EP2438895B1

EP2438895B1 - An orthopedic wheelchair with articulated frame for disabled users

Info

Publication number: EP2438895B1
Application number: EP11182983.4A
Authority: EP
Inventors: Alessandro Cerioni
Original assignee: Centro Ortopedico Marchigiano Srl
Current assignee: Centro Ortopedico Marchigiano Srl
Priority date: 2010-10-06
Filing date: 2011-09-27
Publication date: 2013-05-08
Anticipated expiration: 2031-09-27
Also published as: EP2438895A1; ES2424741T3; IT1401784B1; ITAN20100172A1

Description

The present patent application for industrial invention relates to an orthopedic wheelchair for disabled with articulated frame.
Current models of superlight wheelchairs can be divided into two large groups: folding wheelchairs and rigid wheelchairs.
Although folding wheelchairs are easier to transport for the assistant, they are heavier mainly because of the folding mechanism. Another severe drawback consists in lower rigidity that. In addition to weight, considerably affects the pushing movement, requiring a higher effort from the disabled user.
It must be noted that the majority of folding wheelchairs are provided with collapsible back that can be disposed above the seat, making a rotation of approximately 90°, and are also provided with articulation device to fold footrests by approximately 90° and/or front wheels under the seat.
When said articulation devices are also used to actuate the front wheels, the front wheels can only have two positions designed by the manufacturer, the first being a (non-operating) position with minimum volume and the second being an operating position.
Likewise, rigid wheelchairs can be divided into two types: "fixed" and "adjustable".
The so-called "fixed" wheelchairs are made to measure for the user and are characterized by better performance in terms of weight and rigidity, although they cannot modify their structure.
Instead, the so-called "adjustable" wheelchairs are provided with adjustment options, which must be carried out in authorized centers either before delivery or afterwards, if modification is necessary. These adjustments cannot be made by the user when using the wheelchair.
Among the various adjustment options of the wheelchair defining the user's position, one important option consists in adjusting the angle between knee and footrest (angle α), given the fact that both the longitudinal volume of the wheelchair and the blood circulation of the user's lower limbs depend on this parameter.
With the current models of wheelchairs the value of this angle must be chosen upon placing the order and cannot be changed afterwards, forcing the user to choose one of the two solutions according to the priority given either to compact volume of wheelchair or physiological improvement of user.
DE10228287 , US2001/008335 and W02007/099565 disclose a folding wheelchair for disabled comprising: a front frame and a rear frame articulated by means of a device, in such way to mutually fold two frames in non-operating position with minimum volume. Therefore, said wheelchairs are not adjustable during operation, being only able to have two positions: an operating position and a non-operating position with minimum volume. US2007/029857 discloses an orthopedic wheelchair of adjustable type. Said wheelchair comprises a back, a seat and a footrest that are mutually articulated to allow for ergonomic adjustment that can easily adapted to the patient's needs. However, the frame connected to the front and back wheels of wheelchair is a fixed (not articulated) block. Therefore, such a wheelchair is very bulky when not used.
The purpose of the present invention is to provide a wheelchair that is especially light and is adapted to change the distance between front and back wheels in such way to change the center of gravity of wheelchair along a horizontal axis, allowing wheelchair to have multiple operating positions rapidly and simply.
Another purpose of the present invention is to provide a wheelchair that, in addition to achieving the aforementioned purpose, can change the position of seat with respect to frame, in such way to change the center of gravity of seat, and consequently of wheelchair, both along horizontal and vertical axis.
Another purpose of the present invention is to provide a wheelchair that allows the user, who is sitting on it, to adjust position rapidly and autonomously while remaining comfortably seated on wheelchair.
These and other purposes have been achieved by the wheelchair of invention, as illustrated and claimed in first independent claim.
The peculiarity of wheelchair according to the invention is that it is provided with articulated frame, comprising:

a rear half-frame,
a front half-frame, and
an articulation and locking device connecting two half-frames, in such way to change inclination of front half-frame with respect to sliding plane of wheelchair and to lock in position the front half-frame so that wheelchair can have various operating positions.

