DESCRIPTION

Technical field

The present description generally relates to the technical field of the ergonomic chairs and, more specifically, chairs in which the user’s back and knees are supported with respect to the chair’s seat to improve the anatomical and physiological support so as to avoid back pains linked to postural errors of the user during a prolonged sitting.

Technical background

Many people spend most part of their working day sitting on an office chair, spending many hours at the desk or generally at a working table. The traditional chairs create points pressing on the hip bones, on coccyx and of the legs of a user. Additionally, these chairs impose a physiological sitting position to the user, who consequently will tend to assume an incorrect position which translates into a sitting discomfort, in particular at legs and back.

The posture and suitably planned ergonomic chairs then are important for the comfort and health of many people, since a bad posture may cause a vertebral misalignment or the degeneration of the intervertebral discs, leading to the onset of fatigue and muscle pains.

A correct sitting posture is determined by a correct inclination of the user’s pelvis, in particular by the sacral angle. Under sacral angle the orientation of the sacral plane is meant, that is the plane of the first sacral vertebra (S1), with respect to a horizontal plane, generally the ground plane. The inclination of the sacral angle is directly proportional to the lumbar curvature, or lumber lordosis). Physiologically, an ideal lumbar lordosis angle in a sitting position is comprised between 35 and 45° and characterizes a correct sitting posture. On the contrary, both a lordosis angle lower than 35°, characteristic of the so- called slouching, and a sitting characterized by the forward sliding of the thighs by the user, or higher than 45°, characteristic of a forward sitting (hunching) are indexes of an incorrect posture. A correct sitting portion then provides a pelvis inclination so as to allow the sacral angle to reach an inclination comprised between 35 and 45°, ideally 37°. In order to obtain this result, it would be necessary to prevent the user’s thighs from sliding forwards in order to avoid slouching and, at the same time, to avoid hunching. Such posture results difficult to be maintained for a continuous period as the working hours may be.

The ergonomic chairs currently present on the market expect to provide a comfortable and effective support, by encouraging a correct posture with the purpose of preventing the above problems linked to the spine. However, the support methods provided by the pre-existing chairs do not provide an optimum biomechanical support to the spine and they are often complicated and expensive.

Of the different designs for planning the above-mentioned ergonomic chairs, many of them are oriented to simply adjust the inclination of the backrest or to the weight distribution, but few designs guarantee a correct sitting portion for the user.

Generally, the functions for adjusting the backrest for these chairs include the adjustment of the inclination, of the height of the backrest and the adjustment of the lifting of a lumbar support configured to follow the correct curvature of the user’s spine.

However, since the sitting portion while working is not fixed, the user tends to lean forward to write. The back inclination tends to vary towards an incorrect posture and then the backrest of a chair does not provide an effective ergonomic support of the spine if the user moves.

An additional example is constituted by the so-called “kneeling chair”, wherein the seat is inclined forward so that the knees are lower than the hips and the direction of the femur is inclined by an angle g of about 60° with respect to the axis A of the spine, so that a portion of the weight results to be supported by the knees. In this case a collaboration of the user is requested, who is invited to unload her/his weight on the knees. In this way, the chair induces the pelvis rotation and the user can assume a correct lumbar curvature. However, such solution has revealed ineffective in the long term, since the user collaboration is however requested in keeping the correct posture by using the lumbar muscles, collaboration which results to be tiring in the long term and which tends to fail. When this collaboration fails, the user tends to return to an incorrect posture.

Summary

The invention shown in the present disclosure proposes to overcome the technical limitations of the known art by describing an ergonomic chair configured to keep a user seated with a correct posture spontaneously, without requiring a tiring muscle collaboration, to reduce stress to the back.

According to an aspect of the present invention, the described ergonomic chair comprises a tibial constraint and means to connect the chair to said constraint so that its position can be adjusted with respect to the seat, so that the user could take advantage from the back support deriving from the fixed positioning of the legs with respect to the chair backrest. This guarantees a correct posture since the tibial constraint means prevents the user’s thighs from sliding forward, by avoiding slouching.

