Chair for the sitting of a user

Abstract

Chair comprising a support structure, a seat with an upper face and a lower face, a flexible covering element, a flexible tensioning element and a traction element, which is rotatable in a tensioning sense and is provided with a perimeter toothing. The seat comprises a flexible blocking lever, which extends in a single piece from a first end, connected to the lower face, to a second free end, at which point the blocking lever is provided with a coupling portion. The first end of the blocking lever defines a rotation pivot, and the blocking lever is elastically movable around the rotation pivot between an engagement position, in which the coupling portion engages the perimeter toothing to prevent the rotation of the traction element in a direction opposite to the tensioning sense, and a release position, in which is allowed the free rotation of the traction element in the tensioning sense.

Description

Field of application

[0001] The present invention relates to a Chair for the sitting of a user according to the preamble of independent claim No. 1.

[0002] The chair in question is intended to be used to allow the sitting of a user, both in offices, studies and similar locations (in particular during working hours) and in private homes, for example in studies, kitchens or living rooms.

[0003] The chair in question is advantageously an upholstered chair, i.e. equipped with a layer of padding (such as foam) that is placed on top of the seat panel and covered with a covering element.

[0004] The chair that is the subject of this invention therefore falls within the field of furniture for both work and home environments, and more generally within the field of furniture manufacturing, in particular the manufacture of chairs or chair parts.State of the art

[0005] Chairs of the known type can be made in a single piece, for example in plastic or metal, and therefore provide a support structure and a seat to support a user in a sitting position. Such chairs have proven to be uncomfortable to use for prolonged periods of time, both in the workplace and at home, due to the high rigidity of the seat on which the user rests during use.

[0006] For this purpose, ergonomic chairs have been developed, which feature a padded seat (usually made of polyurethane foam) to create a softer support surface for the user and thus improve seating comfort.

[0007] Such known chairs comprise a support base, for example with fixed support legs or a base with wheels to allow the chair to move on the floor, and a seat mounted on the support base, on which a user can sit during normal use of the chair. In particular, the seat comprises a rigid support, fixed to the support base of the chair, and a covering element (made, for example, of fabric or leather), which is arranged to cover the rigid support.

[0008] In this way, the covering element provides a seating surface for the user while also improving the external appearance of the seat. Normally, the seat also includes a layer of padding (usually made of elastic foam, such as polyurethane foam), which is placed between the rigid support and the covering element to make the seat more comfortable for the user. The padding layer is sometimes shaped with a bulge at its upper surface (on which the covering element is placed), which is elastically yielding, making the seat more comfortable for the user and helping to keep the covering element taut.

[0009] In known chairs, the seat covering element is stretched around the padding layer and fixed to the rigid support by means of nails or staples to ensure that the covering element, wrapped around the rigid support, is fixed under tension.

[0010] This operation is usually carried out by hand by a skilled user, who places the seat upside down and manually tensions (locally) the covering element and then secures it locally to the rigid support using the aforementioned fasteners, repeating this operation numerous times until the covering element is secured along its entire perimeter edge.

[0011] However, the chairs of the type described above have proved to have some drawbacks in practice. The main drawback is that this fastening operation takes a long time to perform and must be carried out by a specialist to ensure that the covering element is pulled evenly across the entire seat, thus preventing the formation of excess fabric due to areas of lower tension, which can make the chair uncomfortable or unattractive.

[0012] A further drawback is that the covering element tends to wear out and / or lose its tension after prolonged use of the chair. To overcome the wear of the covering element, it is necessary to replace it with a new covering. However, replacing the covering element requires the removal of the fasteners that secure the covering element to the seat support body, resulting in an inconvenient and laborious process.

[0013] To overcome this problem, chairs have been developed in which the covering element (e.g. fabric) is equipped with a cord around the perimeter, which can be pulled by the user to simultaneously tension the entire fabric around the rigid seat support. This significantly reduces the time required to cover the seat of the chair, as the user simply pulls on the string to tighten the fabric and then secures it to the rigid support. The fabric is secured using traditional methods, such as nails or staples, but without the need to tighten the fabric locally as in previous chairs.

[0014] However, even the chairs of the type described above have proved to have some drawbacks in practice.

[0015] The main drawback is that this fastening operation also takes a long time to perform, as it requires the same operation of fastening the fabric to the rigid support using nails or staples.

[0016] A further drawback lies in the fact that these chairs are expensive and extremely complex to manufacture and assemble, as they are made up of numerous components that must be joined together, for example using screws, bolts, hinges, etc. This requires a considerable amount of time, as well as highly specialised personnel to assemble the chair correctly for its end use.

[0017] A further drawback lies in the fact that the seat of chairs of the known type cannot be replaced or adjusted in its individual components. More specifically, once the seat is assembled, it is impossible to replace or adjust the covering element, for example due to wear and tear or simply because the chair needs to be used for a different purpose.

[0018] In fact, in chairs of the known type, replacing or adjusting the seat covering element requires removing each nail or staple in order to separate it from the rigid support, and then reattaching it once it has been replaced.

[0019] A further drawback is that the seat of chairs of the known type cannot be re-tensioned after it has been fixed in place. This may be necessary, in particular, if the covering element loosens or creases over time, resulting in it being less taut than it was originally.

[0020] A further drawback is that the seat of chairs of the known type cannot be recycled efficiently, as it does not allow (except in a very complicated and laborious manner) the separation of the individual elements that make up the seat.

