LUMBAR ADJUSTMENT SYSTEM FOR A SEAT WITH A CAM

MEMBER

Technical field

The present invention relates to a lumbar adjustment system for a seat preferably usable on a tractor, which allows to vary accurately the ergonomic adjustment of the lumbar profile of such seat in a comfortable and quickly manner on the bases of the specific user's needs.

State of the art

The vehicle seats, for example car or tractor seats, may advantageously offer the opportunity to adjust the stiffness or flexibility of the respective backrest, in normal use condition of the seat itself.

In particular, such stiffness or flexibility may be adjusted along a direction oriented approximately as the user's spine. The stiffness or flexibility in such direction may be defined as lumbar stiffness or flexibility.

The seats that offer such regulation opportunity are configured for this purpose, to assume, at least in a normal use condition, a plurality of operating configurations, each of which corresponds to, at least, a different lumbar stiffness or flexibility of the respective backrest.

To vary such operating configuration such seats comprise a lumbar adjustment system. Such adjustment system is advantageously integrated in the seat itself and is associated with a control device by which the user can operate on the adjustment system.

The space in which the seat is positioned can be more or less wide depending on the vehicle type and its sizes.

By reducing the available space, the choices with regard to the positioning of the control device itself is reduced, due also to the overall dimensions of the adjustment system.

For example in tractors, there are more stringent constraints with regard to the positioning of the control device, which is thus usually positioned on the back of the seat. Moreover, at present, the control devices of the lumbar adjustment systems of the seats allow a continuous adjustment of the flexibility or ergonomic adjustment of the lumbar profile. However, it may be desirable, for the user, to have the possibility to regain a previously set lumbar stiffness or flexibility, which has been already tested successfully.

The positioning of the control device on the back of the backrest, along with the opportunity to adjust the operating configuration of the backrest in a continuous manner only, make it rather difficult to reset, in a reasonable time, a desired level of flexibility or ergonomic adjustment of the lumbar profile of the backrest itself.

Object of the invention

Object of the present description is to provide a lumbar adjustment system for a seat of a backrest usable on vehicles, preferably on tractors, which overcomes the drawbacks of the prior art mentioned above.

In particular, an object of the present description is to propose a lumbar adjustment system for a seat of a backrest of a seat usable on vehicles, preferably on tractors, which has a better compactness compared to the currently known adjustment systems.

Another object of the present description is to develop a lumbar adjustment system for a seat of a backrest usable on vehicles, preferably on tractors, which allows to comfortably adjust the operating configuration of the backrest with respect to its lumbar stiffness or flexibility in a comfortable and quickly manner.

Further object of the present description is to develop a lumbar adjustment system for a seat of a backrest usable on vehicles, preferably on tractors, which allows to reset a specific operating configuration of the backrest, possibly previously obtained, with a greater rapidity and accuracy compared to the currently known adjustment systems.

Such objects are fully achieved by an adjustment system of the present invention, which is characterized by the content, in any combination, of one or more of the claims below. In particular, the present description relates to a lumbar adjustment system for a backrest of a seat. The backrest is configured to assume, in a normal use condition, a plurality of operating configurations, each corresponding to a respective different lumbar stiffness or flexibility of said backrest.

Such system comprises a cam member configured to have a variable extension along at least one development axis of the cam member itself and to be connected to at least one structure of said backrest so that the variation of said extension of the member causes the variation of said operating configuration.

According to another aspect, the present description relates to a seat or a backrest of such seat, in particular usable on tractors, comprising an adjustment system according to the present description.

Brief description of the drawings

The characteristics of such system and seat or backrest according to the present description will become more apparent from the following detailed description relating to an embodiment example of an adjustment system according to the present description and to an embodiment example of a seat or backrest according to the present description, provided by way of illustration, and not limitation, and with reference to the accompanying drawing tables, in which:

- Figures 1 and 2 are perspective views from mutually opposite parts of a backrest for a seat of a tractor comprising an adjustment system according to a possible embodiment of the present description;

- Figures 3 and 4 are perspective views from mutually opposite parts of an exploded of such backrest;

- Figure 3a is a detail view of a part of Figure 3;

- Figure 5 is a perspective view of an exploded of at least two components of a possible embodiment of an adjustment system according to the present description;

- Figures 6, 7 and 8 are perspective views of such embodiment of the adjustment system in a first, a second and in a third operating condition; - Figure 9 is a perspective view of at least a component of such embodiment of the adjustment system.

Detailed description of preferred embodiments of the invention

In Figures 1 and 2, S indicates a backrest S of a seat. The backrest S is configured to assume, in at least a normal use condition, a plurality of operating configurations, each corresponding to a respective different lumbar or flexural stiffness or flexibility of said backrest S.

