EP3738474B1

EP3738474B1 - Device for adjusting the degree of inclination of the seat of a chair

Info

Publication number: EP3738474B1
Application number: EP20171504.2A
Authority: EP
Inventors: Michael DE MARTIN
Original assignee: OMS SpA
Current assignee: OMS SpA
Priority date: 2019-05-14
Filing date: 2020-04-27
Publication date: 2023-06-07
Anticipated expiration: 2040-04-27
Also published as: EP3738474A1; PL3738474T3

Description

The present invention relates to a device for adjusting the degree of inclination or tilt of the seat of a chair.
Nowadays it is known to provide chairs that are fitted with a mechanism the function of which is to enable for example the height adjustment of the seat and the adjustment of the tilting, or the locking in place, of a backrest.
An example of the mentioned prior art is disclosed in US 6,120,096 , where the activation of the mechanisms which interact with the seat and with the backrest is activated by means of a first lever, the rotation of which leads to the packing or not of special slats in contrast with springs, and also a second lever, the lifting of which leads to its terminal end interacting with a gas-filled piston present on a central gas-operated post.
However, this solution has the drawback of necessitating the use of springs which, in addition to requiring complex adjustment systems, still limit the tilting of the backrest to forward or backward only.
Also known is a solution, accessible at the internet URL www.tiltermotion.com/the-technology, which discloses a chair in which a sleeve, which is associated with the gas-operated post, has a coaxial receptacle for a spring system based on vulcanized rubber.
This entails a chemical assembly between components, so using detailed parts that already have a protective surface finish in the vulcanization and overmolding processes creates great difficulties in adhesion between materials to be bonded, and this does not take account of the difficulties of maintaining the appearance of the surface finish itself.
The document US 2005/218707 A1 discloses an adjusting device according to the state of the art.
The vulcanization or the overmolding generate composite components that are difficult to handle at the end of life of the product.
The adjustment of the degree of inclination or tilt of the chair is furthermore very limited and cannot be customized as a function of the requirements of the user.
The aim of the present application is to solve the above mentioned technical problems, eliminating the drawbacks in the cited known art, by providing a device that makes it possible for a chair to be inclined along all directions of the thrust plane to a desired degree, as a function of the requirements of the user.
Within the above aim, an object of the invention is to provide a device that, in addition to the foregoing characteristic, adds that of being capable of making the thrust plane tilt in all directions for seats, backrests or monocoque chairs, howsoever provided.
Another object of the invention is to provide a device that at the same time makes it possible to preset the degree of freedom of movement of the chair according to requirements, both in terms of breadth of movement, and in terms of resistance to movement.
Another object of the invention is to obtain a device that allows rapid and easy assembly, even when using metallic detailed parts that are zinc-plated, chrome-plated or painted, or sheets preferably in carbon steel, which may be contoured and deformed and normally powder coated.
Another object of the invention is to provide a device that can be removed, replaced and disposed of rapidly and easily.
Another object of the invention is to provide a device that makes it possible to achieve, simply and effectively, an end-of-stroke condition of the inclination that can be assumed by the chair.
Another object of the invention is to provide a device that makes it possible for the chair to tilt in all directions of the thrust plane, while its components remain in an optimal position during their actuation.
Another object of the invention is to obtain a device that is structurally robust, that does not require maintenance and that can be made with the usual conventional machinery and/or plants.
This aim and these and other objects which will become better apparent hereinafter are achieved by a device for adjusting a degree of inclination of a seat of a chair, as recited in claim 1.
