WO2004073456A1

WO2004073456A1 - Armrest assembly for a chair

Info

Publication number: WO2004073456A1
Application number: PCT/IB2004/000421
Authority: WO
Inventors: Giancarlo Piretti
Original assignee: Pro-Cord Spa
Priority date: 2003-02-19
Filing date: 2004-02-16
Publication date: 2004-09-02
Also published as: TW200417345A; ITTO20030123A1

Abstract

Armrest assembly for a chair, comprising: an armrest member (26) movable in the vertical 5 direction, and 10 15 a support arm (24) having a first end connected to the chair and a second end connected to the armrest member (26). The support arm (24) comprises an articulated parallelogram mechanism (28) with a first end (34, 36) articulated to the chair (20) and a second end (84, 86) articulated to the armrest member (26), the articulated parallelogram mechanism (28) being associated to a locking device (88) able to lock the support arm (24) in a plurality of selectable positions.

Description

"Armrest Assembly for a Chair" * * *

The present invention relates to an armrest assembly for a chair, in particular for an office chair.

More specifically, the invention relates to an armrest assembly comprising an armrest member that is movable in the vertical direction and a support arm having a first end connected to the chair and a second end connected to the armrest member.

In the prior art, many armrest assemblies for chairs have been proposed with the capability of adjusting the vertical position of the armrest member. In a traditional solution, the support arm extends in the vertical direction and comprises two telescopic elements, able to slide with respect to one another, with a first element fastened to the chair and a second element bearing the armrest member.

The present invention provides an armrest assembly for a chair in which the support arm comprises an articulated parallelogram mechanism with a first end- articulated to the chair and a second end articulated to the armrest member and in which the articulated parallelogram mechanism is associated to a locking mechanism able to lock the support arm in a plurality of selectable positions.

The armrest assembly according to the present invention is destined to be mounted on a chair with the support arm extending in the longitudinal direction, with a rear end of the support arm articulated to the support structure of the backrest. This arrangement is particularly advantageous from the aesthetic point of view because it frees the backrest of the chair from the vertical uprights supporting the armrests. The features 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, in which: - Figure 1 is a schematic lateral view of a chair provided with an armrest assembly according to the present invention,

- .Figure 2 is a longitudinal section of an armrest assembly according to the present invention in a fully raised position,

- Figure 3 is a longitudinal section similar to Figure 2 showing the armrest assembly in a fully lowered position,

- Figures 4, 5, S and 7 are sections respectively according to the lines IV-IV, V-V, VI-VI and VII-VII of

Figure 3 ,

Figures 8 and 9 are elevation views of the locking mechanism indicated by the arrow VIII in Figure 3, and - Figures 10 and 11 are plan view according to the arrow X of Figure 8 , showing the locking device respectively in closed and in open position.

With reference to Figure 1, the number 10 designates a chair comprising a central support 12 bearing at its upper end a base 14. The base 14 bears a seat 16 and a backrest 18. The backrest 18 comprises a support structure for example formed by two arms 20 (whereof only one is shown in Figure 1) , connected to the base 14 at their front ends. The chair 10 comprises, on each side, an armrest assembly 22 according to the present invention.

With reference to Figures 2 and 3, the armrest assembly 22 comprises a support arm 24 which extends in the longitudinal direction. The rear part of the support arm 24 is connected to the support structure of the backrest and the front part bears an armrest member 26. The support arm 24 is mobile between a fully raised position, illustrated in Figure 2, and a fully lowered position illustrated in Figure 3. In Figure 1, the two positions of the armrest assembly 22 are indicated respectively with continuous line and with dashed line. The armrest assembly 22 can assume a plurality of intermediate positions between the two positions shown in Figure 1. The armrest member 26 is positioned at the front end of the support arm 24 and is movable in the vertical direction. The connection between the armrest member 26 and the support arm 24 is such that, during the motion in the vertical direction, the support member 26 remains constantly parallel to itself. With reference to Figure 2 and 3, the support arm 24 comprises an articulated parallelogram mechanism 28, including a first lever 30 and a second lever 32. The levers 30, 32 have respective first ends 34, 36 articulated to the support structure of the backrest 20 around respective mutually parallel first axes 38, 40. The articulation axis 38 of the first lever 30 is displaced downwards relative to the axis of articulation 40 of the second lever 32. As shown in Figure 4, the support structure of the backrest 20 has an articulation area 42 provided with two holes 44, 46 pivotally engaged by two pivots 48, 50. Each of the two pivots 48, 50 is fastened to the respective end 34, 36 of a respective lever 30, 32. From the constructive point of view, each lever 30, 32 is formed by two mutually fastened metallic rods with flattened rectangular cross section, designated as 52, 54 and 56, 58 in Figures 4 and 5.

With reference to Figures 2, 3 and 4, the articulation area 42 of the .support structure of the backrest 20 bears a stationary case 60 which encloses the ends 34, 36 of the levers 30, 32. The stationary case 60 is preferably formed by two shells 62, 64 fastened to the articulation area 42 by a screw 66. The stationary case 60 has a lateral opening 68 through which extend the levers 30, 32.

