EP0810849B1 - Stationary or wheeled reclining seat device, in particular for a sick or disabled person - Google Patents

Abstract

An inclinable seat arrangement, in particular for a sick or handicapped occupant, is described. It comprises a framework (2) and an inclinable seat (3) connected to the framework by an articulation (4) and by a positioning mechanism arranged so as to facilitate the manipulations for inclining the seat by the occupant or by another person. The axis of the articulation (4) is preferably located proximate a vertical line passing through the center of gravity (G1) of the occupant when in a position corresponding to the equilibrium position of the empty seat. An elastic mechanism, exerting a progressive return couple toward the equilibrium position, comprises elastic bearings (24) within the articulation. The elastic mechanism also preferably comprises a constant force gas thrustor (6) which includes a controlled blocking arrangement. In place of the gas thrustor there may be provided a motorized jack (51) controlled by the occupant (48). The seat arrangement may be employed in stationary or wheeled chairs for the sick or handicapped.

Description

The present invention relates to a seat device reclining, especially for a sick occupant or handicapped, comprising a frame arranged to rest on the floor, a seat mounted on the frame by means of at least one joint with horizontal transverse axis, to be tilt in a range of tilt positions, and positioning means arranged to stabilize the sits in at least one of said positions when the seat supports the weight of the occupant, in which the positioning means include blocking means likely to lock the seat tilt in any position in said range and to be ordered manually, and elastic means connecting the seat to the frame and defining a vacuum equilibrium position when the seat is not occupied, the elastic means being arranged to exert on the seat a couple of return to empty equilibrium position when the seat has a different position from it, the return torque increasing when the seat moves away from said position of equilibrium, and in which at least some of the elastic means are associated with said joint.

We know tilting seat devices in which you can modify and block the tilt of the seat manually, by means of a notch mechanism. The US patent 2,986,200 shows for example a wheelchair for invalid in which the tilting joint of the seat is associated with a locking mechanism and return springs that oppose the tilting torque produced by the weight of the occupant, in order to stabilize the seat and allow it to be maneuvered with little effort. However, such devices were not imposed commercially because the springs must be relatively strong and do not provide a good agreement between the variation of the return torque and the variation of the torque due to the weight of the occupant. he must therefore exert a force large enough to put the seat in a position distant from the position balance, or to bring it back.

Patent application FR 2 693 889 (corresponding to the preamble of claim 1) describes a tilting chair device also having means elastic associated with the joint, in the form of a torsion spring, and blocking means arranged at distance from the joint, in the form of a cylinder to fluid whose piston brakes tilting and has a blocking valve controlled by the occupant. When he is released, the piston cannot contribute to tilting the seat, but only opposing a fast movement. It follows that the spring must be relatively strong, as in the prior art above.

In general, to reduce the risk of tipping untimely seat of this kind, it is expected that the axis articulation is placed in the vicinity of a vertical passing through the occupant's center of gravity. The occupant could then control the tilt movements by movements of his body, for example of the bust, to change the position of its center of gravity and produce thus a tilting of the seat after unlocking. However, these body movements must have a certain magnitude when the center of gravity must pass to one side to the other of the support joint. In such a case, if they are easy enough for a valid person, they can be painful, if not impossible, for a patient or a disabled person. In addition, a premature release or too late blocking of the blocking device can lead to abrupt maneuvers and incidents.

Swiss patent 681,772 shows an office chair with reclining seat mounted on an elastic joint provided with rubber elements, as well as a stop front and a rear stop which limit the range of possible tilt. There are no blocking means in intermediate positions. Such a device is not not applicable to a seat for the sick or disabled. If we adapted it for such an application, it would require particularly strong and heavy elastic elements. Gold a weight saving is an important criterion in the design of a wheelchair, especially in manual propulsion.

Furthermore, we know from the GB patent application 2'029'334 a type of reclining seat device in which the positioning means are formed by a manual or motorized actuator, for example a cylinder linear hydraulic, pneumatic or electric, which controls the spacing between two respective points of the frame and from the seat at a certain distance from the axis hinge. So that a sick or disabled occupant can change the seat tilt itself, the actuator must be able to operate when the seat is busy, so be sized to produce a force large enough to overcome the maximum torque resulting from the weight of the occupant in any seat position. This negatively influences the weight, the size and cost of the positioning means, as well as their energy consumption. If the actuator is manual, operation by a sick or disabled occupant can be quite difficult and trying.