Further characteristics and advantages of the invention will become better apparent from the detailed description of two particular, but not exclusive, embodiments, which are illustrated by way of non-limiting example in the accompanying drawings wherein:

Figure 1 is an exploded view of the device according to the invention;
Figure 2 is a view from above of the device associated with a plate which can be associated with the seat of a chair;
Figures 3 and 4 are two side views of the device assembled to the plate;
Figure 5 is a cross-sectional view taken along the line V-V in Figure 2;
Figure 6 is a cross-sectional view taken along the line VI-VI in Figure 2;
Figure 7 is a cross-sectional view, similar to that in Figure 6, of the device in a condition of inclination that can be assumed by the plate;
Figure 8 is a view similar to that in Figure 1 of the device of an example, not part of the present invention;
Figure 9 is a view from above of the device of the previous figure;
Figure 10 is a cross-sectional view taken along the line X-X of Figure 9 showing the device assembled to the plate and in the inactive condition;
Figure 11 is a view similar to the previous one, in the inclined condition;
Figure 12 is a cross-sectional view taken along the line XII-XII in Figure 9 and in the inactive condition;
Figure 13 is a view similar to Figure 12, in the inclined condition;
Figures 14 and 15 are perspective views of a pair of dampers;
Figures 16 and 17 are perspective views from above and from below of a platelet which can be interposed between the pair of dampers.

In the exemplary embodiments that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.
With reference to the figures, the reference numeral 1 generally designates a device for adjusting the degree of inclination of a seat of a chair (not shown) which is constituted by a box-like element 2 which is composed of a polygonal, preferably square flat base 3 which has a first axial hole 4.
Perimetrically along the flat base 3, first wings 5a, 5b, 5c, 5d protrude at right angles and are substantially L-shaped so as to define wings 6a, 6b, 6c, 6d which are directed toward the outside of the flat base 3.
At least one second hole is provided on each one of the second wings 6a, 6b, 6c, 6d and is designated in the first embodiment with the reference numerals 7a, 7b, 7c, 7d, and is a receptacle for adapted rivets or screws or bolts 8a, 8b, 8c, 8d for the mechanical coupling of the box-like element 2 below the flat bottom 9 of a plate 10 which has a third axial hole 11 and fourth holes 12a, 12b, 12c, 12d which are provided at the second holes 7a, 7b, 7c, 7d.
The plate 10 can in turn be associated below the seat (not shown) of a chair, and is frustum-shaped so as to define a first receptacle 13 for accommodating adapted and conventional mechanisms, such as, for example, a lever 14 which is adapted to interact with a gas-operated post 15.
A pair of flat dampers 18a, 18b are arranged between the lower first surface 16 of the flat bottom 9 of the plate 10 and the upper first surface 17 of the flat base 3, and constitute a damper preferably made of PU or TPU thermoplastic elastomer.
Each component of the pair of dampers 18a, 18b has a plan shape that is substantially complementary to the flat bottom 9 and to the flat base 3 and is provided with a fourth hole 19a, 19b for the passage of the gas-operated post 15.
Adjustment means 20 are interposed between the pair of flat dampers 18a, 18b for adjusting the stroke limit of the inclination of the seat of the chair with respect to the flat base 3 along diametrical planes, the means being constituted by a flat platelet 21, which has a plan shape that is adapted to contain and support the pair of dampers 18a, 18b, and from which second wings 22a, 22b, 22c, 22d protrude perimetrically and in the direction of the plate 10, which have different heights and which constitute a stroke limit with the lower first surface 16 of the flat bottom 9 of the plate 10 following the deformation that can be imparted to the pair of dampers 18a, 18b as a consequence of the inclination of the chair.
Such heights can be variously determined; for example the second wings 22a and 22b, 22c, 22d can constitute respectively the lowest and highest stroke limit that can be achieved as a consequence of the inclination of the chair.
Also for example, the second wings 22a, 22b may or may not have the same height as the second wings 22c, 22d.
Also for example, the second wings 22a, 22b can have the same height and be higher than the second wings 22c, 22d.
In the specific embodiment shown, the second wing 22a is higher than the second wings 22b, 22c, 22d.
The height of the second wings 22a, 22b, 22c, 22d can therefore vary as a function of specific requirements.
