WO2014177959A2

WO2014177959A2 - Device for the execution of exercises for mobilising paravertebral musculature.

Info

Publication number: WO2014177959A2
Application number: PCT/IB2014/060702
Authority: WO
Inventors: Marco FARETRA; Giovanni Barbanti
Original assignee: Barbalab S.R.L.
Priority date: 2013-04-30
Filing date: 2014-04-14
Publication date: 2014-11-06
Also published as: ITBO20130191A1; WO2014177959A3

Abstract

Described is a device (1) for the execution of exercises for mobilising paravertebral musculature comprising: a seat (2); a backrest (3) hinged to the seat (2) in such a way that it can rotate relative to it between a closed position, wherein the backrest is folded on the seat, a first operating position, rotated relative to the closed position in a direction of opening for allowing a person to sit on the seat resting the back on the backrest, and a second operating position, rotated relative to the first operating position in the direction of opening; a pre-loaded elastic element (4), connected by a kinematic mechanism with the seat (2) and the backrest (3), for generating a resistant force opposing a rotation of the backrest from the first to the second operating position, to oppose a thrust applied by the person using the paravertebral musculature; the backrest (3) comprises a frame (5) hinged to the seat (2) and a supporting element (6), designed for being operatively in contact with the back of the person during the exercise and movably connected to the frame (5) of the backrest (3) for moving relative to it under the thrust applied by the person to move the backrest (3) from the first to the second operating position.

Description

DESCRIPTION

DEVICE FOR THE EXECUTION OF EXERCISES MOBILISING PARAVERTEBRAL MUSCULATURE

Technical field

This invention relates to a device for the execution of exercises for mobilising paravertebral musculature.

Background art

The invention relates to the sector of mechanical rehabilitation equipment, aimed at providing an aid in the care of the spinal column pathologies, in order to limit or defer the use of surgery by adopting "conservative physiotherapy treatment".

In effect, the non-surgical treatment of pain caused by back pathologies starts with relaxation therapy and continues with teaching of the correct postures to be adopted and instruction of suitable exercises. To consolidate the work performed and reduce the probability of relapse it is necessary to strengthen the paravertebral musculature, of the lumbar extensors. The aim of this mobilising is to give greater stability to the verterbral column, strengthening the muscles which directly enter its vertebrae, and which form a sort of natural "trunk" for the lumbar section. The stronger the musculature, the more it is unlikely that the adoption of incorrect postures causes a movement of the disk towards structures which cause pain, that is, towards the spinal cord and its nerves.

The correct execution of the exercise for training the spinal paravertebral muscles, enabling the work to be performed solely on these muscles, is carried out with rehabilitation machines.

A correct execution of the exercise requires that the patient adopt a starting position on the machine or device which is seated and upright, in such a way that the vertebral column and the femur form an angle of approximately 90 degrees. The execution of the exercise is performed starting from this initial position, extending the back against a resistant force. The extension must be applied for approximately 40 degrees relative to the upright starting position. After reaching the predetermined position, one returns to the initial position reversing the movement of the back.

It is important that the return movement ends when the back is in a vertical position; in effect, if the back bends beyond this position, the abdominal muscles are worked, which act in the opposite way with respect to the paravertebral muscles and the forward bending presses the rear disk again.

Examples of these devices are provided in patent documents EP1543867A2 and US5100131A.

The prior art devices known from these patent documents are designed to allow a person to perform exercises which strengthen the paravertebral musculature.

More specifically, the device described in patent EP1543867A2 is a portable device which can be folded in a position of minimum dimensions. In effect, the device comprises a seat and a backrest hinged to the seat, wherein the backrest is foldable on the seat in a closed position of minimum dimensions.

In addition, the backrest may be rotated relative to the seat starting from the closed position in a direction of opening, to move the backrest to a first operating position, for starting the exercise, wherein the person sits on the seat and rests the back on the backrest.

During the execution of the exercise, the backrest moves from the first to a second operating position, in an active movement wherein the person overcomes the resistant force and, from the second to the first operating position, in a passive return movement.

The resistant force comprises a pre-loaded elastic element, designed to generate a resistant force opposing a rotation of the backrest from the first to the second operating position, to oppose a thrust applied by the person using the paravertebral musculature.

The elastic element comprises a system of springs housed in a compartment defined by the seat and connected by a kinematic mechanism to the backrest through the agency of a cam.