Therefore, the user can change the geometry of frame as desired, in such way that wheelchair can have different cycling features according to operating position of the front half-frame.
For illustrative reasons the description of wheelchair according to present invention continues with reference to the attached drawings, which only have illustrative, not limiting value, wherein:

Figure 1 is an axonometric view of wheelchair according to present invention, with front frame inclined by 90° with respect to seat in horizontal position;
Figure 2 is an axonometric view of wheelchair according to present invention, with front frame inclined by 75° with respect to seat in horizontal position;
Figure 3 is a side view of wheelchair of Fig. 1 sectioned along longitudinal axis of wheelchair;
Figure 4 is a side view of wheelchair of Fig. 2, sectioned along longitudinal axis of wheelchair;
Figure 5 is a diagrammatic side view of wheelchair according to invention;
Figures 6, 7 and 8 are three axonometric views, the last one being an exploded view, of the articulation and locking device disposed between rear half-frame and front half-frame.
Figure 9 is an axonometric view of wheelchair according to invention, showing structure of articulated frame.

Referring to Fig. 5, wheelchair of invention is provided with articulated frame (T) comprising a first rear half-frame (1) and a second front half-frame (2), respectively connected to a pair of back pushing wheels (3) and a pair of front swiveling wheels (4). The first rear half-frame (1) is pivoted to said second front half-frame (2).
The second front half-frame (2) also supports a pair of footrests (5) (only shown in Fig. 5 and omitted in Figs. 1, 2, 3 and 4 for better understanding of attached drawings) where the disabled user can rest his or her feet when sitting on wheelchair. The footrest (5) can vertically translate in the direction of arrows (E) and rotate in the direction of the arrow (F).
The peculiarity of the wheelchair of the invention is that it is provided with said articulated frame (T), which allows the pair of half-frames (1, 2) to have different positions, changing inclination of front half-frame (2) with respect to sliding plane (P) of wheelchair. So, the wheelchair can have different operating positions.
Referring to Fig. 5, the front half-frame (2) has a substantially tubular shape and a longitudinal axis (Z). An angle (α) is subtended between longitudinal axis (Z) of said front half-frame (2) and direction (X) parallel to sliding plane (P) of wheelchair and passing through pivoting point of two half-frames. When said angle (α) is 90°, the center of gravity of wheelchair has maximum height with respect to sliding plane (P) and the distance between front and back wheels of wheelchair is minimum, as shown in figs. 1 and 3. When angle (α) decreases, the height of center of gravity of wheelchair decreases and distance between wheels increases.
Figures 2 and 4 show the position of wheelchair when said angle (α) is 75°. Therefore the height of center of gravity of wheelchair from sliding plane (P) is lower than height of center of gravity of wheelchair in Figures 1 and 2, whereas distance between wheels of wheelchair in Figs. 2 and 4 is longer than distance between wheels of wheelchair in Fig. 1 and 3.
The wheelchair of invention also comprises a preferably shock-absorbing seat (S) composed of seat (6) and vertically sliding back (7). Back is hinged to seat and adapted to rotate with respect to seat in the direction of arrow (A).
Said seat (S) is supported by rear half-frame (1) with means (8, 9, 10, 11) that allow it to move both along a substantially horizontal plane and a substantially vertical plane.
Referring to Fig. 5, said means (8, 9, 10, 11) comprise horizontal displacement means (8, 9) that allow for displacement of seat (S) along a substantially horizontal direction (direction of arrows B) and vertical displacement means (10, 11) that allow for displacement of seat (S) along a substantially vertical direction (direction of arrows D).
Said horizontal displacement means (8, 9) consist in a pair of guide tracks (8) fixed to rear frame where a pair of sliding blocks (9) slides, being fixed in lower position to seat (6) of seat (S).
Therefore seat (S) can make forward or backward travels with respect to articulated frame (T) of wheelchair, and then stop in desired position, being locked in place with locking means of sliding movement of seat- which are not shown in attached figures for graphic simplification purposes - provided in wheelchair of invention.
