WO2016181173A1

WO2016181173A1 - Motorized standing wheelchair of variable and alternating geometry

Info

Publication number: WO2016181173A1
Application number: PCT/GR2016/000017
Authority: WO
Inventors: Dimitrios PETROTOS; Marios-Ermis PETROTOS
Original assignee: Petrotos Dimitrios; Petrotos Marios-Ermis
Priority date: 2015-05-11
Filing date: 2016-04-26
Publication date: 2016-11-17
Also published as: GR20150100202A

Abstract

Motorized standing wheelchair of variable and alternating geometry, which is comprised by an articulated chassis (1, 2, 3), two pairs of wheels (12, 13) and an integrated seating and fastening arrangement (17, 18, 19, 20, 21) for the user. The wheelchair is characterized mainly by the ability of alternation of its geometry via the appropriate rotation of the drive wheels (12, 13). The wheelchair provides the user, who is fastened to it, with the ability of selecting the desired posture between the sitting position, the standing position and all the positions in-between without additional complex mechanisms. Furthermore, the user can operate, control and steer the wheelchair in the entire range of its geometry variation, independently of the assumed posture.

Description

Motorized standing wheelchair of variable and alternating geometry

The present invention refers to a motorized standing wheelchair of variable and alternating geometry.

Wheelchair is a chair with wheels or a more complex vehicle, which is intended to be used by individuals who cannot walk, permanently or temporarily, due to illness, injury or disability.

Depending on their source of power, wheelchairs are distinguished in manual wheelchairs and motorized wheelchairs. In the first category either an accompanying person, the escort, pushes the wheelchair or users themselves put in motion the wheels of their chair with the muscular power of their hands and torso. On the other hand, in the second category the wheelchairs are equipped with a number of electric motors that propel the wheels.

Motorized wheelchairs have various advantages over manual wheelchairs mainly because users do not need an accompanying person for their mobility and if they are capable to propel the wheelchair by themselves, they do not need to waste their energy. However, motorized wheelchairs are often voluminous, complex and heavy devices, demanding rather high amounts of electric power to set in motion their usually small-diameter wheels. They also lack the ability of manoeuvring in restricted places or in places where even the slightest obstacle renders their passage impossible. Wheelchair technical evolution does not take the actual conditions of public places into account and as a result, wheelchairs do not meet their users' expectations and requirements. Only a few of the existing wheelchairs, which are retrofitted with electric motors and have been converted from manual to motorized, while being light and agile, they maintain the disadvantages of their initial design, requiring a series of acrobatics by the users in order to overcome the slightest architectural barrier. Apart from the diversification, in terms of the way of propulsion, wheelchairs are categorized in those where users remain permanently anchored to the wheelchair seat and in those where users are able to change the level of their position or even the entire geometry of their posture.

The second category, in particular the one where the disabled user is able to set himself in virtually upright position, as recommended mainly by the findings of different brunches of the medical science for the sake of which standing position originally evolved, provides a series of health benefits. These benefits are quantitative and measurable, such as the enhancement of bone density but also, such wheelchairs, grant the user with benefits that are qualitative such as the emotional satisfaction to be standing among other standing persons.

However, the state of the prior art, although modern, has many disadvantages that restrict the already limited wheelchair user. Many standing wheelchairs, despite the fact that they bring the users to a virtually standing or upright position they achieve it manually and in such a way that even neurologically intact persons struggle to achieve.

In many other standing wheelchairs, from the moment the users choose to stand up, they cease to be able to move around and the wheelchairs are converted into simple verticalization devices until the users return to the seating position, when the wheelchair retrieves its use as a wheelchair. In the majority of standing wheelchairs, users must choose either to stay seated or to stand up; they cannot choose an intermediate posture that serves them best.

Only a few standing wheelchairs are able to elevate their occupants almost upright and still provide the ability to move and be manoeuvred though that is achieved by a variety of additional and complex electromechanical components that are energy hungry and require intensive maintenance by qualified technicians. They are heavy, lacking the ability to overcome even relatively small architectural barriers and they have high acquisition costs.

The existing art provides solutions in only some and selective problems that concern the disabled users. It does not satisfy totally and simultaneously all the requirements of disabled users such as low purchase price, easy and economic maintenance, low weight of the wheelchair, low energy consumption and ability to overcome small architectural barriers. Furthermore, the existing wheelchairs do not provide users with the ability to easily adjust their posture between the seated and the upright position, including all the in-between positions, and simultaneously be able to move, control and steer their wheelchair without the use of additional electromechanical components.

According to one embodiment, the present invention refers to a motorized standing wheelchair of variable and alternating geometry that may consist of an articulated chassis made of light metal alloy, four electric powered wheels, integrated seating arrangement where a user can sit fastened in a suitable way. The wheelchair has four wheels independently powered, arranged in pairs at the extremities of the chassis, one pair of wheels in the front and one pair of wheels in the back. Each wheel incorporates an independent electric motor in the corresponding hub. The alteration of the wheelchair chassis geometry is achieved by the opposite relative motion of the two opposing pairs of wheels.

