WO2015101721A1

WO2015101721A1 - Double inclination device for a seat backrest

Info

Publication number: WO2015101721A1
Application number: PCT/FR2013/053291
Authority: WO
Inventors: Jean-Marc Schneider
Original assignee: Steelcase Sa
Priority date: 2013-12-31
Filing date: 2013-12-31
Publication date: 2015-07-09

Abstract

Inclination device for a seat backrest (1) connected to the seat part (2) or to a seat-part support (3) via a band (4) that surrounds the rear of the backrest (1) and is fixed thereto. This device is characterized in that it includes: - a first controlled elastic inclination mechanism (6, 7) that responds to a force exerted on the backrest (1) by the user, and - a second controlled elastic inclination mechanism (5, 4) that responds to a force, greater than a predetermined threshold, exerted on the backrest (1) by the user; the first mechanism (6, 7) being employed individually in a first angular inclination range of the backrest (1) in response to a force lower than said predetermined threshold, and the first (6, 7) and second (5, 4) mechanisms being employed simultaneously in a second angular inclination range of the backrest (1) in response to a force equal to or greater than said predetermined threshold, said ranges being juxtaposed and having a common angle.

Description

Double tilt device for a seat back

The present invention relates to a seat whose backrest is reclining. It can be a meeting chair, or an office chair for example. The innovation focuses on an integrated device at the back of the seat and allowing the user to tilt the file by resting on it. The purpose of the device is to allow the user to tilt the folder in two levels of effort, a low level and a hard level, corresponding in practice to a dynamic response of the folder according to the weight of the user. Indeed, the level of effort to tilt the file is based on the weight of the user. This reclining seat therefore aims to be adaptable to the weight of the user, and offer a comfortable inclination.

There are seats with tilting devices, relatively complex from a mechanical point of view, and where the dynamic response of the backrest is not adapted to the weight of the user. For example, for a heavy-weight user backing the folder, it will tend to bow sharply and quickly until it stops, which is uncomfortable for the user. Conversely, for a rather thin user backing the backrest, the latter will tend not to bow at all, the weight of the user is not sufficient to activate the mechanical tilt device, unless to exert a considerable effort on the file in a voluntary way, thus inconvenient for the user.

The management of the backrest inclination according to the user is delicate, and the current devices are rarely compatible for any type of user.

The objective of the present invention is to meet the disadvantages of the prior art, by providing a reclining backrest with a double level of effort, suitable for any type of user, by means of a simple tilting device. implemented, with a minimum of parts, and with a beautiful exterior aesthetics. The invention consists of a device for tilting a seat back connected to the seat or to a seat support via a band surrounding the back of the backrest and attached thereto.

This device is mainly characterized in that it comprises:

a first controlled elastic inclination mechanism responding to a force exerted on the backrest by the user, and

a second controlled elastic inclination mechanism responding to a force exerted on the backrest by the user greater than a predetermined threshold;

the first mechanism being implemented individually according to a first angular interval of inclination of the backrest responding to a force less than said predetermined threshold, and the first and second mechanisms being implemented simultaneously according to a second angular interval of inclination of the file corresponding to a force equal to or greater than said predetermined threshold, said intervals being juxtaposed and having a common angle.

The main idea of this invention is to provide an inclination of the folder dynamically responding to the weight of the user. Thus, a rather frail user leaning against the backrest can tilt the latter without special effort and position themselves at ease in the seat with the first mechanism of elastic inclination. A heavy-weight user leaning against the backrest will naturally exert a greater effort on the backrest, and will cause its inclination at first via the first elastic tilt mechanism until the end of the first angular tilt interval, and then via the first mechanism and the second elastic tilting mechanism beyond a predetermined force threshold to achieve a controlled inclination in a second angular tilt range. In the second angular interval, the tilting force is harder, the backrest thus better supports the back of the user, and the user will not tend to fall backwards until it reaches the stop, but on the contrary to be supported, cushioned, and guided in an inclined position adapted to its weight and comfortable. According to the invention, the first mechanism consists of at least one first relief capable of bending at least one tongue corresponding to a portion of the strip delimited by two vertical-looking cuts whose lower ends limit a bending axis of pace. horizontal or the said tabs, or the first reliefs protruding from the rear face of the backrest or the front face of said tab of the strip or both and then being positioned vis-à-vis.

Thus, the first tilting mechanism consists of an elastic deformation of a portion of the strip, following the pressure exerted by the backrest on this part of the strip.

