Chair with variously inclinable seat and back

Abstract

 It is a chair with variously inclinable seat and a back, having an oscillating support (12) pivoted on a transversal shaft (16) directly assembled on the rear of a fixed body (11), a seat (17) applied, on its front, on the fixed body and, on its rear ,on the oscillating support through oscillating or elastic elements, a back (19) fixed to the oscillating support, and elements (13) anchored, on one side, to the fixed body and, on the other side, to the oscillating support in an eccentric position relatively to the mentioned shaft (16).

Description

[0001] This invention refers to chairs provided with a vertically adjustable device and with a seat and back whose inclination can be contemporaneously changed.

[0002] Many chairs or armchairs, mostly for offices, are already known and provided with a seat and a back with a so called synchronized changeable inclination, i.e. their inclination can be changed interdependently on corresponding horizontal axes of rotation which are transversally orientated under the seat. In practice, the back can be differently inclinated with respect to an immovable support and according to the recived thrust, while the seat automatically changes its inclination relatively to the setting of the back. The synchronization of the displacement between the seat and the back is usually obtained through additional devices which are installed between the supports of the two parts -seat and back- together with opposing springy means. The main object of this invention is to supply a chair of the above-mentioned type with a simplified, but anyway efficient, structure thanks to an original shape, arrangement and combination of the devices which enable the synchronization of the inclination between the seat and the back.

[0003] Another object of this invention is to supply a chair with variously inclinable seat and back which doesn't need any additional device to the supports of the two parts, being those supports simply pivoted one to the other and joined by the springy device which opposes to the movements of the back.

[0004] This invention supplies a chair with variously inclinable seat and back according to the claim 1. It will, however, be described with further details in the following description referring to the enclosed drawings in which:

Fig. 1

shows a schematic view of a chair of the present invention;

Fig. 2

shows a side sectional view of the supports of the seat and back in a first position;

Fig. 3

shows a view analogous to that in Fig.2, but with the seat and back in another position;

Fig. 4

shows a view from above of the seat and the back supports; and

Figs. 5 and 6

show two detailed view of the opposing springy devices with control means in two different conditions.

[0005] The chair is essentially composed by an upright 10 preferably adjustable in height and fixed at its bottom on a basement (not shown), a body 11 fixed to the top of the upright 10, an oscillating support 12 pivoted to the fixed body and springy elements 13 which connect the fixed body to the oscillating support 12.

[0006] More in detail, the fixed body 11 carries on its front a transversal shaft 14, on which a crossbar 15 is placed which can oscillate, and on its back a second shaft 16, parallel to the first one, on which the oscillating support 12 is pivoted. The crossbar 15 extends transversally above the fixed body 11 and the front part of a seat-carrying element 17 is fixed to it, the rear part of this seat-carrying element being fixed to the oscillating support 12 trough elastic, i.e. flexible, blocks 18. Also a back-carrying element 19 is fixed to the oscillating support 12 so that it looks like a continuation of the seat-carrying element 17 practically without solution of continuity.

[0007] The springy elements 13 which link the fixed body 11 to the oscillating support 12 are usually two and they are symmetrically located at the opposite sides of the upright 10, parallelly to the sides of the fixed body and inside it. Each springy element 13 is set between the first transversal shaft 14, the one which carries the oscillating crossbar 15, and a bar 12a fixed to the oscillating support 12 in an eccentric position relatively to the second transversal shaft 16, and lower than the latter. This is made to oppose to the oscillation of the mentioned support and to mantain it rotated upwards in opposition to the thrust which would incline it backwards together with the back.

[0008] In a preferred realization shown in Figs. 5 and 6, each springy element 13 has a sleeve 20 with a horn end 20a which anchors to the above-mentioned bar 12a, a shaft, which is guided and shifts inside the said sleeve and is provided with a head 21a which anchors to the first shaft 14 and a pre-loaded helical spring 22 which is co-axial to the sleeve 20 and contained in a capsule 22a. The spring 22 is placed between a collar 20b integral with the sleeve 20 and a slider 23 placed on and shifting along the shaft 21 and/or on its head 21a.

[0009] The pre-load of the spring 22 can then be varied by changing the position of the slider 23 along the shaft 21 so to regulate the contrast of the angular shiftings of the oscillating support 12 of the back.

[0010] To this purpose, between the slider 23 and a shoulder 24 -facing it and integral with the head 21a of the shaft 21- there is a wedge-shaped element 25 connected with and adjustable by an adjusting screw 26 which is provided of an adjusting wheel 27 and mounted on the fixed body 11, to rotate without translation. As Figs.5 and 6 show, to the shiftings of the wedge-shaped element 25 coincide different positions of the slider along the shaft and so also different pre-loads of the spring in relation to the level of contrast of the back inclination, according to the requirements.

[0011] In practice, to each variation of the inclination of the oscillating support 12, because of and according to the thrust exerted by the one who leans on it, corresponds a variation of the setting of the seat thanks to the oscillating elements 15, 18 on which it is assembled. The same happens when a different pressure is exerted on other zones than the seat. In any case the shiftings are synchronized and opposed by the springy elements 13 which tend to come back to the starting position as soon as the pressure which caused the variation of the inclination stops.

[0012] Some modifications could be made in the above-described chair without departing from the scope of this invention. So, for example, instead of the helical spring, gas springs could be used as elastic opposing elements.

[0013] Furthermore on the fixed body 11 a lever device 28 as shown in Figs.2 and 4 may be mounted and provided for controlling the adjustment in height of the upright 10 when the latter includes or is made of a gas piston.

Claims

1. A chair provided with variously inclinable seat and back including a vertically adjustable upright (10) and fixed at its bottom on the basement, a body (11) fixed to the top of the said upright, an oscillating support (12) pivoted to the fixed body, and springy elements (13) which link the fixed body to the oscillating support, characterized in that :

- the oscillating support (12) is pivoted to a transversal shaft (16) directly assembled in the back part of the fixed body (11);

- the seat (17) is applied on the front to the fixed body and on the rear to the oscillating support (12) through oscillating or elastic elements;

- the back (19) is fixed to the oscillating support;

- the springy elements (13) are anchored, on a side, to the fixed body and, on the other, to the oscillating support in an eccentric position relatively to the said shaft (16);

- to the variations of the inclination of the oscillating support with the back, which are opposed by the said springy elements, correspond variations of the seal setting.

2. Chair as claimed in claim 1, in which the seat (17) fixed on its front to an oscillating crossbar (15) assembled on a shaft (14) provided on the fixed body, parallel to the oscillating support shaft (16), and on its rear it is connected to the oscillating support through flexible/elastic blocks 18.

3. Chair as claimed in claims 1 and 2, in which the springy elements (13) are symmetrically located on the opposite sides of the upright (10) and are anchorated on their front to the shaft (14) carrying the oscillating crossbar (15) and on their rear to a bar (12a) fixed to the oscillating support far from the shaft (16) of the said oscillating support and lower than it.

4. Chair as claimed in claim 3, in which each springy element (13) has a sleeve (20), to be anchored to said bar (12a), a shaft (21) which shifts in the sleeve and has a head (21a) which anchors to said front shaft (14) and a pre-loaded helical spring (22) located between a collar (20b), integral with the sleeve (20), and a slider (23) which shifts along the shaft (21), and in which between the slider (23) and a shoulder (24) integral with the head of the shaft (21) a wedge-shaped element (25) is fitted for adjusting the position of the slider (23) along the shaft and the pre-load of the spring, said wedge-shaped element being connected to an adjusting screw (26), rotating but without translation, mounted on the fixed body and provided with an adjusting wheel.

Drawing