[0021] A further drawback is that the assembly of the seat of this type of chair also requires the presence of a specialised user. In particular, the aforementioned assembly requires particular sensitivity on the part of the user, who must ensure that, when tensioning the string, the covering element does not move with respect to the padding layer, causing sub-optimal alignment of the seat components. A further drawback lies in the fact that such chairs of the known type have proved to be aesthetically unattractive and unpopular with the public, as they are difficult to fit into contexts where product design is important, such as minimalist contexts.Presentation of the invention

[0022] In this situation, the problem underlying the present invention is therefore to overcome the drawbacks of known chairs by providing a Chair for the sitting of a user which can be assembled easily, without the need for a specialist.

[0023] A further purpose of the present invention is to provide a chair that can be easily and quickly adjusted and dismantled, particularly with regard to the tensioning of the covering element.

[0024] A further purpose of the present invention is to provide a chair which allows the covering element of the support element to be re-tensioned over time.

[0025] A further purpose of the present invention is to provide a chair which allows easy replacement of the covering element.

[0026] A further purpose of the present invention is to provide a chair which is easily recyclable in all its components.

[0027] A further purpose of the present invention is to provide a chair that is simple and inexpensive to manufacture.

[0028] A further purpose of the present invention is to provide a chair that is aesthetically pleasing and attractive.Brief description of the drawings

[0029] The technical characteristics of the invention, according to the aforementioned purposes, are clearly evident from the content of the claims below, and the advantages thereof will be more evident in the detailed description that follows, made with reference to the attached drawings, which represent a purely illustrative and non-limiting form of implementation, in which: Figure 1 shows a perspective view of the Chair for the sitting of a user that is the subject of this invention; Figure 2 shows an exploded view of a seat of the chair that is the subject of the present invention; Figure 3 shows an exploded view and a perspective view of the seat shown in Figure 2; Figure 4 shows an exploded view and a perspective view of the seat shown in Figure 3, equipped with a covering element; Figure 5 shows a perspective view of a traction element of the chair that is the subject of this invention; Figure 6 shows a perspective view and a top view of the traction element in Figure 5, with a tensioning element attached. Figure 7 shows a perspective view and a top view of the traction element during the winding of the tensioning element; Figure 8 shows a view from below of the traction element; Figure 9 shows a sectional view of the traction element in Figure 8, taken along line A-A'. Figure 10 shows a view from below of the traction element, with a blocking lever in the release position. Figure 11 shows a sectional view of the traction element, with the blocking lever in the release position. Figure 12 shows a view from below of the traction element, with the blocking lever in the engaged position. Figure 13 shows a sectional view of the traction element, with the blocking lever in the engaged position. Detailed description of a preferred embodiment

[0030] With reference to the attached drawings, the chair for the sitting of a user that is the subject of this invention is indicated as a whole with 1, which is advantageously suited to be placed as a piece of furniture in both public and private environments, both at work and at home. In particular, chair 1, which is the subject of this invention, is intended to be advantageously used for the sitting of a user, for example, for the sitting of a worker in an office, or for the sitting of a user in a private and / or domestic environment.

[0031] According to the invention, chair 1 comprises a support structure 2, designed to rest on the ground. Advantageously, the support structure 2 comprises a support base 20, intended to be placed on the floor, and on which a column 11 is advantageously mounted, for example a gas column configured to allow height adjustment of a seat of the chair 1.

[0032] Advantageously, the support base 20 of chair 1 comprises multiple support legs 21, which are preferably equipped with wheels 211 to allow chair 1 to be moved across the floor during use. Obviously, it is also possible to provide a support base 20 of the pedestal type, without support legs, or to provide a support base 20 in which the legs are without wheels, so as to allow greater stability of chair 1 during use.

[0033] Advantageously, the support structure 2 of chair 1 can be made of metal, for example steel or aluminium, or alternatively of plastic.

[0034] In accordance with the invention, chair 1 also comprises a seat 3, mounted on the support structure 2, and equipped with an upper face 30, designed to receive a user in a seated position, and an opposite lower face 31, designed to face the floor.

[0035] In particular, chair 1 advantageously comprises a support frame 35, for example a frame with arched arms as shown in Figure 1, which supports seat 3. Preferably, support frame 35 is mechanically mounted at the top of column 11 of support structure 2, and even more preferably, the support frame 35 is advantageously rotatably mounted on the column 11, so as to allow the seat 3 to rotate around the axis of development of the column 11, preferably being able to perform a complete rotation (360°) around the latter.

[0036] Alternatively, the support frame 35 can be fixed to the support structure 2, more precisely to the column 11, and therefore configured to remain in a fixed position. Obviously, without limitation, the seat 3 can be connected to the support structure 2 in different ways and with different degrees of freedom, without this falling outside the scope of protection of the present invention.

[0037] The chair 1 also comprises a flexible covering element 4, for example made of fabric, leather or imitation leather, placed to cover at least the upper face 30 of the seat 3 and equipped with the main portion 40.

[0038] In particular, the covering element 4 is advantageously a flexible sheet-like element, which wraps around the upper face 30 of the seat 3 to define a seating surface for the user and give the seat 1 a particular aesthetic value.