When the pair of the front wheels rotates in reverse and at the same time, the pair of the rear wheels rotates forward, the articulated chassis of the wheelchair changes its geometry and thus alters the posture of the user from the sitting position to the standing position. Gas springs, which can be locked, assist this movement. On the contrary, when the pair of the front wheels rotates forward and at the same time the pair of the rear wheels rotates in reverse, the articulated chassis of the wheelchair changes its geometry, assisted by the gravitational force of the mass of the user and thus the user returns to the sitting position.

The chassis and the seating arrangement of the wheelchair are constructed in such way that can support all the variations of the body posture of the user between the sitting position, the standing position and all the positions in between. The user can select the desired posture, by changing at will the geometry of the chassis of the wheelchair between the sitting and the standing position and all the in-between positions, locking each time the desired geometry by means of a pair of lockable gas springs. These springs are arranged in such way that can also be used as shock absorbers providing at the same time also a level of comfort. At any time, the user is able to move and manoeuvre the wheelchair either from the sitting position or from the standing position or from any of the in-between positions since the wheelchair is always able to be operated independently of the posture of the user.

The way the wheelchair is propelled and controlled is achieved by the appropriate motion of the wheels. The wheels are equipped with independent motors in their hubs that are interconnected in pairs. One pair is positioned in the front and one pair is positioned in the back. For this reason, the wheelchair can be operated even with only one pair active at a time while the other pair remains inactive. When more power and speed or more precise control is required, the wheelchair can be propelled and controlled by all four wheels at the same time. The control of movement and steering of the wheelchair is achieved by using two independent multidirectional programmable controllers, placed in the proximity of the hands of the user, each interconnected with the corresponding pair of wheels. The diameter of the wheels of the front pair is substantially larger than the diameter of the wheels of the rear pair. This arrangement provides the wheelchair with the ability to overcome small architectural barriers.

The front wheels, due to their larger diameter, are capable to overcome the obstacle while at the same time the rear wheels provide the necessary push at the moment that the front set of wheels is on the edge of the obstacle. Subsequently, the front wheels, after having passed the obstacle, pull the wheelchair so that the rear wheels climb the obstacle as well.

The motorized standing wheelchair of variable and alternating geometry, as it is described in the present invention, has a series of advantages. Because of the fact that the wheelchair is able to alter its geometry by using the opposite relative motion of the wheels, it does not require a series of additional components that are used in existing products according to the prior art. Based on its construction, the wheelchair provides the users with the ability to select their posture at will, between a wide range of postures many of which are recommended by the medical science in order for them to maintain their health. Furthermore, a key advantage of the invention, as opposed to the prior art, is that the wheelchair remains operational while its user is at the upright position or any of the intermediate positions between the standing position and the sitting position. For all these functions, low energy consumption is required, resulting in the installation of low-volume and low-mass electric energy storage cells. Another fundamental advantage of the invention is the ability of the wheelchair to overcome small architectural barriers, thanks to the arrangement and the relative sizes of the wheels of the wheelchair and thanks to its light total weight in contrast to the majority of standing wheelchairs that already exist according to the prior art. The simple and robust construction of the wheelchair, other than the fact that it does not need complex and high cost maintenance, turns it into a cost efficient option for the average user with motor disabilities.

The present invention can be fully understood through the following detailed description in combination with the attached drawings in which a longitudinal section of one embodiment of the motorized standing wheelchair of variable and alternating geometry is represented. Each figure depicts the same longitudinal section in a distinctly different geometry. On figure 1 the wheelchair is represented in the lowest position; the sitting position. On figure 2 the wheelchair is represented in the highest position; the standing position. The motorized standing wheelchair of variable and alternating geometry is absolutely symmetrical in respect to the vertical plane to the ground that passes from the middle of the wheelchair to the axis of motion.

On both figures, all the parts of the left side of the wheelchair are represented and due to absolute symmetry, the right side of the wheelchair is composed of the exact same parts. For the economy of the description, an analysis of the left half of the wheelchair follows.

On figure 1, the wheelchair is represented in the sitting position. The wheelchair is composed of four main parts: a) the chassis, b) the wheels, c) the seating and fastening arrangement of the user and d) the electric energy storage cells and the motion and steering control unit.

The chassis of the wheelchair is articulated and composed of three main parts. The anterior part (1), the posterior part (2) and the upper part (3). The parts of the chassis are interconnected between them at joints (4, 5). The chassis of the wheelchair is completed by one gas spring (6), which is suspended from the upper part (3) using the axle (7) and connected to the posterior part (2) using the axle (8) and one lockable gas spring (9) with valve trigger, which is suspended from the anterior part (1) using the axle (10) and connected to the posterior part (2) using the axle (11).

