ES2698204T3 - Chair with flexible lumbar support - Google Patents

Abstract

Chair comprising: a. a tubular base (121, 122, 123, 124); b. a seat (110) fixed to said base, said seat and said base constituting the chair; C. a tubular arch (130) that constitutes the backrest and is attached to two of the legs (123, 124) of the base; d. a dorso-lumbar elastic support (140), comprising two ends, one of which is free and the other is attached to the seat, characterized in that the base (121, 122, 123, 124) and the tubular arch (130) they consist of a composite material with fiber reinforcement, which comprises a natural fiber, in particular a vegetable fiber.

Description

DESCRIPTION

Chair with flexible lumbar support

The invention relates to a chair with flexible lumbar support. The invention relates more particularly to a chair with backrest, of a fixed structure, non-collapsible, light, but which provides effective lumbar support adaptable to the user.

According to the prior art, a chair with a fixed structure, for example, is made of wood and has a backrest. According to an exemplary embodiment, the backrest comprises two uprights that generally come in extension of the rear legs, whose uprights are joined by crossbars. The crosspieces thus provide 3 main functions:

- a mechanical function of stiffness of the backrest and of the chair as a whole;

- a support function for the user's back when seated in the chair;

- a grip function that allows the chair to be supported by the backrest to move it particularly.

These rigid crosspieces do not allow for an effective and adaptable back-lumbar support in relation to the morphology of the user. But an effective back-lumbar support is an element of essential comfort of a chair. For this purpose, according to the prior art, the backrest of the chair is lined with a lumbar support cushion installed between the uprights. Other constructions of the backrest, especially in the field of office chairs, also allow for an adaptable and effective lumbar support. All of these solutions of the prior art have the disadvantage of overloading the chair, both in terms of weight and in aesthetic terms.

US 5501 507 discloses a chair with elastic lumbar support, said lumbar support being attached to the seat of the chair by means of springs.

Document CN1 854 595 discloses a chair comprising a tubular base, constituted by a composite material.

The object of the invention is to solve the drawbacks of the prior art and refers for this purpose to a chair comprising:

to. a tubular base;

b. a seat fixed to said base, said seat and said base constituting the chair;

c. a tubular arch that forms the backrest and is joined to two legs of the base;

d. a dorsal-lumbar elastic support, comprising two ends, one of which is free and the other is joined to the seat;

and wherein, the base and the tubular arch are constituted by a fibrous reinforcing composite material, comprising a natural fiber, in particular a vegetable fiber.

Therefore, the tubular arch of the backrest guarantees rigidity and restraint functions, while the thoracolumbar support, which is not connected to this arch, provides sufficient elasticity and a "spring effect", which allows it to adapt to the morphology of the user while providing effective support. The constitution of the composite material provides, particularly to the chair, sufficient rigidity and solidity to avoid the use of crossbars as are used in a wooden chair of the prior art, and thus allow adapted elastic travel of the back-lumbar support to get this support. The use of one of the reinforcement fibers of natural origin allows the realization of the chair according to a principle of sustainable development, particularly in terms of carbon footprint and extraction of natural resources, at least as advantageous as that of a chair wood, while giving the chair properties of lightness comparable or even superior to those of wood or a metal structure.

The invention is advantageously implemented in accordance with the embodiments and variants set forth below, which must be considered individually or in any technically operative combination.

Advantageously, the connection of the dorso-lumbar support to the seat is a removable joint. Therefore, the chair is adaptable, through the use of different lumbar supports, in terms of firmness and aesthetics.

Advantageously, the tubular section of the arch narrows between its joints on both legs. Therefore, the arch is optimized in terms of strength, weight and rigidity depending on the composite material used. In the same way, the tubular section of the legs of the base narrows between its end intended to rest on the floor and its attachment to the seat.

Advantageously, the seat is constituted by a plastic material. This embodiment makes it possible at the same time to reduce the weight of the chair to adapt it to external use and to allow for economical assembly and manufacturing modes.

According to another embodiment, the seat is constituted by a metallic material. This embodiment allows conferring on the chair a style, called "bistro".

Advantageously, the seat comprises a crown connecting the base and a part, said seat cushion, assembled with said crown. This embodiment allows the seat cushion to be personalized and, in particular, to use a material, color or finish different from those of the crown for the embodiment thereof.

According to alternative embodiments, the dorso-lumbar support is also constituted by a plastic material reinforced or not by fibers. Therefore, depending on the nature of the constituent material, said thoracolumbar support is more or less flexible, to adapt to the maintenance sought by the user and corresponds to different aesthetics of the chair object of the invention.

The invention also relates to a pre-constituted assembly, or kit, comprising a chair, whose junction of the dorso-lumbar support to the seat is removable, and several back-lumbar supports. Therefore, said chair is adaptable in terms of firmness of maintenance and aesthetics.

The invention also relates to a pre-constituted assembly, or kit, comprising a chair and several seat cushions. This embodiment alone or in combination with the previous one allows the end user to customize the chair.