[0039] In particular, seat 3 advantageously comprises at least one support element 34, preferably rigid, and at least one cushioning element 33, which has at least one flexible and yielding layer, preferably made of elastic foam (e.g. polyurethane foam), which is arranged between the support element 34 and the covering element 4, to make sitting on seat 3 more comfortable for a user. Preferably, the support element 34 defines a housing volume within which the cushioning element 33 is at least partially housed, as illustrated in Figure 3.

[0040] Advantageously, the support element 34 and the cushioning element 33 are connected to each other by means of fasteners, not shown in the accompanying figures.

[0041] In particular, cushioning element 33 advantageously defines the upper face 30 of seat 3, while support element 34 advantageously defines the lower face 31 of the same seat 3. Advantageously, cushioning element 33 has an ergonomic, slightly curved shape, so as to define an ergonomic support surface that better adapts to the user in a seated position. Advantageously, the cushioning element 33 may have an upper portion 330, which is formed by the flexible layer, and a lower portion 331, preferably rigid, which is configured to engage with the support element 34 of the seat 3.

[0042] Advantageously, the covering element 4 is fitted to cover at least the cushioning element 33, preferably extending to partially wrap around the support element 34 as well, at least at one of its perimeter edges, as shown in Figure 4.

[0043] More specifically, when fitted onto the seat 3, the covering element 4 wraps around the upper face 30 of the seat and therefore the corresponding surface of the cushioning element 33.

[0044] In accordance with the invention, chair 1 also comprises a flexible tensioning element 5, which is engaged with the main portion 40 of the covering element 4 and is equipped with a grip portion 50.

[0045] In particular, the grip portion 50 of the tensioning element 5 advantageously has two opposite grip ends 50', 50", which may be free or joined together, and extends from one side of the seat 3, preferably substantially orthogonally to that side, along a direction of extension E. Advantageously, the covering element 4 is preferably equipped with a passage seat 41 formed at its main portion 40, inside which at least one engagement portion 51 of the tensioning element 5 is inserted. Advantageously, the engagement portion 51 of the tensioning element 5 is preferably fixed inside the passage seat 41, so as to be integral with the main portion 40 of the covering element 4.

[0046] Advantageously, without departing from the scope of protection of the present invention, the engagement portion 51 of the tensioning element 5 may be slidably engaged with the main portion 40, in particular with the passage seat 41 of the covering element 4, allowing the tensioning element 5 to move relative to the covering element 4.

[0047] Preferably, the passage seat 41 is obtained by folding and sewing the same main portion 40 to create a through slot.

[0048] Alternatively, it is also possible to create the passage seat 41 by sewing an additional element or by sewing the same tensioning element 5.

[0049] For example, in accordance with the embodiment illustrated in the attached figures, the tensioning element 5 is a string or cord, which is inserted along the main portion 40 of the covering element 4, and more precisely inside the passage seat 41.

[0050] Advantageously, the grip portion 50 of the tensioning element 5 can be pulled to tension the covering element 4.

[0051] Preferably, the grip portion 50 of the tensioning element 5 is advantageously separated from the covering element 4, and in particular is detached from the latter and located outside the passage seat 41 of the covering element 4 itself, so that it can be grasped and pulled.

[0052] In this way, the tensioning element 5 is pulled, dragging with it the main portion 40 of the covering element 4 (to which it is engaged), and thus allowing the latter to be tensioned.

[0053] In other words, the covering element 4 advantageously carries the tensioning element 5 connected peripherally in such a way that, by pulling the grip portion 50, it is possible to tension substantially the entire covering element 4, preferably in a uniform manner.

[0054] Advantageously, the support element 34 preferably comprises a plurality of coupling elements 36. In particular, each of the coupling elements 36 defines an upward-facing receiving seat 361, which is designed to receive the grip portion 50 of the tensioning element 5.

[0055] Advantageously, for each coupling element 36, the distance between two consecutive coupling elements 36', 36" is preferably substantially constant.

[0056] In this way, the grip portion 50 of the tensioning element 5 is advantageously uniformly supported by the coupling portions 36, substantially along the entire direction of development E, preventing the grip portion 50 from having loose sections.

[0057] In accordance with the idea underlying the present invention, chair 1 comprises a traction element 6, preferably made of polymeric material, which is mechanically connected to the grip portion 50 of the tensioning element 5 and is mounted, in a rotatable manner, on the lower face 31 of the seat 3, and rotatable about a rotation axis R, in a tensioning sense T (e.g. clockwise).

[0058] Advantageously, the traction element 6 acts as a winding spool for the tensioning element 5.

[0059] In particular, the traction element 6 is mounted on the lower face 31 of the seat 3 and is constrained to the latter in such a way as to allow only the rotation of the traction element 6 around the rotation axis R, as described in more detail below.

[0060] In this way, rotating the traction element 6 in the tensioning sense T allows the tensioning element 5 to be at least partially wound onto the traction element 6 and the covering element 4 to be tensioned, preferably progressively, around the seat 3.

[0061] In other words, the traction element 6, as described in more detail below, advantageously allows both the tensioning element 5 to be secured to the seat 3, and also to tension the tensioning element 5 itself, and therefore the covering element 4, to complete the assembly of the seat 3 with the covering element 4 correctly mounted and tensioned on the seat 3 of the chair 1.

[0062] In this way, the covering element 4 can be easily tensioned when it is fitted onto the support element 33 of the seat 3 by rotating the traction element 6 in the tensioning sense T.

[0063] In particular, after the covering element 4 has been tensioned by pulling the grip portion 50 of the tensioning element 5, the same grip portion 50, constrained to the traction element 6, allows the covering element 4 to be constrained in position, so as to reduce the possibility of any loosening of the covering element 4.