With reference to Figures 2, 3 and 6, the levers 30, 32 have respective central segments which are at least partially superposed to each other in the transverse direction (i.e. in the direction orthogonal to the plane of representation of Figures 2 and 3) . The central segments of the levers 30, 32 are enclosed in a case 70, movable together with the support arm 24. As shown in Figure 6, the case 70 is preferably formed by two shells 72, 74, fastened to each other, for example by means of snap-on connecting elements represented schematically by the reference 76 in Figures 2 and 3.

With reference to Figures 2, 3 and 7, the armrest member 26 comprises a base plate 78 which bears a pair of downward extending flanges 80. The flanges 80 are provided with two pairs of holes engaged by two pivots 82, 83 which define respective axes of articulation 81, 85. A shown in Figures 2, 3, 6 and 7, the levers 30, 32 have respective second ends 84, 86 articulated to the flanges 80 of the base plate 78 by means of the pivots 82, 83. The axes of articulation 81, 85 are mutually parallel and parallel to the axes of articulation 38, 40 of the first ends 34, 36. The axis of articulation 81 of the first lever 30 is displaced downwards relative to the axis of articulation 85 of the second lever 32.

The arrangement including the levers 30, 32 with the related axes of articulation 38, 40 and 81, 85 forms the articulated parallelogram mechanism 28. The levers 30, 32 can oscillate in a vertical plane relative to the stationary axes of articulation 38, 40. The straight line that joins, the axes of articulation 81, 85 always remains parallel to the straight line that joins the axes 38, 40 in every angular position of the support arm 24. This assures that the armrest member 26 moves in the vertical direction whilst always remaining parallel to itself.

The ends 84, 86 of the levers 30, 32 are associated to a locking device 88 able to lock the support arm 24 in a plurality of operative positions, selectable by the user. From the conceptual point of view, the locking device 88 places a securing element between the two rods 30, 32, with the ability to secure the two rods in a series of predetermined locked positions. To each locked position corresponds an angular position of the support arm 24. The locking device 88 can be temporarily unlocked to allow the user to vary the angular position of the support arm and, consequently, the position of the armrest member 26 in the vertical direction. A preferred embodiment of the locking device 88 is described with reference to Figures 2, 3, 6 and 8 - 10. The locking device 88 comprises a securing element 90 constituted by a monolithic element of metallic or plastic material. The securing element 90 has an articulation portion 92 with a hole 94, a segmented stem 96 and, at the opposite end from the articulation portion 92, a cylindrical head 98.

The securing element 90 co-operates with a locking member 100 comprising two pincer elements 102, 104 articulated to each other by means of a pivot 106. The first pincer element 102 has a guiding portion 108 with a smooth-walled hole whose diameter is equal to or greater than the outer diameter of the segment portion 96 . The second pincer element 104 has an actuating portion 112 and a fastening portion 114 with a segment surface whose profile corresponds to that of the segmented portion 96. A compression spring 116 is positioned between the two pincer elements 102, 104 and tends to push the fastening portion 114 to engage the segmented portion 96 of the securing element 90. Figure 10 shows the closed position of the two pincer elements 102, 104. The two pincer elements can be opened by acting manually on the actuating portion 112 in such a way as to free the segment portion 96 from the engagement with the fastening portion 114.

As shown in Figures 10 and 11, the guiding portion 108 has two pivot shaped appendages 118 projecting outwards and forming an axis of articulation 120 parallel to the axis of the hole 94. The segmented portion 96 of the securing element 90 and the corresponding fastening portion 114 have the shape of a succession of annular teeth with triangular profile, according to a general saw tooth configuration. The mutually co-operating profiles 96, 114 are so shaped as to achieve a one-directional lock. When the fastening portion 114 engages the segmented portion 96, the securing element 90 can move relative to the locking member in the direction indicated by the arrow 122 in Figure 8, whilst in the opposite direction the relative motion between the securing element 90 and the locking member 100 is prevented.

With reference to Figures 2 and 3, the locking device 88 is connected in articulated fashion between the end portions 84, 86 of the rods 30, 32. The head 92 of the securing element 90 is articulated to the second rod 32. Preferably, the same pivot 83 which connects in articulated fashion the end portion 86 of the second rod 32 extends through the hole 94 and connects in articulated fashion the securing element 90 around the axis 85. The pivot shaped portions 118 of the locking member 88 engage in articulated fashion respective holes 124 provided on a fork-shaped appendage 126 comprised in the end portion 84 of the first rod 30.