Said vertical displacement means (10, 11) consist in hinge (10) and piston (11), preferably of shock-absorbing type, connecting seat (S) and rear half-frame (1). More precisely, hinge (10) makes seat (S) oscillate with respect to a point of rear half-frame (1) and alternate travels of piston (11) make seat (S) oscillate upwards or downwards. Specifically, said hinge (10) and piston (11) connect rear half-frame (1) to pair of guide tracks (8) above which seat (S) slides. In view of the above, said wheelchair allows the user to change position of both articulated frame (T) and seat (S).
The wheelchair of invention is provided with advantages unknown in the prior art, given the fact that the adjustments that can be made by the disabled user when sitting on wheelchair make it possible to change position during the day according to the specific situation.
For example, in narrow or rough places, or in reduced spaces such as bathrooms and lifts, or when practicing sports, a very compacted position of wheelchair will be necessary, with practically vertical back, seat pulled-back and low in the back and footrest folded backwards, in order to reduce volume and ensure higher stability.
However, compact position creates physiological problems over time, because it does not help blood circulation in lower limbs and increases contact pressure on pelvis and, in particular, ischia and sacrum, favoring onset of decubitus ulcer.
Therefore, for the disabled user it is preferable to sit in extended position as soon as possible (at home, in office) with adjustments opposite to the aforementioned ones, which favor a physiologically correct position.
Other possible adjustments with relevant benefits are: inclination of back to favor circulation, backward displacement to increase blood flow and dynamism.
Moreover, it must be noted that, by reducing the height of seat in the back, the wheelchair has a stable dynamic position, whereas by increasing the height of seat the load will be uniformly distributed between buttocks and legs, avoiding severe pressure in points with higher risk of decubitus ulcer. Being the front wheels of wheelchair of the invention interchangeable, it is possible to mount plugged wheels or wheels with wider diameter, while maintaining the stability of wheelchair unchanged, by simply increasing the value of angle (α).
Referring to Fig. 9, the rear half-frame (1) has a T-shaped tubular configuration comprising a central longitudinal arm (14) and a back transversal arm (12). The transversal arm (12) is provided with two ends (13) where the two back wheels (3) are rotatably fixed, whereas the longitudinal arm (14) is disposed centrally with respect to seat (S) and supports it with vertical displacement means (10, 11).
The longitudinal arm (14) has front end (15) provided with articulation and locking device (16) between rear half-frame (1) and front half-frame (2). So, front half-frame (2) can rotate with respect to rear half-frame (1) in direction of arrow (C), as shown in Fig. 5.
Said front half-frame (2) consists in a single central leg (20) with upper end (17) and lower end (18). Upper end (17) of central leg is connected to articulation device (16); whereas, in correspondence of lower end (18), said central leg (20) supports the pair of footrests (5) and the pair of front wheels (4).
Given the fact that front wheels (4) are swiveling wheels (as in most of wheelchairs), further to a variation of angle (α) of front half-frame (2), wheels (4) must be easily replaced in correct position.
Figs. 3, 4 and 5 are diagrammatic views of swiveling wheels (4), which are supported by the front half-frame (2), with interposition of adjustment means (59) that allow said wheels (4) to change value by angle (β). Said angle (β) is the angle between longitudinal axis (A) of front half-frame (2) and direction (Y) parallel to sliding plane (P) of wheelchair.
The correct operation of wheelchair provides for value of angle (α) to be identical to value of angle (β).
The articulation and locking device (16) between rear half-frame (1) and front half-frame (2) is shown in detail in Figures 6, 7 and 8, and allows front half-frame (2) to have at least two operating positions, wherein angle (α), subtended between longitudinal axis of front half-frame (2) and direction (X) parallel to sliding plane of wheelchair has values lower than 90°. The articulation and locking device (16) may consist in a hinge or clutch.
The articulation and locking device (16) comprises:

