DK178212B1

DK178212B1 - A power wheelchair and an assembly for aiding a power wheelchair in overcoming an obstacle

Info

Publication number: DK178212B1
Application number: DK201470496A
Authority: DK
Inventors: Torben Søndergaard
Original assignee: Roltec El Kørestole As
Priority date: 2014-08-18
Filing date: 2014-08-18
Publication date: 2015-08-24

Abstract

The invention relates to a power wheelchair (1) comprising a chassis (3), front caster wheels (2) adapted to be attached to the chassis (3), center drive wheels (4), rear caster wheels (5), a shaft (7), and an engine (6) adapted to be connected to the drive wheels (4) on each side of the wheelchair (1) by the shaft (7), wherein the wheelchair (1) further comprises an assembly adapted to be mounted on both sides of the wheelchair (1) for aiding the wheelchair (1) in overcoming an obstacle, which assembly includes an engine frame (8) for receiving and lifting/sinking the engine (6), and two arms (9, 10), an upper arm (9) and a lower arm (10), adapted to be rotatably attached to the engine frame (8) and extend rearwards from two front mounting points (11, 12), an upper front mounting point (11) and a lower front mounting point (12), wherein the two arms (9, 10) are adapted to end respectively at two rear mounting points (13, 14), an upper rear mounting point (13) and a lower rear mounting point (14), adapted to be rotatably attached to the chassis (3), the two front mounting points (11, 12) being adapted to be placed on a vertical axis (v1) at a distance (d1) from each other and the two rear mounting points (13, 14) being adapted to be placed on a vertical axis (v2) at a distance (d2) from each other, wherein the distance (d2) between the two rear mounting points (13, 14) is greater than the distance (d1) between the two front mounting points (11, 12). Also, the invention relates to an assembly for aiding a power wheelchair (1) in overcoming an obstacle.

Description

A power wheelchair and an assembly for aiding a power wheelchair in overcoming an obstacle

Field of the invention

The invention relates to the technical field of power wheelchairs, particularly to arrangements for aiding power wheelchairs in overcoming obstacles.

Background of the invention

Power wheelchairs have normally difficulties in overcoming obstacles. A solution to this problem is a power wheelchair as disclosed in US 2011/0012316 A1 which works as follows: when the front caster wheels hit an obstacle and try to move upwards, the drive wheels are pushed downwards, thus permitting the wheelchair to overcome the obstacle. However, this solution has the limitation that the drive wheels shall sit in front of the center of gravity of the wheelchair, as otherwise the wheelchair is not able to overcome the obstacle but just rolls back and forward. Hence, there is a need in the art of overcoming such a drawback.

Aspects of the invention

The first aspect of the invention is to provide an improvement to the state-of-the-art. The second aspect of the invention is to solve the aforementioned drawback of the prior art by providing a solution that aids a power wheelchair in overcoming an obstacle without limiting the placement of the drive wheels in front of the center of gravity of the wheelchair.

Description of the invention

The aforementioned aspects of the invention are achieved by a power wheelchair (e.g., a 6-wheel power wheelchair) comprising a chassis, front caster wheels adapted to be attached to the chassis, center drive wheels, rear caster wheels, a shaft, and an engine adapted to be connected to the drive wheels on each side of the wheelchair by the shaft, wherein the wheelchair further comprises an assembly adapted to be mounted on both sides of the wheelchair for aiding the wheelchair in overcoming an obstacle (e.g., an edge, a curb, a step, etc.), which assembly includes an engine frame for receiving and lifting/sinking the engine, and two arms, an upper arm and a lower arm, adapted to be rotatably attached to the engine frame and extend rearwards from two front mounting points, an upper front mounting point and a lower front mounting point, wherein the two arms are adapted to end respectively at two rear mounting points, an upper rear mounting point and a lower rear mounting point, adapted to be rotatably attached to the chassis, the two front mounting points being adapted to be placed on a vertical axis at a distance from each other and the two rear mounting points being adapted to be placed on a vertical axis at a distance from each other, wherein the distance between the two rear mounting points is greater than the distance between the two front mounting points.

