EP4225243A1

EP4225243A1 - Wheelchair of the self-propelled type

Info

Publication number: EP4225243A1
Application number: EP21773666.9A
Authority: EP
Inventors: Giancarlo Bonfiglioli
Original assignee: ACHA Srl
Current assignee: ACHA Srl
Priority date: 2020-10-12
Filing date: 2021-09-22
Publication date: 2023-08-16
Also published as: WO2022079525A1

Abstract

A wheelchair (1a,1b,1c,1d,1e,1f) of the self-propelled type is described comprising: a frame (5), a pair of wheels (10) for resting on the ground each provided with a hub (15) by means of which the wheel is rotatably associated with the frame (5) with respect to an axis of rotation (R), and a drive arrangement (25,30,35,40,45) configured to set said pair of wheels in rotation with respect to the frame and provided with at least one elec-tric motor (25) adapted to supply the motion to the pair of wheels. Where the electric motor (25) is placed entirely at a vertical height greater than a vertical height of the hub (15) of the wheel (10).

Description

WHEELCHAIR OF THE SELF-PROPELLED TYPE

TECHNICAL FIELD

The present invention relates to a wheelchair, in particular of the self-propelled type. PRIOR ART

Self-propelled wheelchairs are generally provided with small motorized wheels, generally between 15cm and 30cm in diameter and one or more motors adapted to supply the motion to said wheels to move the wheelchair forward, which motors are contained in a box-shaped housing which is located below a seat adapted to support a wheelchair user at the bottom.

A problem with said self-propelled wheelchairs lies in the inability to cross streams or bodies of water deeper than a few centimetres, both due to flooding problems of the motors, and due to problems linked to the uneven terrain generally encountered in such places (for example the housing that contains the motors can collide with small obstacles).

The object of the present invention is that of overcoming this limit of the known art within a practical, efficient and low cost solution.

Such object is achieved by the features of the invention indicated in the independent claim. The dependent claims outline preferred and/or particularly advantageous aspects of the invention.

DISCLOSURE OF THE INVENTION

The invention, particularly, makes available a wheelchair of the self-propelled type comprising:

- a frame,

- a pair of wheels for resting on the ground each provided with a hub by means of which the wheel is rotatably associated with the frame with respect to an axis of rotation,

- a drive arrangement configured to set said pair of wheels in rotation with respect to the frame and provided with at least one electric motor adapted to supply the motion to the pair of wheels, wherein the electric motor is placed entirely at a vertical height greater than a vertical height of the wheel hub.

Thanks to this solution, a self-propelled wheelchair is made available which allows the person sitting in the chair to cross streams and bodies of water much deeper than those that can be crossed with known wheelchairs. Furthermore, in this way the wheelchair user can immerse his legs completely or almost completely in the water even in total autonomy, thus allowing people with motor handicaps in the lower limbs greater freedom of movement and action.

According to another aspect of the invention, in order to further improve the manoeuvring freedom of the wheelchair, the electric motor of which can be placed entirely at a vertical height from the ground greater than the maximum vertical height from the ground of the pair of wheels.

In a first embodiment of the drive arrangement, the motion generated by the electric motor is supplied to the wheels by means of a pair of rollers, each pressed in contact with a respective wheel.

In this way the transmission of the motion is particularly simple, light and resistant to salt and sand.

In a second embodiment of the drive arrangement, the drive arrangement can comprise a first pulley fixed to the output shaft of the motor, a second pulley integral in rotation to a wheel of the pair of wheels, and a flexible connecting member adapted to transmit a rotary motion between the first pulley and the second pulley.

