference numerals 104a, 104b, and a second actuator pair is illustrated by the reference numerals 104c, 104d, each actuator comprising an elongate static strut 107 (Fig.4) and an extendable and retractable piston 108 (Fig.4) connected to a articulated connector in the form of a ball-joint (109) attached to a bracket (111), which again is connected to the underside of the seat (not shown). The respective actuator 104 is connected to the platform 102 by a lower connector 106, pivotal in a plane extending perpendicular to the platform plane. As best is shown in Fig. 5, the lower connector 106 is connected pivotal to the platform 102 about a pin 112 fixed in a bracket 113. In this manner, the respective actuator is mounted to the platform 102 pivotal about an axis of rotation 200 extending parallel to the plane of the platform 102.

As shown particularly in Fig.3, the first actuator 104a in the first actuator pair is connected pivotal to the platform 102, pivotal about a first pivotal axis 200a. A second actuator 104b in the first actuator pair is located in a distance from the first actuator 104a and positioned to exhibit a second pivotal axis 200b extending parallel to the first pivotal axis 200a.

Still referring to Fig.3, a third actuator 104c in the second actuator pair is connected pivotal to the platform 102, pivotal about a third pivotal axis 200c. A fourth actuator 104d in the second actuator pair is located in a distance from the third actuator 104c and positioned to exhibit a fourth pivotal axis 200d extending parallel to the third pivotal axis 200c.

The first 200a and second 200b pivotal axis’s in the first actuator pair are extending perpendicular to the third 200c and fourth 200d pivotal axis’s in the second actuator pair. Accordingly, the respective actuator pair is able to move in a plane only. In Fig.3, the reference numeral 300 refers to the driving axis or driving direction 300 of the wheelchair. According to another important aspect of the invention, the respective pivotal axis’s 200 extend at an angle with the driving direction 300, preferably about 45 degrees. The effect of this arrangement is explained below.

The actuator and upper connector are illustrated in more detail in Fig. 4. The actuator 104 comprises a stator 107 in the form of an elongate hollow static strut. A piston 108 is accommodated in the stator 107 with an end external to the stator 107 connected to a ball joint 109 attached to a bracket 111, arranged to be fixed to the underside of the seat of the wheelchair.

Accordingly, the arrangement with hinged lower connectors 106 and articulated upper connector 105 enables the seat 101 to be tilted in a stepless manner inclined at any angle with respect to the platform 102, only limited by the extendable (and retractable) extension of the actuators 104. As a result, the driver can be seated horizontally even when driving in a laterally sloping ground (reference character T in Figs. 6 and 7) or when driving up or down a sloped ground, as illustrated in Figs. 6 and 7. The angular arrangement of the pivotal axis’s 200 with the driving direction 300 prevents the seat 101 from moving in the driving direction 300 and hence prevent the seat from moving forward when hitting a kerb or a similar obstacle.

Modifications

Whereas the invention has been described above in the form of an exemplary embodiment, the respective components of the wheelchair can be modified by a person skilled in the art. For example, the lower hinged connector can be of any type of connector that allows the connected actuator to be movable in only one plane perpendicular to the platform, and is not limited to a bracket and pin embodiment shown. Moreover, the gyro sensor at the controller can be of any type of tilt sensor capable of sensing the degree of inclination with respect to the horizontal level of the earth. Moreover, the ball joint illustrated can be any type of articulated connectors that makes it possible to position the seat in practically any angle position in three dimensions with respect to the platform.

Claims

1. Self-levelling wheelchair (100) comprising a seat (101), a drive (103) comprising a motor, wheels or belts, a drive control device available to a driver located on the seat (101), a platform (102) attached at the upper side of the drive (103) and exhibiting a substantially horizontal plane, and linear actuators (104) connecting the seat (101) to the platform (102) in a controllable manner and arranged to tilt the seat (101), and a tilt sensor, said actuator (104) and tilt sensor being arranged to tilt the seat (101) in a desired angle of inclination with respect to the platform (102), wherein the wheelchair (200) exhibits an longitudinal axis (300) in a driving direction, characterized in that

a first actuator pair comprising a first actuator (104a) and a second actuator (104b) arranged at a mutual distance along a first horizontal axis (201) and connected pivotal to the platform (102) by respective lower connectors (106), said lower connectors (106) arranged to allow the respective actuators (104a, 104b) to move in a plane perpendicular to the plane of the platform (102) about mutually parallel respective first and second pivotal axis (200a) and (200b), extending in parallel with the plane of the platform (102), wherein the first and second actuators (104a, 104b) are attached to the seat (101) by an articulated upper connector (105), arranged allow tilting of the seat (101) in any position in three dimensions with respect to the platform (102), and

a second actuator pair comprising a third actuator (104c) and a fourth actuator (104d) arranged at a mutual distance along a second horizontal axis (202) and connected pivotal to the platform (102) by respective lower connectors (106), said lower connectors (106) arranged to allow the respective actuators (104c, 104d) to move in a plane perpendicular to the plane of the platform (102) about mutually parallel respective third and fourth pivotal axis (200c) and (200d), extending in parallel with the plane of the platform (102), wherein the third and fourth actuators (104c, 104d) are attached to the seat (101) by an articulated upper connector (105), arranged allow tilting of the seat (101) in any position in three dimensions with respect to the platform (102), wherein

said first horizontal axis (201) is extending perpendicular to the second horizontal axis (202) and at an angle with the longitudinal axis (300) of the wheelchair, and wherein

said first and second pivotal axis (200a, 200b) are extending perpendicular to said third and fourth pivotal axis (200c, 200d).

2. The wheelchair of claim 1, wherein the first and second horizontal axis (201, 202) are extending at an angle of about 45 degrees with the longitudinal axis (300) of the wheelchair.

3. The wheelchair of claim1, wherein the lower connector (106) is a hinge connector in form of a fork-shaped bracket (113) provided with a pivotal pin (112) defining said pivotal axis (200).

4. The wheelchair of claim 1, wherein the upper connector (105) is realized in the form of a balland-socket joint.

5. The wheelchair of claim 1, comprising a controller (114) in communication with said tilt sensor, said actuators (104), and with a user control device at the seat (101), arranged to sense angle of inclination with respect to the horizontal level of earth and adjust individual actuators (104a, 104b; 104c, 104) to keep the seat (101) in the horizontal level of earth.