The purpose of the cam is make the resistant force of the springs intervene only in the rotation from the first to the second operating position, and not in the rotation from the closed position to the first operating position.

However, these prior art devices have several drawbacks.

Firstly, these devices are uncomfortable for the persons executing the exercise.

Moreover, they are particularly complicated, from the construction point of view.

Other portablel devices for performing physical rehabilitation exercises are known from the following patent documents: US6113524A, GB2409177, WO2011/055963, US5441473A, CN201625373U.

However, these devices do not allow an action specifically aimed at mobilising the paravertebral musculature and do not allow folding in such a way as to minimise their dimensions.

Disclosure of the invention

The aim of this invention is to provide a device for the execution of exercises for mobilising paravertebral musculature that overcomes the above mentioned drawbacks of the prior art.

More specifically, the aim of this invention is to provide a device for the execution of exercises for mobilising paravertebral musculature which is particularly comfortable and effective for the person who uses it.

A further aim of this invention is to propose a device for the execution of exercises for mobilising paravertebral musculature which has a particularly simple construction, whilst guaranteeing high performance levels.

These aims are fully achieved by the device according to the invention as characterized in the appended claims.

More specifically, the device according to the invention is a device for the execution of exercises for mobilising paravertebral musculature.

The device comprises a seat and a backrest hinged to the seat.

The backrest and the seat are movable relative to each other for rotation in a direction of closing, towards each other, up to a closed position; and for rotation in a direction of opening, from the closed position to a first operating position and further up to a second operating position.

The first operating position is a position for starting the exercise, wherein the seat and the backrest are substantially perpendicular, to allow a person to be seated on the seat whilst resting the back on the backrest. The second operating position is rotated relative to the first operating position in the direction of opening (for example by approximately 40-50 degrees).

The device comprises a pre-loaded elastic element, connected by a kinematic mechanism with the seat and the backrest, for generating a resistant force opposing a rotation of the backrest from the first to the second operating position.

During the rotation of the backrest relative to the seat between the closed position and the first operating position, and vice versa, the elastic element does not offer resistance (or offers a particularly low resistance), that is, it is in a deactivated operating configuration. On the other hand, during the rotation of the backrest relative to the seat between the first and the second operating position, the elastic element offers a resistance (significantly greater than the resistance offered between the closed position and the first operating position, which is preferably zero or almost zero) opposing the rotation of the backrest in the direction of opening, and, favouring the rotation of the backrest in the direction of closing.

The elastic element is preferably a pre-loaded elastic element.

The purpose of the elastic element is to oppose the thrust applied by the person using the paravertebral musculature, for moving the backrest from the first to the second operating position.

The backrest has a frame. The seat is hinged to the frame; more specifically, the seat is hinged to the frame to allow a relative rotation between the backrest and the seat about at least one axis of rotation.

According to this invention, the backrest comprises a supporting element, designed to be operatively in contact with the back of the person during the exercise, which is movably connected to the frame of the backrest. More specifically, the supporting element is movably connected to the frame to move relative to it under (that is, due to the effect of) the thrust applied by the person for moving the backrest from the first to the second operating position.

For this reason, the supporting element follows the movement of the back of the person and makes the backrest adaptable dynamically to the position of the back, during the exercise, as a function of the angle of inclination between the seat and the backrest (in particular between the first and second operating positions).

This makes the device particularly comfortable and effective because it prevents a rubbing of the back against the backrest.

It should be noted that the frame of the backrest is elongate, away from an axis of rotation of the backrest relative to the seat, along a longitudinal axis. In other words, the frame of the backrest is elongate along a longitudinal axis perpendicular to the axis of rotation between the seat and the backrest (or to an axis parallel to it). For example, the frame of the backrest comprises a bar.

Preferably, the supporting element has at least one mobile surface parallel to the longitudinal axis.

Preferably, the mobile element (of the backrest) comprises a slide slidably coupled to the frame of the backrest, so as to move along the frame (along the longitudinal axis) towards and away from the axis of rotation of the backrest relative to the seat.

More specifically, the slide moves towards the axis of rotation between the backrest and the seat, with the increase in the angle of opening of the backrest relative to the seat, and moves away from the axis of rotation between the backrest and the seat, with the decrease in the angle of opening of the backrest relative to the seat.

In that way, the zone of the backrest in contact with the supporting element remains the same during the exercise.

This makes the device even more comfortable and effective.