In this way the transmission of the motion can take place without uncertainty thanks to the strong connection guaranteed pulleys and flexible connecting member. Furthermore, this solution allows to position the motor at a vertical height greater than in the first embodiment of the drive arrangement, since in said first embodiment the distance of the motor from the wheel affects the diameter of the roller which is pressed on the wheel to set it in rotation, therefore this diameter could become excessively bulky beyond a certain vertical height of the motor. Whereas in the case of the second embodiment of the drive arrangement, the distance has no influence on the size of the first pulley or of the second pulley, thus guaranteeing, always with the same distance, greater compactness and usability of the wheelchair.

Therefore, in this second embodiment, the electric motor can be placed entirely at a vertical height greater than the maximum vertical height of the wheels. For example, it can be placed 20 cm or 30 cm above the maximum vertical height of the wheels.

According to an aspect of the invention, the wheelchair can comprise a roller for resting on the ground associated with the frame and whose longitudinal ends are chamfered. In this way, the wheelchair allows steering operations without uncertainties since the roller thus shaped allows it to crawl on the terrain during steering even on the roughness of the terrain allowing to overcome them. This feature is particularly important because, for example, it allows to overcome the small sand dunes on the beaches. On the contrary, a cylindrical body with flat longitudinal ends during the steering would dig into the sand, making the steering difficult.

According to another aspect of the invention, the longitudinal ends can be truncated conical in shape.

In this way the roller is quick to manufacture.

For example, a portion of the lateral surface of the roller at each end can be inclined between 20° and 40° with respect to a longitudinal axis of the roller.

According to yet another aspect of the invention, the roller can be rotatably associated idle with the frame.

In this way, the force required to the forward movement is reduced because the roller can roll on the surfaces.

According to a further aspect of the invention, the roller can have a maximum diameter, measured along a transverse direction with respect to a longitudinal axis of the roller, of less than half of the diameter of the wheels of the pair of wheels.

In this way the roller does not hinder the access to the seat of the wheelchair by the user. BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will be more apparent after reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the accompanying drawings.

Figure 1 is an orthogonal lateral schematic view of a self-propelled wheelchair according to the invention.

Figure 2 is an orthogonal lateral schematic view of the wheelchair of Figure 1 .

Figure 3 is an orthogonal lateral schematic view of a second embodiment of the self- propelled wheelchair according to the invention.

Figure 4 is an orthogonal lateral schematic view of a third embodiment of the self-propelled wheelchair according to the invention.

Figure 5 is an orthogonal lateral schematic view of a fourth embodiment of the self-propelled wheelchair according to the invention. Figure 6 is an orthogonal lateral schematic view of a fifth embodiment of the self-propelled wheelchair according to the invention.

Figure 7 is an orthogonal lateral schematic view of a sixth embodiment of the self-propelled wheelchair according to the invention.

DETAILED DESCRIPTION

With particular reference to these figures, 1 a,1 b,1 c,1d,1 e,1f generally indicate a wheelchair, in particular of the self-propelled type, i.e. capable of moving independently without the aid of motor power imparted by user of the chair or a companion. For example, the wheelchair can be sized and equipped (with appropriate seats) to carry even more than one person at the same time.

The wheelchair 1 comprises a frame 5, for example tubular, although any other type of frame suitable for the purpose is equivalent.

A seat (not illustrated in the drawings) can be fixed to the frame 5 which has the purpose of supporting the wheelchair user at the bottom, for example this seat can comprise a substantially horizontal cushion which is fixed to the frame 5.

The wheelchair can also comprise a backrest (not illustrated) placed at least partially at a higher level than the seat and shaped so that the wheelchair user can rest his back against it.

The wheelchair 1 comprises at least one pair of wheels 10 for resting on the ground (i.e. which contact the ground while keeping the frame raised therefrom), each of which is provided with a hub 15 by means of which the respective wheel 10 is rotatably associated with the frame 5 with respect to an axis of rotation R.

In particular, the wheels 10 of the pair of wheels 10 are rotatably associated with the frame 5 on opposite sides of the frame thereof. For example, they are rotatably associated with the frame on opposite sides of the frame thereof with respect to a centre plane of the wheelchair which extends from a front area to a rear area of the chair itself.