The invention is set forth below in accordance with its preferred embodiments, in no way limiting, and with reference to Figures 1 and 2, in which:

- Figure 1 shows in a front view an embodiment of the chair object of the invention;

- figure 2 shows in a left partial view, the chair of figure 1;

- and Figure 3 is a partial front view of an embodiment of the chair object of the invention comprising a bow in two parts, a detailed view shows an example of assembly of the two parts of the arch. In Figure 1, according to an example of embodiment, the chair object of the invention comprises a seat (110) which preferably consists of a single piece of a plastic material. By way of example, the plastic material constituting said base is a polymer of biological origin such as a polyethylene, a polyamide, cellulose acetate or a polymethyl methacrylate, such biological-based products are distributed, for example, by the Arkema group ®, 420 Estienne d'Orves Street, 92705 Colombes, France, offering other suppliers similar products. According to a particular embodiment, the material constituting said seat consists of a matrix of a first polymer of biological origin reinforced with fibers of a second polymer of biological origin whose melting temperature is higher than that of the first polymer. Said seat is advantageously constituted by a single molded piece, and therefore, contributes to the rigidity of the chair. According to a particular embodiment, the seat (110) is substantially bowl-shaped and comprises a rigid crown frame (111) and a slightly curved portion (112) which acts as a more flexible seat cushion. According to an alternative embodiment, the seat of the chair object of the invention is constituted by a light metal material, injection moldable, for example, a magnesium alloy.

According to a particular embodiment, the crown (111) and the seat cushion (112) are two separate pieces assembled by trimming, bolting or gluing. This realization allows the chair to be customized while speeding up the production while maintaining the maximum number of common pieces for different models. By way of non-limiting examples, the crown is made of a plastic material and the seat cushion is made of a metallic material, the crown is made of a metallic material and the seat cushion is a grid made of plastic or natural fibers.

According to an exemplary embodiment, the object of the chair of the invention comprises a base comprising 4 legs (121, 122, 123, 124). As an alternative, the base comprises 3 legs. Said legs are tubes preferably constituted by a composite material with fibrous reinforcement. Therefore, the legs are stiff and light. Preferably, the composite material constituting said legs (121, 122, 123, 124) comprises a polymer matrix of biological origin, for example a polyamide, especially PA11, or a polyethylene, reinforced with continuous fibers, wholly or partially of plant origin. . By way of non-limiting example, said vegetable fibers are flax fibers, jute fibers, hemp fibers, sisal fibers or bamboo fibers. The legs are assembled in the seat, thus constituting the seat of the chair object of the invention. Advantageously, the material constituting the legs and the material constituting the seat are chosen so that they can be easily assembled by welding, for example, selecting matrices of thermoplastic polymers, or by heat sealing. This embodiment allows for a very clean style and is preferably used when the seat is made of a transparent material.

As an alternative, or in a complementary manner, the assembly of the legs with the seat is achieved by a mechanical assembly, for example, by fitting the legs in the sleeves made during the molding of the seat. In this case, the seat comprises a smooth-looking face, with the bowl-shaped exterior, and a technical face, with the bowl-shaped interior, comprising arrangements adapted to the set or the ribs. Of According to this embodiment, the seat is made by an injection molding process that uses dynamic heating of the induction mold, as described in EP 2861 399.

The object of the chair of the invention comprises a tubular arc (130), which constitutes the backrest of said chair, and is joined to the two legs (123, 124) of the base. According to variants of embodiment, the connection of the arch to the legs (123, 124) is achieved by integrating the entire crown and the legs in a single piece, in this case, the seat comprises appropriate means to perform the connection with this piece. According to another variant, the connection of the arch (130) with the legs (123, 124) is achieved by means of sleeves molded with the seat, so that the seat, the base and the arch constitute, after assembly, a rigid assembly , without the need for any crossbar.

Said interlocking assembly is completed, according to one embodiment, by gluing or welding, depending on the nature of the materials present. Therefore, the structure of the chair object of the invention is easily assembled without tools, which also facilitates its storage and delivery, particularly in the context of a mail order sale. The tubular arc (130) is made of a composite material similar to that used to make the base. Advantageously, the fiber content and the nature of the fibers or the mixture of reinforcing fibers used in the legs and the arc differ, in order to achieve the mechanical properties suitable for the functions of these components or for aesthetic reasons. In fact, the use of reinforcement fibers of vegetable origin gives the base and arch a particular aesthetic appearance without the need to paint them.

According to this exemplary embodiment, the dorso-lumbar support (140) extends substantially within the space delimited by the tubular arch (130), so that said arch constitutes a means of gripping the chair to move it easily, especially because The materials that make up the chair allow a light construction.

According to another embodiment, the seat (110) is also made of a composite material reinforced with fibers comprising vegetable fibers. According to this particular embodiment, the seat is produced by a process of compaction by consolidation of a pile of fibrous folds, implementing dynamic heating by induction of the mold, as described in EP 2694277. This implementation process also allows integrating in the composite stratification constituting the seat, a printed decoration, in particular in the part (112) that serves as a cushion, whose decoration is unalterable.