With regard to the method of connection of the slide to the frame of the backrest, use is made of rolling elements, or, alternatively, a sliding contact.

In any case, preferably, the frame is equipped with a guide (located along the longitudinal axis along which the frame is elongate); the guide is coupled with rolling elements or sliding elements, for guiding the sliding of the supporting element along the frame.

Preferably, the supporting element of the backrest comprises at least one roller rotating about an axis parallel to the axis of rotation of the backrest relative to the seat. In this case, the back of the person rests on the roller. If the device comprises the above mentioned slide (sliding along the frame of the backrest), the roller is hinged to the slide. That way, the roller has a relative axis of rotation movable along the frame.

It should be noted that there is also an embodiment (without the slide), wherein the supporting element of the backrest comprises the at least one roller, which is hinged the frame of the backrest in a fixed position. In this case, the roller has the respective axis of rotation stationary relative to the frame.

Also in this case, however, during the execution of the exercise the portion of roller instantaneously in contact with the back moves parallel to the plane in which the backrest lies (in practice it moves on a plane parallel to that on which the backrest lies and tangential to the outer surface of the roller).

In the embodiment comprising the slide, the latter defines a supporting surface for the back, without the interposing of a roller.

Thus, according to various embodiments , the back rests directly on a slide slidable along the frame of the backrest, or on a roller sliding along the frame of the backrest, or on a roller coupled in a fixed position relative to the backrest.

According to another aspect of this invention, the seat has a cavity shaped to contain the backrest in the closed position.

This allows a further reduction in the dimensions of the device, in the closed position.

According to another aspect, with regard to the elastic element designed to generate the resistant force, this invention provides particularly simple and effective solutions such that the elastic element intervenes only (or mainly) in the rotation between the first and the second operating position and not (or very seldomly) between the first operating position and the closed position.

In light of this, it should be noted that the backrest and the seat rotate relative to each other about an axis of istantaneous rotation; the axis is not necessarily always the same during the movement of the backrest from the closed position to the second operating position.

Preferably, the elastic element comprises a first end fixed to the backrest (or to the seat) and a second end operatively connected to the seat (or to the backrest, respectively), at a point positioned at a variable distance relative to the axis of instantaneous rotation.

More specifically, the elastic element is preferably a pre-loaded spring; alternatively, for example, an elastic segment has a first end fixed to the backrest (or to the seat) and a second end operatively connected to the seat (or to the backrest, respectively), at a point located, relative to the axis of instantaneous rotation, at least at a first distance, in a first stretch of the relative rotation between the backrest and the seat, and at least at a second distance different from the first, in a second stretch of the rotation. Preferably, more specifically, the backrest and the seat are connected by a kinematic mechanism in such a way as to rotate about a first axis of rotation, between the closed position and the first operating position, and about a second axis of rotation, located at a predetermined distance from the first axis of rotation, between the first and the second operating position.

In this case, preferably, the elastic element is a spring (pre-loaded) having a first end fixed to the backrest (or to the seat) and a second end fixed to the seat (or to the backrest, respectively), at a point lying on the first axis of rotation.

In that way, the spring maintains a constant length during the rotation between the closed position and the first operating position, and varies ots length (due to the force applied by the person on the backrest) in the rotation between the first and second operating positions.

In a variant embodiment, the elastic element is an elastic segment (pre- loaded) fixed to the seat (or to the backrest) and designed for interacting with the backrest (or with the seat, respectively), in the rotation between the first and second operating position, and designed for being moved away from the backrest (or from the seat, respectively), in the rotation between the closed position and the first operating position.

According to another aspect of this invention, the device comprises means for adjusting the pre-loading force of the elastic element.

This allows the device to be adapted to different levels of training or rehabilitation of the person.

For example, if the elastic element is a spring, one of its ends is fixable at different points of the backrest (or of the seat); that is to say, the device comprises a locking and releasing element configured to release the end fixed to the backrest (or to the seat) and to lock the same end at a different point of the backrest (or of the seat).

If the elastic element is a segment, the device comprises a constraining element operatively acting on a portion of the segment located at a distance from the point where the segment is fixed to the seat (or to the backrest); moreover, the device comprises a locking and releasing element configured to release the constraining element from the segment and re-lock it in a different position, at a different distance from the point at which the segment is fixed to the seat (or to the backrest).