Furthermore, the axes of rotation R of the wheels 10 are coaxial, i.e. the pair of wheels is rotatably associated with the frame 5 with respect to a single axis of rotation R.

The axis of rotation R preferably lies on a horizontal plane.

However, it is not excluded that the axes of rotation of the wheels 10 may be incident and inclined to each other, as is the case for example in wheelchairs for sports use.

Each wheel 10 comprises a tyre or tire provided with a tread 20 and which is mounted on a rim integral in rotation with the hub 15, for example by means of spokes, although it cannot be excluded that the rim may be made as a solid discoidal body comprising the hub.

At least the portion of tyre or tire in which the tread is present is made of a material with a high coefficient of friction, for example of rubber.

Each wheel 10 has a diameter, measured in a direction perpendicular to the axis of rotation R, at least greater than 40 cm, preferably comprised between 55 cm and 70 cm. The use of large diameter wheels helps in overcoming uneven terrains.

The wheelchair 1 comprises a drive arrangement configured to set said pair of wheels 10 in rotation with respect to the frame 5 in order to selectively move the wheelchair itself forward or backward.

The drive arrangement comprises at least one electric motor 25 fixed to the frame and which supplies the rotary motion, i.e. the driving torque, necessary to set the wheels in rotation in order to selectively move the wheelchair forward or backward. In particular, the electric motor 25 comprises an output shaft by means of which the rotary motion generated by the electric motor thereof is transmitted, i.e. from which output shaft it is possible to withdraw the rotary motion.

The motor comprises a protective casing or housing in which a plurality of windings (or solenoids) are housed and from which the output shaft which is connected to the wheels 10 to transmit the rotary motion comes out.

Preferably, the electric motor 25 is an electric gearmotor, i.e. inside the casing there is also a gear unit, generally with gears, which is placed upstream of the output shaft with respect to the direction of transmission of the rotary motion.

The electric motor 25 can be supplied by an electric supply battery fixed to the frame 5. The figures show six embodiments of the wheelchair, of which those illustrated in figures 1 to 4 are provided with a first embodiment of the drive arrangement and those illustrated in figures 5 to 5 are provided with a second embodiment of the drive arrangement.

In all the embodiments illustrated, the electric motor 25, i.e. the electric gearmotor, is placed entirely at a vertical height from the ground on which the wheels 10 rest that is greater than the vertical height from the ground of the wheel hub, i.e. greater than the vertical height of both hubs of the two wheels 10 (in the embodiment illustrated, since there is a single axis of rotation R, the hubs are at the same vertical height). These heights are to be understood when the wheelchair is located on a horizontal plane.

In greater detail, the electric motor 25 is located entirely at a vertical height from the ground greater than the height of the intersection point between the axis of rotation R and a vertical plane that intersects the ground at a contact area of the wheel with the ground. For example, the electric motor 25 is placed entirely at a vertical height from the ground greater than 3/4 of the diameter of the wheel 10.

More preferably, as is the case in the second embodiment of the drive arrangement, the electric motor 25 is placed entirely at a vertical height from the ground greater than the diameter of the wheel 10.ln detail, the electric motor 25 is placed at least 20cm above the maximum height of the wheel 10. Overall, the motor can therefore be positioned at a vertical distance of about one meter from the ground on which the wheels 10 rest.

In the various embodiments, the output shaft of the electric motor 25 rotates with respect to an eccentric axis of rotation, and for example parallel to the axis of rotation R.

In all the embodiments illustrated there are two electric motors 25 mechanically independent of each other, each configured to set in rotation, i.e. to transmit the driving torque to, a respective wheel 10 of the pair of wheels 10.

In this way, it is particularly simple to impart a steering command to the wheelchair.

