EP1996140A2

EP1996140A2 - Wheelchair adapted to staircases

Info

Publication number: EP1996140A2
Application number: EP07731164A
Authority: EP
Inventors: Panagiotis Pavlopoulos; Konstantin-Léo PAVLOPOULOS; Samuel Deberles
Original assignee: Heron Technologies SAS
Current assignee: Heron Technologies SAS
Priority date: 2006-03-20
Filing date: 2007-03-20
Publication date: 2008-12-03
Also published as: WO2007107651A2; WO2007107651A3; FR2898489A1; FR2898489B1; US20090174168A1; CN101646409A; WO2007107651A9

Abstract

The invention concerns a wheelchair (1) comprising: a chassis (2) supporting a seat; two rear wheels (4) of large diameter, mobile relative to the chassis between a low position for normal use and a raised position for climbing a staircase, an auxiliary drive mechanism for climbing a staircase.

Description

Wheelchair suitable for stairs

The present invention relates to a wheelchair equipped with an additional propulsion mechanism allowing it to go up or down stairs.

There are two categories of wheelchair users, those who travel with difficulty and can not easily use chairs alone, and those who are generally younger and active, who travel alone and who have a need. imperative of autonomy and independence.

The latter category is able for example to perform the transfer of the chair to a seat of a vehicle and vice versa and to place the wheelchair in the vehicle without intervention of outside help.

As a result, the wheelchair should be as light as possible, compliant with the ergonomic requirements and regulations in force, and if necessary remove the large rear wheels so that it can be placed in the passenger seat or behind the front seat. It is also desirable that the chair is foldable so as to minimize its bulk when not in use.

Many legislations make it mandatory to provide access with inclined planes for wheelchair users. This obligation is however not always respected and even if it is the case, there may be situations where steps precede the inclined plane. In many places, access for people in wheelchairs often remains very difficult and requires help from third parties.

We know wheelchairs fairly complex and heavy, with four sets of independent feet with many electric motors. Such chairs provide user comfort in climbing but are intended only for the rise and fall of stairs and therefore are incompatible with the usual use of a conventional wheelchair.

Another type of known chair includes a device similar to a handling devil leaning against the chair. This device requires the intervention of a third person. US Patent 4,512,588 discloses a chair capable of climbing stairs, under the effect of the sole driving force of the user. This armchair is of manufacture relatively complex, not having large rear wheels, which are replaced by several wheels mounted on a rotating support.

French patent application FR 2,648,038 describes a chair comprising an additional propulsion mechanism intended to be driven by the user. This additional propulsion mechanism comprises racks animated with a relatively complex movement to come into engagement with the steps of the stairs.

There is a need for a chair that can be used in everyday life for its conventional function and that benefits from an auxiliary propulsion system allowing the user to climb stairs, if possible with minimal effort on his part.

The invention aims to meet all or part of the disadvantages of the prior art by providing a wheelchair that is reliable operation and robust construction, easy to use, ergonomic, offering guarantees of safety to the user and that can be easily manipulated by it, especially in order to be loaded in a motor vehicle without outside help.

According to one of its aspects, the subject of the invention is a wheelchair comprising: a frame supporting a seat, two rear wheels of large diameter, movable relative to the frame between a low position for normal use of the chair and a raised position for the crossing of a staircase,

an auxiliary propulsion mechanism for crossing a staircase, comprising:

- Front and rear support elements configured to bear on steps of the stairs when the rear wheels are in the raised position and the chair back to the slope of the stairs, the front support elements and the elements of rear support rotating around distinct axes of rotation,

a transmission system for transmitting a rotation of the large rear wheels in the raised position to the support elements in order to rotate them and cause an ascent or down the stairs, according to the driving direction of the large rear wheels.

The raising of the large rear wheels can be accompanied by a shift of the user's center of gravity downwards and rearwards in his seat, which increases the stability, makes it more comfortable to cross the staircase both uphill only downhill and can reduce the apprehension of the user.

In addition, raising the large rear wheels prevents them from impeding the progression of the wheelchair along the stairs.

The invention avoids accidental fall of the chair, even in case of loss of consciousness of the user during the ascent or descent.

The tilt of the seat may allow the user to more easily maintain a straight posture on the stairs.

