FR3131194A1 - Improved crossing device for electric wheelchair - Google Patents

Abstract

Improved crossing device for electric wheelchair The invention relates to an improved crossing device for an electric wheelchair. It includes a return system to improve the support of the front (3a) and rear (3c) wheels of a motorized wheelchair at ground level. Figure for abstract: Fig. 6

Description

Improved crossing device for electric wheelchair

The present invention relates to an obstacle crossing device for a motorized vehicle.

By motorized vehicle, we mean any vehicle intended to move autonomously, such as a robot, wheelchair, etc.

As an example which will constitute the common thread of this description, the motorized vehicle will more particularly concern a wheelchair.

This obstacle crossing device responds to current issues relating to the movement of people with reduced mobility (disabled or elderly) who use a wheelchair on a daily basis both indoors and outdoors.

In today's society, taking into account people with disabilities constitutes a priority in town planning projects, in the adaptability of housing, in access to roads and public or private transport.

Good accessibility conditions social, educational and professional integration. Mobility and travel are the guarantee of quality of life on a daily and long-term basis.

For freedom of movement to be real, the entire travel chain must meet the specific needs of people.

The first element in this movement chain is undoubtedly the wheelchair which constitutes a technical aid to mobility by allowing a person to be easily transported on a flat surface.

As urban planning projects take a long time to implement, of the order of a few years, the wheelchair must adapt to the current state of cities, roads, housing, etc.

However, roads have many sidewalks, businesses often have a step, housing sometimes has a difference in level from one room to another, etc. A wheelchair must be able to overcome these obstacles.

Many solutions have been proposed for this purpose. Among them, wheelchairs with six-wheel technology exist on the market. They have good maneuverability and good stability, but crossing obstacles is limited to low heights (less than 7.5 cm) and this only with a curb lift option which provides leverage to lift the front wheels.

Other 4x4 type wheelchairs exist and allow you to ride on any type of terrain (grass, gravel, stones) and overcome obstacles up to 15cm. The main disadvantage of these armchairs lies on the one hand in their imposing size preventing their use indoors and on the other hand in their lack of stability, because there is a risk of tipping forward or backward when crossing obstacle.

We know, in particular, from the international application published under the number WO 2011/095753 an obstacle crossing device for a motorized vehicle consisting of:

- a chassis connected to three wheels on each side;

- motor means capable of turning the wheels;

and, on each lateral side of the chassis, there is a mechanism comprising two arms, articulated in pairs around a common pivot axis, on which the three wheels are distributed, respectively a front wheel, an intermediate wheel, and a wheel rear, said mechanism allowing each wheel to pivot relative to the axis of each adjacent wheel.

Said device is particular in that the chassis is connected to each articulated arm mechanism via two shafts mounted free to rotate, at least one of the shafts being able to compensate for the variation in distance between these two shafts when the arms are not aligned.

In other words, this device has the following particularity: the distance between two adjacent wheels is always fixed in order to avoid any impact between them. The wheels can move in height independently of each other when they encounter an obstacle. Concretely, when the wheelchair finds itself facing a sidewalk, the two front wheels will cross it first, while the other two wheels will remain in contact with the ground. Then the next two wheels will arrive facing the sidewalk and cross it, the other wheels remaining in contact with the ground. Eventually, the two rear wheels will cross the curb, the front wheels remaining on the ground. At any time, the chair has more than three points of support in order to define a plane which gives stability to the chair.

As already mentioned, in the device described in this document WO 2011/095753 the chassis is connected to each articulated arm mechanism via two shafts mounted free to rotate, at least one of the shafts being able to compensate for the variation distance between these two shafts when the arms are not aligned in a horizontal plane. In fact, when crossing an obstacle, the wheels are not aligned, and the articulated arms pivot accordingly, thus forming an angle, leading to a rapprochement of the two shafts. However, the chair frame has fixed dimensions and is connected to these two shafts. To avoid any deformation, or even rupture, of the chassis, it is therefore essential to be able to compensate for the modification of the center distance of the fixing shafts of the articulated arms in relation to the distance between fixing of these same shafts to the chassis, when crossing the 'obstacles.