However, it is not excluded that in embodiments not illustrated, there may be a single motor connected to the wheels, a mechanism capable of transmitting the rotary motion to the wheels, i.e., the driving torque, and provided with at least one pair of brakes or clutches that can be selectively driven to reduce the rotary motion, i.e. the driving torque, to one of the two wheels 10 to make the wheel 10 that is closer to the centre of the turning radius rotate at a lower speed than the outer wheel and provided with at least one electric motor adapted to supply the motion to the pair of wheels. This mechanism is not further described as it is known to those skilled in the art.

The motors are both positioned above the vertical heights described above.

In the embodiment of the drive arrangement illustrated in Figures 1 -4, the drive arrangement of the wheelchair 1 a,1 b,1 c comprises a pair of rollers 30 which receive the motion from the electric motor 25, and in which each of said rollers is pressed in contact with a respective wheel 10, possibly with the aid of an elastic element.

In particular, each roller is pressed in contact with the tread 20 of the respective wheel 10. At least in the portion that contacts the wheel, the roller has a layer of material with a high coefficient of friction, for example of rubber.

In the preferred embodiment, these rollers 30 receive the rotary motion, i.e. the driving torque, from a respective electric motor, or electric gearmotor, 25. For example, each roller can be keyed to the output shaft of the respective electric motor, or electric gearmotor 25. In this embodiment of the drive arrangement, the electric motor 25 is placed in a position in which it is located at least partially at a vertical height from the ground comprised between three quarters of the wheel diameter and the entire wheel diameter. However, it is not excluded that the electric motor could be located entirely at a height greater than the maximum height of the wheel.

In the embodiment of the drive arrangement illustrated in Figures 5-7, the electric motor of the wheelchair 1 d, 1 e, 1 f is placed entirely at a vertical height greater than the maximum vertical height of the wheels, for example at least 20 cm or 30 cm above said maximum height, and the drive arrangement comprises a first pulley 35 connected, for example keyed, to the output shaft of the electric motor 25, a second pulley 40 integral in rotation with a wheel 10 of the pair of wheels with respect to the axis of rotation R, and a flexible connecting member 45 at least partially wound on said pulleys to transmit the motion from the first pulley 35 to the second pulley 40.

In particular, the drive arrangement comprises a pair of first pulleys 35 connected to a respective electric motor 25, i.e. to the output shaft thereof, a pair of respective second pulleys 40, each integral in rotation with respect to the axis of rotation R to a respective wheel 10, and a pair of flexible connecting members 45 which connect a first pulley to the respective second pulley.

Preferably, for a slip-free transmission of motion, the flexible connecting member 45 is a chain and the pulleys 35,40 are provided with an external toothing, i.e. they are shaped like toothed wheels with external toothing, which mesh with the links of chain.

It is not excluded that even in this second embodiment, although it has not been illustrated, the motor, i.e. the motors, could also be located only at a vertical height from the ground greater than the vertical height of the hub.

In order to rest stably on the ground, the wheelchair 1 a,1 b,1 c,1 d,1 e,1 f also comprises another element for resting on the ground in addition to the pair of wheels 10.

Preferably, this element for resting on the ground comprises, i.e. is constituted by, a roller for resting on the ground 50 associated with the frame, for example rotatably associated idle with the frame with respect to an axis of rotation K, preferably lying on a horizontal plane, for example parallel to the axis of rotation R. In the illustrated embodiment, this rotation with respect to the axis K is the only degree of freedom of the roller 50 with respect to the frame. However, it is not excluded that the roller could also be tilting with respect to a horizontal axis perpendicular to the K axis.

The roller has an elongated shape along a longitudinal axis and is arranged with a longitudinal axis parallel to the axis of rotation K.

Under normal conditions of use, the roller 50 contacts the ground.

In the preferred embodiment the roller is idle, however it is not excluded that it can be motorized and rotated by a suitable mechanism.

