EP0523012A1

EP0523012A1 - A chair with a seat and back rest of adjustable inclination

Info

Publication number: EP0523012A1
Application number: EP92830255A
Authority: EP
Inventors: Roberto Lucci; Paolo Orlandini
Original assignee: Lamm SpA
Current assignee: Lamm SpA
Priority date: 1991-07-10
Filing date: 1992-05-22
Publication date: 1993-01-13
Also published as: JPH0518342U; IT225115Z2; ITBS910067V0; ITBS910067U1

Abstract

The present invention regards a chair with a seat and back rest having a correlated and synchronized adjustable inclination in which the seat (11) and the back rest (12) are assembled on parallel oscillating axis (13, 15).

The back rest (12) has a lever arm (12a) on its lower part which extends forwards, underneath the seat; the seat rests against said lever arm and oscillates on its rotation axis when the back rest is strained to oscillate on its rotation axis.

Description

The present invention relates to chairs with a seat and back rest of adjustable inclination and more particularly regards a chair having a seat and back rest which are susceptible to angular correlated and synchronized movements.
Chairs having seats and back rests which are susceptible to interdependent angular movements around corresponding horizontal rotation axis are already known. The seat of said chairs can be gradually inclined on and in respect to a fixed support on a base whilst the back rest automatically adjusts its inclination in respect to the position of the seat or vice versa. The correlation or synchronization of the movements of the seat and back rest is usually assured by a mechanic device and from contrast springs which, however, complicate the structure of the chair and negatively effect costs.
The aim of the present invention is to supply a chair with a seat or back rest which are susceptible to correlated, synchronized inclinations but without having to resort to mechanical devices or springs, thus having a simpler structure fitted with an elementary lever system.
Such an aim is accomplished with a chair which is substantially in accordance with claim 1, which will follow.
The backward flexing movement of the body of a person who sits begins with the need to go from an upright position, for example a working position, to a more relaxed position, for example in a conference position.
The chair in accordance with the present invention has a back rest whose backward flexing movement does not depend on a spring but makes use of the weight of the person on the chair through contrast and reaction. Thus the movement of the back rest following the strain which tends to adjust the inclination will always be in proportion to the position and weight of the person using the chair.
In practice, the backward inclination movement of the back rest is coupled with the lifting of the rear part of the seat which is always bucked through the weight of the seated person. The total adjustable angle between the starting position of the seat/back rest therefore corresponds to the sum of the two modifying angles of the inclination of the seat and of the back rest. This means that the strain relieving effect on the spinal cord of the seated person who moves from an upright position to a relaxed position results in being more potential and is more evident than it would be if only the back rest moved.
An example of embodiment of the invention is illustrated in the attached drawings and will be described in further details:

Fig. 1 is a prospective view of the underneath of only the seat;
Fig. 2 is a prospective view of only the back rest;
Fig. 3 is a schematic and side view of the seat and back rest assembled in a first position where the load pushes on the seat; and
Fig. 4 is a similar view to the one in Fig. 3 with the seat and back rest in another position where the back rest is strained towards the back.

The here proposed chair essentially has a seat (11) and a back rest (12) assembled on any support or base (13).
The seat (11) is pivoted at the front to the base (13) through a transversal oscillation axis (14). In turn, the back rest (12) is pivoted on its lower part to the back of the base (13) through a transversal oscillation axis (15). The oscillation axis (14, 15) respectively of the seat and back rest are parallel to each other.
The back rest (12) has a lower lever arm (12a) angled in respect to the back rest itself. Said lever arm (12a) can be integral or inserted and fixed to the back rest in order to move and oscillate with the latter. The lever arm (12a) extends forwards underneath the seat, away from the oscillation axis of the back rest.
Once assembled, the rear part of the seat (11) rests against the lever arm (12a) of the back rest giving the two components the possibility of oscillating on their respective axis (14, 15). The seat and the back rest can be coupled through a pocket slot (16) formed underneath the seat and designed to hold the free end of the lever arm (12a).
Thus, when the weight of the person seated exclusively and predominately rests on the seat, on the arrows F (Fig. 3), the back rest is kept in a more or less erect position through the action of the seat on the lever arm. On the other hand, when the person who is seated moves his body backwards straining the back rest with a force on the arrows G (Fig. 4), the back rest itself oscillates backwards lifting the back part of the seat through the lever arm, the movement of the seat being bucked by the weight of the person who sits so as to correspondingly limit the backward inclination of the back rest.
The movements of the seat and of the back rest are however correlated and synchronized in order to give the possibility of reaching positions and conditions of comfort as described above. Once the strain against the back rest is removed, the person seated automatically returns to the initial positioning (Fig. 3).

Claims

1) A chair with a seat and back rest having an adjustable correlated and synchronized inclination in which the seat (11) is pivoted at the front to a base (13) through a first oscillation axis (14) and the back rest (12) is pivoted on its lower part to said support through a second oscillation axis (15) being parallel to the first, characterized in that the back rest (12) has a lever arm (12a) on its lower part which is angled in respect to the back rest itself and extends forwards underneath the seat, the seat resting against said lever arm and oscillating on the first rotation axis when the back rest is strained to oscillate on the second rotation axis.

2) A chair in accordance with claim 1, characterized in that the lever arm (12a) is integral to or fixed to the back rest and extends forwards underneath the seat beyond the second rotation axis, said lever arm applying pressure from the bottom upwards, underneath the seat when the back rest is strained to oscillate backwards.

3) A chair in accordance with claims 1 and 2, characterized in that said lever arm has a free end which is inserted in a pocket slot (16) formed underneath the seat.