SELF-ADJUSTABLE BACKREST DEVICE

Abstract

The self-adjustable backrest device supplements a seat surface such that said seat surface is a previously existing one and what is covered by the object of this invention adds a backrest or improves the existing one, for which purpose it comprises a mobile plate on which the user rests, wherein said plate swivels on a horizontal shaft that passes through a first set of hubs connected to the plate, that shaft being associated with a second set of hubs connected to a support that may be the backrest itself of the chair or easy chair on which the self-adjustable backrest is going to be used, in which case it will be referred to as pre-existing backrest, or it may be a fixed backrest which forms part of the device, in which case it will be referred to as backrest of the device. The device may include fixing elements to prevent its movement, such as legs, pegs, or a flap.

Claims

1. A self-adjustable backrest device to supplement a seat surface, the backrest device comprising: a mobile plate (1), a first set of hubs (2) connected to the mobile plate, a second set of hubs (4) removably connected to a support (9), and a horizontal shaft (3) connected to the first set of hubs, supported by the second set of hubs and engaging a rotation spring (8) so that the mobile plate is pivotable with respect to the second set of hubs, wherein the horizontal shaft is disposed at a distance from the seat surface (10) of between 12 and 33 cm.

2. The self-adjustable backrest device according to claim 1, wherein the rotation spring, preferably cushioned, is disposed in a resting position where the mobile plate (1) is disposed in an approximately vertical position.

3. The self-adjustable backrest device according to claim 1, further comprising a stop (11) for limiting the movement of the mobile plate.

4. The self-adjustable backrest device according to claim 1, wherein the second set of hubs is adjustable in height along the support.

5. The self-adjustable backrest device according to claim 1, wherein the mobile plate includes more than one element.

6. The self-adjustable backrest device according to claim 1, wherein the distance from the seat surface is between 18 and 27 cm.

Description

DESCRIPTION OF THE DRAWINGS

[0032] For a better understanding of the invention, the following figures are included.

[0033] FIG. 1 shows the invention and shows also a part of a human body. The chair where the device is used has two side bars (one of them is shown) and the backrest claimed is fixed to the support, in this case a pair of bars one of them is shown. In FIG. 1 is shown one of the bars (5), the mobile plate (1), the second set of hubs (4) fixed to the support, in this case two bars, a fixing part (9), the rotation spring (8) The seat surface (10), in this case a chair, is also shown. It is also shown a stop (11) that limits the movement of the plate

[0034] FIG. 2 shows the bar (5) the mobile plate (1), the first set of hubs (2), the shaft (3), the second set of hubs (4) and the rotation spring (8) in this case shown separately exploded from the shaft. It is also shown in FIG. 2 the fixing zone (9) in this case fixed to the bar (5).

[0035] FIG. 3 shows, from above, the mobile plate (1), the first set of hubs (2) fixed to the mobile plate, the shaft (3), the second set of hubs (4), the rotation spring (8) connected to the second set of hubs, the fixing zone (9) suitable for fixing to the bar, not shown in this figure.

EMBODIMENTS OF THE INVENTION

[0036] Briefly described hereunder is an embodiment of the invention, by way of example and without limiting the scope thereof.

[0037] The self-adjustable backrest that supplements a seat surface.

[0038] A mobile plate (1) having a sufficient size to cover the user's back from the coccyx to the area of the shoulder blades.

[0039] A horizontal shaft (3) on which the aforementioned mobile plate swivels, the said shaft being supported by a first set of hubs (2) connected to the mobile plate and a second set of hubs (4) connected to the support, in this case two bars (5), beside the mobile plate so that the mobile plate is between those two bars.

[0040] A rotation spring (8) that is connected to the second set of hubs engages the shaft so that it keeps the mobile plate (1) in an approximately vertical position when it is in a resting position, i.e., when there is no external force acting thereupon.

[0041] The first set of hubs (2) is connected to the mobile plate. The shaft (3) is also associated with the second set of hubs (4) that are connected to the fixing zone (9) suitable for removably fixing to a support.

[0042] The second set of hubs is height-adjustable, and, by varying its height, the height of the plate and the shaft are modified in relation to the seat surface (10).

[0043] The shaft on which the plate swivels is located at a height of 23 cm, the normal height being between 12 and 33 cm from the seat surface and, preferably between 18 and 27 cm

[0044] The action of the first and second set of hubs, and the horizontal shaft associating them, allows the mobile plate to swivel such that the greater the force exerted by the user on the upper part of the mobile plate, the greater the action on the lumbar area, reducing the pressure on the buttocks being lifted.

[0045] A stop (11) limits the movement of the mobile plate (1).