Generally speaking, such a device has the advantage of being able to offer people with reduced mobility a compact electric wheelchair to facilitate their daily movements, said wheelchair being particularly capable of overcoming obstacles up to 20 cm in height and in all angles of attack forward, without risk of tipping, thus making driving easier, particularly for users who have difficulty handling small obstacles.

Indeed, in particular, the chair described in international application WO 2011/095753 can advantageously be provided with a front and/or rear anti-tilting device comprising, on each lateral side of the machine, means for blocking the pivoting of at least one articulated arm when the chassis tilts forwards or backwards.

In addition, this chair can also be supplemented by a device to assist in crossing the rear of the vehicle, comprising on each lateral side of the vehicle, an anti-tip wheel placed at the rear of the vehicle. .

Another advantage of this chair lies in the fact that it allows you to travel in the countryside in grass, gravel, stones, but also in snow and sand.

However, such an obstacle crossing assistance device for a motorized vehicle can still be improved.

In particular, improvements must be made, in particular to avoid shocks and to better match the irregularities of the ground. It is particularly sought to improve the contact, the support, between the wheels, in particular the front and rear wheels, and the ground, in the case of crossing an obstacle, for example the rise or fall of a sidewalk.

To respond to these problems, and force the device to optimally match the unevenness of the ground, it was designed to equip the crossing device with a return system which allows the front and rear wheels to be placed at ground level. , in other words to force the device to make an angle so that said front or rear wheel is, for its part, forced to come into contact with the ground.

Note that, moreover, such a device also makes it possible to improve the traction of the front wheel in the particular case of climbing an obstacle and to facilitate crossing the rear of the chair by lifting the rear wheel before she doesn't hit the obstacle.

For this purpose, the present invention relates more particularly to an obstacle crossing device for a motorized vehicle consisting of a chassis connected to three wheels on each lateral side of said chassis and motor means capable of rotating said wheels and, each lateral side of the chassis, there is a mechanism comprising two arms, articulated in pairs around a common pivot axis, on which two arms are distributed the three wheels, respectively a front wheel, an intermediate wheel and a rear wheel, said mechanism allowing each wheel to pivot relative to the axis of each adjacent wheel.

Said obstacle crossing device according to the invention is particular in that the motor means and the rear wheel are carried by an arm articulated to the chassis on a spar, through a pivot connection, the end of the arm which is 'extends beyond the pivot connection and on the side opposite to the connection of the motor means cooperating with a movable slide on the spar, said pivot connection generating a movement of the rear wheel between two extreme positions, namely a first position in the alignment with the two other wheels or a second lowered position relative to the alignment of the two other wheels, said slide comprising a wall perpendicular to the sliding axis while the spar has a fixed wall perpendicular to the sliding axis , at least one spring means being interposed between said two walls, while the arm is dimensioned so that its free end comes into contact with the wall so as to push back the slide while constraining the spring means against said wall, when said front wheel is in its first position aligned with the other two wheels.

According to particular embodiments of this crossing device:

– the support of the arm on the wall of the slide is done through a roller filling the end of said arm;

– two spring means are positioned between the walls of the slide;

– the motor means and the rear wheel are carried by the arm through a pivot connection;

– the device further comprises, on each lateral side, an anti-tip wheel placed at the rear of the motorized vehicle and fixed to the first end of said arm opposite the end coming into contact with the wall of the slide;

– the device includes a mechanical device for limiting the movement of the arm when raising the seat, consisting of a movable stop under the action of raising the seat;

– said chassis being connected to each articulated arm mechanism via two shafts mounted free to rotate, at least one of the two shafts being able to compensate for the variation in distance between these two shafts when the arms are not aligned .

Other aims and advantages of the present invention will appear during the description which follows relating to embodiments which are given only by way of indicative and non-limiting examples.

Understanding this description will be made easier by referring to the appended drawings in which:

is a schematic side view showing the wheelchair lying flat.

shows, schematically, a partial view of the armchair in section AA.

, , And schematically represent a sectional view of the improved obstacle crossing assistance device according to the invention, in different positions, from a position where the wheels of the chair are flat, on the , to an obstacle crossing position, on the , passing through two intermediate positions in Figures 4 and 5, in order to illustrate the movement of said device and the wheels when crossing an obstacle.

