MX2007008192A

MX2007008192A - Chair with seat and backrest with synchronized movement.

Info

Publication number: MX2007008192A
Application number: MX2007008192A
Authority: MX
Inventors: Giancarlo Piretti
Original assignee: Pro Cord Spa
Priority date: 2006-07-11
Filing date: 2007-07-04
Publication date: 2009-01-07
Also published as: EP1878360A1; CN101103865A; US20080012412A1; JP2008018239A; CA2593292A1

Abstract

Chair comprising: - a support base (12), - a seat (14) including a support structure (38) that is movable relative to the support base (12) between a lowered position and a raised position, and a backrest (16) having a support structure (22) articulated to the support base (12) around a transverse axis (28) and oscillating around said axis between a position of maximum forward inclination and a position of maximum backward inclination, in which the seat (14) and the backrest (16) are mutually connected in such a way that when the backrest is in the position of maximum forward inclination the seat is in the lowered position and when the backrest is in the position of maximum backward inclination the seat is in the raised position.; The support structure of the seat (38) is connected to the support base (12) by means of at least one rocking lever (58) articulated to the support base (12) and to the support structure of the backrest (38) around two mutually parallel transverse axes (60, 62). The support structure of the backrest (22) comprises two lateral sections (26) each of which has a connecting portion (34) that extends beyond the axis of articulation (28) of the backrest (16) to the support base (12), the connecting portions (34) being articulated to the support structure of the seat (38) around a transverse axis (56) displaced forward relative to the axis of articulation (28) of the backrest (16).

Description

CHAIR WITH SEAT AND BACKING WITH SYNCHRONIZED MOVEMENT Field of the Invention The present invention relates to a chair with seat and backrest with synchronized movement. More specifically, the invention relates to a chair comprising a support base, a seat that can be moved relative to the support base between a lower position and an upper position, and an articulated backrest to the support base around a transverse axis that oscillates around the axis between a position of maximum forward inclination and a position of maximum backward inclination, and in which the seat and the backrest are mutually connected in such a way that when the backrest is in the maximum position forward, the seat is in the lower position and when the backrest is in the maximum backward tilt position, the seat is in the upper position. BACKGROUND OF THE INVENTION Chairs of the type defined above are known in the field as "chairs activated by weight". The weight of the user tends to push the seat downward and tends to keep the backrest in the position of maximum forward inclination. When the user leans with the weight back on the backrest, the push of the backrest is counteracted by the weight of the user who is supported in the manner of Ref 183746 descending on the seat. Chairs of this kind are normally provided with an elastic device which tends to push the seat towards the lower position and the backrest towards the position of maximum forward inclination, so that pushing back on the backrest has to overcome both the weight that rests down on the seat as the elastic force that tends to keep the backrest in the position of maximum forward inclination. Brief Description of the Invention The object of the present invention is to provide a chair of the type indicated above having a simpler, more economical and more compact structure than the chairs of the prior art. According to the present invention, the object is achieved by a chair having the features described in claim 1. BRIEF DESCRIPTION OF THE FIGURES The chair according to the present invention will now be described in detail with reference to the figures shown in FIG. append, provided only by way of non-limiting example, in which: Figure 1 is a partial perspective view of a chair according to the present invention. Figure 2 is an exploded perspective view of the part of the chair shown in Figure 1.

