WO2004032686A1

WO2004032686A1 - Chair backrest

Info

Publication number: WO2004032686A1
Application number: PCT/IB2003/004198
Authority: WO
Inventors: Giancarlo Piretti
Original assignee: Pro-Cord Spa
Priority date: 2002-10-08
Filing date: 2003-09-23
Publication date: 2004-04-22
Also published as: AU2003260922A1; ITTO20020867A1; TW200412885A

Abstract

Chair brackrest comprising: a support structure (17); a lumbar support element (26) able to move relative to the support structure (17) along a vertical direction, and a control mechanism (32) able to be operated manually to adjust the position of said lumbar support element (26). The control mechanism (32) comprises: a telescopic lever (33) including a first section (35) articulated to the support structure (17) and a second section (36) able to slide in telescopic fashion relative to the first section (35), a control cursor (39) borne by said second section (36) of the telescopic lever (33), and a connecting member (42) borne by the telescopic lever (33) and engaging in sliding fashion the lumbar support element (26).

Description

"Chair backrest" ***

The present invention relates to a chair backrest according to the preamble to the main claim. Known chair backrests are provided with a lumbar support element able to move vertically relative to the base structure of the backrest and associated to a control mechanism which can be operated manually by the user to adjust the vertical position of the lumbar support element. The document WO-A-02/32263 describes a chair backrest comprising a lumbar support element able to move vertically relative to the support structure of the backrest and associated to an adjustment mechanism comprising two levers articulated to the support structure of the backrest and provided with respective teeth which mesh with each other. The two levers are connected to the lumbar support element by means of respective connecting rods and one of the two levers has a control portion which can be gripped manually by the user which projects to the exterior of the backrest and moves along a circular edge of the backrest . The control mechanism described in the document WO-A- 02/32263 is particularly suitable to be used in a backrest having a lower part with an edge with rounded shape. If this adjustment mechanism were used in a backrest with rectilinear edges, problems would be encountered from the aesthetic point of view because the control portion that extends to the exterior of the backrest would project outside the backrest by a different measure in the various adjustment positions.

The object of the present invention is to provide a chair backrest with adjustable lumbar support element, provided with a simple control mechanism which can be used in backrests with rectilinear edges without aesthetic drawbacks. According to the present invention, said object is achieved by a backrest having the characteristics set out in the main claim.

The characteristics and the advantages of the present invention shall become readily apparent from the detailed description that follows, provided purely by way of non limiting example, with reference to the accompanying drawings, in which:

- Fig. 1 is a schematic lateral view of a chair provided with a backrest according to the present invention,

- Fig. 2 is a rear view of the chair of Fig. 1,

- Fig. 3 is a perspective view of the front view of the backrest of Fig. 1 without its stuffing, - Fig. 4 and 5 are perspective view of the rear part of the backrest illustrating the control mechanism in two operative positions,

- Fig. 6 is a section according to the line VI-VI of Fig. 5 and - Figs. 7 and 8 are rear views showing the control mechanisms in the operative positions of Figs. 4 and 5. In Figs. 1 and 2, the reference number 10 designates a chair comprising a seat 11 and a backrest 12. In conventional fashion, the chair 10 is provided with a central support 13 adjustable in height. At the top of the central support 13 can be positioned a mechanism generically designated by the number 14 which allows a synchronised oscillation movement of the seat 11 and of the backrest 12. The backrest 12 comprises two metallic or plastic uprights 15 having respective connecting sections 16 for connecting the backrest 12 to the oscillation mechanism 14 or to the central support 13.

With reference to Figures 3 to 5, the backrest 12 comprises a support structure 17 formed by a rigid plate, for instance made of moulded or injected plastic material. The support structure 17 has a front face 18, a rear face 19, a lower edge 20 and two lateral edges 22. The support structure 17 is fastened to the upper ends of the uprights 15, for example by means of a pair of tubular elements 23 fastened onto the rear face 19 of the support structure 17 or obtained in integral fashion by moulding with the support structure 17. The support structure 17 is provided with guiding elements extending in the vertical direction, preferably- obtained in the form of two pairs of through slits 24. The support structure 17 is also provided with an arched through groove 25.

The backrest 17 comprises a lumbar support element 26 formed by a body made of plastic material with a convex central part 28 and two lateral portions 29 provided with pivot pins 30 (Fig. 6) which engage in sliding fashion the through slits 24. The lumbar support element 26 is free to move in the vertical direction relative to the support structure 17. The positions in which the pivot pins 30 abut against the respective ends of the slits 24 constitute the fully lowered or fully raised position of the lumbar support element 26. As Fig. 3 shows, the lumbar support element 26 is provided with a horizontal groove 31 whose function shall become readily apparent hereafter.

