DEVICE FOR ADJUSTING THE HEIGHT OF THE BACKREST OF A CHAIR AND THE LIKE

Abstract

 A device (1) for adjusting the height of the backrest of a chair and the like, which comprises a supporting post (2) for a plate (14), with a corresponding complementary plate (15), adapted to slide along the supporting post (2) and to support a backrest of a chair, engagement means (9) being provided for connection to the plate (14) in order to engage sets of teeth (4, 5) defined along a sliding track (3) of the supporting post (2), the engagement means (9) comprising a pair of elastically yielding arms provided with teeth (10, 11) which are adapted to engage with teeth of the sets of teeth (4, 5), the supporting post (2), the plate (14), the complementary plate (15) and the engagement means (9) being made of plastic material.

Description

[0001] The present invention relates to a device for adjusting the height of the backrest of a chair and the like. More specifically, the invention relates to a device for adjusting the height of the backrest of a chair using an integrated up-down mechanism.

[0002] As is known, to adjust the height of the backrest of chairs and the like, an integrated "up-down" mechanism is normally provided which is usually made of sheet steel and is activated with metal springs.

[0003] In substance, by lifting the backrest it is possible to position it at the desired height, and by lifting it completely up to the position of maximum extension, the backrest is released and can begin to descend down to the lowest position, from which it will then be ready to be lifted as normal so as to gradually rise back up again, with the possibility to choose an intermediate height position that can be set by the user.

[0004] The mechanisms described above are, as mentioned, made of sheet steel with springs and normally have a plurality of component elements that on the one hand make them expensive to produce and on the other hand make them subject to problems of breakage, jamming and the like.

[0005] The aim of the present invention is to provide a device for adjusting the height of the backrest of a chair and the like that is made using a small number of components.

[0006] Within this aim, an object of the present invention is to provide a device for adjusting the height of the backrest of a chair and the like that offers an improved use experience, including in terms of the noise made by the device during operation.

[0007] Another object of the present invention is to provide a device for adjusting the height of the backrest of a chair and the like that does not require the use of springs for its operation.

[0008] Another object of the present invention is to provide a device for adjusting the height of the backrest of a chair and the like that can be made without using sheet metal elements.

[0009] Another object of the present invention is to provide a device for adjusting the height of the backrest of a chair and the like that is highly reliable, easily and practically implemented and of low cost.

[0010] This aim and these and other objects which will become better apparent hereinafter are achieved by a device for adjusting the height of the backrest of a chair and the like, characterized in that it comprises a supporting post for a plate, with a corresponding complementary plate, adapted to slide along said supporting post and to support a backrest of a chair, engagement means being provided for connection to said plate, in order to engage in sets of teeth defined along a sliding track of said supporting post, said engagement means comprising a pair of elastically yielding arms provided with teeth which are adapted to engage with teeth of said sets of teeth, said supporting post, said plate, said complementary plate and said engagement means being made of plastic material.

[0011] Further characteristics and advantages of the invention will become better apparent from the description of a preferred, but not exclusive, embodiment of the device according to the present invention, which is illustrated by way of non-limiting example in the accompanying drawings wherein:

Figure 1 is an exploded perspective view of the device according to the present invention;

Figure 2 is a rear perspective view of an element of the device according to the present invention;

Figure 3 shows the device according to the present invention in the configuration of moving upward;

Figure 4 shows the device according to the present invention in the configuration of locked position in the lower stroke limit configuration;

Figure 5 shows the device in the configuration of sliding upward;

Figure 6 shows the device according to the present invention in a locked position at a certain height position;

Figure 7 shows the device according to the present invention in the configuration of the uppermost position; and

Figure 8 shows the device in the configuration of initiating disengagement in an upward region;

Figures 9, 10 and 11 show the device in the configuration of progressive disengagement in an upward region.

[0012] With reference to the figures, the device according to the present invention, generally designated by the reference numeral 1, comprises a supporting post or blade 2, substantially L-shaped, with the long portion of the L allowing a backrest, not shown, to be moved along it.

[0013] Conveniently, the supporting post 2 has a central sliding track 3 which is flanked by a first set of teeth 4 and a second set of teeth 5, which face each other and which are connected in an upward region by conical guides 6 and 7.

[0014] The sets of teeth 4 and 5 are made with the teeth angled upward, i.e. toward the top of the stroke limit of the supporting post 2.