The backrest S comprises at least a structure 3.

The adjustment system 1 , as shown in Figures 6-8, comprises a cam member 2 configured to have a variable extension along at least one development axis X of the cam member itself, to vary such operating configuration of the backrest S.

The cam member 2 is configured to be connected to such at least one structure 3 of the backrest S so that the extension variation of the member 2 along its development axis X causes the variation of such operating configuration of the backrest S.

The structure 3 can be integrated in the backrest S and configured for the connection with said member 2 so that the variation of said extension of the member 2 causes the variation of such operating configuration of the backrest s.

In an embodiment example of the backrest S, the structure 3 comprises a first structural portion 3a and a second structural portion 3b. The structure 3 is configured so that the distance between said structural portions 3a and 3b along a transverse axis to the portions themselves defines said operative configuration of the backrest S.

In an embodiment example of the system 1 , the cam member 2 comprises at least a first body 2a and a second body 2b.

The first body 2a is connectable to said first structural portion 3a of said structure 3 and the second body 2b can be connected to said second structural portion 3b of the structure 3. The cam member 2 is suitable to be arranged so that, by means of the respective connections between first body 2a and first structural portion 3a and between second body 2b and second structural portion 3b, the cam member 2 itself is operatively interposed between said first structural portion 3a and second structural portion 3b, so that the development axis X is operatively coincident with said transverse axis.

In figure 4, thus, the development axis X coincides with the transverse axis to the first structural portion 3a and to the second structural portion 3b, also considered that the backrest components shown in figure 4 are mounted according to said axis X.

In this way, the distance between first portion 3a and second portion 3b along said transverse axis coincides with the extension or length of the cam member 2 along its development axis X.

The extension variation of the cam member 2 along its development axis X causes the variation of the operating configuration of the backrest S, and, thus, the variation of its lumbar stiffness or flexibility.

In an embodiment example of the backrest S, at least the second structural portion 3b is suitable to elastically flex in response to the extension variation of said cam member 2 along its development axis X, so that the extension variation itself of the cam member 2 practically causes a pre-tensioning variation of the second structural portion 3b and, thus, a flexural or lumbar stiffness variation of the second structural portion 3b itself, and, therefore, also of the backrest S.

In an embodiment example of the system 1 , such system 1 could also comprise the structure 3.

In the embodiment example of the backrest S of the attached figures, the backrest S comprises a rear portion 3c, which defines a rear surface of the backrest S.

In the embodiment example of the backrest S of the attached figures, the backrest S also comprises a front portion 3d, which defines a front surface of the backrest S on which the user's back rests, at least in a normal use condition of the backrest S itself. In the embodiment example of the backrest S of the attached figures, the first structural portion 3a is secured to the rear portion and is interposed between the cam member 2 and the rear portion 3c.

In the embodiment example of the backrest S of the attached figures, the second structural portion 3c is interposed between the cam member 2 and the front portion 3d.

As regards the configuration of the cam member 2, the first body 2a is suitable to rotate around the development axis X, as indicated for example by the arrow Y of Figure 6. The second body 2b is suitable to translate along the development axis X and with respect to the first body 2a, to cause the extension variation of the cam member 2 along the development axis X, and, consequently, the operating configuration variation of the backrest S. The translation of the second body 2b is indicated by the arrow X' of Figure 6.

The rotation of the first body 2a and the translation of the second body 2b, however, can also take place in directions which are opposite to those of their respective arrows Y and X'.

The first body 2a and the second body 2b can be advantageously coupled so that the rotation of the first body 2a around the development axis X causes the translation of the second body 2b along the development axis X and with respect to the first body 2a. Such first body 2a and second body 2b, in an embodiment example of the system 1 , can be coupled by at least one contact and sliding coupling.

Such member 2 comprises at least a first pair of profiles. Such first pair comprises two profiles 4a and 4b. A first profile 4a of such first pair is integral to the first body 2a and a second profile 4b of such first pair is integral to the second body 2b.

The first profile 4a and the second profile 4b of such first pair of profiles can be operatively coupled so that the rotation of the first body 2a around the development axis X causes the translation of the second body 2b along the development axis X and with respect to the first body 2a. The first profile 4a and the second profile 4b realize at least a contact and sliding coupling between the first body 2a and the second body 2b.

At least one of such first profile 4a and second profile 4b is defined by a surface which, in the coupling condition between first body 2a and second body 2b shown in Figures 6-8, is facing the other such first profile 4a and second profile 4b.

Each of said profiles 4a and 4b delimits a side surface of the respective body 2a or 2b, said surface developing around said development axis X. Figures 6-8 shown respectively the first body 2a in respective different angular positions around the development axis X and, consequently, the second body 2b in respective different positions along the development axis X itself.