This roller has (only) two opposite longitudinal ends of chamfered shape, i.e. at least at the opposite longitudinal ends the area of a cross section of the roller (identified by the intersection of the roller with an imaginary section plane perpendicular to the longitudinal axis) gradually decreases with respect to the area of a cross section of a central portion of the roller.

This chamfer, i.e. the portion in which the cross-sectional area gradually decreases, has a length equal to or greater than 5 cm measured along a direction parallel to the longitudinal axis of the roller 5, i.e. parallel to the axis of rotation K. It is not excluded that from a plane of central symmetry perpendicular to the longitudinal axis of the roller, the roller always has a decreasing section area running from this plane to the respective longitudinal ends.

At the point where the cross section of a longitudinal end is smaller, it has an area of less than at least 3/4 of the cross section of a central portion of the roller.

Said longitudinal ends, i.e. the chamfers, truncated conical in shape, i.e. at least at the longitudinal ends the roller 50 comprises respective outer surfaces that are truncated conical in shape.

For the avoidance of doubt, it should be noted that these surfaces have a greater circumference in their portion that is closer to the central portion of the roller.

For example, these conical surfaces are inclined at an angle comprised between 20° and 30° with respect to the longitudinal axis of the roller.

In the illustrated embodiment, the roller comprises a cylindrical central portion from which the two truncated conical surfaces present at the longitudinal ends extend in the distancing direction.

In a less preferred embodiment, not illustrated, the longitudinal ends could each be shaped like a hemisphere.

The roller, at least in the central portion thereof, i.e. the cylindrical one, has a diameter of less than half of the diameter of the wheel 10.

The roller 50 can be rigid, i.e. not deformable in bending or twisting or crushing under the normal work loads to which it is subjected when the wheelchair is used. For example, the roller can be made of plastic.

In all the embodiments illustrated, the wheelchair rests on the ground solely by means of the wheels 10 and the roller 50.

The roller 50 for resting on the ground can be positioned both in front and behind the pair of wheels 10 with respect to the normal forward direction of the wheelchair.

It is not excluded that, in a less preferred and not illustrated embodiment, the other element for resting on the ground may comprise a pair of wheels, for example of smaller diameter than the pair of wheels 10-That is, in an embodiment not illustrated, the wheelchair does not comprise the roller 50, but is in any case provided with the drive arrangement of the wheels as described above.

With particular reference to Figures 3 and 6, in addition to the roller 50, when the roller 50 is placed in front of the pair of wheels 10, the wheelchair can comprise a further roller 55 associated with the frame, for example rotatably associated with it in an idle manner, and positioned behind the pair of wheels 10.

In particular, it is rotatably associated with the frame according to an axis of rotation parallel to the axis of rotation R.

The further roller 55 is positioned so as not to touch the ground when the wheelchair is located on a flat, horizontal surface. In practice, when the chair touches the ground by means of the pair of wheels 10 and the roller 50, the roller 55 is raised from the ground.

In this way, the further roller 55 offers a backward anti-tipping function for the wheelchair, without hindering the forward movement under normal conditions.

The wheelchair described herein is available in different embodiments which combine differently the described features.

Figures 1 and 2 illustrates a first embodiment of the wheelchair indicated with 1 a and which differs in particular from the other embodiments in that the drive arrangement comprises the rollers 30 and in that the roller 50 is positioned in front of the pair of wheels 10. Figure 3 illustrates a second embodiment of the wheelchair indicated with 1 b, which has the same characteristics as the embodiment indicated with 1 a and which in addition is provided with the further roller 55.

Figure 4 illustrates a third embodiment of the wheelchair indicated with 1 c, which has the same characteristics as the embodiment indicated with 1 a except for the fact that in the form of action 1 c the roller 50 is placed behind the pair of wheels 10 instead of at the front as in 1 a.

Figure 5 illustrates a fourth embodiment of the wheelchair indicated with 1 d, which has the same characteristics as the embodiment indicated with 1 a except for the fact that in the form of action 1 d the drive arrangement is the one of the second embodiment of the drive arrangement, i.e. the drive arrangement in place of the roller that contacts the wheel comprises the pulleys connected by the flexible connecting member.