[0015] A stop tooth 8 is provided at the lower stroke limit position, to stop the downward stroke of the backrest, as will be explained below.

[0016] Conveniently, sliding engagement means 9 engage the sets of teeth 4 and 5 and are conveniently constituted by an elastic forked element with two arms, each arm supporting at least one tooth 10, 11, so as to engage the teeth 10 and 11 respectively with the left-hand set of teeth 4 and the right hand set of teeth 5.

[0017] The teeth 10, 11 of the engagement means 9 are angled downward, therefore with an angle opposite to that of the teeth of the sets of teeth 4 and 5.

[0018] The forked element is further provided with a pin 12 that can engage a slot 13 in a plate 14 which is coupled to an opposing plate 15 (a complementary plate), with the two plates 14 and 15 sandwiching the supporting post 2 between them, and with the forked element 9 sandwiched between the plate 14 and the supporting post 2, so as to be able to slide along the lane 3 of the supporting post 2.

[0019] Conveniently, the arms of the forked element 9 are elastic so as to allow the forked element 9 to splay apart and to close again, as will be explained in detail below.

[0020] Furthermore, the engagement means 9 have an undercut 24 for each one of the two arms that constitute said means, which is adapted to come into contact with a step 16, 17 which is present at each set of teeth 4 and 5, at the lower ends of the sets of teeth.

[0021] Even furthermore, the plate 14 is internally provided (i.e. at the side of the plate adapted to be directed toward the supporting post 2) with snap-acting containment means 18, 19 (protrusions) which are integrated in vertical guides 20, 21 arranged adjacent to the slot 13. The vertical guides 20 and 21 are constituted by profiles that protrude from the plate 14 and are provided with thinning recesses 25 and 26 which are adapted to allow a slight outward deflection of the guides.

[0022] With reference to the figures, the operation of the device for adjusting the height of the backrest according to the present invention is as follows.

[0023] Firstly, the user, by lifting the backrest while he is seated, positions it at the desired height. In this step, i.e. during the lifting of the backrest, the teeth 10 and 11 of the engagement means 9 enter in and exit from the left-hand and right-hand sets of teeth 4 and 5 of the supporting post 2 (by virtue of the elasticity of the arms of the engagement means 9) until the user decides to stop the backrest at the height he or she desires and, therefore, with the teeth 10 and 11 remaining anchored in the corresponding seats of the teeth of the sets of teeth 4 and 5.

[0024] As is evident from the figures (for example Figure 6), once the teeth 10 and 11 are engaged in the sets of teeth 4 and 5, the plate 14 to which the backrest is connected can no longer descend because the teeth in the sets of teeth 4 and 5 are angled upward, which therefore prevents the descent of the engagement means 9 along the sliding track 3.

[0025] The ascent of the engagement means 9 along the track 3, by contrast, is controlled by the elasticity of the arms that constitute the engagement means 9, arms which have the corresponding teeth 10 and 11 on the outside. In this manner the engagement means 9 have the capacity to bend, and therefore can contract and allow the upward stroke of the engagement means 9 and therefore of the plate 14 which in turn is coupled to the engagement means 9 by way of the pin 12 engaged in the slot 13.

[0026] Figures 4 and 5 show the step in which the engagement means 9 ascend within the sliding track 3 of the supporting post 2.

[0027] When the topmost stroke position or height extension of the backrest is reached (Figure 8), the arms of the engagement means 9 come into contact with the conical guides 6 and 7 which push the arms of the engagement means 9 closer to each other, with the consequence that the teeth 10 and 11 disengage from the sets of teeth 4 and 5 of the supporting post 2 (Figure 10).

[0028] This allows the engagement means 9 to free the undercuts 24 from the guides 20 and 21 arranged behind the plate 14, so allowing a further ascent of the backrest by an additional stroke which is defined by the center-to-center distance of displacement of the slot 13, i.e., the displacement of the slot 13 with respect to the pin 12 of the engagement means 9 (Figure 11).

[0029] In substance, the engagement means 9 are fixed in position and the plate 14 (and the associated complementary plate 15) moves upward with the slot 13 sliding on the pin 12.