With reference to Figures 1 and 2 of the attached drawings, the present invention relates to an obstacle crossing device for a motorized vehicle consisting of:

- a chassis 2 on which an armchair 1 is fixed, said chassis 2 being connected to three wheels 3a, 3b, 3c on each lateral side;

- motor means 5 capable of rotating the wheels 3a, 3b, 3c.

On each lateral side of the chassis 2, there is a mechanism comprising two arms 7a, 7b, articulated in pairs around a common pivot axis 6, on which the three wheels 3a, 3b, 3c are distributed, respectively:

- a front wheel 3a, positioned at the front of the first articulated arm 7a,

- an intermediate wheel 3b, positioned at the level of the articulation between the two arms 7a, 7b,

- and a rear wheel 3c, positioned at the rear of the second articulated arm 7b.

The two arms 7a, 7b are thus articulated around a common axis corresponding to axis 6 of the intermediate wheel 3b.

Said mechanism comprising the two arms 7a, 7b allows each wheel to pivot relative to the axis of each adjacent wheel.

The articulation between the two arms 7a, 7b therefore corresponds to a pivot connection. This allows the front wheels 3a and rear 3c to pivot around the axis 6 of the intermediate wheel 3b. The three wheels 3a, 3b, 3c can thus move up and down independently of each other when crossing an obstacle.

According to an advantageous characteristic of the crossing device of the invention, the chassis 2 of the armchair 1 is connected to each mechanism with articulated arms 7a, 7b via two shafts 8, 12 mounted free to rotate, at least one shafts being able to compensate for the variation in distance between these two shafts 8, 12 when the arms 7a, 7b are not aligned.

According to a first variant, this condition can be met by a crankshaft type shaft composed of two cylindrical sections offset relative to each other. This offset makes up for the variation in distance between the two shafts when the wheels are not aligned.

According to a second variant, the crankshaft type shaft can be composed of a first shaft section connected to an articulated arm and a second shaft section connected to the chassis, the two shaft sections being articulated together. by a connecting rod.

According to a third variant, this condition can be met by a horizontal sliding shaft between two stops defining the maximum and minimum distance authorized between the two shafts. This sliding shaft allows you to vary the distance between the two shafts at the level of the articulated arms or at the level of the chassis. For example, this sliding shaft can be inserted into a horizontal slot provided for this purpose in an articulated arm, or into a horizontal slot provided for this purpose on the chassis.

There reveals part of the electrical system located under the seat of the chair 1. There is a battery pack 4 connected on each lateral side to the front of the articulated arm mechanism 7a, 7b via a motor 5 and a motor axis 8, and at the rear of the mechanism by a crankshaft type axis 12 mounted idle.

The battery pack 4 is itself fixed to the chassis 2 of the chair. The axis of the crankshaft 12 is preferably broken down into two shafts 12a, 12b having their axes of rotation slightly offset relative to each other, in accordance with the first variant mentioned above, the first shaft 12a being integral with the chassis 2, in particular the battery block 4 while the second shaft 12b is integral with an articulated arm 7b.

Now, with reference to Figures 3 to 6, the obstacle crossing device for a motorized vehicle of the invention is particular in that the motor means 5 as well as the rear wheel 3c whose axis, referenced 3c', is shown in said Figures 3 to 6, are carried by an arm 10. Note that the axes 3a' and 3b' of the front wheels 3a and intermediate 3b are also represented.

Said arm 10 is articulated to the chassis 2, through a pivot connection 13, on a spar 14, in the form of a beam.

One of the ends of said arm 10, the end referenced 11 in the figures, which extends beyond said pivot connection 13, and on the side opposite to the connection of the motor means 5 and the rear wheel 3c on said arm 10 , cooperates with a slide 15, which is movable on the spar 14.