According to another aspect of the present invention, the described ergonomic chair comprises a lumbar support means configured to allow the user to assume a correct lumber lordosis.

Both of them, the tibial constraint and the lumbar support, support the legs and the back of a user in a position sitting on the chair to improve the anatomical and physiological support thereof and to prevent the onset of pains and damages deriving from a prolonged incorrect sitting posture.

Brief description of the drawings

Additional advantages and features of the invention according to the present disclosure will result evident to those skilled in the art from the following detailed and not limiting description of some embodiments thereof, with reference to the enclosed drawings wherein:

Figure 1 shows a perspective view of an ergonomic postural chair according to the present invention;

Figure 2 shows a side view of the ergonomic postural chair shown in Figure 1; Figure 3 shows a side view of a user sitting on the ergonomic postural chair shown in Figure 2.

Detailed description of some embodiments

By making reference to Figures 1-3 an ergonomic postural chair 1 is herein described, configured to oblige a user to a predetermined posture, comprising a support base 6 of the chair 1 on the floor, a seat 8 supported by the base 6 and defining a seat plane PS, and a backrest 3, constrained to said seat 8.

The backrest 3 of the seat 1 is configured to provide primary support to the user’s spine. According to an embodiment of the present invention, the inclination of the backrest 3 with respect to the seat 8 is adjustable forward or backward, whereas the user adjusts her/his own position on the chair, by means for adjusting the inclination 9 of the backrest 3, situated at the constraint of the backrest 3 to the seat 8, wherein said means for adjusting the inclination 9 can be a lever, a knob, a swinging mechanism or any other means for adjusting the inclination of the backrest and wherein said means 9 is capable of locking the backrest 3 at a selected inclination.

According to another embodiment, the seat 8 can be inclined by a first angle a with respect to the ground plane PT, wherein said first angle a is the angle comprised between the seat plane PS and the ground plane PT and it is comprised between 0° and 30°, preferably equal to 22°, so that the knees Gi, G2 of the user, in a sitting position, are higher than the hips Fi, F2 and the angle g formed between the direction of the femur Df and the axis A of the user’s spine is equal or lower than a right angle, that is equal to an angle of (90 - a)°, wherein the axis A of the spine is defined as the axis passing through the first cervical vertebra C1 and the second sacral vertebra S2 (coccyx) and wherein the direction of the femur Df is the direction passing through the hips Fi, F2and the knees Gi , G2. The inclination of the seat 8 can be adjusted, so that said first angle (a) assumes any other value comprised between 0° and 30°, by means for adjusting the inclination 7 of the seat 8, which can be a lever, a knob, a swinging mechanism or any other means capable of adjusting the inclination of the seat 8 and wherein said means 7 is capable of locking the seat 8 in the selected inclined position. The support base 6 can include a support column 6a of the seat 8 and height adjusting means 6b, constrained to the support column and configured to vary the height of the seat 8 from the ground, wherein the support column 6a preferably is a telescopic column and the height adjusting means 6b can be a pin, a lever, a knob or any other means capable of keeping the support column 6a at a wished height.

According to an embodiment of the present invention, the height adjusting means 6b can provide one or more height levels of the seat 8, said levels being predetermined depending upon the height of the user.

The support base 6 can further include a plurality of legs with relative movement wheels 6c, capable of providing mobility to the chair 1 on the floor.

The ergonomic chair 1 further comprises a lumbar thrust support 4, constrained to the backrest 3 so that its position can be adjusted in height along said backrest 3, and front constraint means 5, constrained to the seat 8.

The lumbar thrust support 4 is configured to provide support at a dorsal region of interest, generally the region contiguous to the junction between the lower dorsal vertebrae and the upper lumbar vertebrae of the user, or at the junction between the vertebrae T12 and L1, so as to provide support to the lumbar lordosis. This configuration allows to follow the physiological curvature of the spine, so that the lumbar lordosis angle tends to 37°.