The present invention aims to improve a reclining seat device of the type indicated in preamble, so as to avoid the aforementioned drawbacks prior art devices by facilitating seat tilt maneuvers, with construction simple, as light as possible and inexpensive. according to a particular object of the invention, all the maneuvers should be able to be produced with effort relatively weak, whether these are exerted by the occupant himself, by another person or by motorized means.

To this end, a first aspect of the invention relates to a reclining seat device as defined in the preamble, characterized in that the elastic means further include a gas spring arranged to exercise a force between the frame and the seat at a distance from the axis of articulation, said force being substantially constant at least when the blocking means are released.

Thus, it is possible to obtain, by the action combined elastic means associated with the joint and the force of the gas spring, a restoring torque which varies non-linearly with the seat tilt at from the equilibrium position when empty or under load. In the moment of the force of the gas spring can vary during seat tilt movements, because the distance between the joint and the cylinder axis varies also. You can choose the respective anchor points of the gas spring on the frame and on the seat so as to obtain the appropriate variation, minimizing the effort required for maneuvering across the entire tilt range. In general, the empty equilibrium position will be located rather forward and preferably the gas spring will be arranged so that its force is opposed to a tilting towards the rear, where the torque due to the weight of the occupant is relatively large. So the elastic means incorporated into the joint may be weaker, lighter and less expensive.

It should be noted that in the prior art illustrated by documents US 2 986 200 and FR 2 693 889 cited more top, the elastic means associated with the joint exert a restoring torque which increases linearly with seat recline from position balance. On the contrary, the torque due to the weight of the occupant does not vary linearly, but according to a law sinusoidal with respect to the inclination. That's why we can't seem to get a good match between these two couples in the range of useful inclinations with the devices of the prior art. The invention defined above allows to overcome this drawback by a choice suitable for gas cylinder anchor points.

Preferably, the blocking means are associated with the gas spring and arranged to block or unblock it on order, the gas spring being of a force type substantially constant when unlocked. As the gas spring serves both as elastic means and as a means of blocking, this represents a saving of material and weight. When blocked, the cylinder exerts the force of reaction necessary to keep the seat in the chosen position.

Preferably, the axis of the joint is located at proximity of a vertical passing through the center of gravity of the occupant when the seat is in said position vacuum balance. The seat is preferably reclining forward and backward relative to position vacuum balance.

In a preferred embodiment of the device, the elastic means comprise at least one bearing elastic forming said joint and comprising rubber elements arranged to produce at least one part of the booster couple.

In addition, provision can be made for the seat to have a seat, mounted on the frame, and a folder mounted so reclining on the seat by means of another articulation associated with elastic return means urging the folder.

In a particularly advantageous application of the invention, the device is produced in the form of a wheelchair or stroller for the sick or disabled. Preferably, the frame has two wheels main ones arranged along a common central axis located near a vertical passing through the center of common gravity of the device and the occupant, at least a steerable front wheel located in front of the axle central, and at least one rear safety caster arranged to rest on the ground at least in the event of tilting of the device backwards around the axis central. Said rear caster can advantageously be movable in height on the frame, to which it is linked by elastic return means capable of pressing it on the ground at least when the device tends to tip over backwards around the central axis.

• La figure 1 est une vue latérale schématique d'un dispositif selon l'invention, dont le siège se trouve dans une position d'équilibre en charge;
• la figure 2 est une vue schématique de l'arrière du dispositif;
• la figure 3 représente en perspective un élément formant un palier élastique dans le dispositif des figures 1 et 2, et
• la figure 4 est un diagramme schématique représentant un exemple typique de courbe caractéristique couple-angle de pivotement d'un palier élastique selon la figure 3.

Other characteristics and advantages of the present invention will emerge from the following description of a preferred embodiment, presented by way of example with reference to the appended drawings, in which:

• Figure 1 is a schematic side view of a device according to the invention, the seat of which is in a load-balanced position;
• Figure 2 is a schematic view of the rear of the device;
• FIG. 3 shows in perspective an element forming an elastic bearing in the device of FIGS. 1 and 2, and
• FIG. 4 is a schematic diagram representing a typical example of a characteristic torque-pivot angle curve of an elastic bearing according to FIG. 3.

