AN ADJUSTABLE CHAIR

Abstract: An adjustable chair structure comprises a support frame (2) of substantially L-shape conformation supported by a base (3) which is preferably an upright column (6) supported on a set of radial feet (4) carried on castors (5). The L-shape support frame (2) has a horizontal arm (7) for supporting a seat part (11) of a seat body, and an upright (i.e. vertical or inclined at an acute angle to the vertical) arm (7) which supports a seat back part (13) of the seat body. The seat part (11) is rigidly connected to the seat back part (13) by means of a flexible tongue (12) projecting from the middle of the rear edge of the seat part (11) of the seat body, which tongue (12) has notches by which the position of the seat back (13) with respect to the seat part (11) can be deter­ mined.

Description: The present invention relates to an adjustable chair, and particularly to an anatomic chair structure which can be adjusted to a plurality of different positions. There are currently available on the market various types of adjustable chairs which are particularly designed for office use. One of the most popular structures for an office chair comprises a base which supports a seat and a seat back. Both the seat and the seat back may be provided with independent means for their positional adjustment to suit individual users. This type of chair structure has substantial disadvantages in that the use of separate mechanisms for the positioning of the seat back and for the positioning of the seat significantly increase the manufacturing costs because of the complexity of the structure. Moreover, in use, such known chair structures have disadvantages due to the fact that, by providing separate actuating mechanisms for the two different adjustments it is difficult to synchronise their movement in relation to the movement of the human body. In particular, it is not always possible to have an adiequate adaptation of the inclination of the seat back, with consequent lack of convenience for the utiliser. The GB-A-1549041 reference discloses an adjustable chair structure comprising a support frame carried on a base and having a substantially L-shaped configuration with a substantially horizontal arm for the support of the seat part of a seat body, and an upright arm for the support of a seat back part of the seat body, said horizontal arm being slidably carried on the base and connected at the rear of the seat back part of the seat body, which is slidably guided on the upright arm such that adjustment of the position of the seat body causes a corresponding adjustment in the position of the seat back part of the seat body. The present invention seeks therefore to overcome the above noted disadvantages by providing an adjustable chair structure which is adjustable in such a way that simultaneous adjustment of the position of the seat and of the seat back can be obtained without needing the actuation of mechanisms which are difficult for the utiliser to gain access to. A particular feature of the invention is that a chair structure formed in accordance with the invention offers the possibility of obtaining the whole of a wide range of positions with an automatic adjustment of the seat back to correspond to different selected positions of the seat. This substantially improves the convenience of use and the comfort of the chair. According to the present invention, the above aim is achieved by an adjustable chair structure having the features of the characterizing part of the main claim. A particular advantage of the present invention is that it provides an adjustable chair structure which, because of its particular constructional characteristics is able to offer the widest guarantees of reliability, comfort and security in use. Another advantage of the present invention is that it provides a chair structure which, as well as having significantly improved performance over chairs of the same general type known from the prior art, has a very much simplified structure and is such as to facilitate manufacture and assembly thereof. One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a chair formed as an embodiment of the invention; Figure 2 is a schematic perspective view of the body of the chair; Figure 3 is a perspective view from below of the chair with the projection for connection to the seat back clearly in view; Figure 4 is a view from below the seat of a portion of the horizontal support arm; Figure 5 is a section taken on the line V-V of Figure 4; Figure 6 is a perspective view of the vertical arm of the support frame; Figure 7 is a section, taken on the line VII-VII of Figure 6; Figure 8 is a view from the rear of the chair back, together with the sliding carriage connected to the vertical arm; Figure 9 is a side view of the chair showing diferent positions of the seat back and the seat; and Figure 10 is a schematic view on an enlarged scale showing the connection of the seat back to the seat back carrier. Referring now to the drawings, the multiple position chair structure of the invention, which is indicated generally with the reference numeral 1 comprises a support frame 2 of substantially L-shape conformation which is supported by a base 3. The base 3, in this preferred embodiment has a plurality of radially extending feet 4 provided with castors 5. The feet 4 support a vertical stem 6 to which the support frame 2 is connected. The support frame 2, which, as indicated above, has an L-shape conformation, comprises a horizontal arm 7 and an upright arm 8. The upright arm 8 may be vertical or inclined at a small angle to the vertical and is provided for the support of the seat back whilst the horizontal arm 7 provides support for the seat. Although referred to hereinafter as a "horizontal" arm, the arm 7 may in fact be inclined at a small angle to the horizontal. To the said support frame 2 there is connected a composite body, generally indicated with the reference numeral 10, which comprises a seat 11 which, by means of a flexible projection 12, is connected to a seat back generally indicated 13. In more detail, as can be seen in Figures from 3 to 5, the seat 11 has longitudinal ribs 20 in its underside which constitute guide and slide elements for coupling with corresponding recesses 21 formed on the said horizontal arm 7 of the support frame 2. In this way the seat 11 is slidable with respect to the horizontal arm 7 so as to be able to assume the whole of a wide range of positions selectable by the utiliser. Parallel to the ribs 20 and outwardly of these there are provided two parallel flanges 22 having an L-shape in transverse section which flanges couple with the lateral edges 23 of the horizontal arm 7 in such a way as to form an interconnection between the seat 11 and the horizontal arm 7. From the middle of the rear portion of the seat 11 there extends a flexible projection 12 which, on its rear face, that is to say on the face which is not in view during use, there are provided a plurality of spaced notches 30 which allow an adjustable connection to be effected with the said seat back 13 as will be described in more detail below. More specifically, the seat back 13 has a carrier portion, generally indicated 40, which is coupled to the notches 30 of the flexible projection 12 and which is slidably supported by the upright arm 8 in a manner which will be explained with reference to Figures 6 and 7. The upright arm 8 of the support frame 2 has central longitudinal ribs 41 which engage in longitudinal recesses 42 in the carrier 40, and two lateral flanges 43 which function as retainers. The main body of the seat back, indicated 12 a , is pivoted to the upper corner of the carrier as can be better seen in Figures 9 and 10, and has thus the possibility of freely turning about a substantially horizontal axis perpendicular to the plane defined by the two arms of the support frame 2, thus allowing an automatic adaptation of the inclination of the seat back in dependence on the sitting position adopted by a utiliser. With this coupling as described above, when sliding of the seat with respect to the horizontal arm 7 is effected, there is contemporaneously and automatically a corresponding and analogous displacement of the seat back which is linked to the seat itself by means of the connection made by the flexible projection 12 which follows the conformation of the supporting frame 2 and which, in practice, serves as displacement transmission means between the seat and the seat back. In this way there is always an extremely comfortable positioning of the seat in that any forward displacement of the seat causes a corresponding lowering of the seat back, therefore allowing the utiliser to assume a more extended position, whilst if the seat is adjusted rearwardly a corresponding raising of the seat back occurs therefore assuming a more erect sitting position for the trunk of the user. Moreover, there is no fixed rotational position of the body 13 a of the seat back 13. It is the contact of the back of a person sitting in the chair which causes the pivoting of the seat back, and therefore the positioning of the body of the seat back is always adapted perfectly to the back of the utiliser. The chair of the present invention can thus assume a very wide range of positions without requiring a complex adjustment mechanism. Indeed, simply by exploiting the slidable coupling between the chair body parts and the support frame therefor it is possible to provide a chair with the advantage of having the seat back and the seat mutually interconnected by means which allow the mutual positioning between the seat and the seat back to be predetermined whilst the sitting position of a user is nevertheless adjustable over a very wide range.