According to an embodiment, the lumbar support 4 can be configured to cover a wider lumbar support area, for example including the tenth and eleventh dorsal vertebrae (T10, T11) and the second and third lumbar vertebrae (L2, L3). This provides an upper support to the spine and reduces more the fatigue in the lumbar region, by improving the comfort of the sitting user.

According to an additional embodiment, the lumbar thrust support 4 is constrained to the backrest 3 so that its position can be adjusted in height by the user along said backrest 3, based upon the comfort needs and the sizes of the user.

The front constraint means 5 comprises a constraint element 5a and means 5b, 5d for adjusting the distance of the constraint element 5a from the seat 8. The constraint 5a is configured so as to implement a constraint for a tibial portion of the legs of the user, when seated.

According to an alternative embodiment, the constraint element 5a can be a knee brace, configured to provide to the user even a surface for resting the knees.

The adjusting means 5b, 5d in turn comprises an elongated element 5b, or shaft, sliding with respect to the seat 8 and lockable in a predefined number of positions by means of a locking element 5d, preferably a pin, a lever or any other means for adjusting the position of the shaft 5b sliding with respect to the seat 8, said positions being predetermined depending upon the height of the user.

Advantageously, the adjustment of the position of the shaft 5b depending upon the height does not hinder the lifting of the user from the seat. In this way it is not necessary to unlock the locking element 5d and to modify the position of the elongated element 5b when the user wants to get up from the chair.

According to an embodiment, the constraint element 5a is connected to an end 5c of the elongated element 5b so as to be able to rotate by a second angle b around an axis Z, passing through the end 5c and parallel to the ground plane PT, wherein said second angle (b) is comprised between -20° e + 20°.

The configuration of the ergonomic postural chair 1 described in the present disclosure results to be advantageous since the user, when seated, can keep the predetermined posture thanks to the combined action of at least said constraint element 5a and said lumbar thrust support 4.

When the constraint element is positioned, as shown in Figure 3, at a suitable distance from the seat 8, the user could sit on the chair 1 , actuate the locking element 5d to unlock the shaft 5b and make it to slide towards the seat 8, so that the constraint element 5a is positioned in front of the user’s legs. Afterwards, the user could unlock the position of the constraint element 5a, by actuating the locking element 5d, in one of the predetermined positions, depending upon her/his own height. The constraint element 5a could be suitably rotated around the axis Z so as to provide a support to a tibial portion of the user’s legs, based upon the sizes of the legs and to the sought comfort.

At last, the user could adjust her/his own sitting so that her/his back is comfortably supported at the lumber region by the lumbar thrust support 4 and at the same time the legs are comfortably rested against the constraint element 5a, so as to be obliged to assume an optimum sitting, by properly rotating her/his own pelvis. As it can be seen in Figure 3, the so positioned user on the chair will not tend to lean forward or backward (slouching), so as to keep said correct position for an indefinite period of time.

In order to get up and leave the chair 1, the user could get up from the seat 8 without requiring to actuate again the locking element 5d to modify the position of the shaft 5b. This results to be advantageous since, once adjusted the position of the shaft 5b depending upon the user’s height, this will not require to be further modified while sitting or to get up from the chair 1. Wholly analogously, even the inclination of the backrest 3, the height and the inclination of the seat 8 and the position of the lumber support 4 do not require to be further modified, once the user has adjusted them based upon her/his needs or based upon her/his height while sitting or to get up from the chair 1.

Alternatively, the user could actuate again the locking element 5d to allow the sliding of the shaft 5b and to increase the distance of the constraint element 5a from the seat 8, in order then to get up.

Possible variants or additions could be introduced by those skilled in the art to the herein described and illustrated embodiments, while remaining within the scope of the following claims. In particular, additional embodiments can comprise the technical features of one of the following claims with the addition of one or more technical features described in the text or illustrated in the drawings, taken singularly or in any mutual combination.