[0064] In particular, at least one of the grip ends 50', 50" of the grip portion 50 is mechanically connected to the traction element 6.

[0065] Advantageously, the traction element 6 is removably connected to the grip portion 50 of the tensioning element 5, so as to allow the tensioning element 5 to be detached from the traction element 6 and vice versa.

[0066] Advantageously, the grip portion 50 is constrained to the traction element 6 to maintain tension on the covering element 4.

[0067] Advantageously, operationally, since the traction element 6 is connected to the tensioning element 5, and more precisely to the grip portion 50 of the latter, the rotation of the traction element 6 around the rotation axis R, particularly in the tensioning sense, implies the pulling of the tensioning element 5 and therefore the tensioning of the covering element 4 to which the tensioning element 5 is engaged.

[0068] In particular, pulling the grip portion 50 of the tensioning element 5 also pulls the engagement portion 51 of the latter, which is advantageously fixed to the main portion 40 of the covering element 4.

[0069] Consequently, since the engagement portion 51 is preferably integral with the main portion 40, it in turn tensions the covering element 4 on the cushioning element 33 of the seat 3.

[0070] In this way, if the covering element 4 loosens and / or wrinkles, it can be easily retensioned by acting on the traction element 6.

[0071] In accordance with the idea underlying the present invention, the traction element 6 is provided with a perimeter toothing 610, configured to engage with the seat 3, to lock the traction element 6 in position, preventing it from rotating about the rotation axis R, in a blocking sense B, preferably counterclockwise, opposite to the tensioning sense T.

[0072] In accordance with the invention, seat 3 comprises a flexible blocking lever 7, which extends in a single piece from the lower face 31 of seat 3, starting from a first end 7', connected to the lower face 31, to a second free end 7", at which point the blocking lever 7 is provided with a coupling portion 70.

[0073] In accordance with the idea underlying the present invention, the first end 7' of the blocking lever 7 defines a rotation pivot F of the blocking lever 7, and the blocking lever 7 is elastically movable about said rotation pivot F between an engagement position, in which the coupling portion 70 engages with the perimeter toothing 610 of the traction element 6, to prevent rotation of the traction element 6 about the rotation axis R, in the blocking sense B opposite to the tensioning sense T, and a release position, in which the coupling portion 70 is disengaged from the perimeter toothing 610 of the traction element 6, to allow free rotation of the traction element 6 about the rotation axis R, and thus allowing, for example, the tensioning of the covering element 4.

[0074] In particular, the aforementioned blocking lever 7 is elastically flexible between the two aforementioned positions, and its movement is advantageously provided automatically following the rotation of the traction element 6 and the action of the perimeter toothing 610 of the same traction element 6.

[0075] In this way, it is possible to obtain a chair 1 equipped with an integrated upholstery tensioning mechanism, which is quick and easy for a user to operate and offers significant advantages in terms of cost-effectiveness and production and assembly times, since it is equipped with a blocking lever 7 that is formed in a single piece directly on the lower face 31 of the seat 3, and is automatically elastic in response to the rotation of the traction element 6 around the rotation axis R.

[0076] Therefore, the blocking lever 7, which is moulded as a single piece with the seat 3, allows chair 1 to be produced and assembled quickly and easily.

[0077] Advantageously, seat 3 is provided with a first housing seat 311, which extends downward from the lower face 31 of seat 3, in particular along a substantially vertical direction (preferably when chair 1 is assembled and in the position of use).

[0078] Advantageously, the traction element 6 is preferably housed in the first housing seat 311.

[0079] Preferably, the first housing seat 311 is formed from the lower face 31 of the seat 3. More specifically, the first housing seat 311 is bounded at the bottom by a bottom wall 312 and at the sides by a lateral wall 313, which extends substantially parallel to the rotation axis R from the lower face 31 of the seat 3 to the aforementioned bottom wall 312.

[0080] Advantageously, the support element 34 of the seat 3 comprises a snap-fit fastening device 37, which is positioned on the bottom wall 312 of the first housing seat 311.

[0081] Advantageously, the lateral wall 313 of the first housing seat 311 is provided with a first lateral opening 313', into which the tensioning element 5 is inserted, so as to allow the grip portion 50 to be arranged in the first housing seat 311, in particular by connecting it to the traction element 6. Advantageously, the lateral wall 313 of the first housing seat 311 is provided with a second lateral opening 313", through which at least part of the coupling portion 70 of the blocking lever 7 can be inserted, so as to allow at least part of said coupling portion 70 to be placed in the first housing seat 311, thereby interfering with the perimeter toothing 610 of the traction element 6. Preferably, the support element 34 is provided on its own s lateral ide wall with an inlet opening 315, opposite the first lateral opening 313' of the first housing seat 311, through which the grip portion 50 is inserted, and a first guide channel 316, through which the tensioning element 5 is guided to position the grip portion 50 in the first lateral opening 313' of the first housing seat 311. In particular, the first guide channel 316 has two first lateral walls 316' that extend from the inlet opening 315 to the first lateral opening 313', along a direction of extension S substantially orthogonal to the rotation axis R. Advantageously, the direction of extension S is rectilinear. In this way, the tensioning of the covering element 4 can be carried out more easily by pulling the tensioning element 5, and more particularly the grip portion 50, along the straight direction of development S.