The large rear wheels can for example go from the lowered position to the raised position at the end of an angular stroke greater than or equal to 45 °, after an upward movement for example greater than or equal to 8 cm for a race of

60 ° and after a forward movement for example greater than or equal to 4 cm for a stroke of 60 °.

The distance between the axis of rotation of the front support elements and the axis of rotation of the large rear wheels in the climbing configuration being greater than or equal to 70 cm, better still to 75 cm and the distance between the axis of rotation large rear wheels and the axis of rotation of the rear support elements being greater than or equal to 50 cm, in climbing configuration.

This last distance is for example of the order of 46 cm in the configuration of normal use of the chair. The rear support members may be rotatably mounted on the frame, being synchronous in rotation with the front support members.

Large rear wheels can be dismantled.

The chair may comprise at least one pivoting structure relative to the frame about an axis of rotation, the passage of a large rear wheel at least from the low position to the raised position and conversely by rotating the pivoting structure. . The auxiliary propulsion mechanism may comprise a transmission system arranged to reduce a force exerted on the large rear wheels in the raised position to rotate the support elements. Thus, even a user does not have much strength in the arms can easily cross a staircase.

The auxiliary propulsion mechanism may comprise at least one first driving element and the large rear wheels may rotate with at least one second driving element, this second driving element being in driving engagement with the first driving element. drive only when the large rear wheels are in the up position. This can allow a triggering of the additional propulsion mechanism only when the large rear wheels in the raised position.

The auxiliary propulsion mechanism may include left and right sub-mechanisms, the left sub-mechanism being associated with left front and rear support members and the left large left wheel and the right sub-mechanism being associated with elements. front and rear support and right rear large wheel.

The left and right sub-mechanisms can be connected by a coupling shaft so that the rotation of the left and right support elements is synchronous. This coupling shaft can be foldable, retractable or removable, so as not to hinder the folding of the frame, when the latter is foldable in the width direction.

Each large rear wheel can be supported by a structure pivoting relative to the frame, preferably in a removable manner to facilitate the handling of the chair.

The pivoting structure comprises for example at least one lever operable by a user sitting on the seat and allowing, when actuated, to move the large rear wheels from the low position to the raised position and vice versa. Alternatively, the pivoting structure can be rotated by a screw drive mechanism, including a screw rotated by a crank, or by a pneumatic mechanism, hydraulic or electrically powered. The chair may comprise two pivoting structures, respectively associated with the left and right sub-mechanisms. The chair may comprise a locking system of the pivoting structures in the positions respectively corresponding to the raised position of the large rear wheels and the lowered position of the large rear wheels. This locking system may comprise, for example, a release button of the pivoting structure integrated in the aforementioned operating lever.

Each pivoting structure may comprise front and rear arms respectively carrying the corresponding large rear wheel and a front support element. The aforementioned operating lever can be connected between the arms near the axis of rotation of the pivoting structure. The front arm carrying the front support element can be retractable to reduce the size of the additional propulsion mechanism during normal use of the chair and not interfering with the lateral transfer of the person sitting on the chair on a other seat.

The support elements may comprise crosses, each cross may comprise four branches substantially perpendicular to each other.

The dimension of each branch, at its distal end, measured perpendicular to the axis of rotation of the large rear wheels, may be relatively large, to increase the stability of the chair on the steps.

In an exemplary implementation of the invention, the passage of the large rear wheels from the lowered position to the raised position is performed manually, without motorized assistance. The rotation drive of the large rear wheels, in raised position, can also be carried out without motorized assistance.

Each sub-mechanism may comprise a primary transmission shaft for transmitting a rotation of the large rear wheel associated with the corresponding front and rear support elements.

The primary transmission shaft may comprise two teeth connected by transmission elements to corresponding teeth rotating with the bearing elements respectively front and rear. These transmission elements may be chains or belts, for example, or comprise at least one secondary transmission shaft optionally including at least one gimbal. This secondary transmission shaft can be retractable, if necessary, to allow closer support elements before large rear wheels and reduce the size of the wheelchair during normal use.

The primary drive shaft can rotate with a third toothing and mesh with an intermediate gear. The corresponding large rear wheel may comprise an associated toothing for, when the large rear wheel is in the raised position, come into engagement with the intermediate gear, so as to transmit the rotational movement of the large rear wheel to the support elements.

