|
(11) | EP 1 992 254 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
||||||||||||||||||||
| (54) | Device for changing the positioning of a seat |
| (57) The invention relates to a device for changing the set up of a seat (12) associated
to a seat support unit and operating between a stationary body (13) and a seat support
(18) pivoted to said stationary unit (13) so as to be capable of oscillating about
a pivoting axis (Y). The set up changing device comprises cam means (24) turnable
by a user and transmission means (25) interacting with said cam means (24) so as to
transform the rotating movement of the cam means into an oscillating movement of the
support (18).
|
[0001] The present invention relates to chairs or armchairs, especially for the office, of the type with variable set up seat, that is, tilting relative to a starting position, generally horizontal, for example forward, to make the use of the keyboard of a computer more comfortable. In particular, the invention relates to a device for changing the set up of such seat between a substantially horizontal position and a tilted position.
[0002] A chair of the type mentioned above usually has a support group located at the top of a base, for example with adjustable height, and a seat support, carrying the seat of the chair or armchair, tilting relative to said support group. In turn, the support group usually comprises a box body attached to the base and a back support bracket that may be fixed or oscillating (independent of the seat or synchronised) relative to the stationary body.
[0003] In some known solutions, the inclination of the seat support relative to the support group is obtained by the coupling of shaped pins into respective seats. In any case, in the known technical solutions it is not possible to make the adjustment while sitting on the seat, but it is necessary to stand up or in any case relieve the weight resting on the seat.
[0004] The object of the present invention is to propose and make a device for changing the set up of a seat which should allow making such adjustment while sitting on the seat of the chair or armchair.
[0006] Further details and advantages of the device according to the invention will appear more clearly from the following description of preferred embodiments thereof, made with reference to the annexed indicative non-limiting drawings, wherein:
[0008] Figures 2 and 2a show a perspective view and a side view of the assembled device in a position corresponding to a horizontal seat;
[0009] Figures 3 and 3a show a perspective view and a side view of the assembled device in a position corresponding to a tilted seat;
[0010] figure 4 shows the device applied to an office armchair, with seat in horizontal position; and
[0012] In said drawings, reference numeral 10 generally indicates a support unit of a seat 12. A seat support 18 is pivoted on support unit 10. The latter supports a chair 20 of seat 12 (figures 4 and 5). Support unit 10 and seat support 18 are further connected by a set up changing device 14 suitable for defining the inclination of the seat support 18 and thus of seat 20.
[0013] In the following description, reference is made to a support unit 10 for a seat wherein the seat and the back oscillate (in independent or synchronised manner) relative to an upright 16 of a seat 12 on which the support unit is mounted. In this case, the support unit 10 essentially comprises a stationary body 13 applied to the top of upright 16, for example with adjustable height, and a bracket 8, to which a back 7 of the seat is connected, oscillating relative to said stationary body 13. In the drawings, reference letter Q indicates the horizontal pivoting axis between bracket 8 and body 13. In such embodiment, the set up changing device 14 is associated to the support bracket 8.
[0014] In other words, in the embodiment described, seat 20 and back 7 are oscillating about axis Q following a movement of the weight of the sitting person. Moreover, irrespective of such oscillation and thus of the user's position, the seat inclination may be changed between a substantially horizontal position and an inclined position, for example up to 10-15°, preferably by about 5 hexagesimal degrees, with the result of changing the seat set up.
[0015] The set up changing device according to the present invention may in any case be applied also to a fixed support unit, where the stationary body 13 and bracket 8 are integral to each other, for example made as a single piece.
[0016] Going back to the preferred embodiment described and shown, the seat support 18 is pivoted to bracket 8 so as to be capable of oscillating about a pivoting axis Y.
[0017] The seat support 18 comprises, at the top, a plate 22 for fixing seat 20. The movement of support 18 relative to bracket 8 is given by the set up changing device 14 described hereinafter.
[0018] In accordance with a general embodiment, the set up changing device 14 comprises cam means 24 associated to one between bracket 8 and support 18 so as to be turnable between at least two positions (to which the two set ups of the seat correspond, substantially horizontal and tilted), and transmission means 25 associated to the other of said two bodies and interacting with said cam means 24. By transmission means it is meant any element placed in contact with the cam means 24 and suitable for transforming the rotating movement of the cam means into a movement of raising and lowering an end (for example the back end), and thus of oscillation, of the seat support 18 relative to the point of connection thereof with bracket 8. It should be noted that, at least when support 18 is in tilted position, the transmission means 25 also transmit the support weight, plus any weight resting on the seat, to the cam means 24, or vice versa.
[0019] In accordance with one embodiment, the transmission means 25 are rigidly connected to the body they are associated to.
