EP3282901B1

EP3282901B1 - Oscillation device for a chair

Info

Publication number: EP3282901B1
Application number: EP16724706.3A
Authority: EP
Inventors: Sergio Moreschi
Original assignee: CO FE MO Industrie Srl
Current assignee: CO FE MO Industrie Srl
Priority date: 2015-04-15
Filing date: 2016-04-15
Publication date: 2018-11-28
Anticipated expiration: 2036-04-15
Also published as: EP3282901A1; ITMI20150538A1; WO2016166723A1

Description

The present invention relates to an oscillation device for a chair, that is, a mechanism interposed between the seat and the support stem of a chair, preferably an office chair, capable of imparting to the seat a certain forward and backward oscillation movement relative to the stem.
As is known, oscillation devices comprise a main body having a substantially box-like conformation, engaged on the top of a support stem of the chair.
The box-like body defines a member for housing and supporting articulation means of the seat, which are suitable for permitting the oscillation of the seat.
There are known oscillation devices for chairs which have a first spring able to produce the forward oscillation and a second spring, independent of the first one, able to produce the backward oscillation; however, these devices have numerous drawbacks.
WO 2004/056238 A1 , DE 297 00 437 U1 and DE 202 00 298 U1 show examples of known oscillation devices for a chair.
First of all, the known devices are structurally complicated and cumbersome.
The construction of the known oscillation devices entails long times and high costs of manufacture and assembly, which have an impact on the final cost of the chair.
Moreover, some known devices are characterized by an oscillation that is not fluid and not very stable because of the configuration of the springs that control the oscillating motion.
In this context, the technical task at the basis of the present invention is to provide an oscillation device for a chair which overcomes one or more of the above-mentioned drawbacks of the prior art.
In particular, it is an object of the present invention to provide an oscillation device for a chair that is structurally simple, compact and easy and/or inexpensive to make.
A further object of the present invention is to provide an oscillation device for a chair that is capable of improving the efficiency of the oscillation mechanism and the stability of the user while seated.
The stated technical task and specified objects are substantially reached by an oscillation device for a chair, comprising the technical features disclosed in one or more of the claims appended hereto and/or described below.
In a first aspect the present invention relates to an oscillation device for a chair according to claim 1.
Advantageously, therefore, the change in the distance between the two bars enables the forward and backward oscillation of the seat.
The present invention avoids complicated adjustment mechanisms, providing a device that is simple to make and practical to use, ensuring a great comfort of the seat by virtue of the presence of elastic means which control the oscillation - being activated according to the external oscillation forces impressed by a seated user who wishes to oscillate forward or backward - by means of an engagement of the second body with the bars, which are movable in a differentiated manner relative to the first body. Advantageously, in this manner, with a single elastic reaction system interposed between the two bars one can obtain the desired oscillation both forward and backward.
Preferably, the engagement means are configured in such a way that, following the application of an external oscillation force, the other bar will remain stationary within the respective slots. Thus, advantageously, the distance between the bars is changed in a simple manner.
Preferably, the engagement means are configured to engage the second body with the bars through contact. Advantageously, therefore, it is not necessary to provide complicated gear mechanisms or linkages, which considerably simplifies the structure.
Preferably, the slots extend along a path forming an arc of a circle having its center on the oscillation axis.
Preferably, the first body has two pairs of slots respectively engaged by the two bars. Each pair of slots is formed on opposite walls of the first body and each slot has a first abutment portion and a second abutment portion.
During the resting configuration, the bars are arranged in contact with the respective first abutment portions or in proximity thereto, whereas during an oscillation configuration, in which an external oscillation force with a value other than zero is applied, a first bar remains retained by the first abutment portions of respective first slots in which the first bar is inserted and a second bar moves towards the second abutment portions of second slots in which said second bar is inserted, so as to activate the elastic means.
