CHAIR WITH SEAT AND BACKREST MOVABLE IN A SYNCHRONIZED WAY
A chair comprising: a base structure comprising a support, a seat connected to the support via a synchronization mechanism and movable with respect to the base structure between a lowered position and a raised position, and a backrest connected to the synchronization mechanism and movable between an upright position, corresponding to the lowered position of the seat, and a backward-inclined position corresponding to the raised position of the seat, wherein said synchronization mechanism comprises two loop-shaped elastic elements spaced apart in a transverse direction and each comprising a lower portion fixed to a rigid support, an upper portion fixed to the seat, a front elastic portion and an essentially C-shaped rear elastic portion that connect the upper portion to the lower portion, wherein the backrest is fixed to the rear elastic portions of said loop-shaped elastic elements.
This application claims benefit of Italian patent application number TO2014A000936, filed Nov. 11, 2014, which is herein incorporated by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a chair with seat and backrest movable in a synchronized way.
More precisely, the invention relates to a chair in which the seat is movable between a lowered position and a raised position and the backrest is movable between an upright position corresponding to the lowered position of the seat and a backward-inclined position corresponding to the raised position of the seat.
In seats of this type, the resistance opposed by the backrest against the movement of backward inclination is proportional to the weight of the user. Mechanisms of this type are usually known as “weight-activated”.
2. Description of Prior Art
One of the first “weight-activated” mechanisms is described in the document EP-A-0249584 by the same Applicant, which describes a chair in which the seat is connected to the support structure by means of at least one parallelogram mechanism comprising two rods whose ends are articulated to the seat and to the support structure, so as to allow a movement of the seat between a lowered position and a raised position. The backrest has a support structure which oscillates between an upright position, corresponding to the lowered position of the seat, and a backward-inclined position, corresponding to the raised position of the seat. The support structure of the seat is rigidly connected to one of the rods of the parallelogram mechanism. The parallelogram mechanism is equipped with elastic elements to push the backrest towards its upright position.
The main drawback of chairs equipped with parallelogram mechanisms with articulated rods is the high complexity due to the high number of components.
WO2009/039231 (Herman Miller, Inc.) describes a chair with a deformable seat and backrest, which adapts to the user's weight. This chair comprises two side profiles between which a flexible material is stretched, forming the support surfaces of the seat and the backrest. Each of the two side profiles is formed of an integral element of plastic material with two beam elements connected together by means of integral connecting elements.
This chair structure is specifically dedicated to chairs in which the support surface of the seat and the backrest is formed by a flexible sheet and is not easily adaptable to chairs with different configurations of the seat and backrest.
SUMMARY OF THE INVENTIONThe present invention aims to provide a chair with seat and backrest movable in a synchronized way having a simple structure and easily adaptable to different configurations of the seat and backrest.
According to the present invention, this scope is achieved by a chair having the characteristics forming the subject of claim 1.
The claims form an integral part of the disclosure provided here in relation to the invention.
The present invention will now be described in detail, with reference to the attached drawings, given purely by way of non-limiting example, wherein:
With reference to
In the embodiment illustrated by way of example in the figures, the base structure 12 comprises a rotatable and height-adjustable central column 20, connected to a plurality of radial arms 22 carrying respective pivoting wheels 24. The present invention is, however, not limited to a chair with a base structure of this type. The solution according to the present invention can also be applied to chairs with four legs or with a cantilever frame.
The synchronizing mechanism 18 comprises a support 26 fixed to the base structure 12. The support 26 can be formed of aluminum or any other rigid material. The support 26 comprises a central base 28 from which two front side arms 30′ and two rear side arms 30″ extend. The side arms 30′, 30″ protrude laterally outwards from the central base 28. The front and rear side arms 30′, 30″ have respective transverse portions 32′, 32″ and respective longitudinal portions 34′, 34″.
The synchronization mechanism 18 comprises two loop-shaped elastic elements 36 spaced apart in the transverse direction. With reference to
The upper portion 40 of each loop-shaped elastic element 36 has the shape of a longitudinal rectilinear bar, parallel to the longitudinal portions 50′, 50″ of the respective fastening elements 46′, 46″.
The front elastic portion 42 has an upper end integrally connected to a front end of the upper portion 40 and a lower end integrally connected to a front end of the longitudinal portion 50′. The rear elastic portion 44 has an upper end integrally connected to a rear end of the upper portion 40 and a lower end integrally connected to a rear end of the longitudinal portion 50″.
The rear elastic portion 44 of each loop-shaped elastic element 36 has a rear projection 52 integrally connected with the curved part of the rear elastic portion 44. The rear projection 52 extends in the longitudinal direction and protrudes rearward from the respective loop-shaped elastic element 36.