Brief description of the drawings

These and other features will become more apparent from the following detailed description of a preferred, non-limiting embodiment of the invention, with reference to the accompanying drawings, in which:

- Figure 1 is a perspective view of a device according to this invention;

- Figure 2 is a side view in a closed position of the device of Figure 1 ;

- Figure 3 is a side view in a first operating position of the device of Figure

1 ;

- Figure 4 is a side view in a second operating position of the device of Figure 1 ;

- Figure 5 illustrates the device of Figure 1 schematically and in a first embodiment of a movable element;

- Figure 6 illustrates the device of Figure 1 schematically and in a first embodiment of the movable element, in the first operating position;

- Figure 7 illustrates the device of Figure 6 in the second operating position;

- Figure 8 illustrates the device of Figure 1 schematically and in a second embodiment of the movable element, in the first operating position;

- Figure 9 illustrates the device of Figure 8 in the second operating position;

- Figure 10 illustrates the device of Figure 8 in the closed position;

- Figure 11 illustrates a detail of the device of Figure 8, according to a variant embodiment;

Figure 12 illustrates the detail of Figure 1 1 , according to a variant embodiment;

- Figure 3 illustrates the detail of Figure 12, according to a further variant embodiment;

- Figure 14 illustrates a detail of the device of Figure 1 , in a partly open view and in the closed position;.

- Figure 15 illustrates the detail of Figure 14, in the first operating position; - Figure 16 illustrates the detail of Figure 14, in the second operating position.

Detailed description of preferred embodiments of the invention

With reference to the accompanying drawings, the numeral 1 denotes a device according to the invention.

The device 1 is a device for the execution of exercises for mobilising paravertebral musculature.

The device 1 comprises a seat 2 and a backrest 3.

The backrest 3 is movably coupled to the seat 2 so as to rotate relative to it, without interruption, between the following positions:

- a closed position, of minimum distance between the backrest 3 and the seat (in practice, the backrest 3 is folded on the seat 2);

- a first operating position, rotated relative to the closed position in a direction of opening (it is an initial position for execution of the exercise, wherein the person is seated on the seat 2 with the backrest at approximately 90 degrees relative to the seat);

- a second operating position, rotated relative to the first operating position in the direction of opening (in such a way that the backrest 3 forms with the seat an angle greater than 90 degrees, approximately 130-150 degrees, for example).

Preferably, the backrest 3 is hinged to the seat 2 so as to rotate relative to it.

The device 1 comprises a pre-loaded elastic element 4.

The elastic element (a spring in the example illustrated) is connected by a kinematic mechanism with the seat 2 and the backrest 3, for generating a resistant force designed to oppose a rotation of the backrest from the first to the second operating position, to oppose a thrust (that is, a torque) applied by the person using the paravertebral musculature.

The backrest 3 comprises a frame 5. For example, the frame 5 is a bar, or an upright, or a rod-shaped element.

The frame 5 has a first end hinged to the seat 2 and a second free end. In addition, the backrest 3 comprises a supporting element 6 configured to be operatively in contact with the back of the person during the exercise. More specifically, the supporting element 6 defines least one portion projecting in cantilever fashion from a wall 7 of the frame 5 directed towards the seat 2.

The supporting element 6 is movably connected to the frame 5 of the backrest 3 for moving relative to it; more specfically, under the thrust applied by the person to move the backrest 3 from the first to the second operating position.

The frame 5 of the backrest 3 is elongate along a longitudinal axis, directed from a zone wherein the frame 5 is hinged to the seat 2 and proceeding away from the hinge zone (that is to say, away from an axis of rotation of the backrest 3 relative to the seat 2).

The supporting element 6 defines at least one surface 8 which is movable parallel to the longitudinal axis. The surface 8 of the supporting element 6 is a surface which is operatively in contact with the back of the person during execution of the exercise.

The supporting element 6 (more specifically, the surface 8 of the supporting element 6) rotates and/or translates relative to the frame 5 of the backrest 3, as well as moving as one with the backrest 3 during the rotation of it relative to the seat 2.

In a possible embodiment, the device 1 comprises a slide 9 slidably coupled to the frame 5; the slide 9 is slidably coupled to the frame 5 for translating along the longitudinal axis of the frame 5. It should be noted that, functionally, the slide is part of the supporting element 6 (even if it does not necessarily constitute a support for the back of the person). Thus, the slide 9 is slidably coupled to the frame 5 of the backrest 3, so as to move along the frame towards and away from the at least one axis of rotation of the backrest 3 relative to the seat 2.