In the embodiment shown, it is furthermore assumed that the back of the chair is directed in the direction of the second wing 22b.
An axial sleeve 23 is present axially with respect to the platelet 21 and is a receptacle for the gas-operated post 15.
In the embodiment shown, perimetrically to the first axial hole 4 of the flat base 3, a substantially frustum-shaped first surface 24, open in an upward region, extends upward, from the free end of which, on the same plane, second wings 6a, 6b, 6c, 6d protrude which are directed toward the outside of the flat base 3.
A pair of second holes 7a, 7b, 7c, 7d is provided, which are receptacles for adapted rivets and/or screws and/or bolts 8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h for the mechanical coupling of the box-like element 2 below the frustum-shaped plate 10 with a flat bottom 9 on which a third axial hole 11 is provided.
From the flat bottom 9 of the plate 10 a substantially frustum-shaped second surface 25, open in an upward region, extends upward, from the free end of which, on the same plane, third wings 26a, 26b, 26c, 26d protrude which are directed toward the outside of the plate 10.
Preferably the perimetric space occupation of the second wings 6a, 6b, 6c, 6d of the box-like element 2 and of the third wings 26a, 26b, 26c, 26d of the plate 10 is identical, with the plate 10 penetrating slightly into the box-like element 2.
Defined in the substantially frustum-shaped second surface 25 is the first receptacle 13 for accommodating adapted and conventional mechanisms such as, for example, the lever 14 which is adapted to interact with the gas-operated post 15.
A pair of flat dampers 18a, 18b are arranged between the lower first surface 16 of the flat bottom 9 of the plate 10 and the upper first surface 17 of the flat base 3, and constitute a damper preferably made of elastomer obtained by cast molding or by injection molding or by vulcanization or by compression molding.
In order to strengthen the structure of the flat base 3 of the box-like element 2 and of the plate 10 and also in order to contain and limit any movement of the pair of dampers 18a, 18b and therefore their displacement off center during the phase of inclination that can be assumed by the chair, there are, at the first axial hole 4 of the flat base 3 and at the third axial hole 11 of the flat bottom 9 of the plate 10, a first flap or lip 27a and a second flap or lip 27b, which are arranged substantially perpendicularly to the flat base 3 and to the flat bottom 9, mutually opposite and therefore both directed toward the interspace between the flat base 3 and the flat bottom 9.
Each element that makes up the pair of dampers 18a, 18b has a polygonal plan shape, preferably square-based and has a fourth hole 19a, 19b for the passage of the gas-operated post 15, while adjustment means 20 are interposed between the pair of flat dampers 18a, 18b for adjusting the stroke limit of the inclination of the chair with respect to the flat base 3 along diametrical planes, such means being constituted by a flat platelet 21, which has a plan shape that is adapted to perimetrically support and contain the pair of dampers 18a, 18b, an axial sleeve 23 also being present axially with respect to the platelet 21 and being a receptacle for the gas-operated post 15.
A series of spokes 28 protrude radially from the sleeve 23 and are joined to an annular perimetric ridge 29 which is adapted to contain the pair of dampers 18a, 18b inside it.
These spokes 28 lie on the same plane and branch off at a desired point of the lateral surface of the sleeve 23.
One of the pair of dampers 18a, 18b is positionable, in a fixed position, above and below the spokes 28, the dampers having, at the surfaces that interact with the spokes 28, adapted and complementarily- shaped grooves 30a, 30b.
The platelet 21 is thus interposed between the pair of dampers 18a, 18b.
The adjustment means 20 determine different stroke limit values that can be reached when the inclination that can be imparted to the chair occurs along separate diametric axes.
In fact the perimetric ridge 29 is annular and has a different shape structure at, for example, mutually opposite sides.
In the particular solution shown, the annular perimetric ridge 29 has a square plan shape, corresponding to the shape of the pair of sleeves 18a, 18b but of larger dimensions in order to be able to contain the pair of sleeves 18a, 18b inside it.