The rear projections 52 of the loop-shaped elastic elements 36 are fixed to respective L-shaped lower arms 54 of the backrest 16. In the illustrated example, the L-shaped lower arms 54 protrude downwards from a lower edge of the backrest 16 and have respective hollow horizontal portions 56 in which respective rear projections 52 are inserted. The rear projections 52 are fixed to respective arms 54 by transverse screws 58. In the example illustrated in the figures, the backrest 16 has a perimeter frame 60 of plastic material and the L-shaped lower arms 54 are integrally connected at their upper ends with the lower side of the frame 60. A sheet of flexible material 62, stretched over the frame 60, forms the support surface of the backrest 16. Alternatively, the backrest 16 could be formed of a shaped panel of plastic material. In an alternative embodiment, the backrest 16 (or the frame 60 of the backrest 16) could be integrally connected with the loop-shaped elastic elements 36.
The seat 14 comprises a seat support panel 64 and a padding 66 fixed on the upper surface of the seat support panel 64. The seat support panel 64 has two longitudinal rectilinear ribs 68 integrally formed on the lower surface of the seat support panel 64 and spaced apart in the transverse direction. The longitudinal rectilinear ribs 68 rest on the respective upper portions 40 of the loop-shaped elastic elements 36. The seat support panel 64 is fixed to the two upper portions 40 of the loop-shaped elastic elements 36, for example by means of screws (not illustrated).
With reference to
With reference to
The operation of the chair according to the present invention is as follows.
Each of the two loop-shaped elastic elements 36, from a kinematic point of view, is equivalent to an articulated parallelogram. The front and rear elastic portions 42, 44 maintain the loop-shaped elastic element 36 in a rest position. In the rest position, the backrest 16 is in an upright position and the seat 14 is in a lowered position. In the rest position, the seat 14 rests on the upper support surface 74 of the upright 72.
As can be seen from
As is visible in
When the user gets up from the chair 10, the elastic portions 42, 44 return to their undeformed position and return the seat 14 to the lowered position and the backrest 16 to the upright position. The elasticity of the mechanism is provided by the intrinsic elastic properties of the material forming the loop-shaped elastic elements 36. Elastic components are not necessary to provide the return action of the seat and the backrest into the rest position.
The locking device 82 allows locking of the backward movement of the backrest 16 and the upward movement of the seat 14. Indeed, as shown in Figure 10, when the locking pin 86 engages the seat 88 of the upright 72, the seat 14 is locked with respect to the rigid support 26. Consequently, the upward movement of the seat 14 and the backward-inclined movement of the backrest 16 are prevented.
Of course, without prejudice to the principle of the invention, the details of construction and the embodiments can be widely varied with respect to those described and illustrated, without thereby departing from the scope of the invention as defined by the claims that follow.
Claims
1. A chair comprising:
- a base structure comprising a support;
- a seat connected to the support via a synchronization mechanism and movable with respect to the base structure between a lowered position and a raised position; and
- a backrest connected to the synchronization mechanism and movable between an upright position corresponding to the lowered position of the seat and a backward inclined position corresponding to the raised position of the seat,
- wherein said synchronization mechanism comprises two loop-shaped elastic elements spaced apart in a transverse direction and each comprising a lower portion fixed to the support, an upper portion fixed to the seat, a front elastic portion and a rear elastic portion, which connect the upper portion to the lower portion, wherein the backrest is fixed to the rear elastic portions of said loop-shaped elastic elements.
2. A chair according to claim 1, wherein the backrest comprises two L-shaped lower arms fixed to respective rear elastic portions of said loop-shaped elastic elements.
3. A chair according to claim 2, wherein the rear elastic portion of each of said loop-shaped elastic elements has a rear projection fixed to a respective L-shaped lower arm.
4. A chair according to claim 1, wherein the lower portion of each of said loop-shaped elastic elements comprises two fastening elements fixed to respective side arms of said support.
5. A chair according to claim 4, wherein each of said fastening elements comprises a transverse portion and a longitudinal portion, which are coupled, respectively, with a transverse portion and with a longitudinal portion of the respective side arm.
6. A chair according to claim 1, wherein the upper portion of each of said loop-shaped elastic elements has the shape of a longitudinal rectilinear beam fixed to a corresponding longitudinal rib of the seat.
7. A chair according to claim 1, wherein each of said loop-shaped elastic elements is made from a single piece of molded plastic material.
8. A chair according to claim 1, further comprising a limit stop device operatively interposed between said support and said seat, said limit stop device comprising an upright projecting upwardly from said support and having a slot engaged by a transverse pin fixed to said seat.
9. A chair according to claim 1, further comprising a locking device comprising a housing fixed to the seat, a locking pin movable relative to the housing between a locking position and an unlocking position and cooperating with a fixed locking seat, the locking device further comprising a control device connected to said locking pin via a flexible cable.
Type: Application
Filed: Nov 10, 2015
Publication Date: May 12, 2016
Inventor: Alessandro PIRETTI (Bologna)
Application Number: 14/937,615