In a particularly advantageous manner, said pivot connection 13 of the arm 10 on the spar 14 makes it possible to generate a movement of the front wheel 3a between two extreme positions that the latter can take, namely:

– a first position 20, shown in Figures 3 and 4 attached, in which said front wheel 3a is in alignment with the two other intermediate 3b and rear 3c wheels; note here that we are talking about an alignment of the three wheels 3a, 3b and 3c when said three wheels 3a, 3b and 3c are on a flat surface;

– a second position 21, shown on the , in which said front wheel 3a is no longer in alignment with the two other intermediate 3b and rear 3c wheels, but is lowered relative to a plane passing through the axis 3b' and 3c' of the intermediate 3b and rear 3c wheels .

Note that the illustrates an intermediate position of the front wheel 3a, when the latter is passing from its first position 20, in which it is in alignment with the two other wheels 3b and 3c, to its second position 21, in which it is lowered relative to the two intermediate wheels 3b and rear 3c.

In addition, said slide 15 has a wall 16, perpendicular to the sliding axis, on which the end 11 of the arm 10 rests.

The beam 14 comprises, for its part, a fixed wall 17 which is also perpendicular to the sliding axis.

Between the wall 16 of the slide 15 and the wall 17 of the beam 14 is inserted at least one spring means 18.

Note that, preferably, two spring means 18 are positioned between the two walls 16 of the slide 15 and 17 of the spar 14 to balance the pressure and ensure perfect sliding of the slide 15.

The spring means 18 between the wall 16 of the slide 15 and the wall 17 of the spar 14 is put under tension when said two walls 16, 17 are brought closer to each other, when the front wheel 3a is in its first position 20, in alignment with the two other intermediate wheels 3b and rear 3a.

For this purpose, the arm 10 is dimensioned so that its end 11 comes into contact with the wall 16 of the slide 15, so as to push back and move the latter, by constraining said at least one spring means 18.

According to an advantageous characteristic of the crossing device of the invention, the support of the arm 10 on the wall 16 of the slide 15 is carried out through a roller 111.

The fact that the end 11 of the arm 10 is fitted with a roller 111, which then rolls on the wall 16 of the slide 15, makes it possible to avoid deterioration of said wall 16.

Furthermore, advantageously, the motor means 5 and the rear wheel 3c are carried by the arm 10 through a pivot connection 19.

Crossing an obstacle, climbing a sidewalk for example, takes place as follows:

- initially the three wheels 3a, 3b and 3c rest on the ground at the foot of the sidewalk and are aligned,

- during the next step, the front wheel 3a climbs the sidewalk, the wheels 3a, 3b and 3c remaining aligned knowing that the intermediate wheel 3b is “in the air”,

- during the next step, under the driving action of the front wheels 3a and rear 3c, the intermediate wheel 3b comes into contact with the sidewalk which has the effect of a load shedding which generates, under the effect of the relaxation of the means spring , the relative angulation of the arm 10 relative to the spar 14, around the pivot connection 13, and consequently the elevation of the intermediate wheel 3b, thus preventing it from hitting the edge of the sidewalk.

Particularly preferably, the obstacle crossing device also includes, on each lateral side and at the rear of the chair 1, an anti-tip wheel 9.

Each of said anti-tip wheels 9 with which the device of the invention is fitted is fixed to the end of the arm 10 which is opposite the end 11 of said arm 10 which comes into contact with the wall 16 of the slide 15.

The anti-tip wheels 9 also allow, when crossing an obstacle such as a sidewalk, from a certain height, temporary support as long as the rear wheel 3c has not come into contact with the sidewalk thus preventing it from hitting the edge of the sidewalk.

The present obstacle crossing device also has, most preferably, a mechanical device for limiting the movement of the arm 10, during the elevation of the seat 23 that the chair 1 comprises. This device for limiting the movement of the arm 10 consists of a mobile stop 22 movable under the action of the elevation of the seat 23.

Such an elevation of the seat 24 is shown in particular on the , which clearly illustrates that said seat 24 is raised compared to the position it occupies in the other figures.

When the chair is moving on ground which is horizontal or substantially horizontal, the weight of the assembly (user, chair, etc.) comes to bear on the intermediate wheel 3b, the three wheels 3a, 3b and 3c are aligned, the The end 11 of the arm 10 presses on the wall 16, causing compression of the spring means(s) 18.