When the front caster wheels of a wheelchair hit an obstacle, the torque Τχ generated by the rotation of the drive wheels against the ground is transferred to the chassis. Due to the assembly of the invention, the torque Τχ at the two front mounting points generates a force F that propagates through the two arms to the two rear mounting points. Since the distance d2 between the two rear mounting points is greater than the distance dx between the two front mounting points (i.e., d2 > dj), the torque T2 generated at the two rear mounting points is greater than Τχ (i.e., T2 = (F d2) > Τχ = (F ' dx)). This greater torque T2 provides a greater rotating, lifting force to the chassis that helps the front caster wheels over the obstacle. In particular, while the two rear mounting points are attached to the chassis, the two front mounting points are attached to the engine frame, thus permitting to lift/sink the engine frame, and thereby the engine, according to the actual torque. Thanks to its design, the power wheelchair of the invention enables the drive wheels to sit by the center of the chassis and not necessarily in front of the center of gravity of the wheelchair.

In an embodiment of the invention, the distance between the two rear mounting points is 20-40% greater than the distance between the two front mounting points. Advantageously, the distance between the two rear mounting points is 30% greater than the distance between the two front mounting points. This embodiment has the advantage that the wheelchair is aided in overcoming an obstacle without hopping.

In an embodiment of the invention, the lower arm is adapted to extend along a horizontal axis whereas the upper arm is adapted to extend upwards along an axis at an angle with respect to the horizontal axis. This embodiment has the advantage of providing a way of creating the distance d2. Also, the advantage of placing the upper arm at an angle with respect to the lower arm and not vice versa is that when the wheelchair drives in reverse gear and hits an obstacle, the generated torque will help to lift the rear caster wheels, thus overcoming the obstacle.

In an embodiment of the invention, the rear caster wheels are adapted to be attached to the lower rear mounting points. The engine normally provides the weight that generates the friction to the ground. This embodiment has therefore the advantage of increasing the weight and thereby the generated friction to the ground. Advantageously, the wheelchair may also comprise more than one engine and/or one or more springs associated to the one or more engines.

Also, the aforementioned aspects of the invention are achieved by an assembly for aiding a power wheelchair as described above in overcoming an obstacle, wherein the assembly is adapted to be mounted on both sides of the wheelchair, which assembly includes an engine frame for receiving and lifting/sinking the engine, and two arms, an upper arm and a lower arm, adapted to be rotatably attached to the engine frame and extend rearwards from two front mounting points, an upper front mounting point and a lower front mounting point, wherein the two arms are adapted to end respectively at two rear mounting points, an upper rear mounting point and a lower rear mounting point, adapted to be rotatably attached to the chassis, the two front mounting points being adapted to be placed on a vertical axis at a distance from each other and the two rear mounting points being adapted to be placed on a vertical axis at a distance from each other, wherein the distance between the two rear mounting points is greater than the distance between the two front mounting points.

Note that all the aforementioned advantages of the power wheelchair are also met by the assembly.

Hereafter, the invention will be described in connection with drawings illustrating non-limiting examples of a power wheelchair and an assembly for aiding a power wheelchair in overcoming an obstacle.

Brief description of the drawings FIG.l: Side view of a power wheelchair according to the invention. FIG.2: Close-up of an assembly according to the invention.

Notations a: angle between the upper arm and the horizontal axis.

a: axis along which the upper arm extends.

di: Distance between the two front mounting points.

d2: Distance between the two rear mounting points.

h: Horizontal axis.

vi: Vertical axis.

v2: Vertical axis.

1: Wheelchair.

2: Front caster wheels.

3: Chassis.

4: Drive wheels.

5: Rear caster wheels.

6: Engine.

7: Shaft.

8: Engine frame.

9: Upper arm.

10: Lower arm.

11: Upper front mounting point.

12: Lower front mounting point.

13: Upper rear mounting point.

14: Lower rear mounting point.

15: Lront stability springs.

16: Rear stability springs.

17: Inner plate of the engine frame.

18: Outer plate of the engine frame.

19: Opening of the inner plate.

20: Opening of the outer plate.

21: Gear.

22: Upper front bearing.

23: Lower front bearing.

24: Upper rear bearing.

25: Lower rear bearing.

26: Right suspension spring.

27: Left suspension spring.

Preferred embodiments of the invention FIG.l shows a side view of a power wheelchair 1 according to the invention. The wheelchair 1 comprises front caster wheels 2 attached to a chassis 3 of the wheelchair 1, center drive wheels 4 (the right drive wheel has been removed for showing the assembly of the invention), and rear caster wheels 5 attached to the lower rear mounting points 14. An engine 6 is connected to the drive wheels 4 on each side of the wheelchair 1 by a shaft 7.