Figure 3 and Figure 4 are longitudinal sections according to the line III-III of Figure 1, showing the chair according to the invention in two positions. Figure 5 is a partial cross-sectional view according to the line V-V of Figure 1, and Figure 6 and Figure 7 are bottom plan views of the chair according to the invention. Detailed Description of the Invention With reference to Figures 1 and 2, the reference number 10 designates a chair according to the present invention. The chair 10 comprises a fixed support base 12, a seat 14 and a backrest 16. The support base 12 comprises a channel-shaped transversal element 18, provided at its lateral ends with two projections 20 extending upwards. The base 12 is connected to a central, vertical support (not shown) with an adjustable height, which projects upwards from a support formed by a plurality of radial arms provided at their outer ends with oscillating washers, according to an arrangement that It is widely known in the office chair industry. The backrest 16 comprises a support structure 22 which rests on a panel 24 to support the back of the occupant. Support structure 22 of the backrest 16 has two side sections 26 extending in the longitudinal direction. The two side sections 26 are articulated to the projections 20 of the support base 12 about a transverse horizontal axis 28. The two side sections 26 of the backrest 16 are provided with transverse holes 30 with mutually aligned axes, which are connected by means of trunnions (not shown) to the corresponding holes 32 provided in the upper ends of the projections 20 of the support base 12. The two lateral sections 26 of the backrest 16 are provided with respective connection portions 34 which they extend forward in relation to the axis of articulation 28. The connection portions 34 are provided at their front ends with transverse holes 36 with mutually aligned axes. Still referring to FIGS. 1 and 2, the backrest 14 comprises a support structure 38 and a panel 40. The support structure 38 comprises in turn a transverse element 42 and two longitudinal elements 44 fastened to the transverse element 42. The two longitudinal members 44 have respective longitudinal guides coupled by blocks 46 fastened to the lower part of the panel 40. This arrangement makes it possible to adjust the position of the panel 40 in the longitudinal direction relative to the support structure 38. One of the two blocks 46 is provided with a stop device that allows the panel 40 to be fixed in a pre-selected position, which can be decoupled by means of a lever 48. The transverse element 42 of the support structure of the backrest 38 is provided at its lateral ends with two vertical arms 50 so as to be fixed relative to the transverse element 42. The two arms 50 are provided with respective holes with the transverse axis 52. The vertical arms 50 of the cross member 42 are hinged to the connection portions 34 of the backrest 16 by means of two pivot pins 54, each of which couples two aligned holes 36, 52. The pivot pins 54 achieve an articulated connection between the transverse member 42 of the back support structure 38 and the back support structure 22, about an axis designated with the reference 56. The hinge axis 56 is parallel and is displaced forward relative to the hinge axis 28 between the backrest 16 and the support base 12. The support structure of the backrest 38 is connected to the support base 12 by means of two oscillating levers 58. Each oscillating lever 58 has a first end hinged to the support base 12 and a second end hinged to the support structure of the backrest 38. More specifically, the second end of each lever 58 is articulated to the respective longitudinal element 44 of the support structure of the backrest 38. The articulation axes of the levers 58 are designated respectively by the references 60 and 62. The axes are mutually parallel and in turn are parallel with respect to the axes of articulations 28 and 56 previously defined. In the example shown in the figures, two levers 58 are provided, but a single lever 58 could also be sufficient to achieve the same result. With reference to Figures 2 and 5, the support base 12 rests on an elastic member constituted by a flexible bar 64. The flexible bar 64 extends in the transverse direction, parallel to the articulation shafts 28, 56. The ends of the flexible bar 54 extend in the transverse direction beyond the transverse member 42 of the seat support structure 38. The ends engage respective holes of two vertical levers 66. The upper ends of the vertical levers 66 are hinged to the portions of connection 34 of the backrest 16. In the embodiment illustrated in the figures, the upper ends of the levers 66 are hinged to the connection portions 34 by means of the same pivot bolts 54 which are connected in an articulated manner to the connecting portions. 34 of the backrest 16 to the vertical projections 50 of the support structure of the backrest 38. The Flexible bar 34 may be constituted by a metal bar with any cross section, for example, circular, square, rectangular, etc. The flexible bar 64 could also be formed as a spring, with a plurality of superimposed strips fastened to each other. A central part of the flexible bar 64 is fastened to the support base 12 while the side portions of the flexible bar 64 can be elastically deformed relative to the fixed central portion. With reference to Figures 2 and 5, the support base 12 comprises two fixed pivot bolts 68 and two movable pivot bolts 70. The pivot bolts 68, 70 are provided with through holes with the transverse shaft through which the flexible bar 64 extends. The holes of the pivot bolts 68, 70 are mutually aligned and the movable pivot bolts 70 are positioned externally in the transverse direction relative to the fixed pivot pins 68. The movable pivot pins 70 extend through the respective transverse grooves 72 of the support base 12. The movable pivot pins 70 engage with a clearance on the flexible bar 64 and can to be displaced relative to the support base 12 by means of an adjustment mechanism that makes it possible to move the pivot bolts 70 together. The displacement of the pivot pins 70 varies with the free inflection length of the side ends of the bar 64. Accordingly, the displacement of the movable pivot pins 70 varies with the rigidity of the flexible bar 64. Figures 6 and 7 show an example of the adjustment mechanism that controls the movement of the movable pivot pins 70. Each movable pivot pin 70 is attached to a respective adjustment rod 74. The two rods 74 are placed on the lower surface of the support base 12 and have respective racks 76 which mesh with a same gear wheel 78 that can rotate freely about a vertical axis. One of the two adjustment rods 74 is provided with an actuation handle 80. If the handle 80 is moved in the transverse direction, the two rods 78 are moved together in the direction indicated by the arrows 82 in figures 6 and 7. Figure 6 shows the condition in which the pivot pins 70 are in the most external position, which corresponds to the maximum stiffness of the flexible bar 64. Figure 7 shows the condition in which the pivot pins 70 are in the most upright position. internal, which corresponds to the maximum flexibility (or minimum stiffness) of the flexible bar 74. Figures 3 and 4 show the two extreme positions of the chair according to the present invention. In the configuration shown in Figure 3, the flexible bar 64 is in an undeformed position. The backrest 16 is in the position of maximum forward inclination and the seat 14 is in its fully lowered position. The chair assumes this configuration when it is not occupied by a user or when the user sits on the seat 14 but does not exert a backward force on the backrest 16. Figure 4 shows the backrest 16 in the configuration of maximum inclination towards behind. The flexible bar 64 is in the condition of maximum inflection and the seat 14 is in the fully raised position. This is the configuration assumed by the chair when the user leans back on the backrest with all its weight. The backward thrust imparted by the user is counteracted by the weight of the user on the seat 14 and by the return force of the flexible bar 64. The connection between the seat 14 and the support base 12 is achieved by means of the levers oscillating 58 and by means of the connecting portions 34. The geometry of this connection is such that the seat moves forward during its movement from the lower position to its upper position and, simultaneously, the same changes its inclination relative to a horizontal plane. This movement of the backrest makes it possible to obtain ideal conditions from the ergonomic point of view in any position of the chair. The use of a flexible bar 64 as an elastic element to return the backrest 16 in the position of maximum forward inclination makes it possible to considerably reduce the dimensions of the support base 12. With an elastic element constituted by a flexible bar, the mechanism for adjusting the stiffness of the elastic element also becomes particularly simple. In a possible variant, the ends of the flexible bar can be connected to descending extensions of the vertical arms 50. It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is the which is clear from the present description of the invention.