The reclining seat device according to the invention, as shown in Figures 1 and 2, is made in the form of a stroller for the sick or disabled. However, the same construction principle would be applicable to a stationary seat or an armchair rolling, whether it is powered by the occupant himself or by a motorized drive incorporated in armchair.

The stroller 1 shown has a lower frame 2 and a reclining seat 3 which are connected by a articulation 4 with horizontal axis 5 and by an element of retainer which, in this case, is a gas spring 6 provided with a built-in locking device.

Frame 2 mainly comprises a rigid chassis composed of longitudinal metal tubes 10, 11, transverse 12 and vertical 13, 14, two wheels main lateral 15 centered on a transverse axis common 16 and two freely steerable front wheels 17 around a vertical axis, the wheels 15 and 17 resting on the floor 18 to support the entire stroller in normal conditions. The two main wheels 15 are mounted on an axle 19 which is fixed to the chassis, preferably in a longitudinally adjustable position. AT rear, frame 2 still has two crutches angled 20, each carrying a rear caster of safety 21 which is normally slightly above from soil 18, but can rely on it to prevent a possible tilting of the chair backwards around the axle 16 if the front wheels 17 are raised for a whatever reason. In this example, the crutches 20 are fitted into the horizontal tubes 10 of the chassis, where they are fixed in an adjustable position longitudinally. Note that the frame 2, according to a variant, could have a single front wheel 17 and / bu a single rear wheel 21. It will also be noted that such a frame could be equipped with a drive system motorized actuating the main wheels 15, in the case a motorized wheelchair. This frame could also be that of a manual wheelchair if the main wheels 15 were arranged accordingly, especially with an annular handle which is within reach of hand of the occupier.

The frame of frame 2 further comprises two supports 22 on which are fixed, by means of metal flanges 23, two pivoting elastic bearings 24 which will be described below and are aligned on axis 5 to form together the joint 4.

The seat 3 has a rigid metal frame 26 supporting an upholstered armchair 27 on which takes place occupant 28. At the front, the chassis 26 carries a footrest adjustable 29. At the back, it carries two arms inclined 30 provided with handles 31 to allow a auxiliary person to move and steer the stroller 1. One of the handles 31 is equipped with a lever 32 which control, for example, by cable transmission 33, the release of the jack 6. Preferably, the arms 30 are integral with the backrest 34 of the chair 27 and are mounted on chassis 26 by means of a pair articulations 35 for adjusting the inclination of the backrest relative to seat 36 of the chair. These joints can also include means return elastic, for example elastic elements similar to those of bearings 24. To allow readjust the position of the center of gravity of the seat and occupying it according to the position of the backrest, we can provide a device for longitudinal translation of the chassis 26 relative to articulation 4, for example at by means of a crank actuating a screw mechanism and nut.

Figure 3 shows the structure of one of the bearings elastic 24 forming the joint 4. In this example, it is an elastic element ROSTA (registered trademark) of type DR-S, manufactured by ROSTA-WERK AG in Hunzenschwil (Switzerland). This element has a tube square steel outer 40, square inner tube 41 also made of steel, placed inside the tube outside without touching it, and four rubber blocks 42 of prismatic shape with cross section approximately triangular. The blocks 42 are arranged in the corners of the outer tube 40 and each rest on one side of the inner tube 41 which, in its rest position, is rotated 45 ° relative to the outer tube 40, the blocks 42 being slightly compressed between the two tubes. When the tube 40 is fixed, this assembly supports elastically the inner tube 41 in all directions and allows it to rotate by an angle ± α around of an axis 5 from the rest position, this angle α can reach at least 30 °. In this case, a end of the tube 41 of each elastic bearing 24 is fixed to the seat frame 26 by means of a flange metallic 44. The rubber blocks 42 exert on the tube 41 a return torque M which gradually increases with the angle α. As shown in Figure 4, this progressivity is not linear, the variation of the torque M being relatively small for small values of the angle α, and higher when the angle becomes more tall. In addition, the strain-stress diagram of rubber blocks presents a hysteresis which results by a difference between the load curve 61 and the discharge 62, in FIG. 4. Thus, the elastic bearing 24 also constitutes a shock absorber for all vibrations of one tube 40, 41 relative to the other, also well in translation than in rotation.