In the same way, the second mechanism consists of at least one second relief capable of imparting an elastic torsion to the strip along a torsion axis of horizontal shape, the second relief or projections protruding from the back face of the backrest or the backrest. front face of the portion of the strip surrounding the tongue or both and then being positioned vis-à-vis, the strip being designed of a material capable of working in elastic torsion in an angular range of at least the amplitude of the second inclination interval of the backrest.

Thus, the second inclination mechanism consists of an elastic deformation of the entire headband, following the pressure exerted by the backrest on the headband.

Concretely, the torsion axis of the strip is coincident with the axis of flexion of the tongue. Thus, for a backing effort exceeding the predetermined threshold, the entire strip, including the tongue, is deformed along the same line of bending / twisting, in a synchronized manner.

Therefore, the two inclination mechanisms are based on elastic deformations of the strip connecting the backrest to the seat or a seat support. This invention has the advantage of being simple, both in terms of components, and at the level of its implementation, because there is no sophisticated means of mechanical adjustment of the inclination with a handle, or a joystick or a button for example, as is often the case in the prior art. In this invention, the inclination depends solely on the backing effort of the user.

More specifically, the first angular range of inclination of the backrest is preferably between 0 ° and 10 ° for a first level of effort between 0 N and 300 N and the second angular interval of inclination of the backrest is preferably between 10 ° and 20 ° for a second level of effort between 300 N and 900 N.

This means that, for a reduced effort between 0 N and 300 N, the user can easily tilt the backrest of his seat and put himself at ease in a first angular interval extended over 10 °. Such an inclination corresponds to the classical case.

A person of strong build or exerting a greater effort on the backrest, between 300 and 900 N, will cause the inclination of the backrest in a second angular range wide of 10 °. The inclination is therefore deliberately harder to obtain, to prevent the user from tilting too easily back only because of his weight or without his wish, but while allowing him to put at ease .

To obtain this double level of inclination, the first relief consists of a projecting portion of the second relief. Thus, the first relief will first deform the tongue of the strip in the context of the first inclination level implemented by the first inclination mechanism, then the first and second reliefs will simultaneously deform respectively the tongue and the rest of the headband in the context of the second inclination level implemented by the first and second inclination mechanisms.

In a possible configuration, the tongue is fixed by screwing to the first relief protruding from the back of the backrest. In this case, the reliefs protrude from the folder, and cause the deformation of the band while coming to rely on it. It would have been quite possible that the reliefs protrude from the headband, and cause its deformation by pressing the backrest. While remaining in this configuration, the lower portion of the strip located under the tongue is secured to the second relief protruding from the back of the backrest by means of a mechanical connection allowing a degree of freedom of the backrest along a pivot axis parallel to said axis torsion. This degree of freedom between the backrest and the headband allows the backrest to follow the bending / twisting movement of the headband, and also prevents any breakage of the workpiece.

Said mechanical connection consists of:

- A hemicylindrical element whose flat face is positioned against said lower portion of the strip and the rounded face is inserted into a corresponding cavity provided for this purpose in the second relief;

- At least one pin adapted to be inserted and pivoted along said pivot axis in a corresponding cavity provided for this purpose in the hemicylindrical element and ending in a window vis-à-vis the second relief;

screws fastening the band to the hemicylindrical element;

- screws fixing the pawn to the file.

The pin has a pin inserted in the window and being adapted to come into contact with the upper and lower edges delimiting the window, the latter acting as stops for limiting the pivoting of the pin in the cavity, the pin being provided with a through hole through which passes the fixing screw of the pawn to the folder. The pivoting of this piece corresponds to the degree of freedom between the folder and the band, as explained above.

The present invention also relates to a seat with a backrest recliner as described above.

The invention will now be described in more detail, with reference to the appended figures, for which:

- Figures 1a and 1b are respectively a general view and an enlarged view of the folder when not inclined, according to a first implementation of the invention; - Figures 2a and 2b are respectively a general view and an enlarged view of the folder when the first inclination mechanism is requested, according to a first implementation of the invention;

- Figures 3a and 3b are respectively a general view and an enlarged view of the folder when the first and second inclination mechanisms are solicited, according to a first implementation of the invention;

- Figure 4 is a graph representing the effort to be applied to the backrest according to the desired inclination;

- Figure 5 is a rear view showing a seat with a tilting device according to a second implementation of the invention;

- Figure 6 is a side view of the seat according to section A-A of Figure 5;

- Figures 7 and 8 are exploded views, general and in section, of the tilting device according to the second implementation of the invention;

- Figure 9 shows the inner part of the tilting device according to the second implementation of the invention;

- Figure 10 is a sectional view of the inclination device attached to the file along the line A-A of Figure 5, when the file is not inclined;

- Figure 1 1 is a sectional view of the inclination device attached to the file along the line B-B or C-C of Figure 5, when the file is not inclined;

- Figures 12 and 13 are respectively general and enlarged sectional views of the inclination device attached to the file along the line B-B or C-C of Figure 5, when the backrest is inclined;

- Figures 14 to 16 illustrate the principle of the degree of freedom between the backrest and the tilting device.