Claims: An adjustable chair structure comprising a support frame (2) carried on a base (3) and having a substantially L-shape conformation with a substantially horizontal arm (7) for the support of the seat part (11) of a seat body, and an upright arm (8) for the support of a seat back part (13) of the seat body, said seat part (11) being slidably carried on said substantially horizontal arm (7), said seat part being provided at the rear with a projection (12) for connection to said seat back part (13) which is slidably guided on the upright arm (8) so that horizontal forward displacement of said seat part causes corresponding vertical lowerings of said seat back thereby allowing an utiliser to assume more extended positions, whilst horizontal rearwardly displacements of said seat part cause corresponding vertical raisings of said seat back thereby allowing said utiliser to assume a more erect sitting positions, said seat part (11) having longitudinal ribs (20) on its under face slidably engaged in longitudinal recesses (21) formed on said substantially horizontal arm (7), said seat part (11) further having lateral flanges (22) engageable over the lateral edges (23) of the horizontal arm (7), characterized in that said projection (12) is flexible and extends from the middle of the rear edge of the seat part (11) and in that said flexible projection (12) is provided with a plurality of coupling notches (30) for connection with said seat back (13), for determining the mutual positioning between the seat part (11) and the seat back (13). An adjustable chair structure according to Claim 1, said seat back (13) including a carrier (40) slidably guided on the upright arm (8) of the support frame and connected for pivotal movement to a body part (13 a ) of the seat back (13), characterized in that said body (13 a ) is connected to the upper edge of the carrier (40) by means of a pivotal connection allowing the seat back body (13 a ) to freely turn upon contact of the back of said utiliser clockwise and anticlockwise about a substantially horizontal axis perpendicular to the plane defined by the two arms (7, 8) of said support frame.

Inventors: LUCCI, ROBERTO, ORLANDINI, PAOLO
Applicants: FANTONI ARREDAMENTI S.P.A.
Application year: 1985
Main classification: A47C3
IPC codes: A47C1, A47C3