In the embodiment described here, the cylinder 6 is a constant force and locking gas spring automatic, BLOC-O-LIFT (registered trademark) type manufactured by the company STABILUS in Koblenz (Germany). when is released, it exerts a constant pushing force F 500 N. Its lower end is hinged on a support 45 integral with a crosspiece 46 fixed to the tubes 10 of the chassis in an adjustable position. Its end upper is articulated at 47 at a rear end of the seat frame 26.

As cylinder 6 is always at a certain distance from hinge pin 5, its force produces a permanent couple who tends to straighten the seat. When this one is not busy, this couple topples the forward seat and elastic bearings produce a resistant couple increasing until the two couples balance, thus defining a position of equilibrium empty of the seat. This position is adjustable in particular by displacement of the cross-member 46, which also makes it possible to modify the torque produced by the force F with respect to axis 5 of articulation 4.

Note, however, that the gas spring 6 must not must be provided with a blocking device. This could be an organ separate from the cylinder, for example in the form described in the patent application FR 2 693 889. However, the combination described here has the advantage of combining the two callback functions and blockage in a single organ, which represents a gain of weight and space.

Preferably, the position of the joint 4 by report to seat 3 is such that when occupant 28 normally rests on the seat, a vertical g1 passing through the occupant's center of gravity G1 goes to proximity to axis 5 of the joint, at least when the seat is in the so-called equilibrium position at empty. In this position, the seat is preferably rather straightened, so that the footrest 29 is not too high and the occupant can sit easily. It is then preferable that the vertical g1 is slightly behind the hinge pin 5, so it suffices to unlock the cylinder 6 so that the seat automatically tilts backward due to torque produced by the weight of the occupant. If we keeps the jack 6 unlocked by means of the lever 32, seat 3 stabilizes in a position of equilibrium load, where the torque due to the weight of the occupant is counterbalanced by the torque resulting from the elements elastic bands 6 and 24. This results in an equilibrium position in charge specific to each position of the occupant. For define another tilt position, just raise or lower the handles 31 and release the joystick 32 to lock the cylinder 6 when the desired position is reached.

In a variant shown in broken lines at Figure 2, the release control of the cylinder 6 can also include a control handle 48 disposed on seat 3 so as to be accessible to the occupant, so that he can maneuver the seat himself. This command replaces that of the controller 32 in the case from a wheelchair. When the occupant wants to modify the seat tilt 3 itself, it changes if necessary the position of its center of gravity G1 by moving a part of his body, for example by slightly advancing his head, chest or arm if he wants to tip forward, and it unlocks the cylinder 6. The resulting change in the torque due to its weight then produces the movement desired, until the recall torque of the elements elastic has changed enough to hold the seat in the new load equilibrium position, even if the vertical g1 has not changed sides with respect to the axis 5. Therefore, even a weak patient or disabled can effortlessly change the tilt of his seat.

In Figure 1, we note that the central axis 16 main wheel 15 is located near a vertical g2 passing through the common center of gravity G2 of the device 1 and occupant 28, this vertical being slightly in front of axis 16 for any position of the seat 3 so that the front wheels 17 rest on the ground. So it's easy to tilt back the entire device 1, including its frame 2, around axle 16 to lift the front wheels when they must overcome an obstacle such as a threshold or a curb. Tipping is then stopped by the rear casters 21. The arms 20 can also be mounted on the frame 2 in an elastic manner, for example at using elastic ROSTA elements similar to those of bearings 24 and forming an articulation 50 (FIG. 1) with an axis horizontal, so that each roller 21 is movable in height on the frame, according to a principle described in the Patent application WO 96/15752 from the same applicant. In this in this case, the rollers 21 can rest lightly on the floor even in the normal position of the frame in accordance with FIG. 1, where the front wheels 17 also touch the ground, and their bearing force will increase if the whole of the device tends to tip back. In combination with such a progressive elastic support of the or rear castors 21, a reclining seat according to the present invention allows to use a change seat tilt to easily move the center of gravity of the occupant in order to produce a transfer of load from front wheels to rear casters or vice versa, especially to take advantage of the elasticity of support on the rear casters. For example when the occupant of such a wheelchair, motorized or not, must descend a steep slope, it can slope its seat backwards, on the one hand to compensate tilting the frame forward due to the slope off the ground, and on the other hand to offload the front wheels and load more the main wheels, which are the ones on which it has means of action for the propulsion, the braking and steering of his chair. By emphasizing still tilt, it can even tilt the frame backwards to lift the front wheels, for example to get them over an obstacle. energy potential thus accumulated in the return springs rear wheels 21 is reusable when straightening the chair, especially to facilitate main wheels mounted on the obstacle. This phenomenon and its advantageous applications are described in detail in the aforementioned patent application.