[0020] In order to obtain the movement of support 18, it is necessary that the set up changing device 14 does not act at the hinging axis Y between support 18 and bracket 8, but it is arranged at a distance from said axis. In other words, the cam means 24 are turning about an axis X substantially horizontal and parallel relative to the hinging axis Y, but not coincident therewith.
[0021] Advantageously, the greater the distance between axis X of the cam means 24 and the hinging axis Y, the smaller the torque that must be applied to the cam means 24, for example for opposing the weight force of as person sitting on seat 20.
[0022] For example, in accordance with a preferred embodiment, the hinging axis Y that connects bracket 8 to the seat support 18 is located in the proximity of the front end of the support unit 10, whereas the set up changing device 14 is provided in the proximity of the back end of the support unit 10.
[0023] In accordance with a preferred embodiment, the cam means 24 are associated to the support bracket 8 whereas the transmission means 25 are integral to the seat support 18.
[0024] More in detail, the cam means 24 comprise a plate 26 keyed on a control bar 27 that defines axis X of rotation of said plate 26. According to one embodiment, bar 27 is supported by and rotates into bushes 28 seated in respective seats obtained in bracket 8.
[0025] In plate 26 there is obtained a curved slot 29 whose contact profile with the transmission means 25 is eccentric relative to the plate rotation axis X. In other words, slot 29 extends between a first end 29' close to axis X (Figures 3, 3a) and a second end 29" farther than said axis X (Figures 2, 2a). Advantageously, the control bar 27 has a polygonal section and inserts into a complementary polygonal hole 30 obtained in plate 26. Bar 27 ends with a control knob 31 that protrudes laterally from the support unit 10 so as to be easily accessible and manoeuvrable by a user, even when this is sitting on the seat.
[0026] According to a preferred embodiment, the transmission means 25 comprise a pin 33 engaging in the curved slot 29 of plate 26. Pin 33 is integral to the seat support 18 and is arranged parallel to the axis of rotation X of the cam means 24.
[0027] According to a preferred embodiment, the control barf 27 crosses bracket 8 from one side to the other. The cam means 24 comprise a pair of plates 26 mounted on opposite end portions of bar 27 protruding from bracket 8. Similarly, pin 33 extends substantially by the entire width of the seat support 18 so that the ends thereof insert each in a respective curved slot 29.
[0028] In accordance with a particularly advantageous embodiment, the eccentric profile of the cam means 24 extends along such an arc that at least when said means are rotated so as to cause the inclination of the seat support 18 (figures 3, 3a), the transmission means 25 are in a force balance condition relative to the axes of pivoting Y of the seat support 18 and of rotation X of the cam means 24.
[0029] In other words, when plate 26 is in the two travel end positions, that is, when pin 33 is in contact with ends 29' 29" of slot 29, if we define, in the plane of plate 26, the Z axis as the axis passing by pin 33 and by the centre of rotation of plate 26 determined by axis X, said axis Z is inclined so as to be substantially perpendicular to axis W that passes by pin 33 and by the hinging axis Y. In this condition, the component of the weight force that would act on pin 33 so as to apply a moment tending to rotate the plate is exactly directed towards the hinging axis Y of support 18 to the stationary body 13, and is therefore totally annulled. In other words, there is no component of the weight force that acts so as to cause the rotation of plate 26.
[0030] A "jibbing" situation therefore occurs, so that the higher weight resting on the seat, the more the set up changing device locks into the tilted seat position.
[0031] Advantageously, when the plate is rotated to the position of tilting of the seat support, angle α between axis Z and axis W is at the most equal to 90 hexagesimal degrees, preferably slightly less. In this condition in fact, the weight resting on pin 33 would tend to further rotate plate 26 (in counter clockwise direction in figure 2a). However, the plate cannot rotate in this direction since it engages with the end 29" thereof in pin 33.
[0032] On the other hand, when the plate is in the substantially horizontal position of the seat support, angle β between axis Z and axis W is at least equal to 90 hexagesimal degrees, preferably slightly more. In this condition in fact, the weight resting on pin 33 would tend to further rotate plate 26 in opposite direction relative to that of inclination of the seat (in clockwise direction in figure 2a). However, the plate cannot rotate in this direction since it engages with the first end 29' thereof in pin 33.
[0033] Starting from the horizontal seat position, wherein pin 33 is in contact with the first end 29' of slot 29, the seat set up can therefore be changed by rotating the control knob, for example in counter clockwise direction, until pin 33 reaches the second end 29" of the slot. Thanks to the eccentricity of the contact profile between the slot and the pin, the latter raises tilting the seat support. As mentioned above, thanks to the distance between the point of application of the cam-return element gear and the hinging axis between the seat support and the stationary body, a distance that makes the arm of a lever, it is possible for a user to tilt the seat even while sitting on the seat itself. Once the travel end position of the cam element has been reached, the person's weight will contribute to stabilising the seat set up thanks to the above configuration of the cam element.