The invention further relates to a wheelchair comprising a frame supporting a seat, able to overcome an obstacle with at least one rotary support element, this rotary bearing element allowing the crossing of substantially successive planar levels, such as stair steps, being fit during its rotation, successively to bear on a first plane level and then two supports respectively on the first level and the next level. This rotary bearing element may be cross-shaped with at least two branches whose distal ends are able to bear on two steps or successive levels. The chair may have four rotatable support elements, two on each side of the frame, each in the form of a cross with four branches. The front support elements can be retractable and retract and / or be put in place by means of actuating means. The means of propulsion of the chair can be adapted to cooperate with transmission means to allow the rotary drive of the rotary elements. These transmission means may be constituted by two drive shafts and a coupling shaft, the drive shafts being able to cooperate with pinions and chains or belts as well as with gears and gears in order to obtain a drive shaft. reduction of the rotation speed. The transmission means may be constituted by any other means adapted to ensure the transmission of the rotation of the rear wheels to ensure the climbing function of the chair for the crossing of an obstacle.

When the large rear wheels are lowered, the additional propulsion system does not interfere with the normal use of the wheelchair.

The frame may comprise tubular frames constituting the skeleton of the seat and support means, for example of generally parallelepipedal shape, to form reinforcements on each side of the chair and support means that can receive the weight of the user and maintain the chair in a configuration of operation. The frame may comprise lattices or braces, which may be foldable by means of screws or other pivot means, for example in their center.

The length of the operating levers may be longer than that of the front arms. The rotational indexing of the pivoting structure can be effected by any means for fixing the angles of the pivoting structure corresponding respectively to the lowered and raised positions and the large rear wheels, the angles being calculated for the normal function of the chair and that climbing.

Alternatively, the two pivoting structures can be interconnected so that the tilting of one of the pivoting structures causes the tilting of the other pivoting structure.

At each turn of the rear wheel, the support elements turn for example a quarter turn. It can be provided a locking system in case the user would stop his effort up or down the stairs, which allows to maintain the chair without any possibility of tipping or runaway.

The invention will be better understood on reading the following detailed description, nonlimiting exemplary embodiments thereof, and on examining the appended drawing, in which:

- Figures 1 and 2 show schematically and partially in perspective, an exemplary wheelchair embodiment according to the invention, the large rear wheels being respectively in the lowered and raised positions,

FIG. 3 illustrates an example of positioning of a support element on a consecutive step,

FIGS. 4 to 7 illustrate various details of embodiment of the chair of FIGS. 1 and 2,

FIG. 8 schematically represents in perspective another embodiment of the chair,

FIG. 9 represents the chair of FIG. 8 in side view,

FIG. 10 illustrates the use of the auxiliary propulsion system of the chair of FIGS. 8 and 9 for climbing or descending steps,

FIGS. 11 and 13 illustrate alternative embodiments of means for transmitting the movement of the large rear wheels towards the support elements, and - Figure 12 illustrates the mounting of a front support member on a retractable arm.

The wheelchairs 1 shown in Figures 1, 2 and 8 comprise a frame 2 supporting a seat 3. Conventionally, the chair 1 comprises two large rear wheels 4 each provided with a handrail 100 visible in Figure 8 and two small front wheels 101, also visible in this figure, which can be carried by forks 102 pivoting about axes which can be vertical.

The chair may include a footrest that can be seen in Figure 8. The seat 3 comprises a backrest 5 and a seat 6. The backrest 5 and the seat 6 may be made of textile material or any other material suitable for support the user and can bend to accompany the folding of the chassis 2, if any.

The frame 2 comprises a frame supporting the seat 3 and lateral uprights 105, which can serve as armrests, if necessary.

The frame 2 is advantageously made so as to be foldable, folding being effected by bringing the large rear wheels 4 closer to one another.

The frame of the frame 2 comprises for example two lateral frames that can be brought together to allow the folding of the chair through an articulated structure, which may comprise elements forming a lattice and hinged together.

The large rear wheels 4 can be dismountable.

The frame 2 can advantageously allow the ergonomic adjustments of conventional manual propulsion chairs.

The chair 1 comprises an auxiliary propulsion mechanism to ensure the function "up / down" stairs. This auxiliary propulsion mechanism comprises two front rotary support elements 21 and two rear rotary support elements 21, respectively arranged on the left and right sides of the chassis.