Operatively, during execution of the exercise, the slide 9 moves close to the axis of rotation between the seat 2 and the backrest 3, with the increase in the angle of opening of the backrest 3 relative to the seat 2. The slide 9 is coupled to the frame 5 of the backrest 3 according to different possible ways.

For example (Figures 8-10) the slide 9 is coupled to the frame 5 of the backrest 3 by a runner 10 sliding on a guide defined by the frame 5 (for example, the runner 0 is formed by the slide).

In another example, the slide 9 is coupled to the frame 5 of the backrest 3 by rolling elements, such as bearings 11 (spherical or cylindrical or other type).

In this case, the rolling elements may be coupled to the slide 9 to translate with it along the frame (example of Figure 13) or, alternatively, they may be coupled to the frame 5 to remain stationary relative to the movement of the slide 9 relative to the frame 5 (example of Figure 12).

In a variant embodiment (example of Figure 11), the slide 9 is coupled to the frame 5 of the backrest 3 by rolling elements, consisting of one or more toothed cylinders 12 engaged in a rack 13 defined by the frame 5. The supporting element 6 comprises (defines) the supporting surface 8 (which is operatively in contact with the back of the person during execution of the exercise).

According to a possible embodiment, the supporting surface 8 is defined by the slide 9, that is, it is integral with the slide.

In this case, the supporting surface 8 is translated relative to the frame 5 but does rotate relative to it.

According to another possible embodiment, the supporting surface 8 is defined by a roller 14.

In light of this, the supporting element 6 comprises one or more of the rollers 14.

The roller 14 is rotatably coupled to the frame 5 at a distance from the axis of rotation between the seat 2 and the backrest 3.

According to a possible embodiment (example of Figure 5), the roller 14 (or the rollers 14) is hinged to the frame 5 in a fixed position.

In this case, the supporting surface 8 translates relative to the frame 5 but does not rotate relative to it; the translation is caused by a rotation about an axis of the roller 14 and the supporting surface 8 changes with the variation in the inclination between the backrest 3 and the seat 2, as the roller 14 rotates relative to the back of the person but its axis of rotation remains stationary relative to the frame 5.

According to another possible embodiment (example of Figures 6 and 7), the roller 14 (or the rollers 14) is hinged to the frame 5 in such a way that the axis of rotation of the roller can slide (translate) along the frame 5. For example, in that case the roller 14 is hinged to a slide 9 (the slide 9 is, for example, according to any of the types described above).

Whatever the case, the roller 14 is rotatable about its own axis which is parallel to an axis of rotation of the backrest relative to the seat.

Preferably, the seat 2 has a cavity shaped to contain the backrest 3 in the closed position.

Preferably, the cavity 5 of the seat 2 comprises a flare in a zone of the cavity facing the opposite side relative to a hinge zone between the backrest 3 and the seat 2.

Preferably, the elastic element 4 comprises a first end fixed to the backrest 3 (or to the seat 2) and a second end operatively connected to the seat 2 (or to the backrest 3, respectively), at a point positioned at a variable distance relative to the axis of instantaneous rotation (meaning the rotation between the seat 2 and the backrest 3).

Preferably, the backrest 3 and the seat 2 are connected by a kinematic mechanism in such a way as to rotate about a first axis of rotation 16, between the closed position and the first operating position, and a second axis of rotation 17, located at a predetermined distance from the first axis of rotation 16, between the first and the second operating position.

Moreover, the elastic element 4 comprises a first end fixed to the backrest 3 (or to the seat 2) and a second end fixed to the seat 2 (or to the backrest 3, respectively), at a point lying on the first axis of rotation 6.

In that case, the elastic element 4 is a spring (pre-loaded to act in traction or compression).

To obtain the effect of change of the relative axis of rotation between the seat 2 and the backrest 3, the seat 2 comprises, for example (example illustrated in Figures 14-16), a contact element 18 hinged to rotate around the second axis of rotation 17 and shaped in such a way as to interact with one end of the backrest 3, for moving as one with the backrest 3 by angles of opening of the backrest 3 relative to the seat 2 greater than or equal to that corresponding to the first operating position.

In a variant embodiment, not illustrated, of the elastic element 4 (relative to the embodiment consisting of a spring), the elastic element is an elastic segment fixed to the seat 2 (or to the backrest 3).

