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. *Self-adjustable backrest device of the type which supplement a seat surface characterized in that it comprises a mobile plate (1), a first set of hubs (2) connected to the mobile plate, a horizontal shaft (3) on which the plate swivels and a second set of hubs (4) associated on the one hand with the horizontal shaft and on the other hand connected to a support on which the self-adjustable backrest is disposed and configured as a pre-existing backrest or a fixed backrest which is a part of the device, wherein the shaft is disposed at a distance from the seat surface (10) of between 12 and 33 cm.

2. *Self-adjustable backrest device of claim 1 wherein it further comprises a rotation spring that associates the plate and the horizontal shaft forcing their relative position, preferably cushioned, in the resting position of which the plate is in an approximately vertical position.

3. *Self-adjustable backrest device of claim 1 wherein the shaft run is limited by a stop.

4. Self-adjustable backrest device of claim 1 wherein the assembly consisting of the mobile plate, first and second set of hubs and the support is included in a semi-rigid casing.

5. Self-adjustable backrest device of claim 1 wherein the lower part of the plate has an elastic element that closes the space between the plate and the seat surface.

6. Self-adjustable backrest device of claim 1 wherein the support is a backrest of the device (6) and is fixed.

7. Self-adjustable backrest device of claim 1 wherein the backrest of the device (6) has pegs (7).

8. Self-adjustable backrest device of claim 1 wherein the backrest of the device (6) has a flap (9).

9. *Self-adjustable backrest device of claim 1 wherein the connection of the first set of hubs and the plate comprises movement guides, the position of this first set of hubs being adjustable relative to the plate.

10. *Self-adjustable backrest device of claim 1 wherein the connection of the second set of hubs and the support comprises movement guides, the position of this second set of hubs being adjustable relative to the plate.

11. Self-adjustable backrest device of claim 1 wherein it has more than one plate.

12. Self-adjustable backrest device of claim 1 wherein the shaft is disposed at a distance from the seat surface (10) of between 18 and 27 cm.

Description

DESCRIPTION OF THE DRAWINGS

[0038] For a better understanding of the invention, the following figures are included.

[0039] FIG. 1 shows the invention in an embodiment which uses the backrest itself of the chair where the device is used as a fixed backrest and thus we find the mobile plate (1), the first set of hubs (2) connected to the mobile plate, the shaft (3) and the second set of hubs (4) connected to the support, in this case a pre-existing backrest (5). The seat surface (10), in this case a chair, is also shown.

[0040] FIG. 2 graphically shows an adjustable backrest device that does incorporate a fixed backrest in this case prepared to lean on the backrest of an armchair, with the mobile plate (1), the first set of hubs (2), the shaft (3), the second set of hubs (4) and the backrest of the device (6).

[0041] FIG. 3 shows an embodiment wherein the backrest of the device (6) that presents a triangular cross-section, incorporates pegs (7) for anchoring the backrest to a soft and penetrable ground, such as earth or sand.

[0042] FIG. 4 shows an embodiment wherein the backrest of the device (6) incorporates bases (8) suitable for affixing the device onto smooth ground.

[0043] FIG. 5 shows an embodiment wherein the backrest of the device incorporates a flap (9) between the seat surface (10), in this case the floor, and the user such that, in this way, the user, prevents the movement of the device with his or her own weight.

EMBODIMENTS OF THE INVENTION

[0044] Briefly described hereunder is an embodiment of the invention, by way of example and without limiting the scope thereof.

[0045] The self-adjustable backrest that is supplemented with a seat surface comprising:

[0046] A mobile plate (1) having a sufficient size to cover the user's back from the coccyx to the area of the shoulder blades.

[0047] 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 backrest of the device (6).

[0048] A rotation spring that keeps the plate in an approximately vertical position when it is in resting position, i.e., when there is no external force acting thereupon.

[0049] The device is resting on a seat surface (10), such as a bed or the floor.

[0050] The first set of hubs (2) that is adjustable in height is connected to the mobile plate. When varying the relative height of the first set of hubs, and therefore the shaft, in relation to the plate, the point on which the plate swivels is altered modifying the torque exerted by the plate.

[0051] The shaft (3) is also associated with the second set of hubs (4) that are connected to the backrest of the device (6).

[0052] In this embodiment the second set of hubs is further height-adjustable, and, by varying its height, the height of the plate and the shaft are modified in relation to the seat surface.

[0053] 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

[0054] The action of the first and second set of hubs, and the horizontal shaft associating them, allows the mobile plate to swivel on the backrest of the device 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.

[0055] In this embodiment being explained, to prevent the movement of the self-adjustable backrest device due to the horizontal force exerted by the user when leaning thereon, it comprises a flap by way of brace on which the user sits which, with his or her weight, prevents the assembly from moving.