Preferably, the first abutment portions formed on a same wall of the first body are opposite each other and the second abutment portions formed on a same wall of the first body are opposite each other.
Preferably, the first abutment portions are inner abutment portions and the second abutment portions are external abutment portions and the elastic means are activated in extension.
In this manner, during oscillation a first bar remains retained by the inner abutment portions of respective first slots in which the first bar is inserted and the second bar moves towards the external abutment portions of second slots in which said second bar is inserted, activating the elastic means in extension as a result of the increasing distance between the two bars. Therefore, the elastic means oppose the external oscillation forces until reaching the point of equilibrium of the oscillation in which the user intends to maintain his or her seat.
Preferably, the engagement means comprise ribs integral with the second body and configured to abut against engagement portions of the bars. Advantageously, therefore, the ribs follow the oscillatory movement of the second body and hence of the user's seat.
Preferably, the ribs are interposed between the engagement portions of the bars and the first abutment portions are proximal to each other. Advantageously, the ribs extend for an external distance that is less than or equal to the inner distance between the two bars, so that the ribs are insertable between the two bars and by oscillating forward or backward integrally with the second body they can engage one of the two bars positioned in the inner respective abutment portions.
The ribs thus work by pushing on the bars, which extend the elastic means according to the value of the external oscillation forces applied by the user.
Preferably, the engagement portions of the bars are end portions of the bars arranged outside the first body and the ribs are preferably arranged on the inner side of the second body. Advantageously, in this manner the bars pass through the first body via the pairs of slots of and come out of first body with an end portion that acts as a portion for engaging the ribs. The ribs, on the other hand, are formed on the inner surface of the second body facing the first body so as to correctly engage the engagement portions of the bars.
Preferably, the elastic means are subject to a preload (more preferably a traction) in the resting configuration.
Preferably, the elastic means comprise at least one spring having its ends connected to the two bars. Advantageously, the presence of a single elastic system between the two bars which reacts to the forward and backward oscillations enables a non-insignificant structural simplification, which besides improving the stability and fluidity of the oscillation device, conveniently decreases production costs and assembly times.
Preferably, the elastic means are arranged inside the first body. Advantageously, in this manner the elastic means remain protected against external agents during the life cycle of the chair.
In an alternative embodiment of the present invention, the first abutment portions are external abutment portions and the second abutment portions are inner abutment portions (which could also offset each other in the event of a single slot), the engagement portions of the bars are interposed between the ribs and the elastic means are activated in compression. In this manner, during oscillation a first bar will remain retained by the external abutment portions of respective first slots in which the first bar is inserted and the second bar will move away from the external abutment portions of second slots in which the second bar is inserted, so as to activate the elastic means in compression as a result of the nearing between the two bars. In such a case, the elastic means are preferably under a slight compression preload in the resting configuration (in order to maintain the two bars at a distance).
Preferably, the bars extend along parallel extending directions, which are in turn parallel to the oscillation axis.
Preferably, the oscillation axis lies under the bars.
Preferably, the device comprises an oscillation pin extending along the oscillation axis and more preferably fixed to either the first or the second body.
Preferably, the oscillation pin is rotatably connected to the other of the first body and the second body by interposition of a bush.
Preferably, the device (at least as regards the parts of interest) has a plane of symmetry perpendicular to said oscillation axis.
In accordance with a second aspect, the present invention relates to a chair comprising an oscillation device according to the first aspect of the present invention, a support stem engaged with the first body and a seat engaged with the second body.
Additional features and advantages of the present invention will become more apparent from the approximate, and hence non-limiting, description of a preferred, but non-exclusive embodiment of an oscillation device for a chair, as illustrated in the accompanying drawings, in which:

figure 1 is a schematic perspective view of an oscillation device for a chair according to one possible embodiment of the present invention,
figure 2 is a schematic perspective view of a portion of the device of figure 1, and figures 3a, 3b and 3c are side views of the device of figure 1 in three different operating configurations.

With reference to the appended figures, 1 denotes in its entirety an oscillation device for a chair, hereinafter simply the device 1.
With reference to figure 1, the device 1 comprises a first body 2 engageable on a support stem 3 of the chair and a second body 4 suitable for supporting a seat of the chair, not illustrated in the appended figures, and mounted on the first body 2 so as to oscillate about an oscillation axis "X" forward and backward relative to a resting configuration in which the second body 4 is not subject to external oscillation forces.
The device 1 comprises two bars 5 arranged so as to pass through respective slots 6 fashioned in opposite walls 2' of the first body 2 and movable within the slots 6.
Preferably, the bars are cylindrical in shape.
The device 1 comprises elastic means 7 interposed between the two bars 5 and configured to react to a change in the distance between the two bars 5 relative to the resting configuration.
The device 1 further comprises engagement means 8 interposed between the second body 4 and the first body 2 and configured to engage the second body 4 with the bars 5 in such a way that, following the application of an external oscillation force forward or backward on the second body 4, one of the bars 5 is shifted within the respective slots, causing a change in the distance between the two bars 5.
Preferably, the engagement means 8 are are configured in such a way that, following the application of an external oscillation force, the other bar 5 will remain stationary within the respective slots 6.
It should be noted that in one possible embodiment of the present invention, not illustrated in the appended figures, the first body 2 and the second body 4 could also be inverted, i.e. the first body 2 could be the one associated with the seat and the second body 4 could be the one associated with the support stem 3.
Preferably, the engagement means 8 are configured to engage the second body 4 with the bars 5 through contact.
Preferably, the slots 6 extend along a path forming an arc of a circle having its center on the oscillation axis "X".
Preferably, the first body 2 has two pairs of slots 6 respectively engaged by the bars 5. Each pair of slots 6 is formed on opposite walls 2' of the first body 2 and each slot 6 has a first abutment portion 6a and a second abutment portion 6b.
Preferably, during the resting configuration the bars 5 are arranged in contact with the respective first abutment portions 6a or in proximity thereto, whereas during an oscillation configuration, in which an external oscillation force with a value other than zero is applied, a first bar 5 remains retained by the first abutment portions 6a of respective first slots 6' in which the first bar is inserted 5 and a second bar 5 moves towards the second abutment portions 6b of second slots 6" in which said second bar is inserted 5, so as to activate the elastic means 7.
Preferably, the first abutment portions 6a formed on a same wall 2' of the first body 2 are opposite each other and the second abutment portions 6b formed on a same wall 2' of the first body 2 are opposite each other.
In one possible embodiment not illustrated in the appended figures, a single slot 6 could be provided on each opposite wall 2', the wall being endowed with end stop elements defining the first abutment portions 6a of the slots 6.
Preferably, the first abutment portions 6a are inner abutment portions (i.e. proximal to each other) of the slots 6 and the second abutment portions 6b are external abutment portions (i.e. reciprocally distal) of the slots 6 and the elastic means are activated in extension.
Preferably, the engagement means 8 comprise ribs 8a integral with the second body 4 and configured to abut against engagement portions 5a of the bars 5.
With reference to the embodiment illustrated in the appended figures, there are preferably two ribs 8a per wall 2' of the first body 2 and they extend parallel.
Moreover, the ribs 8a are preferably interposed between the engagement portions 5a of the bars 5 and the first abutment portions 6a are proximal to each other.
Preferably, the engagement portions 5a of the bars 5 are end portions of the bars 5 arranged outside the first body 2 and the ribs 8a are preferably arranged on the inner side of the second body 4.
With reference to the embodiment illustrated in the appended figures, figure 3a illustrates the resting configuration in which the bars 5', 5" are arranged in contact with the respective first abutment portions 6a and the ribs 8a typically in contact with or in proximity to the engagement portions of the bars.
With reference to figure 3b, during an oscillation configuration, in which an external oscillation force with a value sufficiently different from zero is applied (such as to cause a forward oscillation of the second body 4), a first bar 5' remains retained by the first abutment portions 6a of respective first slots 6' in which the first bar 5' is inserted, since the respective proximal rib 8a loses contact with it on moving away therefrom, and a second bar 5" moves towards the second abutment portions 6b of second slots 6" in which said second bar 5" is inserted, since it is pushed by the respective proximal rib, thus activating the elastic means 7.
By contrast, with reference to figure 3c, during an oscillation configuration, in which an external oscillation force with a value other than zero is applied (such as to cause a backward oscillation of the second body 4), the second bar 5" remains retained by the first abutment portions 6a of the respective second slots 6" in which the second bar 5" is inserted and the first bar 5' moves towards the second abutment portions 6b of first slots 6' in which the first bar is inserted 5', thus activating the elastic means 7.
In one possibile embodiment, not illustrated in the appended figures, the first abutment portions are external abutment portions and the second abutment portions are inner abutment portions (i.e. proximal to each other), which could also offset each other in the event of a single slot, and the elastic means are activated in compression. Moreover, the ribs are arranged outside the engagement portions of the bars in such a way as to push, alternatively, one of the two bars towards the other, which remains stationary against the external abutment portion (or any end stop integral with the first body), since the respective proximal rib is detached from it and moves away.
According to the present invention, the elastic means 7 preferably comprise at least one spring 7a endowed with a traction preload and having its ends connected to the two bars 5.
In one possibile embodiment not illustrated in the appended figures, however, the spring 7a could be replaced by a piston (hydraulic or pneumatic) or by an elastically deformable passive element.
Preferably, the elastic means 7 are arranged inside the first body 2.
Preferably, the bars 5 extend along parallel extending directions "Y", which are in turn parallel to the oscillation axis "X".
Preferably, the oscillation axis "X" lies under the bars 5.
Preferably, the device 1 comprises an oscillation pin 9 extending along the oscillation axis "X" and fixed to either the first body 2 or the second body 4.
Preferably, the oscillation pin 9 is rotatably connected to the other of the first body 2 and the second body 4 by interposition of a bush 10.
Preferably, the oscillation pin 9 is screwed into the first body 2.
The present invention achieves the set objectives by providing the user with an oscillation device applicable to any chair having a support stem and a seat (to which, a backrest can be advantageously applied, rigidly connected to the seat or articulated relative to the seat), thus overcoming the drawbacks of the prior art.