This results in the definition of a pair of first opposite sides 31a, 31b which tilt between the upper first surface 17 of the flat base 3 and the lower first surface 16 of the flat bottom 9 of the plate 10 along a first direction, also indicated as left-right, with respect to the inclination that can be assumed by the seat of the chair, and a pair of second opposite sides 32a, 32b which tilt between the upper first surface 17 of the flat base 3 and the lower first surface 16 of the flat bottom 9 of the plate 10 along a second direction, also indicated as front-back, with respect to the inclination that can be assumed by the seat of the chair.
Advantageously the pair of second opposite sides 32a, 32b has a greater overall extension, in the direction of the axis of the sleeve 23, than that of the pair of first opposite sides 31a, 31b.
Conveniently, the second opposite sides 32a, 32b are mutually mirror-symmetrical, and therefore differently oriented, with respect to a median plane thereof that is diametrical to the sleeve 23, and each one has a third flap 33a, 33b which is directed, respectively, toward the upper first surface 17 of the flat base 3 and toward the lower first surface 16 of the flat bottom 9.
The third flaps 33a and 33b are therefore oriented mutually opposite with respect to a plane that is transverse to the sleeve 23.
Such third flaps 33a and 33b and the second opposite sides 32a, 32b can have the same or a desired shape or size, which can be the same or different.
Conveniently the first opposite sides 31a, 31b are mutually identical, have the same overall extension in the direction of the axis of the sleeve 23, and the overall extension is smaller than that of the second opposite sides 32a, 32b.
In the embodiment shown, it is assumed that the back of the chair is directed in the direction of the second side 32b.
There is a niche 35, 36 on each one of the pair of dampers 18a, 18b, respectively at the lower second surface 33c directed away from the grooves 30a, and at the upper second surface 34 directed away from the grooves 30b.
Advantageously each one of the niches 35, 36 is obtained coaxially with respect to the fourth holes 19a, 19b so as to define, in the area adjacent to the perimetric rim of the pair of dampers 18a, 18b, a fourth flap 37a, 37b which is arranged, once the device 1 is installed, respectively adjoining the upper first surface 17 of the flat base 3 and at an annular second receptacle 38, which is provided via drawing on the lower first surface 16 of the flat bottom 9 of the plate 10 in an area adjacent to the second flap or lip 27b.
The device 1 therefore makes it possible to contain the compression of the pair of dampers 18a, 18b, such compression being controlled mechanically only at the plate 10 given that the shape structure and the size of the third flaps 33a, 33b have terminal ends which interact, in the phase of maximum inclination that can be assumed by the seat of the chair along the second direction, also indicated as front-back and as shown in Figure 13, with the bottom of the second receptacle 38 present on the flat bottom 9 of the plate 10 and with the upper first surface 17 of the flat base 3.
Differently, when an inclination along the first direction, also indicated as left-right, is imparted to the seat of the chair, the pair of dampers 18a, 18b can still be compressed without ensuring that a desired maximum travel is reached, but the pair of dampers can exceed such travel without a limit.
The ends of the third flaps 33a, 33b therefore act as a stroke limit and ensure the impossibility of exceeding the maximum angle, according to a determined (and determinable) inclination, for which it is desired to calibrate the tilting of the seat in the various directions.
The hypothetical-ideal center of rotation is always considered the center of gravity of the sleeve 23.
Thus it has been found that the invention fully achieves the intended aim and objects, a device having been obtained that makes it possible to incline, along all directions of the thrust plane and to a desired degree, seats, backrests or monocoque chairs, howsoever provided, as a function of the requirements of the user.
The device at the same time makes it possible to preset the degree of freedom of movement of the chair according to requirements, both in terms of breadth of movement, and in terms of resistance to movement, simply by using a desired elastomer contoured according to the requirements and mixed according to the hardness required by the end user, in order to have different elastic responses.