[0034] To return the seat to horizontal position it is sufficient to rotate the control knob to the opposite direction. As soon as the gear is not in the above binding situation anymore, the weight resting on the pin facilitates the rotation of the cam element towards the starting position.
1. Device for changing the set up of a seat (12), wherein said seat comprises a support
unit (10) applied at the top of an upright (16), and a seat support (18) pivoted to
said support unit (10) so as to be capable of oscillating about a pivoting axis (Y)
at least between a position substantially horizontal and a tilted position, the set
up changing device comprising cam means (24) associated to one between the support
unit (10) and the seat support (18) so as to be turning about an axis (X) between
two travel end positions, and transmission means (25) associated to the other of said
support unit (10) and seat support (18) and interacting with said cam means (24) so
as to transform the rotating movement of the cam means into an oscillating movement
of the seat support (18).
2. Device according to claim 1, wherein the transmission means (25) are positioned so
that, at least when the cam means (24) are in the travel end position that corresponds
to an inclined seat support, defining as axis (Z) the axis passing by the transmission
means (25) and by the axis (X) of rotation of the cam means (24), said axis (Z) is
inclined so as to be substantially perpendicular to the axis (W) passing by the transmission
means (25) and by the hinging axis (Y).
3. Device according to claim 1 or 2, wherein the transmission means (25) are rigidly
connected to the body they are associated to.
4. Device according to any one of the previous claims, wherein the axis of rotation (X)
of the cam means (24) is substantially horizontal and parallel relative to the hinging
axis (Y).
5. Device according to any one of the previous claims, wherein the hinging axis (Y) is
located in the proximity of the front end of the support unit (10), and wherein the
axis of rotation (X) of the cam means (24) is provided in the proximity of the back
end of the support unit (10).
6. Device according to any one of the previous claims, wherein the cam means (24) are
associated to the support unit (10) whereas the transmission means (25) are integral
to the seat support (18).
7. Device according to any one of the previous claims, wherein the support unit (10)
comprises a stationary body (10) fixed to the top of the upright (16) and a seat support
bracket (8) pivoted on said stationary body (13) so as to be capable of oscillating
about a pivoting axis (Q).
8. Device according to claim 7, wherein the cam means (24) are associated to the back
support bracket (8).
9. Device according to any one of the previous claims, wherein the cam means (24) comprise
at least one plate (26) keyed on a control bar (27) that defines the axis of rotation
(X), said plate (26) having an eccentric profile relative to said axis of rotation
(X).
10. Device according to claim 9, wherein a curved slot (29) having said eccentric profile
is obtained in said plate (26).
11. Device according to claim 10, wherein said slot (29) extends between a first end (29')
close to the axis of rotation (X) and a second end (29") farther than said axis.
12. Device according to any one of claims 9 to 11, wherein the control bar (27) exhibits
a polygonal section and inserts in a complementary polygonal hole (30) obtained in
the plate (26).
13. Device according to any one of claims 9 to 12, wherein the control bar (27) is supported
by and rotates into bushes (28) seated into respective seats obtained in the support
unit (10).
14. Device according to any one of claims 9 to 13, wherein the control bar (27) ends with
a control knob (31) that protrudes laterally from the support unit (10) so as to be
easily accessible and manoeuvrable by a user, even when this is sitting on the seat.
15. Device according to any one of claims 9 to 14, wherein the transmission means (25)
comprise a support pin (33) interacting with the eccentric profile of the plate (26).
16. Device according to claim 15, wherein the support pin (33) is integral to the seat
support (18) and is arranged parallel to the axis of rotation (X) of the cam means
(24).
17. Device according to any one of claims 9 to 16, wherein the control bar (27) crosses
the support unit from one side to the other, and wherein the cam means (24) comprise
a pair of plates (26) mounted on opposite end portions of said bar (27) protruding
from the support unit.
18. Device according to claim 17, wherein the support pin (33) extends substantially by
the entire length of the seat support (18) so that the ends thereof insert each in
a respective curved slot (29).
19. Device according to any one of the previous claims, wherein the eccentric profile
of the cam means (24) extends along such an arc that at least when said means are
rotated so as to cause the inclination of the seat support (18), the transmission
means (25) are in a force balance condition relative to the axes of pivoting (Y) of
the seat support (18) and of rotation (X) of the cam means (24).
20. Device according to claim 19, wherein when the plate (26) is rotated to the two travel
end positions, the axis (Z) is inclined so as to be substantially perpendicular to
the axis (W) passing by the pin (33) and by the hinging axis (Y).
21. Seat comprising a support unit (10) applied to the top of an upright (16) and a seat
support (18) pivoted to said support unit (10) so as to be capable of oscillating
about a pivoting axis (Y) at least between a substantially horizontal position and
a tilted position, characterised in that it comprises a set up changing device (14) according to any one of the previous claims
suitable for making said oscillation of the seat support.