[0030] In this manner the guides 20 and 21 are positioned laterally to the teeth 10 and 11 which are retracted inward, forcing said teeth into a stable locked position and with the consequent impossibility of performing the step of anchoring to the sets of teeth 4 and 5 anew.

[0031] In order to be certain of holding the position of the teeth 10 and 11 which are retracted and constrained between the guides 20 and 21 during the descent of the backrest, snap-acting containment elements 18 and 19 are provided.

[0032] Once the disengagement of the teeth 10 and 11 from the sets of teeth 4 and 5 is achieved, it is possible to automatically make the engagement means 9, and therefore the backrest of the chair, descend, with the engagement means reaching a lower stroke limit position and stopping against the stop tooth 8, while the backrest connected to those means, by virtue of an additional short stroke downward, defined by the center-to-center distance of displacement of the slot 13 of the plate 14, allows the disengagement of the guides 20 and 21 from the containment of the teeth 10 and 11, which return elastically to the starting engagement position, ready for a new use cycle, i.e. for a new ascent of the backrest.

[0033] The condition of descent is illustrated in Figures 8 and 9.

[0034] The device thus described is conveniently made of plastic material, thus without using sheet metal and springs, and is made of just four component elements, i.e., the supporting post 2, the engagement means 9, the plate 14 and the associated complementary plate 15.

[0035] In practice it has been found that the device for adjusting the height of the backrest of a chair according to the present invention fully achieves the set aim and objects, in that it is made of a small number of components and it is made of plastic material, to the advantage of simplicity of construction and reliability of operation, as well as of reduction of noise during operation of the device.

[0036] The device thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

[0037] Moreover, all the details may be substituted by other, technically equivalent elements.

[0038] In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to the requirements and to the state of the art.

[0039] The disclosures in Italian Patent Application No. 102022000020088 from which this application claims priority are incorporated herein by reference.

[0040] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A device (1) for adjusting the height of the backrest of a chair and the like, characterized in that it comprises a supporting post (2) for a plate (14), with a corresponding complementary plate (15), adapted to slide along said supporting post (2) and to support a backrest of a chair, engagement means (9) being provided for connection to said plate (14), in order to engage in sets of teeth (4, 5) defined along a sliding track (3) of said supporting post (2), said engagement means (9) comprising a pair of elastically yielding arms provided with teeth (10, 11) which are adapted to engage with teeth of said sets of teeth (4, 5), said supporting post (2), said plate (14), said complementary plate (15) and said engagement means (9) being made of plastic material.

2. The adjustment device according to claim 1, characterized in that said sets of teeth (4, 5) of said supporting post (2) end in conical guides (6, 7) which are adapted to allow the deflection of said arms of said engagement means (9).

3. The adjustment device according to claim 1 or 2, characterized in that said engagement means (9) comprise a pin (12) adapted to engage a slot (13) defined at said plate (14) for supporting the backrest, in order to allow said slot (13) to slide with respect to said pin (12).

4. The adjustment device according to one or more of the preceding claims, characterized in that said plate (14) is provided, laterally with respect to said slot (13), with a pair of guides (20, 21) and with snap-acting containment elements (18, 19).

5. The adjustment device according to one or more of the preceding claims, characterized in that said engagement means (9) comprise, in addition to at least one tooth for engagement with said sets of teeth of said supporting post (2), an undercut (24) for each of the arms, for engagement with respective steps (16, 17) defined at the lower end of said sets of teeth (4, 5).

6. The adjustment device according to one or more of the preceding claims, characterized in that said conical guides (6, 7) are arranged at the top of said sets of teeth (4, 5), in a position that is opposite to said steps.

7. The adjustment device according to one or more of the preceding claims, characterized in that said slot (13) and said guides (20, 21) of said plate for supporting said backrest are defined at the lower side of said plate (14).

8. The adjustment device according to one or more of the preceding claims, characterized in that said sets of teeth (4, 5) of said supporting post (2) face each other and have teeth that are angled upward.

9. The adjustment device according to one or more of the preceding claims, characterized in that said engagement means (9) have said at least one tooth which is angled downward in order to allow engagement with the teeth of said sets of teeth (4, 5) of the supporting post (2).

10. The adjustment device according to one or more of the preceding claims, characterized in that it comprises a stop tooth (8) which is arranged at the sliding track (3) of said supporting post (2) and is adapted to define a lower stroke limit of said plate (14).

Drawing