[0082] Preferably, the traction element 6 is substantially entirely housed in the first housing seat 311, without protruding substantially outside the first housing seat 311. In particular, when the traction element 6 is housed in the first housing seat 311, it does not protrude with respect to the lower face 31 of the seat 3, preferably remaining substantially coplanar with the latter.

[0083] This reduces the risk of a user accidentally touching and moving the traction element 6 during use, as well as improving the aesthetic appearance of chair 1.

[0084] In particular, the traction element 6 comprises a connection pin 60, which is rotatably mounted in the first housing seat 311 of the seat 3, to support the traction element 6 in its rotation about the rotation axis R.

[0085] More specifically, as described in greater detail below, the snap-fit fastening device 37 is positioned between the connection pin 60 of the traction element 6 and the first housing seat 311 of the seat 3.

[0086] More clearly, the traction element 6 can rotate around the rotation axis R, inside the first housing seat 311, by means of the aforementioned connection pin 60.

[0087] Advantageously, the traction element 6 comprises an operating portion 61, which comprises the perimeter toothing 610.

[0088] In particular, the operating portion 61 extends, parallel to the rotation axis R, from a first face 6', facing the interior of the first housing seat 311.

[0089] Advantageously, the connection pin 60 extends, in particular, from the operating portion 61, and more specifically from the first face 6', along an axial direction X, preferably substantially parallel to the rotation axis R, and more specifically preferably substantially coincident with the rotation axis R.

[0090] Preferably, in accordance with the embodiment illustrated in the attached figures, the connection pin 60 has a first coupling flap 601 and a second coupling flap 602, preferably semi-cylindrical in shape, which are advantageously arranged symmetrically and protrude from the operating portion 61.

[0091] In particular, the first coupling flap 601 and the second coupling flap 602 rise along the axial direction X starting from a common base 603, up to corresponding terminal ends, which are spaced apart along a direction Y substantially orthogonal to the axial direction X, to allow the first coupling flap 601 and the second coupling flap 602 to move away from and / or towards each other during the coupling and uncoupling of the connection pin 60 from the first housing seat 311, respectively.

[0092] In particular, each snap-fit tab 601, 602 engages the snap-fit fastening device 37 of the support element 34, allowing guided sliding of the connection pin 60 in the snap-fit fastening device 37, keeping the traction element 6 stably housed in the first housing seat 311 and preventing accidental disengagement.

[0093] Advantageously, the snap-fit fasteners 37 are equipped with an internal support surface 371, preferably facing upwards, designed to receive each fastening flaps 601, 602 during the rotary assembly of the connection pin 60 in the first housing seat 311.

[0094] In this way, vertical movements of the traction element 6 relative to the snap-in fastening device 37 are prevented, which would cause, for example, loose winding of the tensioning element 5 on the traction element 6.

[0095] Preferably, the connection pin 60 comprises a widened portion 615, which extends radially with respect to the rotation axis R, and delimits with the first face 6' of the operating portion 61 a first retention seat S' for the tensioning element 5, to prevent the tensioning element 5 from disengaging from the traction element 6 parallel to the rotation axis R.

[0096] In particular, each fastening flap 601, 602 has its own corresponding widened portion 615 on its outer surface, as shown in Figures 6 and 7.

[0097] Advantageously, the first fastening flap 601 and the second fastening flap 602 define between them a second retention seat S", which is delimited by the inner surfaces of the fastening flaps 601, 602 and by the common base 603.

[0098] Advantageously, the support element 34 comprises, at the inlet opening 315, a tensioner 362, preferably arranged between two coupling elements 36', 36", intended to receive the two grip ends 50', 50" of the tensioning element 5.

[0099] In particular, each grip end 50', 50" is first hooked to the tensioner 362 along a direction substantially parallel to one side of the seat 3, and more specifically along the direction of development E, and then returned by the tensioner 362 along a direction orthogonal to the aforementioned side of the seat 3, as illustrated in Figure 5.

[0100] More specifically, after the grip ends 50' 50" have been hooked to the tensioner 362, the first grip end 50' is pulled along a first pulling direction, substantially orthogonal to the rotation axis R, and the second grip end 50" is pulled along a second pulling direction, substantially orthogonal to the rotation axis R.

[0101] In this way, during rotation of the traction element 6 in the tensioning sense T, the grip ends 50', 50" of the grip portion 50 are pulled equally by the traction element 6, tensioning the covering element 4 evenly.

[0102] Operationally, preferably before connecting the traction element 6 in the first housing seat 311 and preferably before tensioning the tensioning element 5, the grip ends 50', 50" of the grip portion 50 are preferably arranged around the first fastening flap 601.

[0103] In particular, according to one embodiment of the present invention, the grip ends 50', 50" are joined together to form a loop, which is hooked, for example, to the first fastening flap 601. More specifically, the first grip end 50' is preferably positioned at the first retention seat S', while the second grip end 50" is preferably positioned at the second retention seat S".

[0104] In this way, during rotation of the traction element 6 in the tensioning sense T, the grip portion 50 of the tensioning element 5 is wrapped around the connection pin 60.

[0105] In this way, the tensioning element 5 is secured to the traction element 6 without having to fix the grip ends 50', 50" of the tensioning element 5 to the fastening flaps 601, 602 by means of, for example, fasteners.