The elastic segment is fixed at one end and is connected to a further point at a predetermined distance from the end, to define a pre-loading.

The elastic segment is configured to interact with the backrest 3 (or with the seat 2, that is to say, with the element, between seat and backrest, to which it is not fixed), in the rotation between the first and the second operating position, for generating a resistant force which opposes a rotation of the backrest in the direction of opening; moreover, the elastic segment is configured to be in a position of non-interference with the backrest 3 (or with the seat 2, that is to say, with the element, between seat and backrest, to which is not fixed), in the rotation between the closed position and the first operating position.

Claims

1. A device (1) for the execution of exercises for mobilising paravertebral musculature, comprising:

- a seat (2);

- a backrest (3) hinged to the seat (2) in such a way that it can rotate relative to it between a closed position, wherein the backrest is folded on the seat, a first operating position, rotated relative to the closed position in a direction of opening for allowing a person to sit on the seat resting the back on the backrest, and a second operating position, rotated relative to the first operating position in the direction of opening;

- a pre-loaded elastic element (4), connected by a kinematic mechanism with the seat (2) and the backrest (3), for generating a resistant force opposing a rotation of the backrest from the first to the second operating position, to oppose a thrust applied by the person using the paravertebral musculature,

characterised in that the backrest (3) comprises:

- a frame (5), the seat (2) being hinged to the frame;

- a supporting element (6) designed for being operatively in contact with the back of the person during the exercise and movably connected to the frame (5) of the backrest (3) for moving relative to it under the thrust applied by the person to move the backrest (3) from the first to the second operating position.

2. The device according to claim 1 , wherein the frame (5) of the backrest (3) extends along a longitudinal axis away from an axis of rotation of the backrest (3) relative to the seat (2), and wherein the supporting element (6) has at least one surface (8) movable parallel to the longitudinal axis.

3. The device according to claim 1 or 2, wherein the supporting element (6) of the backrest (3) comprises a slide (9) slidably coupled with the frame (5) of the backrest, for moving along the frame (5) towards and away from an axis of rotation of the backrest (3) relative to the seat (2), with the increasing and decreasing of an angle of opening of the backrest relative to the seat, respectively.

4. The device according to claim 3, wherein the slide (9) is coupled to the frame (5) of the backrest (3) by rolling elements (11 , 12) or by sliding elements (10), interacting with a guide integral with the frame (5).

5. The device according to claim 3 or 4, wherein the supporting element (6) of the backrest (3) comprises at least one roller (14) hinged to the slide (9) and rotating about an axis parallel to an axis of rotation of the backrest (3) relative to the seat (2).

6. The device according to claim 1 or 2, wherein the supporting element (6) of the backrest (3) comprises at least one roller (14) rotating about an axis parallel to an axis of rotation of the backrest (3) relative to the seat (2) and hinged to the frame (5) of the backrest (3) in a fixed position.

7. The device according to any one of the preceding claims, wherein the seat (2) has a cavity (15) shaped for containing the backrest (3) in the closed position.

8. The device according to any one of the preceding claims, wherein the backrest (3) and the seat (2) rotate relative to each other about an axis of instantaneous rotation, and wherein the elastic element (4) has a first end fixed to the backrest (3) or to the seat (2) and a second end operatively connected to the seat (2) or to the backrest (3), respectively, at a point positioned, relative to the instantaneous axis of rotation, at least at a first distance, in a first stretch of the relative rotation between backrest and seat, and at a second distance different from the first, in a second stretch of the rotation.

9. The device according to any one of the preceding claims, wherein the backrest (3) and the seat (2) are connected by a kinematic mechanism in such a way as to rotate about a first axis of rotation (16), between the closed position and the first operating position, and a second axis of rotation (17) located at a predetermined distance from the first axis of rotation (16), between the first and the second operating position, and wherein the elastic element (4) is a spring having a first end fixed to the backrest (3) or the seat (2) and a second end fixed to the seat (2) or the backrest (3), respectively, at a point lying on the first axis of rotation (16).

10. The device according to any one of claims 1 to 8, wherein the elastic element (4) is an elastic segment fixed to the backrest (3) or to the seat (2) and designed for interacting with the seat (2) or with the backrest (3), respectively, in the rotation between the first and second operating position, and designed for being moved away from the seat (2) or from the backrest (3), respectively, in the rotation between the closed position and the first operating position.