EP0360763A1 - Chair with a pivoting backrest restrained by an adjustable spring - Google Patents

Abstract

A chair or armchair comprising an element (12) supporting the backrest articulated at an intermediate portion below the plate (10) of the seat by means of a horizontal shaft (14) positioned transversely, while the plate of the seat and the element which supports the backrest are connected, at a distance from the axis of articulation (14), by a tie rod (17) associated with a capsule with telescopic elements (18, 19) containing a precompressed spring (20) capable of offsetting the displacements of the backrest about the abovementioned shaft as a function of the thrust forces applied thereto. <IMAGE>

Description

This utility model concerns a chair or armchair with swinging backrest.

Office chairs or armchairs are already known, the seat of which is adjustable in height, since it is fixed to an amount of extendable support and the back of which is articulated to the seat and liable to oscillations due to the backward push. exercised by the person seated on the chair or armchair, these oscillations being contrasted by elastic means.

It is the object of the invention to provide a chair or armchair of the aforementioned type comprising a particular form of articulation of the seat to the backrest and an encapsulated helical spring with adjustable load capable of contrasting the thrusts exerted on the folder.

For this purpose the chair or armchair proposed here and comprising a plate supporting the seat fixed on a height-adjustable upright and an element supporting the backrest, is characterized in that the element which supports the backrest is articulated at an intermediate part at the - below the seat plate by means of a horizontal axis positioned transversely to the seat surface, and in that the seat and the backrest are connected, at a distance from the articulation axis, by an associated tie rod to a capsule with telescopic elements comprising a precompressed spring capable of contrasting the displacements of the backrest around the above-mentioned axis as a function of the thrusts applied thereto.

• la Fig. 1 montre une vue latérale, en section, de l'ensemble plaque porte-siège et support dossier associés et, par des lignes en ti­rets, un déplacement en arrière du support dossier;
• la Fig. 2 montre une vue d'en haut en section par­ tielle de l'ensemble dont à la Fig. 1; et les Figures 3 et 4 montrent deux vues en section longitudinale et d'avant respectivement des moyens de contraste à ressort.

The details of a practical embodiment of the proposed system are specified in the following description with reference to the attached drawing, where:

• Fig. 1 shows a side view, in section, of the associated seat carrier plate and back support and, by dashed lines, a rearward movement of the back support;
• Fig. 2 shows a view from above in section through tielle of the assembly of which in FIG. 1; and Figures 3 and 4 show two views in longitudinal section and before respectively of the spring contrast means.

The chair in question comprises a plate (10) for supporting the seat which is fixed to the top of an upright (11) applied to a base for chairs - not shown - and extensible in height either mechanically or by means of a spring gas, but in any case in a known manner which does not require a detailed description. Below the plate (10), in its intermediate part, is articulated the foot of an L-shaped element (12) intended to carry the back of the chair.

This support element (12) has a forked part (13), possibly applied, mounted on a pivot (14), that is to say on the articulation axis of the aforementioned element, mounted inside a sleeve (15) fixed transversely below the plate (10).

The back support element is therefore capable of angular displacements relative to the plate (10) of the seat on the pivot (14), these displacements being however contrasted by an adjustable spring device (16) placed below the aforementioned plate (10).

The device (16) comprises a rigid tie rod (17) hooked in (17 ′) to the plate (10) at a certain distance from the articulation axis (14) and extinguishing downwards through an eyelet ( 12 ′) in the support element (12) of the backrest. The lower end of the tie rod (17) is screwed into a conical metal washer (17˝), placed and stopped by a cup (18) associated with a sliding and complementary cover (19) so that these two elements (v. Fig. 3) form a capsule containing a precompressed helical spring (20). The cover (19) of the capsule acts against the support element (12) of the seat and the action of the spring tends to maintain this support in a position moved forward - continuous lines in FIG. 1 - and limited by the support of the support (12) and / or its fork (13) below the plate (10). From this position, each push (F) from front to back towards the back of the backrest will determine, on the other hand, a rearward movement of the backrest support (12) according to the rotation on the pivot, the maximum displacement being limited by at least one projection (13 ′) of the fork (13) and intended to press below the plate (10). However, this displacement is contrasted by the spring (20) which will load and therefore limit it depending on the thrust exerted on the backrest.

The contrast on the part of the spring and therefore the oscillation behind the back support (12) can on the other hand be adjusted with precision by means of a focusing of the preload of the spring itself inside the capsule by screwing the cup (18) or pulling it (17).

Claims (3)

1.) Chair or armchair of the type comprising a plate (10) supporting the seat fixed to an amount adjustable in height and an element (12) supporting the backrest and oscillating relative to the seat, characterized in that the element (12) which supports the backrest is articulated at an intermediate part below the seat plate by means of a horizontal axis (14) positioned transversely with respect to the seat surface, and in that the seat plate and the element which supports the backrest are connected, at a distance from the articulation axis (14), by a tie rod associated with a capsule with telescopic elements (18, 19) containing a precompressed spring capable of contrasting the displacements of the backrest around the aforementioned axis as a function of the thrusts applied thereto. 2.) Chair or armchair according to claim 1), where the lower end of the element supporting the backrest is provided with a forked portion (13) which is mounted on an articulation pivot (14) passing through a sleeve (15) fixed transversely below the seat plate (10). 3.) Chair or armchair according to claim 1), in which the precompressed contrasting spring is load adjustable within the capsule with telescopic elements.

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