The rear support elements 21 are rotatably mounted on the chassis around a geometric axis of rotation X located for example very slightly behind the seat 3, parallel to the axis of rotation Y of the large rear wheels 4. The pivoting structure is for example mounted in rotation on structural elements of the frame 2 forming means support of the seat. The rear rotary support member may be rotatably mounted on, for example, a side frame of the frame.

The support elements 21 front left and right are mounted on respective pivoting structures 22 left and right, rotatable about a geometric axis of rotation Z parallel to the X and Y axes.

In the example considered, each pivoting structure 22 comprises a front arm 150 and a rear arm 151 hinged around the geometric axis Z.

The rotational displacement of each structure 22 can be effected for example by means of an operating lever 152 connecting to the arms 150 and 151 near the Z axis.

The rear arm 151 carries the corresponding large rear wheel 4, preferably so as to allow its removal.

The operating lever 152 can switch between two positions respectively shown in Figures 1 and 2, corresponding to the lowered position of the large rear wheels 4 and the raised position thereof.

The locking of the pivoting structures 22 in the raised and lowered positions can be effected in various ways, for example by means of a cooperation between the operating lever 152 and the chassis 2, for example between the operating lever 152 and a lateral upright 105. As can be seen more specifically in FIG. 8, the operating levers 152 can each carry a locking pin which can engage in notches 160 provided on a corresponding lateral upright 105, the unlocking being possible for example through a push button 156 provided at the end of the operating lever 152 and on which the user can press to move or retract the locking finger to allow a tilting of the pivoting structure about the Z axis.

The additional propulsion mechanism of the chair 1 comprises two left and right sub-mechanisms respectively arranged on the left and right sides of the chair.

Each sub-mechanism comprises, as can be seen in particular in Figure 4, a primary drive shaft 160 which carries in the example considered first and second teeth 161 and 162. The teeth 161 and 162 are respectively connected by chains 163 and 164, as can be seen in particular in Figures 6 and 7, to gears 168 and 169 respectively rotating with the bearing elements 21 front and rear.

The primary drive shaft 160 rotates with a drive element 18, for example a toothed wheel, which meshes with an intermediate drive element 16, for example also a toothed wheel, as can be seen in FIG. 4 .

The large rear wheels 4 rotate with drive elements 17 which are for example gear wheels. When the large rear wheels 4 are in the lowered position, as illustrated in FIG. 6, the large rear wheels can rotate independently of the additional propulsion mechanism, the driving element 17 not being engaged on the driving element. intermediate 16.

When the large rear wheels 4 are raised, as shown in FIG. 7, the driving element 17 comes into driving engagement with the intermediate driving element 16, so that a rotation of the large rear wheels is transmitted to the primary transmission shaft 160, which in turn drives the bearing elements 21 through the chains 163 and 164, which do not appear in Figure 4 for the sake of clarity of the drawing. The rotation of the front support elements 21 takes place around an axis of rotation W which is parallel to the axis of rotation X of the rear support elements 21.

The various driving elements which cooperate to transform the rotation of the primary transmission shaft 160 into a rotation of the front and rear support elements 21 are arranged in such a way that the rotation of the support elements 21 is synchronous. .

In addition, in the illustrated example, the primary transmission shafts 160 of the left and right sub-mechanisms are connected by a coupling shaft 13, so that the rotation is synchronous between the left and right bearing elements 21. The right and left sub-mechanisms are for example identical. The primary transmission shafts 160 can be connected to the coupling shaft 13 by means of sleeves 25 which can be indexed in rotation by means of wedges 26. In the illustrated example, the support elements 21 each form a cross with four branches 180 arranged perpendicular to each other.

The distal end 181 of each branch 180 is located at a distance from the axis W which is greater than or equal to the height of the step to be crossed. The length of a branch 180 may for example be greater than or equal to the height and half-length of a step.

Figure 3 illustrates that the distance from the end of a branch to the axis of rotation W may be slightly greater than the height of the steps.

Optionally, the support element can rest in equilibrium on two points, which increases the stability of the chair.

The support elements 21 may be protected by housings 23, as shown in Figures 1 and 2.

The support elements 21 front and rear are preferably arranged so that the legs 180 are parallel to each other when the chair is in climbing configuration, as shown in Figure 10.

