FI76682B - STOL MED GLIDBAR SITS OCH LUTBART RYGGSTOED. - Google Patents

Description

76682

Chair with sliding seat and reclining backrest

A person spends most of his waking time 5 often sitting. In contrast to the lying or upright position, the sitting position strains anatomically mainly the back. The ergonomics of the seat can be improved to some extent by shaping the seat and backrest correctly: the surfaces must be correctly dimensioned, correctly shaped, at the right 10 angles and at the right height.

A significant improvement is also the possibility to change the supported sitting position: the inclination of the backrest and the corresponding position and height of the seat. The oldest known solution is probably a rocking chair, in which the stability is maintained by making the radius of curvature of Jalas larger than the vertical position in the limit positions, so that the height of the metacentre increases. In order to provide a solution that mimics a rocking chair, a chair that rotates about a fixed axis relative to the base has also been widely used. If the axle is not placed under the 20 seats but on the backrest, the position of the seat in relation to the backrest can be changed with different rails by means of lever mechanisms so that it remains ergonomically correct. Instead, when using a fixed pivot axis, it is not possible to eliminate the instability that arises when the center of gravity of the body moves backwards when the backrest is tilted, unless the pivot axis is placed so high that the seat moves sufficiently forward when the backrest is tilted. However, placing the pivot axis high means a significant lift of the center of gravity of the body upwards when the backrest is tilted. Thus, work is required for tilting, the chair must be locked in its tilting position and rising from the seat is in itself uncomfortable. In order to achieve sufficient stability without the seat rising significantly at the same time, the stand has had to be made 35 long and / or heavy.

The present invention eliminates said drawback. It is characterized mainly by the factors defined in the claims.

2,76682

Two embodiments of the invention are described in detail below with reference to Figures 1 and 2.

Figure 1 shows a chair with a footrest.

Figure 2 shows a chair without a footrest.

5 The solid line in each figure shows the positions corresponding to the vertical backrest of the different members and the dotted line to the inclined backrest. A rail 3 is attached to the backrest somewhat above the joint between the backrest 1 and the seat 2, which can be slid by a joint 5 attached to the stand 4 along the length of the seat.

When the backrest 1 is tilted backwards, the seat 2 slides along the locked rail 6 on the base 4 - forward due to pivoting movement around the joint 5, as in known chairs 15 but also because the joint 5 slides upwards along the rail 3, the seat 2 protrudes and up. Thus, due to the sufficiently high joint 5, the center of gravity of the body does not remain approximately stationary only in the horizontal plane, as in the known solutions, but also remains stationary in the vertical direction. Tilting is thus easy, as it does not require the work required to lift the seat, the chair remains unlocked in all its positions and the seat does not rise uncomfortably.

25 In addition to maintaining stability, the height of the seat 2 is thus not substantially altered.

As the backrest tilts, it is desirable for the comfort of the seat that the front edge of the seat rises somewhat. In the embodiment with the footrest 8 shown in Fig. 1, this increase is solved in such a way that the inclination of the rail 6 is considerably greater than that of the seat 2. The rear part of the seat mounted on the backrest joint 9 thus slides approximately as far downwards as the joint 9 therefore rises. At the same time, however, the front edge 10 of the seat rises.

In order for the sliding mechanisms to remain in place when the backrest 1 is upright and the seat pressure is applied to the front edge of the seat 2 76682 but the pressure on the front edge 10 is released and the from the articulated edge of the footrest 8 only at some distance 11 this is articulated to the base piece 12 of the chair seat sliding along the rail 6.

10 The footrest is thus made to rise from under the seat by relieving the seat pressure at the front edge of the seat and leaning on the backrest. When getting up from the chair, the lever mechanism automatically returns the footrest under the seat.

In the solution shown in Fig. 2, the seat is made to remain at the desired inclination so that the rail 6 is divided into parts 6A and 6B below the rear and front edge of the seat. Thus, the rear edge of the seat lowers, if desired, and the front edge rises to the desired extent when the backrest 1 is tilted.