Figures 1 to 3b show the progressive inclination of the folder according to a first implementation of the invention. FIGS. 1a, 2a and 3a thus show a seat provided with a seat (2) resting on the ground via a base or a seat support (3) and a backrest (1) connected to the base (3) via a band (4) surrounding the back of the backrest (1), an intermediate piece (5, 6) being arranged between the backrest (1) ) and the headband (4). This intermediate piece (5, 6) consists of a parallelogram-shaped block whose front face is flat and fixed against the rear face of the backrest (1) and whose rear face comprises a central protuberance (6) fixed against the central portion the strip (4) corresponding to a tongue (7) cut in the strip (4) via two lateral cutouts (8) defining two counter-cuts (1 1) around the tongue (7). The latter extends over half the height of the strip (4) in the upper part of the strip (4).

As illustrated in FIG. 1b, when the backrest (1) is not inclined, the central protuberance (6) of the intermediate piece is positioned against the tongue (7) which lies in the plane of the headband (4) while the parts (12) of the rear face of the intermediate piece (5), on either side of the central protuberance (6), are located at a distance from the counter-cuts (1 1) of the strip (4).

Concretely, the central protuberance (6) corresponds to a first relief (6) belonging to a first inclination mechanism, and the intermediate piece (5) with its parts (12) of the rear face corresponds to a second relief (5). belonging to a second inclination mechanism.

In Figure 2b, the backrest (1) is found in a first inclined position where the first relief (6) abuts against the tongue (7). In this case, the tongue (7) flexes along a bending line (9) and thus leaves the plane of the strip (4), while the second relief (5) comes closer to come into contact with the counter-cuts (1 1) without coming to rely on it.

In Figure 3b, the folder (1) is found in an even more inclined position following a greater effort by the user on the folder (1). In this case, the first relief (6) continues to rest against the tongue (7) and continues to bend along the bending line (9) while the second relief (5) abuts against and deform the counter-cuts (1 1), causing a general torsion of the strip (4) along a torsion axis (10) which coincides with said bending line (9).

It therefore emerges from these figures that the backrest tilts firstly via a first elastic tilting mechanism which consists of bending the tongue (7) via the first relief (6). This first tilting mechanism is implemented individually and in a first angular range of inclination of the backrest. When the effort on the back is greater, this first tilting mechanism continues to be implemented by the further bending of the tongue (7) and a second elastic tilting mechanism is also implemented so simultaneously. This second inclination mechanism consists of the torsion of the strip (4) via the second relief (6). The combination of these two mechanisms of elastic inclination allows the file to tilt in a second angular interval when the support force on the backrest (1) exceeds a certain predetermined threshold.

The two angular intervals are juxtaposed and have a common angle, which is particularly illustrated in Figure 4, where a graph shows the effort required to tilt the file (1). In this case, when no effort (0 Newton) is applied to the backrest (1), its inclination is 15 ° nominal position. The more the user will rely on the folder (1), the more the latter will tilt proportionally, and this in a first angular range wide of 10 °. For a force of 300 N, the inclination of the backrest will be 25 °. In this first angular interval, the inclination is quite easy to obtain and corresponds to the classic case for a user to be comfortable. Only the first tilting mechanism is implemented.

Beyond a predetermined threshold of 300 N for example, the inclination of the backrest (1) is more difficult to obtain because the second reclining mechanism is implemented simultaneously with the first inclination mechanism. Thus, for a force of 300 N, the inclination is 25 °, and for a force of 900 N, the inclination will be 29 °, the inclination is always proportional to the effort. This second angular interval is therefore wide of only 4 ° for a total effort of 600 N. This second level of effort, harder, therefore allows to incline the backrest (1) more sustained and less fast, especially for people of high build.

This is only one possible example of a stress curve. It could very well be different in order to adapt to other users, the main thing being to have two different angular intervals for two different levels of effort. By extrapolating, this type of tilting device could very well be adapted for three angular intervals relating to three different levels of effort, by introducing a third relief and additional cuts in the strip (4).

Figures 5 to 13 show a second more detailed example of implementation of the tilting device according to the invention. The same references were kept in order to maintain consistency between the two examples of implementation.

Thus, Figures 5 and 6 show a seat with a seat (2) resting on the ground via a base or a seat support (3), and a backrest (1) connected to the base (3) via a headband (4) surrounding the back of the folder (1). The tilting device according to the invention is located at the central portion of the strip (4) and three cuts are proposed (A-A, B-B and C-C) to detail the tilting device as we will see later.