The use of a procedure that implements the heating by induction of the mold, allows to obtain a uniform temperature in the whole surface of the mold and, therefore, obtain a very flattering appearance, without defects of appearance and discoloration, of the visible face of the mold. seat, whether or not said seat comprises a technical face, whether made of plastic, composite material or light metal alloy. When the seat has a technical face, it is advantageously overmoulded, in particular by injection, in the preform.

The obtaining of a uniform temperature in the mold and, therefore, the control of the viscosity of the molded material, also makes it possible to mold the decorations in relief or gravure in the various elements that constitute the chair object of the invention.

Advantageously, the tubes constituting the legs and the crown are also made by implementing a dynamic induction heating process, as described, for example, in FR 2915053, using a braided preform comprising polymer fibers combined with the reinforcing fibers. . These methods allow the structure of the chair to be produced quickly according to a series production. The section of the tubes constituting the legs and the arch is an ovoid or polygonal section, advantageously of variable section between the two ends of each of these components. To obtain this variation of section, the braid that constitutes the preform is made on a solid core or in the form of an inflatable rubber, reproducing the section variation.

The use of plastics and composite materials, shaped in molds for the realization of the structure of the chair object of the invention, allows to produce pieces of precise dimensions, which can be assembled easily without slack, not sensitive to humidity and of stable size. Therefore, although light, the chair object of the invention is durable.

The rigid structure of the backrest and the seat allows integrating a back-lumbar support (140), which according to an exemplary embodiment is included in the space defined by the crown. Said lumbar support (140) consists of a polymeric material reinforced or not with fibers comprising natural fibers. According to an exemplary implementation, said support is made by a compaction process by consolidation in the manner described in EP 2694277 and comprises a decoration integrated with the stratification. Said support (140) is attached to the seat, for example, by fitting one of its ends in a sleeve molded in the seat, or even by fixing and / or screwing into the frame (111) of said seat.

Figure 2, according to an embodiment of the dorso-lumbar support (140) and the arch (130) are curved toward the back of the chair. According to this embodiment, the arch is manufactured by molding in a drawer mold for guarantee its demoulding.

In Figure 3, according to an alternative embodiment, the tubular arc (330) is made in two parts (331, 332), the two parts being connected by an assembly part (335), advantageously obtained by injection molding of a polymer of biological origin, reinforced or not by short fibers, which are of biological origin. This embodiment avoids the use of a drawer mold for making the tubular arch and, therefore, reduces the investment required for the production of the chair object of the invention.

Returning to figure 2, the free end of the dorso-lumbar support and the nature of the material that constitutes it give said support a flexibility that allows it to adapt relatively to the morphology of the user of the chair object of the invention. Said back-lumbar support (140) is assembled with the seat, preferably without fixing or interlocking tools, and the chair object of the invention is advantageously proposed in a kit with different back-lumbar supports of shapes, material, stiffness or decoration different Advantageously, said kit is proposed in accordance with an online sales model in which the customer selects a set of seat and back-lumbar support with a base and a bow to constitute a custom chair, which is sent easily disassembled by a courier service and is assembled by the customer.

The above description and exemplary embodiments show that the invention achieves the desired purpose, namely, a comfortable, light and durable chair comprising a back support that is easily customizable and can be produced in series.

Claims (12)

1. Chair comprising: to. a tubular base (121, 122, 123, 124); b. a seat (110) fixed to said base, said seat and said base constituting the chair; c. a tubular arc (130) that constitutes the backrest and is joined to two of the legs (123, 124) of the base; d. a dorsal-lumbar elastic support (140), comprising two ends, one of which is free and the other is attached to the seat, characterized in that the base (121, 122, 123, 124) and the tubular arc (130) are constituted by a composite material with fiber reinforcement, comprising a natural fiber, in particular a vegetable fiber. Chair according to claim 1, in which the tubular arc (130) is constituted by a single piece. Chair according to claim 1, in which the junction of the dorso-lumbar support (140) and the seat is a removable joint. Chair according to claim 3, in which the tubular section of the arch (130) tapers between its connections to the two legs (123, 124). Chair according to claim 3, in which the tubular section of the legs (121, 122, 123, 124) of the base narrows between its end intended to rest on the floor and its attachment to the seat. Chair according to claim 1, wherein the seat (110) is made of a plastic material. Chair according to claim 1, wherein the seat (110) is made of a metallic material. Chair according to claim 1, wherein the seat (110) comprises a connecting crown (111) to the base and a part (112), called a seat cushion, assembled with said crown. Chair according to claim 1, wherein the dorso-lumbar support (140) is constituted by a plastic material. Chair according to claim 1, wherein the dorso-lumbar support (140) is constituted by a composite material with fibrous reinforcement. 11. Pre-constituted assembly, or kit, comprising a chair according to claim 3 and a plurality of dorso-lumbar supports. 12. Pre-constituted assembly, or kit, comprising a chair according to claim 8 and a plurality of seat cushions (112).