The interaction between the parallel planes of the flat base 3 and of the plate 10 and the pair of dampers 18a, 18b derives from a mechanical, not chemical, assembly, which makes it possible to perform a precompression/preloading of the elastomer proper; in this manner the elastic material is already in an optimal working configuration when in the inactive condition (in the absence of the weight of the user) and the elastic response generated is similar to its guaranteed load curve.
The device further allows rapid and easy assembly, even when using metallic detailed parts that are zinc-plated, chrome-plated or painted, or sheets preferably in carbon steel, which may be contoured and deformed and normally powder coated, and it can be removed, rapidly and easily replaced using normal tools (wrenches, hexagonal Allen keys, a hammer), and its components can also be disposed of individually with differentiation of metals and plastics.
Furthermore, with regard to the disclosed example, the pair of dampers 18a, 18b is kept correctly in position even during their activation, by virtue of the presence of the first flap or lip 27a and of the second flap or lip 27b, the ends of which are facing toward the niches 35, 36.
Furthermore the invention makes it possible to achieve, simply and effectively, an end-of-stroke condition of the inclination that can be assumed by the seat of the chair in the phase of maximum inclination along the second direction, also indicated as front-back.
Naturally the materials used as well as the dimensions of the individual components of the device according to the invention may be more relevant according to specific requirements.
The characteristics indicated above as advantageous, convenient or the like, may also be missing or be substituted by equivalent characteristics.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A device (1) for adjusting a degree of inclination of a seat of a chair, having a box-like element (2), which can be associated mechanically below an axially perforated plate (10), which in turn can be associated below said seat, said box-like element being adapted to contain a pair of flat dampers (18a, 18b) between which adjustment means (20) are interposed for adjusting a stroke limit of the inclination of said seat with respect to said plate (10) along two distinct diametrical planes, said adjustment means (20) comprising a receptacle for a gas-operated post (15) of said seat, characterized in that said box-like element (2) is composed of a polygonal flat base (3) which has a first axial hole (4), first wings (5a, 5b, 5c, 5d) protruding at right angles from said flat base (3) and being substantially L-shaped so as to define wings (6a, 6b, 6c, 6d) which are directed toward the outside of said flat base (3), a second hole (7a, 7b, 7c, 7d) being provided on each one of said wings (6a, 6b, 6c, 6d) and being a receptacle for adapted rivets or screws or bolts (8a, 8b, 8c, 8d) for the mechanical coupling of said box-like element (2) below a flat bottom (9) of said plate (10), which has a third axial hole (11) and fourth holes (12a, 12b, 12c, 12d) which are provided at said second holes (7a, 7b, 7c, 7d), and said plate (10) can in turn be associated below a seat of a chair and is frustum-shaped so as to define a first receptacle (13) for accommodating mechanisms, such as a lever (14) which is adapted to interact with a gas-operated post (15), said pair of flat dampers (18a, 18b) being arranged between the lower first surface (16) of said flat bottom (9) of said plate (10) and the upper first surface (17) of said flat base (3), and constituting a damper preferably made of PU or TPU thermoplastic elastomer.
The device (1) according to claim 1, characterized in that each component of said pair of dampers (18a, 18b) has a plan shape that is substantially complementary to said flat bottom (9) and to said flat base (3) and is provided with a fourth hole (19a, 19b) for the passage of said gas-operated post (15).
The device (1) according to one or more of the preceding claims, characterized in that said adjustment means (20) are constituted by a flat platelet (21), which has a plan shape that is adapted to contain and support said pair of dampers (18a, 18b), and from which second wings (22a, 22b, 22c, 22d) protrude perimetrically and in the direction of said plate (10), which have different or partly identical heights and which constitute a stroke limit with said lower first surface (16) of said flat bottom (9) of said plate (10) following the deformation that can be imparted to said pair of dampers (18a, 18b) as a consequence of the inclination of said chair.