Referring to Figures 7 and 8 showing exploded views of the tilting device, the latter comprises a plate (20), whose size corresponds to that of the backrest (1) and being adapted to come and press against the face back of the folder (1). This plate (20) has a first central protuberance (5) from which protrudes a second protuberance (6). This second protrusion (6) corresponds to the first relief (6) as described in the invention while the first protuberance (5) corresponds to the second relief (5) as described in the invention. The inclination device also comprises a strip (4) secured to the plate (20) via, on the one hand, in the upper part, fixing screws, and on the other hand, in the lower part, a mechanical connection consisting mainly of a hemicylindrical element (22) and two pins (23).

Thus, on the one hand, the upper part of the strip (4), in this case the tongue (7), is fixed to the plate (20), therefore a fortiori back (1), via two screws (38) inserting into two orifices (24) of the tongue (7) and two orifices (25) of the plate (20). On the other hand, at the lower part of the strip (4), the rounded portion (31) of semicylindrical element (22) is inserted inside a corresponding cavity (35) provided for this purpose in the second relief (6) of the plate (20), while the flat portion (32) of the hemicylindrical element (22) is positioned in front of the strip (4). This hemicylindrical element (22) is fixed to the strip (4) via three screws (29) respectively inserting in the orifices (27) of the strip (4) and in orifices (28) of the hemicylindrical element (22). Figures 9 and 10 illustrate precisely the attachment between the hemicylindrical element (22) and the strip (4), in particular with the cutting plane A-A.

The fastening screws (29, 38) passing through the strip (4) are all hidden by a cover (21) coming to press over the tilting device and having integrated nuts (26, 34) for bolting said screws. (29, 38).

Between the fixing screws (29) are two cavities (33) hollowed out in the flat part (32) of the semi-cylindrical element (22) and opening in the form of a window (39) in the rounded part (31) in vis-à-vis with the second relief (5). Each cavity (33) is able to accommodate a pin (23) having a rounded face visible from the window (39) and a beveled rear face facing the strip (4), as can be seen in Figures 1 1 to 13 in BB or CC cup view (identical) at a peg (23). A pin (37) protruding from the rounded portion (31) of each pin (23) protrudes from the respective window (39). The two pins (23) are fixed to the plate (20), and therefore a fortiori to the backrest (1), via two screws (30) each fitting into an orifice (36) passing through the pin (23) and its pin ( 37) and in a hole (43) provided for this purpose in the plate (20). The pieces (23) are therefore attached to the plate (20), but remain free to pivot in the hemicylindrical part

(22). In this case, each pin (23) can pivot about a pivot axis parallel to the axis of bending and twisting of the strip (4) and its pivoting is limited when the stud (37) abuts against the upper edge (41), or against the lower edge (40) of the corresponding window (39). This pivoting allows the headband (4) to have a degree of freedom with the folder (1) at its lower part.

More specifically, the pin (23) can move inside the cavity (33) provided in the hemicylindrical element (22), because its rear face (42), opposite the pin (37), is not flat , but beveled, as can be seen more clearly in FIG. 13. Thus, when the pin (37) projecting from the pin (23) is movable between the upper (41) and lower (40) edges of the cavity window (39) (33), the rear face (42) of the pin (23) moves away and approaches the strip (4), without bumping into it to allow the pivoting of the pin (23). If the rear face (42) of the pin (23) was flat, it would be pressed against the strip (4) and could not allow any pivoting movement of the pin (23).

In FIG. 11, in the absence of biasing the backrest (1), the first relief (6) protruding from the plate (20) is positioned against the tongue (7) of the headband (4), the tongue (7) not being biased, therefore not deformed, and the stud (37) of the pin (23) is located in the middle of the window (39) of the semicylindrical element (22).

In FIGS. 12 and 13, following a pressure exerted on the backrest (1), the latter tilts backwards, pivoted around the pivot link provided by the pin (23) in the semi-cylindrical element (22). the first relief (6) protruding from the plate (20) leads the tongue (7) of the strip (4) rearward by deforming it by flexion, and the pin (37) of the pin

(23) pivoted thus closer to the upper edge (41) of the window (39) of the hemicylindrical element (22).

Such a mechanical connection permitting pivoting is necessary for the backrest (1) and the associated plate (20), made of a material rigid, can tilt and generate the bending / torsion movement of the strip (4) designed in a flexible material, and without breaking part, as is illustrated very schematically in Figures 14 to 16.