In this configuration, shown in Figures 3 and 4 (the illustrating a view in which the seat of the armchair 1 has been raised relative to the view of the ), the arm 10 carrying, at the rear relative to the pivot connection 13, the motor means 5 and the rear wheel 3c and also, preferably, at its rear end, the anti-tip wheel 9, is aligned, or substantially aligned , with the spar 14.

Still in this configuration, the end 11 of the arm presses on the wall 16 of the slide 15 which, by its movement, compresses the spring means 18, or the spring means 18 if necessary.

When crossing an obstacle, for example when the user of the chair 1 wishes to climb onto a sidewalk, or get off a sidewalk, the weight of the assembly is no longer sufficient to align the wheels 3a, 3b and 3c .

With reference to Figures 5 and 6, the spring 18 then pushes back the wall 16 and the slide 15, causing a pivoting of the arm 10 via the pivot connection 13, and a formation of the angle between the axes 3a', 3b' and 3c' of the three front wheels 3a, intermediate 3b, rear 3c and optimal support on the ground of the front wheel 3a in particular.

When descending a sidewalk, the thrust of the springs 18 prevents the rear wheel 3c from lifting and avoids the risk of the chair tipping forward.

.

Claims (7)

Obstacle crossing device for motorized vehicle consisting of a chassis (2) connected to three wheels (3a, 3b, 3c) on each lateral side of said chassis (2) and motor means (5) capable of rotating said wheels (3a, 3b, 3c) and, on each lateral side of the chassis, there is a mechanism comprising two arms (7a, 7b), articulated in pairs around a common pivot axis (6), on which two arms ( 7a, 7b) the three wheels are distributed, respectively a front wheel (3a), an intermediate wheel (3b) and a rear wheel (3c), said mechanism allowing each wheel to pivot relative to the axis of each adjacent wheel , said device being characterized in that the motor means (5) and the rear wheel (3c) are carried by an arm (10) articulated to the chassis (2) on a spar (14) through a pivot connection (13 ), the end (11) of said arm (10) which extends beyond the pivot connection (13) and on the side opposite to the connection of the motor means (5) cooperating with a slide (15) movable on the spar (14), said pivot connection (13) generating a movement of the front wheel (3a) between two extreme positions, namely a first position (20) in alignment with the two other wheels (3b, 3c) and a second position (21) lowered relative to the alignment of the two other wheels (3b, 3c), said slide (15) comprising a wall (16) perpendicular to the sliding axis while the spar (14) comprises a wall fixed (17) perpendicular to the sliding axis (22), at least one spring means (18) being interposed between said two walls (16,17), while the arm (10) is dimensioned so that its free end ( 11) comes into contact with the wall (16) so as to push back the slide (15) while forcing the spring means (18) against said wall (16), when said front wheel (3a) is in its first position (20). ) aligned with the other two wheels (3b, 3c). Obstacle crossing device for motorized vehicle according to claim 1 characterized in that the support of the arm (10) on the wall (16) of the slide (15) is done through a roller (111) filling the end (11) of said arm (10). Obstacle crossing device for motorized vehicle according to claim 1 or claim 2 characterized in that two spring means (18) are positioned between the walls (16, 17) of the slide (15). Obstacle crossing device for motorized vehicle according to any one of claims 1 to 3 characterized in that the motor means (5) and the rear wheel (3c) are carried by the arm (10) through a connection pivot (19). Obstacle crossing device for motorized vehicle according to any one of claims 1 to 4 characterized in that it further comprises, on each lateral side, an anti-tip roller (9) placed at the rear of the motorized machine and fixed to the first end of said arm (10) opposite the end (11) coming into contact with the wall (16) of the slide (15). Obstacle crossing device for motorized vehicle according to claim 5 characterized in that it comprises a mechanical device for limiting the movement of the arm (10) during the elevation of the seat (23), consisting of a stop (22) movable under the action of the elevation of the seat (23). Obstacle crossing device for motorized vehicle according to any one of claims 1 to 6 characterized in that said chassis (2) being connected to each articulated arm mechanism (7a, 7b) via two shafts (8 , 12) mounted free to rotate, at least one of the two shafts (12) being able to compensate for the variation in distance between these two shafts (8, 12) when the arms are not aligned.