Claims

Oscillation device (1) for a chair comprising:
- a first body (2) engageable on a support stem (3) of said chair,

- a second body (4) suitable for supporting a seat of said chair and mounted on said first body (2) so as to oscillate about an oscillation axis (X) forward and backward with respect to a resting configuration in which the second body (4) is not subject to external oscillation forces;

- two bars (5) arranged passing through respective slots (6) made in the opposite walls (2') of said first body (2),

- engagement means (8) interposed between said second body (4) and said first body (2),
characterized in that:
- the two bars (5) are movable within said slots (6);

- the oscillation device comprises elastic means (7) interposed between said two bars (5) and configured to react to a change in the distance between said two bars (5) with respect to said resting configuration, and in that
the engagement means are configured to engage said second body (4) with said bars (5), in such a way that, following the application of an oscillation external force forward or backward on the second body (4), one of said bars (5) is shifted within the respective slots (6), causing a change in said distance between said two bars (5).
Device (1) according to claim 1, wherein said engagement means (8) are configured in such a way that, following the application of said external oscillation force, the other bar (5) remains stationary inside the respective slots (6).
Device (1) according to claim 1 or 2, wherein said engagement means (8) are configured to engage said second body (4) with said bars (5) by means of a contact.
Device (1) according to one or more of the preceding claims, wherein the first body (2) has two pairs of slots (6) respectively engaged by said two bars (5), each pair of slots (6) being formed on opposite walls (2') of the first body (2), wherein each of said slots (6) has a first abutment portion (6a) and a second abutment portion (6b).
Device (1) according to claim 4, wherein said first abutment portions (6a) formed on a same wall (2') of the first body (2) are opposite to each other and said second abutment portions (6b) formed on a same wall (2') of the first body (2) are opposite to each other.
Device (1) according to claim 4 or 5, wherein said bars (5) during the resting configuration are arranged in contact with the respective first abutment portions (6a), or close to them; on the other hand, during an oscillation configuration, in which an external oscillation force with a value other than zero is applied, a first bar (5') remains retained by the first abutment portions (6a) of the respective first slots (6') in which the first bar (5') is inserted and a second bar (5") moves towards the second abutment portions (6b) of second slots (6") in which said second bar (5") is inserted, so as to activate said elastic means (7).
Device (1) according to claim 4 or 5 or 6, wherein said first abutment portions (6a) are inner abutment portions and said second abutment portions (6b) are external abutment portions, and wherein said elastic means (7) are activated in extension.
Device (1) according to one or more of the preceding claims, wherein said engagement means (8) comprise ribs (8a) integral to said second body (4) and configured to abut against engagement portions (5a) of the bars (5).
Device (1) according to claim 8, wherein said engagement portions (5a) of the bars (5) are end portions of the bars (5) arranged outside the first body (2), and wherein the ribs (8a) are arranged on the inner side of the second body (4).
Device (1) according to claim 8 when dependent on claim 7, wherein said ribs (8a) are interposed between said engagement portions (5a) of the bars (5', 5"), and wherein said first abutment portions (6a) are proximal to each other.
Device (1) according to one or more of the preceding claims, wherein said elastic means (7) comprise at least one spring (7a) provided with preload and having its ends connected to the two bars (5).
Device (1) according to one or more of the preceding claims, wherein said elastic means (7) are arranged inside the first body (2).
Device (1) according to one or more of the preceding claims, wherein said slots (6) extend along a path forming an arc of a circle having its center on the oscillation axis (X), in which said bars (5) extend along parallel extending directions (Y), which are in turn parallel to the oscillation axis (X), wherein said oscillation axis (X) lies under the bars (5).
Device (1) according to one or more of the preceding claims, wherein the device further comprises an oscillation pin (9) extending along said oscillation axis (X) and attached to one of said first body (2) and said second body (4), said oscillation pin (9) being rotatably connected to the other of said first body (2) and said second body (4) by interposition of a bush (10).
A chair comprising a device (1) according to one or more of the preceding claims, said support stem (3) being engaged with said first body (2) and said seat being engaged with said second body (4).