To use the chairs shown in Figures 1 and 10, the user is back to the slope and pushes on the control levers 152 so as to raise the large rear wheels 4. This recovery accompanied by a movement upwards and forward of the large rear wheels and a lowering of the seat 3, which has the effect of moving the user's center of gravity to bring it to a position where the stability of the chair is increased and where the user is well anchored in the back of his seat and thus meets less apprehensive to cross the stairs.

Due to the position of the user in the example considered, more than half of the weight of the user, for example two-thirds of the weight of the user, can be supported by the two rear rotating support elements , which can contribute to safety and allow stabilization of the chair uphill or downhill on the previous step if the user relaxes his effort. A large width of the branches can contribute to safety, because the wider the branches, the more the chair resists the tilting of the support elements. The front support members may have branches having a greater width than the rear support elements to increase the torque required for movement while ensuring the safety of the user. The user can drive the large rear wheels in rotation, thanks to the handrails in the direction corresponding to the rise or the descent of the staircase.

Each sub-mechanism of the additional propulsion mechanism provides a reduction in the rotation of the large rear wheels 4, so that the user has a moderate effort to provide to cross a staircase.

Once the staircase is over, the user can return to a normal use configuration of the wheelchair, by pulling the levers to lower the large rear wheels. This lowering is accompanied by a disengagement of the transmission connecting the large rear wheels to the support elements. Of course, the invention is not limited to the examples described.

In particular, it is possible to make numerous modifications to the chassis as well as to the additional propulsion mechanism.

As can be seen in particular in FIG. 11, it is possible to rotate a bearing element 21 by means of a secondary drive shaft 200 which is, for example, provided with conical toothed wheels 201 and 202 at its ends, so as to allow a right angle return of the transmission.

Where appropriate, as illustrated in Figure 12, the front arm 150 which supports the front support member 21 may be retractable longitudinally, for example over a distance greater than or equal to 20 cm, for example of the order of 25 cm, to allow to bring the front support member 21 of the large rear wheel 4 and facilitate the lateral movement of the person sitting on the chair to another seat.

The front arm 150 may comprise two rectangular profiles sliding one inside the other or a foldable tree.

The retraction of the front arm 150 can be effected for example by a secondary transmission shaft as shown in Figure 13, for example comprising two gimbals 205 and 206 connected by a retractable portion 207.

The operating levers 152 may be replaced by other means for driving the pivoting structures, for example a screw mechanism driven by a crank, the latter being for example arranged set back from the upper edge of the lateral uprights 105.

The screw can cooperate with a nut integral with the associated pivoting structure, so that a rotation of the screw in one direction or the other can lower or raising the pivoting structure 22. Where appropriate, the screw can provide a locking function of the associated pivoting structure in the raised or lowered position.

In other variants, the chains are replaced by a closed hydraulic system in which a pump is actuated by the rotation of the large rear wheels and hydraulic motors rotate the support elements.

The storage of the chair 1 is made for example by folding the frame, including elements that connect the side frames. The sleeves 25 can slide to release the coupling shaft 13 connecting the sub-mechanisms.

The coupling shaft 13 can be removable or foldable, for example by virtue of a hinge at its center which has an axis perpendicular to the axis Z.

The expression "having one" shall be understood as being synonymous with "having at least one", unless the opposite is specified.

It is possible to combine, within non-illustrated variants, various embodiments. The rotational drive of the large wheels can be electrically assisted, if necessary, as well as the tilting of the pivoting structures supporting the front support elements and the large rear wheels.

Claims

1. Wheelchair (1) comprising:

- a frame (2) supporting a seat (3), - two rear wheels (4) of large diameter, movable relative to the frame (2) between a low position for normal use of the chair and a raised position for the crossing of a stairway, an auxiliary propulsion mechanism for the crossing of a staircase, comprising: - front and rear support elements (2) configured to bear on steps of the stairway when the rear wheels are in the raised position and the chair back to the slope of the staircase, the front support elements and the rear support elements rotating about distinct axes of rotation (X, W), - a transmission system for transmitting a rotation of the large wheels rearward (4) in the raised position to the support elements to drive in rotation thereof and cause an ascent or descent of the staircase, according to the driving direction of the large rear wheels (4).

2. Armchair according to claim 1, the large rear wheels being carried by at least one structure (22) pivoting relative to the frame (2) about an axis of rotation (Z), the passage of the large rear wheels of the low position. in the raised position and vice versa being effected by a rotation of the pivoting structure (22).