The wheels of the wheelchair are of two sizes. The larger wheel (12) is the front wheel and the smaller wheel (13) is the rear wheel. Each wheel incorporates an integrated independent electric motor (14), which is complete with electronic control units. Each motor is able to rotate in both directions and with variable number of revolutions per time unit. The axles of the motors are equipped with quick release pins (15, 16) which can be attached to corresponding hubs at the anterior and posterior parts (1, 2) of the chassis of the wheelchair.

The seating and fastening arrangement is composed of a backrest (17), a seat post (18), a thoracic support arm (19) which is adjustable, a knee support arm (20) which is also adjustable, a footrest (21), a swiss seat three-point harness and a thigh belt. On figure 1, the thoracic and knee support arms (19, 20) are represented as adjusted in position for the entry of the user to the wheelchair. On figure 2, the thoracic and knee support arms (19, 20) are represented as adjusted in position for the actual support of the user on the wheelchair. The electric energy storage cells are arranged in groups and positioned in the cavities of the anterior part (1) and posterior part (2). The multidirectional programmable controller (22) of motion and steering is placed within the reach of the user's hand. It comprises the brakes of the wheels and the valve trigger of the lockable gas spring (6). The above-described left half side of the wheelchair is connected with the other half, the right side, via five transversal beams (23, 24, 25, 26, On figure 2, the wheelchair is represented at the standing position. The alternation of the geometry from the lowest position, as represented in figure 1, to the highest position, as represented in figure 2, is achieved by the opposite relative motion of the wheels (12, 13) through commands from the multidirectional programmable controller (22). Each multidirectional programmable controller (22) activates one of the two pairs of wheels respectively, the front wheels (12) and the rear wheels (13).

The reverse rotation of the front wheels (12), in relation with the forward rotation of the rear wheels (13), force the anterior part (1) and the posterior part (2) to rotate around the axle (4). Following this rotation, the axles of suspension of the wheels (15, 16) converge. This convergence results in the decrease of the angle δ,4,β that the anterior part (1) forms with the posterior part (2) and thus in the elevation of the axis of rotation (4) since both the anterior and posterior parts (1, 2) are of certain length. The result of this motion is the increase of the angle δΑβ that the anterior part (1) forms with the horizontal y and therefore the posture of the user changes from sitting to standing. Simultaneously, the axis of rotation (5) of the upper part (3) is being elevated as well and thanks to the support of the gas spring (6) the upper part (3) always remains in the vertical position. At this point, the user through the activation of the valve of the lockable gas spring (9) can stabilize the size of the gas spring (9) and the geometry of the chassis of the wheelchair can be locked without the need of additional power provided from the wheels.

Alternatively, the alteration of the geometry can be achieved by immobilizing the rear pair of wheels (13) with the brakes and at the same time by the reverse rotation of the front pair of wheels (12). The same result of geometry alteration can be achieved by immobilizing the front pair of wheels (12) with the brakes and at the same time by the forward rotation of the rear pair of wheels (13). In order for the user to return to the sitting position or an intermediate one, they can activate the valve of the lockable gas spring (9) and due to the lack of support from the gas spring, which decreases in length, the chassis of the wheelchair follows the reverse movement of geometry variation from the one described for the elevation.

The energy required for this change is provided mainly from the gravitational potential energy of the user body in the upright position. During the alternation of the geometry of the chassis of the wheelchair both from the sitting to the standing position and from the standing to the sitting position, the user can activate the valve of the lockable gas spring (9) and stabilize its dimension at any point in the range of the lockable gas spring length. In this way, the user can assume any posture that the alternating geometry of the chassis of the wheelchair supports.

Motion control and steering of the wheelchair is achieved by the revolutions of the wheels (12, 13) activating the motors (14) accordingly through the multidirectional programmable controllers (22).

The wheelchair can be controlled either by using only the front pair of wheels (12) or by using only the rear pair of wheels (13) or by using both pairs of wheels (12, 13) at the same time, depending on the user requirements.

Claims

1. Motorized standing wheelchair of variable and alternating geometry characterized by the ability of alternation of its geometry via the opposite relative rotation of the two pairs of wheels (12, 13) or via the immobilization of one of the two pairs of wheels (12 or 13) and the appropriate rotation of the other pair of wheels (13 or 12), resulting in the alteration of the posture of the user fastened to the wheelchair.

2. Motorized standing wheelchair of variable and alternating geometry that according to claim 1 is characterized by the ability of the user to assume any desired posture within the entire range of the geometry variation of the wheelchair.

3. Motorized standing wheelchair of variable and alternating geometry that according to claim 1 is characterized by the ability of the user to control, steer and manoeuvre the wheelchair from any posture assumed within the entire range of the geometry variation of the wheelchair.

4. Motorized standing wheelchair of variable and alternating geometry that according to claim 1 is characterized by front wheels (12) significantly larger in diameter compared to the rear wheels (13) of the wheelchair.