In an embodiment example of the system 1 , the member 2 comprises a plurality of teeth 5 and a plurality of respective recesses 6 in which such teeth 5 are suitable to fit to block such rotation of the first body 2a and/or to block such translation of the second body 2b with respect to the first body 2a.

In an embodiment example of the system 1 , at least one of such first body 2a and second body 2b comprises such plurality of teeth 5 and the other of said first body 2a and second body 2b comprises such plurality of respective recesses 6.

In an embodiment example of the system 1 , at least one of such first profile 4a and second profile 4b comprises such plurality of teeth 5 and the other of said first profile 4a and second profile 4b comprises such plurality of respective recesses 6.

Such teeth 5 and recesses 6, thus, block the extension of the member 2 along the development axis X, consequently, the lumbar or flexural stiffness or flexibility of the backrest S, and, therefore, the operating configuration of the backrest S or of the seat S on which the backrest S is mounted.

Such teeth 5 and recesses 6, thus, are suitable to help the definition of a plurality of different predetermined and discrete extensions, of such cam member 2 along the development axis X, and a corresponding plurality of different discrete and predetermined operating configurations of said backrest S.

During the transition from an operating condition to another of the member 2, for example from that of Figure 6 to that of Figure 7 or from that of Figure 7 to that of Figure 8, any tooth 5 integral to one of the profiles 4a or 4b passes from a recess 6 of the other of said profiles 4a and 4b to the following recess 6, so that the translation of the second body 2b with respect to the first body 2a is step-by-step, to obtain a discontinuous or discrete adjustment of the lumbar stiffness or flexibility of the backrest S and/or of its operating configuration.

In an embodiment example of the system 1 , the member 2 comprises a plurality of pairs each comprising a first profile and a second profile having the functions and characteristics of the respectively profiles 4a and 4b just described.

Such pairs of respective profiles, in the example of the attached figures, are angularly distributed around said development axis X, to increase the coupling effect between first body 2a and second body 2b and the movement stability of such first body 2a and second body 2b.

A first pair comprises the profiles 4a and 4b. A second pair comprises the profiles 4a', integral to the first body 2a, and 4b', integral to the second body 2b. A third pair comprises the profiles 4a", integral to the first body 2a, and 4b", integral to the second body 2b.

For clarity, it is noted that the profile 4a' and the profile 4b' are shown in Figure 5, in which also some recesses 6' located on such profile 4a' are shown. In figure 5 one of the teeth 5' located on such profile 4b' is also visible, such tooth 5' being suitable to fit together with any one of the recesses 6'.

For clarity, it is noted that the profile 4a" is shown in Figures 5, 7, 8 and 9, in which also some recesses 6" located on such profile 4a" are show. The profile 4b" is shown only in Figure 8.

Some respective teeth suitable to fit together with the recesses 6 of the profile 4a" are located on the profile 4b".

In an embodiment example, the system 1 comprises a movement system 7 of the member 2 to cause the extension variation of the member 2 along the development axis X.

The movement system 7, in cooperation with, at least, the teeth 5 and the recesses 6, is configured to define a plurality of different predetermined and discrete extensions of such cam member 2 along the development axis X and, consequently, a plurality of different discrete and predetermined operating configurations of said backrest S.

In an embodiment example of the system 1 , the movement system 7 comprises a flange 8 suitable to rotate around at least one axis of rotation R parallel to said development axis X.

In an embodiment example of the system 1 , the movement system 7 comprises a transmission 9 suitable to couple the rotation of said flange 8 around said axis of rotation R to the rotation of the first body 2a around said development axis X.

In the embodiment of the attached figures, the transmission 9 comprises two elongated elements 9' and 9". Such elongated elements 9' and 9" can be flexible.

In an embodiment example of the system 1, the movement system 7 is associated with a control device which is either manual or motorized.

In the embodiment of the system 1 of the attached figures, the control device is manual, because it does not comprise any artificial engine.

Such control device, if motorized, may comprise an artificial engine suitable to cause the rotation of the first body 2a.

In any case, such control device may comprise an activation element 10, which, in the case of the attached figures, comprises a handle. Such handle can rotate according to the arrow R1 of Figure 6, to cause the rotation of the flange 8. As can be seen in Figure 3a, in one embodiment example of the system 1 , it comprises at least one stop element 11 and at least one slot 12 which can be mutually coupled to limit the rotation of the first body 2a around the development axis X.

In the embodiment of the attached figures, such slot 12 is formed in the first structural portion 3a and such locking element 11 is a projection integral to the first body 2a.

According to another aspect, the present description relates to one backrest S, or a seat, comprising a system 1 having one or more of the previous characteristics.