Claims

Claims Having described the invention as above, the content of the following claims is claimed as property. A chair comprising: - a support base, - a seat including a support structure that can be moved relative to the support base between a lower position and an upper position, and - a backrest having a structure of support articulated to the support base about a transverse axis and which oscillates around the axis in a position of maximum forward inclination and a position of maximum backward inclination, in which the seat and the backrest are mutually connected in such a way that when the backrest is in the maximum forward inclination position, the seat is in the lower position and when the backrest is in the maximum backward tilt position, the seat is in the upper position, characterized by: the supporting structure of the seat is connected to the support base by means of at least one pivoting lever hinged to the support base and to the support structure of the backing around two mutually parallel transverse axes, - the support structure of the backrest comprises two side sections each of which has a connection portion extending beyond the articulation axis of the backrest to the support base, the connection portions are articulated to the support structure of the backrest. seat around a transverse axis displaced forward in relation to the axis of articulation of the backrest.
2. The chair according to claim 1, characterized in that it comprises an elastic device that tends to push the backrest towards its position of maximum forward inclination and the seat towards the lower position, the elastic device comprises a transverse flexible bar having a central portion that is fixed relative to the support base and two ends connected to the connection portions of the backrest. The chair according to claim 2, characterized in that the flexible bar is connected to the connection portions of the backrest by means of two vertical levers. The chair according to claim 2, characterized in that it comprises a device for adjusting the stiffness of the flexible bar including two movable pivot pins having respective, mutually aligned transverse holes, through which the flexible bar The chair according to claim 4, characterized in that the adjustment device comprises two rods fastened to the respective movable pivot bolts, and provided with two respective racks that mesh with the same gear wheel. The chair according to claim 1, characterized in that the support base comprises two lateral projections extending upwards so that they are articulated to the lateral sections of the support structure of the backrest. The chair according to claim 6, characterized in that the support structure of the backrest comprises a transverse element provided with two lateral vertical arms whose upper ends are articulated to the connection portions of the backrest. Summary of the Invention The present invention relates to a chair comprising: - a support base (12), - a seat (14) that includes support structures (38) that can be moved relative to the support base (12) between a lower position and an upper position, and a backrest (16) having a support structure (22) hinged to the support base (12) about a transverse axis (28) and that oscillates around a axis between a position of maximum forward inclination and a maximum backward inclination position, in which the seat (14) and the backrest (16) are mutually connected in such a way that when the backrest is in the position of maximum inclination towards in front, the seat is in the lower position and when the backrest is in the maximum backward tilt position, the seat is in the upper position. The seat support structure (38) is connected to the support base (12) by means of at least one oscillating lever (58) articulated to the support base (12) and to the support structure of the backrest (38) around it. of two mutually parallel transverse axes (60, 62). The support structure of the backrest (22) comprises two side sections (26) each of which has a connecting portion (34) extending beyond the hinge axis (28) of the backrest (16) to the support base (12), the connecting portions (34) are hinged to the seat support structure (38) ) around a transverse axis (56) displaced forward relative to the articulation axis (28) of the backrest (16).