[0106] Operationally, when the traction element 6 is rotated in the tensioning sense T, the tensioning element 5 engaged with the latter via the connection pin 60 is also tensioned and, consequently, the tensioning element 5 tensions the covering element 4.

[0107] Advantageously, the traction element 6 comprises a cover portion 62, extending from a second face 6" facing the outside of the first housing seat 311, and opposite the first face 6' of the operating portion 61.

[0108] Preferably, the cover portion 62 is substantially disc-shaped and has a first diameter D1.

[0109] In particular, the cover portion 62 extends, parallel to the rotation axis R, between the second face 6" and an upper surface 62' facing the operating portion 61.

[0110] Advantageously, the operating portion 61 has a second diameter D2, which is defined by the perimeter toothing 610.

[0111] Preferably, the second diameter D2 of the operating portion 61 is smaller than the first diameter D1 of the covering portion 62.

[0112] In this way, on the covering portion 62, in particular on the upper surface 62' of the covering portion 62, a free annular portion L is defined, substantially in the shape of a circular crown. Advantageously, seat 3 has, on the inner face of lateral wall 313 of the first housing seat 311, a shoulder 314 which extends towards the inside of the first housing seat 311.

[0113] In particular, during the rotary assembly of the traction element 6 in the first housing seat 311, the shoulder 314 is designed to receive the free annular portion L of the cover portion 62 of the traction element 6, in order to guide the rotation of the traction element 6 around the rotation axis R, during the winding / unwinding of the tensioning element 5 on the traction element 6.

[0114] In this way, when the traction element 6 is housed in the first housing seat 311, the covering portion 62 allows the first housing seat 311 to be covered, reducing the risk that a user may accidentally touch the traction element 6, and in particular the perimeter toothing 610, during use. Furthermore, the cover portion 62 advantageously prevents dust or fine particles from entering the first housing seat 311, which could compromise the operation of the traction element 6.

[0115] Advantageously, the operating portion 61 comprises a central portion 611 and the perimeter toothing 610.

[0116] Advantageously, the perimeter toothing 610 of the traction element 6 comprises a plurality of teeth 612 (for example, with reference to the embodiment illustrated in the attached figures, twelve teeth 612), each of which has an arcuate profile.

[0117] In particular, the perimeter toothing 610 comprises between one and twenty teeth 612, and more preferably between 8 and 16, for example twelve.

[0118] In particular, each of the teeth 612 of the perimeter toothing 610 is preferably formed as a projection from the central portion 611, and extends radially from the central portion 611 to a corresponding extreme edge 616. More specifically, the extreme edges 616 of the teeth 612 are parallel to each other and arranged along the same first circumference C'.

[0119] More specifically, the free annular portion L lies between the first circumference C', defined by the extreme edges 616 of the teeth 612, and the second circumference C", defined by the perimeter of the upper surface 62', as shown in Figure 7.

[0120] Advantageously, each tooth 612 is equipped with a stop surface 613, extending along a direction substantially orthogonal to the rotation axis R, and a support surface 614, which is preferably connected to the stop surface 613 and in particular has a substantially arcuate shape. Advantageously, the stopping surface 613 of a tooth 612' delimits, with the bearing surface 614 of a subsequent tooth 612", an engagement seat 617.

[0121] Advantageously, when the blocking lever 7 is in the engagement position, the coupling portion 70 is positioned and engaged in the engagement seat 617, to constrain the traction element 6 in a predetermined tensioning position.

[0122] Advantageously, the blocking lever 7 has a substantially L-shaped form.

[0123] In particular, the blocking lever 7 has, at the rotation pivot F, a first narrow portion 71 and, at the second free end 7", a second portion 72, which is wider than the first portion 71. Advantageously, the first portion 71 defines an elongated stem of the blocking lever 7. Advantageously, the second portion 72 defines the coupling portion 70 of the blocking lever 7.

[0124] More specifically, the second portion 72 extends in projection from one end of the first portion 71 to its own end, at which point it has a concave portion 721, which has a concavity facing the teeth 612, in particular towards the bearing surface 614 of each tooth 601, intended to bear against the bearing surface 614.

[0125] In particular, the concave portion 721 delimits, at the upper face 722 of the coupling portion 70, a protuberance 723, substantially elbow-shaped, intended, during rotation of the traction element 6 in the blocking sense B, to engage with the tooth 601, and in particular to receive the stop surface 613 of the tooth 601 in abutment, inserting itself into the engagement seat 617.

[0126] Preferably, the first narrow portion 71 of the blocking lever 7 is shaped to flex elastically, allowing the blocking lever 7 to rotate about the rotation pivot F. For example, the first portion 71 of the blocking lever 7 has a thickness of between 1.5 and 5 mm, and more preferably 2.5 mm. Preferably, the blocking lever 7 is made of a polymeric material, such as polypropylene (PP) or PA6, for example glass-filled PA6 (in particular having 30% glass fibres), which is even more preferably the same material as that used to make the seat 3 (and in particular the support element 34 of the seat 3).

[0127] Advantageously, the blocking lever 7, and more preferably the second portion 72, comprises an engagement opening 73, which can be manually engaged by a user, for example by means of a tool, to manually move the locking lever 7 from the engagement position to the release position, to release the blocking lever 7 from the perimeter toothing 610 and allow free rotation of the traction element 6, both in the tensioning sense T and in the blocking sense B.

[0128] For example, the engagement opening 73 allows a user to hold the blocking lever 7 in a release position so that the traction element 6 can be removed.