With reference to Figs . 4 through 8 , the backrest 12 is provided with a control mechanism 32 which can be operated manually to adjust the position in the vertical direction of the lumbar support element 26. The control mechanism 32 comprises a telescopic lever 33 articulated on the rear face 19 of the support structure 17. The articulation point of the telescopic lever 33 to the support structure 17 is designated by the number 34. The lever 33 comprises a first section 35 and a second section 36, each of which is preferably constituted by a thin metal bar. The two sections 35,

36 are free to slide relative to one another and are mutually connected by guiding means . In the embodiment illustrated in the figures, the two sections 35, 36 are mutually connected by means of a pivot point and slit coupling. The first section 35 is for instance provided with a pair of pivot pins 37 which engage in sliding fashion a rectilinear slit 38 formed in the second section 36.

The second section 36 of the telescopic lever 33 bears a control cursor 39 able to be operated manually. The control cursor 39 is articulated to the second section 36 by means of a pivot pin 40 and engage in sliding fashion a . guiding element 41 obtained integrally with the support structure 17 or fastened thereto by means of rivets or screws 42.

The telescopic lever 33 bears a connecting member

42 which engages in sliding fashion the groove 31 of the lumbar support element 26. The connecting member 42 can be constituted by a pivot pin which extends through the arched groove 25 and which engages the groove 31 with its end portion projecting from the front face 18 of the support structure 17. In the embodiment shown in the figures, the connecting member 42 is integrally formed with the first section 35 of the telescopic lever 33 whereto it is connected by means of a bracket

43 which extends laterally relative to the telescopic lever 33. The backrest 12 comprises a stuffing element 44 fastened onto the front face 18 of the support structure 17. As Fig. 6 shows, the lumbar support element 26 can move in the space existing between the front face 18 of the support structure 17 and the rear face of the stuffing element 44. With reference again to Fig. 6, the backrest 12 comprises a rear closure shell 45 fastened to the support structure 17 which covers the rear part of the backrest and hides the control mechanism 32. The control cursor 39 projects outside the backrest 12 from the lower edge of the rear closure shell 45.

The user can adjust the position in the vertical direction of the lumbar support element 26 by letting the control cursor 39 slide along the rear edge 20 of the backrest 12. With reference to Figs. 4, 5 and 7, 8, the movement of the cursor 39 commands a rotation of the telescopic rod 33 about the axis of articulation 34. As a result of the rotation of the telescopic rod 33, the connecting member 42 moves along the arched groove 25. The connecting organ 42 acts against the walls of the groove 31 and in turn produces a vertical upwards or downwards movement of the lumbar support element 26. Figs. 7 and 8 show the configurations of the control mechanism 32 that correspond to the completely lowered position and, respectively, to the completely raised position of the lumbar support element 26. The lumbar support element 26 can assume any intermediate position between the positions shown in Figures 7 and 8. The lumbar support element 26 is held in the position selected by the user by the friction force produced by the stuffing element 44.

Naturally, the backrest according to the invention may be subject to numerous variations without thereby departing from the scope of the invention as defined by the claims that follow. For example, the control cursor 39 could be movable along one of the lateral edges 22 of the backrest 12 instead of along the lower edge 20.

Claims

1. Chair backrest comprising:

- a support structure (17) , a lumbar support element (26) able to move relative to the support structure (17) along a vertical direction, and

- a control mechanism (32) able to be operated manually to adjust the position of said lumbar support element (26) , characterised in that said control mechanism (32) comprises : a telescopic lever (33) including a first section (35) articulated to the support structure (17) and a second section (36) able to slide in telescopic fashion relative to the first section (35) , a control cursor (39) borne by said second section (36) of the telescopic lever (33) , and

- a connecting member (42) borne by the telescopic lever (33) and engaging in sliding fashion the lumbar support element (26) .

2. Backrest as claimed in claim 1, characterised in that said support structure (17) comprises a rigid plate having a front face (18) along which the lumbar support element (26) is movable and a rear face (19) whereto the telescopic lever (33) is articulated.

3. Backrest as claimed in claim 2, characterised in that said connecting member (42) extends through a through opening (25) of the support structure (17) .

4. Backrest as claimed in claim 3, characterised in that said connecting member (42) has a portion that projects from the front face (18) of the support structure (17) and engages in sliding fashion a groove (31) of the lumbar support element (26) .

5. Backrest as claimed in claim 1, characterised in that said control cursor (39) is articulated to said second section (36) of the telescopic rod (32) .

6. Backrest as claimed in claim 5, characterised in that said control cursor (39) engages in sliding fashion a guiding element (41) fastened to said support structure (17) .

7. Backrest as claimed in claim 1, characterised in that said sections (35, 36) of the telescopic lever (32) are connected to each other by means of a pivot pin and slit coupling (37, 38) .

8. Backrest as claimed in claim 1, characterised in that the lumbar support element (26) is provided with pivot pins (30) which engage in sliding fashion slits extending vertically (24) of the support structure (17) .