The device (1) according to one or more of the preceding claims, characterized in that the heights of said second wings (22a, 22b, 22c, 22d) define a lowest and highest stroke limit that can be achieved as a consequence of the inclination of said chair.
The device (1) according to one or more of the preceding claims, characterized in that the heights of a first pair (22a, 22b) of said second wings (22a, 22b, 22c, 22d) have the same height as a second pair of (22c,22d) of said second wings (22a, 22b, 22c, 22d).
The device (1) according to one or more of the preceding claims, characterized in that the heights of a first pair (22a, 22b) of said second wings (22a, 22b, 22c, 22d) are different with respect to the heights of a second pair (22c, 22d) of said second wings (22a, 22b, 22c, 22d).
The device (1) according to one or more of the preceding claims, characterized in that said first pair (22a,22b) of said second wings (22a, 22b, 22c, 22d) have the same height and are higher than said second pair (22c, 22d) of second wings (22a, 22b, 22c, 22d).
The device (1) according to one or more of the preceding claims, characterized in that one wing (22a) of said first pair (22a, 22b) of said second wings (22a, 22b, 22c, 22d) is higher than all the other said second wings (22b, 22c, 22d).
The device (1) according to one or more of the preceding claims, characterized in that an axial sleeve (23) is present axially with respect to said platelet (21) and is a receptacle for said gas-operated post (15).
The device (1) according to claim 1, characterized in that said adjustment means (20) have different stroke limit values that can be reached when the inclination that can be imparted to said seat of said chair occurs along a first direction, indicated as left-right, and along a second direction, at right angles to said first direction and indicated as front-back.
The device (1) according to claim 10,
characterized in that said flat base (3) has a polygonal shape, preferably square, and has a first axial hole (4), perimetrically to which a substantially frustum-shaped first surface (24), open in an upper region, extends upward, from the free end of which, on the same plane, second wings (6a, 6b, 6c, 6d) protrude which are directed toward the outside of said flat base (3), on each one of which a pair of second holes (7a, 7b, 7c, 7d) is provided which are receptacles for rivets and/or screws and/or bolts (8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h) for the mechanical coupling of said box-like element (2) below said frustum-shaped plate (10) with a flat bottom (9) on which a third axial hole (11) is provided, from said flat bottom (9) a substantially frustum-shaped second surface (25), open in an upper region, extending upward, from the free end of which, on the same plane, third wings (26a, 26b, 26c, 26d) protrude which are directed toward the outside of said plate (10), said second wings (6a, 6b, 6c, 6d) and said third wings (26a, 26b, 26c, 26d) being identical to each other and said plate (10) penetrating slightly into said box-like element (2).
The device (1) according to one or more of the preceding claims, characterized in that, between the lower first surface (16) of said flat bottom (9) and the upper first surface (17) of said flat base (3), a pair of dampers (18a, 18b) are arranged at said first and third axial holes (4, 11), a first flap or lip (27a) and a second flap or lip (27b) are arranged substantially perpendicularly to said flat base (3) and to said flat bottom (9), mutually opposite and therefore both directed toward an interspace between said flat base (3) and said flat bottom (9), each element that makes up said pair of dampers (18a, 18b) having a polygonal plan shape, preferably square-based and having a fourth hole (19a, 19b) for the passage of a gas-operated post (15).
The device (1) according to one or more of the preceding claims, characterized in that a series of spokes (28) protrude radially from said sleeve (23) and are joined to an annular perimetric ridge (29) which is adapted to contain said pair of dampers (18a, 18b) inside it, said spokes (28) lying on the same plane and branching off at a desired point of the lateral surface of said sleeve (23), one of said pair of dampers (18a, 18b) being positionable, in a fixed position, above and below said spokes (28), said dampers having, at the surfaces that interact with said spokes (28), adapted and complementarily-shaped grooves (30a, 30b).