Figure 6 illustrates a fifth embodiment of the wheelchair indicated with 1 e, which has the same characteristics as the embodiment indicated with 1 d and which in addition is provided with the further roller 55.

Figure 7 illustrates a sixth embodiment of the wheelchair indicated with 1f, which has the same characteristics as the embodiment indicated with 1 d except for the fact that in the form of action 1 f the roller 50 is placed behind the pair of wheels 10 instead of front as in 1d.

The operation of the wheelchair according to the invention is as follows.

To drive forward or backward or forward/backward simultaneously with the steering, the wheels 10 are selectively or simultaneously set in rotation by means of the driving torque generated by the electric motor 25, i.e. by the two electric motors 25, which being located at a high height compared to known wheelchairs, are protected from water, thus allowing them to tackle streams or bodies of water of considerable depth.

Furthermore, under the particular steering condition, the roller 55 crawls and rotates on the terrain, and therefore on the roughness present, such as for example small sand dunes, guaranteeing steering without uncertainty.

The invention thus conceived is susceptible to several modifications and variations, all falling within the scope of the inventive concept. Moreover, all the details can be replaced by other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and sizes, can be whatever according to the requirements without for this reason departing from the scope of protection of the following claims.

Claims

1. A wheelchair (1 a,1 b,1 c,1 d,1 e,1 f) of the self-propelled type comprising:

- a frame (5),

- a pair of wheels (10) for resting on the ground each provided with a hub (15) by means of which the wheel is rotatably associated with the frame (5) with respect to an axis of rotation (R), and

- a drive arrangement (25,30,35,40,45) configured to set said pair of wheels in rotation with respect to the frame and provided with at least one electric motor (25) adapted to supply the motion to the pair of wheels, wherein the electric motor (25) is placed entirely at a vertical height greater than a vertical height of the hub (15) of the wheel (10).

2. The wheelchair (1 d, 1 e,1 f) according to claim 1 , wherein the electric motor is placed entirely at a vertical height from the ground greater than the maximum vertical height from the ground of the pair of wheels.

3. The wheelchair (1 a,1 b,1 c) according to any one of the preceding claims, wherein the motion generated by the electric motor (25) is supplied to the wheels (10) by means of a pair of rollers (30), each pressed in contact with a respective wheel (10).

4. The wheelchair (1 d,1 e,1 f) according to claim 1 or 2, wherein the drive arrangement comprises a first pulley (35) fixed to an output shaft of the motor, a second pulley (40) integral in rotation with a wheel (10) of the pair of wheels (10), and a flexible connecting member (45) adapted to transmit a rotary motion between the first pulley and the second pulley.

5. The wheelchair (1 a,1 b,1 c,1 d,1 e,1 f) according to any one of the preceding claims, comprising a roller (50) for resting on the ground associated with the frame (5) and whose longitudinal ends are chamfered.

6. The wheelchair (1 a,1 b,1 c,1 d,1 e,1 f) according to claim 5, wherein the longitudinal ends of the roller (50) are truncated conical in shape.

7. The wheelchair (1 a,1 b,1 c,1 d,1 e,1 f) according to claim 6, wherein a lateral surface of the roller (50) at the longitudinal ends is inclined between 20° and 40° with respect to a longitudinal axis of the roller thereof.

8. The wheelchair (1 a,1 b,1 c,1 d,1 e,1 f) according to claim 5, wherein the roller (50) is rotatably associated idle with the frame (5).

9. The wheelchair (1 a,1 b,1 c,1 d,1 e,1 f) according to claim 5, wherein the roller (50) has a maximum diameter, measured along a transverse direction with respect to a longitudinal axis of the roller thereof, of less than half of the diameter of the wheels (10) of the pair of wheels (10).