The end portions 84, 86 of the rods 30, 32 and the locking device 88 are enclosed in a case 128, preferably formed by two shells 130, 132 connected to appendages 134, 136 of the case 70 by snap-on engagement elements 138 and 140 (Figure 6) . As shown in Figures 2 and 3, the case 128 has an opening 142 through which extend the arms 30, 32. The shell 130 of the case 128 is provided with a lateral hole 144 at the actuation portion 112 of the locking device 88. An elastic membrane 146 is fastened to the case 128 at the hole 144. With reference to Figures 2 and 3, the armrest member 26 comprises an armrest body 150 and an intermediate support element 152. The intermediate support element 152 is slidably mounted relative to the base plate 78 bearing the axes of articulation 81, 85 in the direction indicated by the arrow 154. The intermediate support element 152 bears a screw 155 defining a vertical axis of articulation 156 around which is articulated the armrest body 150. The armrest body 150 is then provided with a mechanism for adjustment relative to the base plate 78 in the longitudinal direction (in the direction of the arrow 154) and is further provided with a movement of rotation around the axis 156.

The adjustments of the armrest body 150 around the axis 156 and in the longitudinal direction should be considered optional. In a simplified version, one or both such adjustments could be eliminated. In the simplest embodiment, the armrest body 150 could be fastened directly tp the base plate 78. In this case, the armrest 150 would be provided solely with the height adjustment capability. The armrest body 150 could also be provided with other kinds of adjustment motions relative to the base plate 78: for example, an adjustment in the transverse direction could be provided by sliding the armrest body 150 in the transverse direction relative to the intermediate support element 152 or relative to the base plate 78.

As stated previously, the locking device 88 is preferably obtained in such a way as to achieve a one- directional locking. To move the armrest upwards starting from the fully lowered position of Figure 3, the user just has to raise the armrest until reaching the desired vertical position. To lower the armrest, the user must instead press on the actuating portion 112 situated behind the deformable membrane 156 to disengage the locking device 88 and then lower the armrest to the desired position. When the pressure on the actuating portion 112 is released, the locking device 88 locks the arm 24 in the new position.

Claims

1. An armrest assembly for a chair, comprising:

- an armrest member (26) movable in the vertical direction, and - a support arm (24) having a first end connected to the chair and a second end connected to the armrest member (26) , characterised in that the support arm (24) comprises an articulated parallelogram mechanism (28) with a first end (34, 36) articulated to the chair (20) and a second end (84, 86) articulated to the armrest member (26) , the articulated parallelogram mechanism (28) being associated to a locking device (88) able to lock the support arm (24) in a plurality of selectable positions.

2. Armrest assembly as ^'claimed in claim 1, characterised in that the articulated parallelogram mechanism (28) comprises a first and a second lever

(30, 32) having respective first ends (34, 36) articulated to the chair (20) around respective mutually parallel axes (38, 40) and respective second ends (84, 86) articulated to a base plate (78) of the armrest member (26) .

3. Armrest assembly as claimed in claim 2, characterised in that the locking device (88) comprises a securing element (90) able to fasten said second ends (84, 86) of the levers (30, 32) to each other. . Armrest assembly as claimed in claim 3 , characterised in that the locking device (88) comprises a locking member (100) co-operating with said securing element (90) .

5. Armrest assembly as claimed in claim 4, characterised in that the securing element (90) is connected in articulated fashion to the second end (86) of one of said levers (30, 32) and the locking member (100) is connected in articulated fashion to the second end (84) of the other of said levers (30, 32) .

6. Armrest assembly as claimed in claim 5, characterised in that the locking member (100) comprises two mutually articulated pincer elements (102, 104), movable between an open position and a closed position.

7. Armrest assembly as claimed in claim 6, characterised in that the locking device (88) achieves a one-directional lock.

8. Armrest assembly as claimed in claim 7, characterised in that the securing element (90) has a segmented portion (96) ^' with saw tooth profile cooperating with a fastening portion (114) whose shape corresponds to one of said pincer elements (102, 104) .

9. Armrest assembly as claimed in claim 2, characterised in that said first ends (36) of the levers (30, 32) are enclosed in a stationary case (60) .

10. Armrest assembly as claimed in claim 2, characterised in that said levers (30, 32) have central segments that are at least partially superposed to each other in the transverse direction.

11. Armrest assembly as claimed in claim 10, characterised in that said central segments of the levers (30, 32) are housed in a case (70) .

12. Armrest assembly as claimed in claim 3 , characterised in that the second ends (84, 86) of the levers (30, 32) and the locking device (88) are enclosed in a case (128) that is movable together with the armrest member (26) in the vertical direction.

13. Armrest assembly as claimed in claim 2, characterised in that the second ends (84, 86) of the levers (30, 32) are articulated to a pair of flanges (80) projecting downwards from the base plate (78) .

14. Armrest assembly as claimed in claim 2, characterised in that the armrest member (26) comprises an intermediate support element (152) mounted able to slide in the longitudinal direction relative to said base plate (78) .

15. Armrest assembly as claimed in claim 14, characterised in that the armrest member (26) comprises an armrest body (150) articulated around a vertical axis (156) relative to said intermediate support element (152) .