The device (1) according to one or more of the preceding claims, characterized in that said adjustment means (20) determine different stroke limit values that can be reached when the inclination that can be imparted to said seat of said chair occurs along separate diametric axes, said perimetric ridge (29) being annular and having a different shape structure at mutually opposite sides, said perimetric ridge (29) having a square plan shape, corresponding to the shape of said pair of sleeves (18a, 18b) but of larger dimensions in order to be able to contain said pair of sleeves (18a, 18b) so as to define a pair of first opposite sides (31a, 31b) which tilt between said upper first surface (17) of said flat base (3) and said lower first surface (16) of said flat bottom (9) of said plate (10) along a first direction, also indicated as left-right, with respect to the inclination that can be assumed by said seat of said chair, and a pair of second opposite sides (32a, 32b) which tilt between said upper first surface (17) of said flat base (3) and said lower first surface (16) of said flat bottom (9) of said plate (10) along a second direction, also indicated as front-back, with respect to the inclination that can be assumed by said seat of said chair.
The device (1) according to one or more of the preceding claims, characterized in that said pair of second opposite sides (32a, 32b) has a greater overall extension, in the direction of the axis of said sleeve (23), than that of said pair of first opposite sides (31a, 31b).
The device (1) according to one or more of the preceding claims, characterized in that said second opposite sides (32a, 32b) are mutually mirror-symmetrical, and therefore differently oriented, with respect to a median plane thereof that is diametrical to said sleeve (23), and each one has a third flap (33a, 33b) which is directed, respectively, toward said upper first surface (17) of said flat base (3) and toward said lower first surface (16) of said flat bottom (9), said third flaps (33a, 33b) being therefore oriented mutually opposite with respect to a plane that is transverse to said sleeve (23).
The device (1) according to one or more of the preceding claims, characterized in that said third flaps (33a, 33b) and said second opposite sides (32a, 32b) have the same or a desired shape or size, which can be the same or different.
The device (1) according to one or more of the preceding claims, characterized in that said first opposite sides (31a, 31b) are mutually identical, have the same overall extension in the direction of the axis of said sleeve (23), and said overall extension is smaller than that of said second opposite sides (32a, 32b).
The device (1) according to one or more of the preceding claims, characterized in that there is a niche (35, 36) on each one of said pair of dampers (18a, 18b), respectively at a lower second surface (33c) directed away from said grooves (30a), and at said upper second surface (34) directed away from said grooves (30b), each one of said niches (35, 36) being obtained coaxially with respect to said fourth holes (19a, 19b) so as to define, in the area adjacent to the perimetric rim of said pair of dampers (18a, 18b), a fourth flap (37a, 37b) which is arranged, once the device (1) is installed, respectively adjoining said upper first surface (17) of said flat base (3) and at an annular second receptacle (38), which is provided via drawing on said lower first surface (16) of said flat bottom (9) of said plate (10) in an area adjacent to said second flap or lip (27b).
The device (1) according to one or more of the preceding claims, characterized in that the compression of said pair of dampers (18a, 18b) is controlled mechanically only at said plate (10) given the shape structure and the size of said third flaps (33a, 33b) the terminal ends of which interact, in the phase of maximum inclination that can be assumed by the seat of the chair along said second direction, also indicated as front-back, with said bottom of said second receptacle (38) present on said flat bottom (9) of said plate (10) and with said upper first surface (17) of said flat base (3).
The device (1) according to one or more of the preceding claims, characterized in that the compression of said pair of dampers (18a, 18b), in the condition in which an inclination imparted to said seat of said chair along said first direction, also indicated as left-right, is permitted without ensuring that a desired maximum travel is reached, but such travel can be exceeded without a limit.
The device (1) according to one or more of the preceding claims, characterized in that said ends of said third flaps (33a, 33b) act as a stroke limit and ensure the impossibility of exceeding the maximum angle, according to a determined and determinable inclination, for which it is desired to calibrate the tilting of said seat in the various directions.