[0129] In this way, the user can rotate the traction element 6 in the blocking sense B without the coupling portion 70 of the blocking lever 7 engaging with the perimeter toothing 610 of the traction element 6, allowing the covering element 4 to be unwound from the traction element 6.

[0130] Advantageously, seat 3, and more specifically support element 34, is also provided with a second housing seat 320, which extends downwards from the lower face 31 of seat 3.

[0131] Advantageously, the cushioning element 33 is provided with a third housing seat 340 and a fourth housing seat 350, which face the floor.

[0132] Preferably, the third housing seat 340 has the same profile as the first housing seat 311. Preferably, the fourth housing seat 350 has the same profile as the second housing seat 320.

[0133] In particular, when chair 1 is assembled and in the position of use, the housing seats 340, 350 are preferably aligned with, respectively, the first housing seat 311 and the second housing seat 320. Advantageously, the second housing seat 320 defines a second guide channel 317, in which the blocking lever 7 is arranged, which has two second lateral walls 317' extending from the second lateral opening 313" of the first housing seat 311 to substantially correspond to the second fee end 7" of the blocking lever 7.

[0134] In particular, the second lateral walls 317' define a movement region M in which the blocking lever 7 can be moved, preferably with some play.

[0135] More specifically, in this movement region M, the blocking lever 7 can be moved, preferably elastically, between the release position, along a movement direction X1, and the engagement position, along the same direction X1 but in the opposite direction. Preferably, this movement direction X1 is substantially orthogonal to the rotation axis R of the traction element 6.

[0136] In particular, the bearing surface 614 of each tooth 601 extends, preferably in an arcuate manner, with a convex profile that substantially coincides with the profile of the concave portion 721 of the coupling portion 70 of the blocking lever 7, so as to improve the engagement between the bearing surface 614 of the tooth 601 and the concave portion 721 of the blocking lever 7. Furthermore, this defines two inclined planes (given by the concave portion 721 and the support surface 614) that allow relative movement, and in particular allow elastic movement of the blocking lever 7 between the engagement position and the release position following the rotation of the traction element 6 around the rotation axis R.

[0137] In other words, the bearing surface 614 of each tooth 601 of the perimeter toothing 610 acts as a thrust on the blocking lever 7, in particular against the concave portion 721 of the coupling portion 70, forcing its movement from the engaged position to the disengaged position. Advantageously, in the rest condition, the blocking lever 7 is positioned in the engagement position.

[0138] In particular, during rotation of the traction element 6 in the tensioning sense T, with the blocking lever 7 in the engaged position, the coupling portion 70 rests on the support surface 614 of tooth 612', until it first reaches the extreme edge 616 and then the support surface 614 of the next tooth 612", allowing continuous rotation of the traction element 6 in the tensioning sense T.

[0139] In this way, the traction element 6 allows the covering element 4 to be progressively tensioned without excessive and sudden tension, thereby reducing the risk of breaking it.

[0140] In particular, during rotation of the traction element 6 in the tensioning sense T, with the blocking lever 7 in the engaged position, the blocking lever 7 is subjected to an elastic force F1, directed along the direction of movement X1, which allows the blocking lever 7 to flex elastically around the fulcrum F, advantageously also thanks to the polymeric material from which the blocking lever 7 is made, remaining in the engagement position.

[0141] In this way, the blocking lever 7 rotates around the fulcrum F to remain in the engaged position without the use of any pivoting means.

[0142] Otherwise, during rotation of the traction element 6 in the blocking sense B, with the blocking lever 7 in the engagement position, the coupling portion 70 rests on the support surface 614 until it engages the engagement seat 617 of tooth 612' and stops against the stop surface 613 of the next tooth 612".

[0143] In this way, the traction element 6 is securely locked in the blocking sense B in a predetermined tensioning position.

[0144] In this way, the traction element 6 remains tensioned in the predetermined tensioning position without the risk of the covering element 4 loosening.

[0145] Advantageously, as described above, the blocking lever 7 can be moved elastically between the release position and the engagement position. In particular, in the release position, the teeth 601 act on the second portion 72, causing the blocking lever 7, and in particular the coupling portion 70, to retract substantially inside the second channel 317.

[0146] Advantageously, the blocking lever 7 can then retract into the movement region M, where it can preferably be housed with play, allowing the traction element 6 to rotate freely around the rotation axis R in the blocking sense B or in the tensioning sense T.

[0147] Conversely, in the engagement position, the second portion 72, and in particular the coupling portion 70, emerges from the second channel 317 and inserts itself into the engagement seat 617, engaging with the tooth 601.

[0148] In this way, the blocking lever 7 prevents the traction element 6 from moving when the traction element 6 is rotated in the blocking sense B, or allows the traction element 6 to move when the traction element 6 is rotated in the tensioning sense T.

[0149] Advantageously, the traction element 6 comprises, preferably at the second face 6", a gripping element 63, which can be engaged by a user to rotate the traction element 6 about the rotation axis R.

[0150] Preferably, the gripping element 63 is equipped with a guide portion 631, for example a knob, which preferably extends in a depression starting from the second face 6" of the traction element 6, and allows a user to grasp the traction element 6 in order to rotate it around the rotation axis R. Preferably, the gripping element 63 is equipped with a through hole 632 (e.g., hexagonal in shape), which allows a user to grasp the traction element 6 in order to rotate it about the rotation axis R. For this purpose, the user can use a special tool, such as a spanner or screwdriver, inserting it into the through hole 632 to rotate the traction element 6 around the rotation axis R.