A person skilled in the art will understand that if the gas spring 6 described above was replaced by a simple blocking, that is to say if we did without the push constant exerted by this cylinder, the return torque would be then produced only by the elastic bearings 24. However, the cylinder 6 has the advantage of exerting a preload on elastic bearings, resulting in a higher recall torque as soon as the seat deviates from its equilibrium position. In addition, it will be recalled that the choice of the position of the jack 6 makes it possible to adjust its distance to the axis of the joint and therefore to modulate the torque produced by its force F.

Another variant consists in making the joint 4 by means of ordinary bearings, the return torque then being secured by one or more spring elements connecting the seat 3 to the frame 2, for example with a spring of torsion associated with the joint 4.

In another variant not shown, the device can be stationary and devoid of wheels. In this case, the frame 2 can be a simple base resting on the ground, or generally any structure able to support seat 3 and articulation 4, by example in a medical or dental office, or in a vehicle.

Claims (11)

1. Inclinable seat arrangement, in particular for a sick or handicapped occupant, comprising a framework (2) arranged to rest on the ground, a seat (3) mounted on the framework by means of at least one articulation (4) with a horizontal transverse axis so as to be inclinable in a range of inclined positions, and positioning means arranged so as to stabilize the seat (3) in at least one of said positions when the seat supports the weight of the occupant, in which the positioning means include blocking means (6, 32, 33, 48) adapted to block the inclination of the seat in every position within said range and to be manually controlled, and elastic means (6, 24) coupling the seat (3) to the framework (2) and defining a no-load equilibrium position when the seat is not occupied, the elastic means (6, 24) being arranged to exert a return couple on the seat toward the no-load equilibrium position whenever the seat occupies a position different therefrom, the return couple increasing as the seat is moved away from said equilibrium position, and in which at least certain (24) of the elastic means are associated with said articulation(4), characterized in that the elastic means further comprise a gas thrustor (6) arranged to exert a force (F) between the framework (2) and the seat (3) at a distance from the articulation axis (5), said force (F) being substantially constant at least when the blocking means (6, 32, 33, 48) are unblocked.
2. Arrangement according to claim 1, characterized in that the blocking means (6, 32, 33, 48) are associated with the gas thrustor (6) and arranged so as to block or unblock the latter upon order.
3. Arrangement according to any of the preceding claims, characterized in that the gas thrustor (6) is hinged on a support (45), the position of which is longitudinally ajustable on the framework (2)
4. Arrangement according to any of the preceding claims, characterized in that the axis (5) of the articulation (4) is located proximate a vertical line passing through the center of gravity (G1) of the occupant whenever the seat (3) is in said no-load equilibrium position.
5. Arrangement according to any of the preceding claims, characterized in that the seat (3) is inclinable toward the front and toward the rear relative to the no-load equilibrium position.
6. Arrangement according to any of the preceding claims, characterized in that the elastic means comprise at least one elastic bearing (24) forming said articulation (4) and including rubber elements (42) arranged to produce at least a part of the return couple.
7. Arrangement according to claim 6, characterized in that said articulation (4) is formed of a pair of said elastic bearings (24).
8. Arrangement according to any of the preceding claims, characterized in that the seat (3) includes a sole plate (36) mounted on the framework and a back support (34) inclinably mounted on the sole plate by means of another articulation (35) associated with elastic return means acting on the back support.
9. Arrangement according to any of the preceding claims, characterized in that it is made in the form of a wheeled armchair or pushchair for the sick or handicapped.
10. Arrangement according to claim 9, characterized in that the framework (2) includes two principal wheels (15) arranged along a common central axis (16) located proximate a vertical line passing through the common center of gravity (G2) of the arrangement and of the occupant, at least one directable front wheel (17) located ahead of the central axis, and at least one rear safety roller (21) arranged so as to bear on the ground at least in the event of tipping over of the arrangement toward the rear about the central axis.
11. Arrangement according to claim 10, characterized in that said rear roller (21) is movable in height on the framework to which it is connected by elastic return means (50) adapted to press it onto the ground at least when the arrangement tends to tip over toward the rear about the central axis (16).

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