In Figure 14, in the absence of pressure exerted on the backrest (1), the backrest (1) and the headband (4) are positioned against each other, without inclination and without deformation.

In FIG. 16, in the presence of a pressure exerted on the backrest (1), the latter tilts backwards, driven by pivoting around the pivot connection allowed by the pin (23) in the semicylindrical element (22), and deforms the band (4).

If the inclination device did not include this pivot connection, the backrest (1) would remain in its initial position, despite the possibility of flexion / torsion of the headband (4), as illustrated in FIG. 15. The pivot connection is thus essential for that the assembly can cooperate and tilt in a synchronized and smooth manner.

The configurations shown in the figures cited are only possible examples, in no way limiting, of the invention which, on the contrary, encompasses variants of shapes and designs within the reach of those skilled in the art.

Claims

Device for tilting a seat back (1) connected to the seat

(2) or to a support

(3) seat via a band (4) surrounding the rear of the backrest (1) and being fixed there, characterized in that it comprises:

- a first controlled elastic inclination mechanism (6, 7) responding to a force exerted on the backrest (1) by the user, and

- a second controlled elastic inclination mechanism (5, 4) responding to a force exerted on the backrest (1) by the user greater than a predetermined threshold;

the first mechanism (6, 7) being implemented individually according to a first angular interval of inclination of the backrest (1) responding to a force lower than said predetermined threshold, and the first (6, 7) and second (5, 4) mechanisms being implemented simultaneously according to a second angular interval of inclination of the backrest (1) responding to a force equal to or greater than said predetermined threshold, said intervals being juxtaposed and having a common angle.

Device according to the preceding claim, characterized in that the first mechanism (6, 7) consists of at least a first relief (6) capable of bending at least one tongue (7) corresponding to a portion of the strip (4) delimited by two vertical cutouts (8) whose lower ends border a horizontal axis of flexion (9) of said tongue(s) (7), the first relief(s) (6) protruding from the rear face of the backrest (1) or the front face of said tongue (7) of the headband (4) or both and then being positioned opposite each other.

Device according to the preceding claim, characterized in that the second mechanism (5, 4) consists of at least one second relief (5) capable of imparting an elastic twist to the strip (4) along a torsion axis (10) d horizontal appearance, the second relief(s) (5) projecting from the rear face of the backrest (1) or from the front face of the part of the headband (4) surrounding the tongue (7) or both and then being positioned opposite each other, the headband ( 4) being designed in a material capable of working in elastic torsion in an angular interval of at least the amplitude of the second inclination interval of the backrest (1).

4. Device according to the preceding claim, characterized in that the axis of torsion (10) of the strip (4) coincides with the axis of flexion (9) of the tongue (7).

5. Device according to one of the preceding claims, characterized in that the first angular interval of inclination of the backrest (1) is preferably between 0° and 10° for a first level of effort between 0 N and 300 N .

6. Device according to one of the preceding claims, characterized in that the second angular interval of inclination of the backrest (1) is preferably between 10° and 20° for a second level of effort between 300 N and 900 N .

7. Device according to one of claims 3 to 6, characterized in that the first relief (6) consists of a projecting portion of the second relief (5).

8. Device according to one of claims 2 to 7, characterized in that the tongue (7) is fixed by screwing to the first relief (6) projecting from the rear face of the backrest (1).

9. Device according to the preceding claim, characterized in that the lower part of the strip (4) located under the tongue (7) is secured to the second relief (5) projecting from the rear face of the backrest (1) by means of a mechanical connection allowing a degree of freedom of the backrest (1) along a pivot axis parallel to said torsion axis (10).

10. Device according to the preceding claim, characterized in that said mechanical connection consists of: - a semi-cylindrical element (22) whose flat part (32) is positioned against said lower part of the strip (4) and the rounded part (31) is inserted into a corresponding cavity (35) provided for this purpose in the second relief (5);

- at least one pin (23) capable of being inserted and pivoting along said pivot axis in a corresponding cavity (33) provided for this purpose in the semi-cylindrical element (22) and ending in a window (39) in opposite the second relief (5);

- screws (29) fixing the strip (4) to the semi-cylindrical element (22);

- screws (30) fixing the pin (23) to the backrest (1).

1 1 . Device according to the preceding claim, characterized in that the pin (23) comprises a pin (37) inserting into the window (39) and being able to come into contact with the upper (41) and lower (40) edges delimiting the window (39), the latter playing the role of stops limiting the pivoting of the pin (23) in the cavity (33), the pin (37) being provided with a through hole (26) through which the screw passes fixing (30) of the pin (23) to the backrest (1).

12. Seat equipped with a backrest tilting device (1) as described in the preceding claims.