[0151] Advantageously, the gripping element 63 is provided with both the guide portion 631 and the through hole 632.

[0152] The invention thus conceived therefore achieves the intended objectives.

Claims

1. Chair for the sitting of a user, in particular office chair, which comprises: - a support structure (2), intended to be abutted against the ground; - a seat (3), mounted on said support structure (2) and provided with an upper face (30), intended to receive a user in seated position, and with an opposite lower face (31), intended to be directed towards the floor; - a flexible covering element (4), placed to cover at least the upper face (30) of said seat (3) and provided with a main portion (40); - a flexible tensioning element (5), which is engaged with the main portion (40) of said covering element (4) and is provided with a grip portion (50); - a traction element (6), which is mechanically connected to the grip portion (50) of said tensioning element (5), is rotatably mounted on the lower face (31) of said seat (3) and rotatable around a rotation axis (R) in a tensioning sense (T), in order to at least partially enclose said tensioning element (5) on said traction element (6) and tension said covering element (4) to enclose said seat (3); in which said traction element (6) is provided with a perimeter toothing (610), configured in order to be coupled to said seat (3), in order to block said traction element (6) in position, preventing the rotation thereof around said rotation axis (R), in a blocking sense (B), opposite said tensioning sense (T); said chair (1) being characterized in that said seat (3) comprises a flexible blocking lever (7), which is extended in a single body starting from the lower face (31) of said seat (3), starting from a first end (7'), connected to the lower face (31) of said seat (3), up to a second free end (7"), at which said blocking lever (7) is provided with a coupling portion (70); in which the first end (7') of said blocking lever (7) defines a rotation pivot (F) of said blocking lever (7), and in which said blocking lever (7) is elastically movable, around said rotation pivot (F), between an engagement position, in which said coupling portion (70) is engaged with the perimeter toothing (610) of said traction element (6), in order to prevent the rotation of said traction element (6) around said rotation axis (R), in said blocking sense (B), and a release position, in which said coupling portion (70) is disengaged from the perimeter toothing (610) of said traction element (6), in order to allow the free rotation of said traction element (6) around said rotation axis (R).

2. Chair according to claim 1, characterized in that said blocking lever (7) has, at said rotation pivot (F), a narrow first portion (71), and, at said second free end (7"), a second portion (72), widened with respect to said first portion (71); in which the first portion (71) of said blocking lever (7) is configured for allowing the elastic bending of said blocking lever (7) around said rotation pivot (F).

3. Chair according to claim 1, characterized in that said seat (3) is provided with a first housing seat (311), which is extended in a depression starting from said lower face (31), and that said traction element (6) is housed in said first housing seat (311) and comprises a connection pin (60), which is rotatably mounted in the first housing seat (311) of said seat (3), in order to support said traction element (6) in its rotation around said rotation axis (R).

4. Chair according to claim 3, characterized in that said first housing seat (311) is delimited by a bottom wall (312), and laterally by a lateral wall (313), which is extended, along said rotation axis (R), starting from the lower face (31) of said seat (3) up to said bottom wall (312); said lateral wall (313) being provided with a first lateral opening (313'), through which said tensioning element (5) is inserted, in order to place said grip portion (50) in said first housing seat (311), and with a second lateral opening (313), through which the coupling portion (70) of said blocking lever (7) is susceptible of being inserted, in order to interfere with the perimeter toothing (610) of said traction element (6).

5. Chair according to claim 3, characterized in that said traction element (6) is substantially entirely housed in said first housing seat (311), without substantially projecting outside said first housing seat (311).

6. Chair according to claim 4, characterized in that said traction element (6) comprises an operative portion (61), which comprises said perimeter toothing (610) and is extended, parallel to said rotation axis (R), from a first face (6'), directed towards the interior of said first housing seat (311), and in that said connection pin (60) comprises a widened portion (615), which is extended radially with respect to said rotation axis (R), and delimits, with said first face (6'), a first retention seat (S') for said tensioning element (5), in order to prevent the disengagement of said tensioning element (5) from said traction element (6) parallel to said rotation axis (R).

7. Chair according to claim 6, characterized in that said traction element (6) comprises a covering portion (62), in which said covering portion (62) has a first diameter (D1) and said operative portion (61) has a second diameter (D2) defined by said perimeter toothing (610), in which said second diameter (D2) is smaller than said first diameter (D1), in order to define, on said operative portion (61), a free annular portion (L) with circular crown form; in which said seat (3) has, on the internal face of said lateral wall (313), a shoulder (314), which is extended towards the interior of said first housing seat (311) and which is intended to abuttingly receive the free annular portion (L) of the operative portion (61) of said traction element (6), in order to guide the rotation of said traction element (6) around said rotation axis (R).

8. Chair according to claim 1, characterized in that said traction element (6) comprises a grip element (63), engageable by a user in order to rotate said traction element (6) around said rotation axis (R).

9. Chair according to claim 1, characterized in that said perimeter toothing (610) comprises a plurality of teeth (612), each of which having a curved profile.

10. Chair according to claim 1, characterized in that said blocking lever (7) comprises an engagement opening (73), manually engageable by a user, by means of an engagement element, in order to move said blocking lever (7) from said engagement position to said release position, in order to release said blocking lever (7) from said perimeter toothing (610).

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