3. A chair according to claim 1 or 2, the auxiliary mechanism comprising a transmission system arranged to reduce a force exerted on the large rear wheels in the raised position to rotate the support elements.

4. Chair according to any one of the preceding claims, the auxiliary mechanism comprising at least a first drive element (16) and the large rear wheels rotating with at least one second drive element (17), the second element d driving in drive engagement with the first drive element only when the large rear wheels are in the raised position.

5. Chair according to any one of the preceding claims, the auxiliary mechanism comprising left and right sub-mechanisms, the left sub-mechanism being associated with the left front and rear support elements and the left rear large wheel and the sub-mechanism. - Right mechanism being associated with the right front and rear support elements and the right rear large wheel.

6. Chair according to the preceding claim, the left and right sub-mechanisms being connected by a coupling shaft (13) so that the rotation of the left and right support elements is synchronous.

7. Chair according to any one of the preceding claims, each large rear wheel (4) being supported by a structure (22) pivoting relative to the frame.

8. A chair according to claim 7, the structure (22) comprising at least one actuating lever (152) operable by a user sitting on the seat and allowing, when actuated, to move the large rear wheels from the low position to the raised position and vice versa.

9. A chair according to claim 7, comprising a locking system of the pivoting structures (22) in the positions respectively corresponding to the raised position of the large rear wheels and the lowered position of the large rear wheels.

10. A chair according to claim 7, each pivoting structure comprising a rear arm (15) carrying the corresponding large rear wheel and a front arm (150) carrying a front support element.

11. Chair according to claims 8 and 10, the operating lever (152) connecting between the arms near the axis of rotation (Z) of the structure.

12. Chair according to any one of the preceding claims, the rear support elements (21) being rotatably mounted on the frame (22).

13. Chair according to claim 6, the coupling shaft (13) being foldable, removable or retractable.

14. Chair according to any one of the preceding claims, the frame (2) being foldable in the width direction.

15. Chair according to any one of the preceding claims, the large rear wheels (4) being removable.

16. Chair according to any one of claims 1 to 15, the large rear wheels (4) passing from the lowered position to the raised position at the end of an angular travel greater than or equal to 45 °.

17. Chair according to any one of claims 1 to 16, the large rear wheels passing from the lowered position to the raised position and at the end of an upward movement greater than or equal to 8 cm, especially in the case of an angular stroke up to 60 °.

18. Chair according to any one of the preceding claims, the large rear wheels passing from the lowered position to the raised position after a forward movement greater than or equal to 4 cm, especially in the case of a race. angular up to 60 °.

19. Chair according to any one of the preceding claims, the support elements (21) having crosses.

20. Chair according to the preceding claim, each cross comprising four branches (180) perpendicular to each other.

21. Chair according to the preceding claim, the distance between the axis (W) of rotation of the front support elements and the axis (Y) of rotation of the large rear wheels climbing configuration being greater than or equal to 70 cm. , better at 75 cm and the distance between the axis (Y) of rotation of the large rear wheels and the axis (X) of rotation of the rear support elements being greater than or equal to 50 cm, in climbing configuration.

22. Chair according to any one of the preceding claims, the passage of the large rear wheels from the lowered position to the raised position being effected manually, without motorized assistance.

23. Chair according to any one of the preceding claims, the drive in rotation of the large rear wheels, in the raised position, being performed without motorized assistance.

24. A chair according to claim 5, each sub-mechanism comprising a primary transmission shaft (160) having two toothing (161, 162) connected by transmission elements (163, 164) to corresponding teeth (168, 169) rotating. with the support elements respectively front and back.

25. Chair according to the preceding claim, the transmission elements comprising chains or at least a secondary transmission shaft, optionally retractable, provided if necessary with at least one bevel gear and / or at least one gimbal.

26. The chair according to claim 1, the propulsion mechanism comprising a hydraulic system comprising a pump actuated by the large wheels and hydraulic motors connected by a circuit closed to the pump and driving the front and rear support elements (160).

27. Chair according to claim 24, the primary transmission shaft (160) rotating with a toothing (18) meshing with an intermediate gear (16), the corresponding large rear wheel having an associated toothing (17) which, when the large wheel is in the raised position, come into engagement with the intermediate gear (16), so as to transmit the rotational movement (4) of the ferris wheel to the support elements (21).