a first element (19) fixed to said from half-frame (2),
a second element (22) fixed to said rear half-frame (1) and hinged to first element (19) in such way that first element (1) can rotate with respect to second element (22), and
selective locking means (27, 28) adapted to lock said element (19) in at least two different positions with respect to said second element (22), in such way that wheelchair can have at least two different operating positions.

Advantageously, first element is a striker (19) shaped as plate and second element is an arched tubular body (22) provided with longitudinal seat or slot (23) adapted to receive striker (19).
In particular, said device (16) comprises:

the striker (19) connected to disk (21) adapted to be fixed to upper end (17) of said front half-frame (2);
the body (22) adapted to be fixed to front end (15) of rear half-frame (1), provided with seat (23) where said striker (19) is inserted.
a pivoting pin (24) inserted into first hole (25), transversally obtained on said body (22), and into second hole (26), transversally obtained on said striker (19);
a locking-unlocking button (27) with return spring (27a), inserted into a seat (22a) obtained in said body (22) and adapted to be inserted into one of a series of holes (28) obtained on said striker (19).

Fig. 8 shows three holes (28) in striker (19) corresponding to three operating positions of front frame (2), for instance, three operating positions wherein angle (α) is comprised between 90° and 75°. Clearly, width of striker (19) can be higher and more locking holes (28) can be provided to obtain finer adjustment and higher variation of angle (α).
As shown in the enclosed figures, the button (27) is provided with actuated end (29) and operating end (30) adapted to be inserted into one of the series of holes (28) obtained on said striker (19).
In order to actuate the articulation and locking device (16) the button (27) is actuated (27) to disengage the operating end (30) from one of the holes (28), make striker (19) oscillate and lock it in desired position as soon as operating end (30) is inserted again into another hole (28).

Claims

A wheelchair comprising:
- a frame (T) wherein said frame (T) is articulated and comprises first rear half-frame (1), second front half-frame (2) and an articulation device (16) between rear half-frame (1) and front half-frame (2);

- a pair of back pushing wheels (3) connected to said rear half-frame (1);

- a pair of front wheels (4) connected to said front half-frame (2);

- a seat (S) supported by said frame (T);

- a pair of footrests (5) supported by said frame (T),
characterized by the fact that
said articulation device (16) is also a locking device adapted to lock said front half-frame (2) in at least two operating positions, which define at least two different operating positions of wheelchair according to user's requirements.
A wheelchair according to claim 1, characterized by the fact that said front half-frame (2) has a substantially tubular shape with longitudinal axis (A) and in said at least two operating positions of front half-frame (2) the angle (α), subtended between longitudinal axis (A) of said front half-frame (2) and direction (X) parallel to sliding plane (P) of wheelchair has values lower than 90 °.
A wheelchair according to claim 1 or 2, characterized by the fact that said articulation and locking device (16) comprises:
- a first element (19) fixed to said front half-frame (2),

- a second element (22) fixed to said rear frame (1) and hinged to first element (19) in such way that first element can rotate with respect to second element, and

- selective locking means (27, 28) adapted to lock said first element (19) in at least two different positions with respect to said second element (22), in such way that wheelchair can have said at least two different operating positions.
A wheelchair according to claim 3, characterized by the fact that said selective locking means comprise at least two locking holes (28) obtained on said first element (19) and a locking-unlocking button (27) that comprises a first end (29) actuated by user and second operating end (30) adapted to be selectively inserted into one of said at least two locking holes (28).
A wheelchair according to claim 4, characterized by the fact that said locking-unlocking button (27) is stressed by a return spring (27a).
A wheelchair according to any one of claims 3 to 5, characterized by the fact that said first element (19) is a plate-shaped striker adapted to be inserted into a slot (23) of said second element (22), it being provided with a transversal pin (24) transversally crossing second element (22) and striker (19) for mutual hinging.
A wheelchair according to one of preceding claims, characterized by the fact that said seat (S) is composed of seat (6) and vertically sliding back (7); said seat (S) being supported by rear half-frame (1) with means (8, 9, 10,11) that allow it to move both along a substantially horizontal direction (8,9) and along a substantially vertical direction (10,11).
A wheelchair according to the preceding claim, characterized by the fact that said means allowing seat (S) to move along a substantially horizontal direction (8,9) consist in:
- a pair of guide tracks (8);

- a pair of sliding blocks (9), fixed in lower position to seat (6) of seat (S) and sliding on said pair of guide tracks (8);

- locking means of sliding movement of seat (S).
A wheelchair according to claim 7 and 8, characterized by the fact that said means adapted to allow displacement along a substantially vertical direction (10,11) consist in hinge (10) and piston (11) connecting seat (S) and rear half-frame (1).
A wheelchair according to the preceding claim, characterized by the fact that said piston (11) comprises a shock-absorbing device.
A wheelchair according to one of the preceding claims, characterized by the fact that said rear half-frame (1) has a T-shaped tubular configuration comprising a central longitudinal arm (14) supporting seat (S) and a back transversal arm (12) provided with two ends (13) where two back wheels (3) are rotatably fixed; said articulation and locking device (16) being disposed in correspondence with front end (15) of said longitudinal arm (14) of rear frame.
A wheelchair according to one of claims 2 to 11, characterized by the fact that said front half-frame (2) consists in a single central leg (20); the upper end (17) of said central leg (20) being connected to articulation device (16) whereas, in correspondence of lower end (18), said central leg (20) supports the pair of footrests (5) and pair of front wheels (4).