The wheelchair 1 further comprises an assembly on both sides for aiding in overcoming an obstacle. The assembly includes an engine frame 8 for receiving and lift-ing/sinking the engine 6, and two arms 9, 10, an upper arm 9 and a lower arm 10, being rotatably attached to the engine frame 8 and extending rearwards from two front mounting points 11, 12, an upper front mounting point 11 and a lower front mounting point 12, and ending respectively at two rear mounting points 13, 14, an upper rear mounting point 13 and a lower rear mounting point 14, being rotatably attached to the chassis 3. The two front mounting points 11, 12 are placed on a vertical axis vi at a distance di from each other and the two rear mounting points 13, 14 are placed on a vertical axis v2 at a distance d2 from each other, wherein the distance d2 between the two rear mounting points 13, 14 is greater than the distance di between the two front mounting points 11, 12. In particular, the lower arm 10 extends along a horizontal axis h whereas the upper arm 9 extends upwards along an axis a at an angle a with respect to the horizontal axis h.

Advantageously, the springs 15, 16 at the front and rear caster wheels 2, 4 are used to provide stability to the wheelchair 1; in fact, they prevent the wheelchair 1 from tipping over forward, backward or sidewards.

FIG.2 shows a close-up of an assembly according to the invention. The engine frame 8 comprises two opposing plates 17, 18 with openings 19, 20 for receiving the engine 6 (in particular, the gear part 21 of the engine 6). The two arms 9, 10 are attached to the front mounting points 11, 12 via bearings 22, 23 interconnecting the two plates 17, 18. The two arms 9, 10 are attached to the two rear mounting points 13, 14 via bearings 24, 25 (e.g., ball bearings).

Advantageously, the springs 26, 27 (the left spring 27 is not visible) are used to provide suspension to the seat.

Claims

A motorized wheelchair (1) comprising a chassis (3), front steering wheel (2) adapted to be secured to the chassis (3), center drive wheel (4), rear steering wheel (5), a shaft (7) and a motor (6). ) adapted to be connected to the center drive wheels (4) on each side of the wheelchair (1) by the shaft (7), wherein the wheelchair (1) further comprises an assembly adapted to be mounted on both sides of the wheelchair (1) to assist the wheelchair ( 1) overcoming an obstacle, comprising an engine frame (8) for receiving and lifting / lowering the motor (6) and two arms (9, 10), an upper arm (9) and a lower arm (10), arranged for rotatable attachment to the motor frame (8) and extending rearwardly from two front mounting points (11, 12), an upper front mounting point (11) and a lower front mounting place (12), characterized in that the two arms (9, 10) are arranged to terminate at two rear mounting points (13, 14), one upper mounting point (13) and one lower, respectively. mounting point (14) arranged for rotatable attachment to the chassis (3), wherein the two front mounting points (11, 12) are arranged to be placed on a vertical axis (vi) at a distance (di) from each other, and the two rear mounting locations (13, 14) are arranged to be placed on a vertical axis (V2) at a distance (d2) from each other, the distance (d2) between the two rear mounting locations (13, 14) being greater than the distance ( di) between the two front mounting locations (11, 12).

The wheelchair (1) of claim 1, wherein the distance (d2) between the two rear mounting locations (13, 14) is 20-40% greater than the distance (d1) between the two front mounting locations (11, 12).

A wheelchair (1) according to claim 1 or 2, wherein the lower arm (10) is arranged to extend along a horizontal axis (h), whereas the upper arm (9) is adapted to extend upwards along an axis. (a) at an angle (a) with respect to the horizontal axis (h).

A wheelchair (1) according to any one of the preceding claims, wherein the rear guide wheels (5) are arranged to be secured to the lower rear mounting locations (14).

An assembly for assisting a motorized wheelchair (1) according to any one of the preceding claims for overcoming an obstacle in which the assembly is arranged to be mounted on both sides of the wheelchair (1), said assembly comprising an engine frame (8) for picking and lifting / lowering the motor (6) and two arms (9, 10), an upper arm (9) and a lower arm (10) arranged for rotatable attachment to the motor frame (8) and extending rearwardly from two front mounting locations (11, 12), an upper front mounting site (11) and a lower front mounting location (12), characterized in that the two arms (9, 10) are arranged to terminate at two rear mounting locations (13, respectively). 14), an upper mounting location (13) and a lower mounting location (14) arranged for rotatable attachment to the chassis (3), wherein the two front mounting locations (11, 12) are arranged to be placed on a vertical axis ( vi) at a distance (di) from each other and the two rear mounting points (13, 14) are arranged ten 1 to be placed on a vertical axis (V2) at a distance (di) from each other, wherein the distance (d2) between the two rear mounting locations (13, 14) is greater than the distance (di) between the two front mounting locations (11) , 12).