EP2061359A1

EP2061359A1 - Suspension component for seat or bed base that can be produced automatically or semiautomatically at high production rates

Info

Publication number: EP2061359A1
Application number: EP07848219A
Authority: EP
Inventors: Christian Le Caz
Original assignee: Services France Agence (sfa)
Current assignee: Defta SAS
Priority date: 2006-09-13
Filing date: 2007-09-13
Publication date: 2009-05-27
Also published as: WO2008031944A1; FR2905578A1

Abstract

The suspension component according to the invention comprises a planar supporting grid (G) and a series of flat springs (R1 to R3) of sinuous or crenellated shape, oriented preferably parallel to each other, each of these springs (R1 to R3) being fixed to one of the faces of the grid (G) by means of easily disconnectable fixing components (F1, F2). The fixing means (F1, F2) can be spring clamps in which the wires of the springs (R1 to R3) are engaged by snap action.

Description

SUSPENSION ELEMENT FOR SEAT OR SOMMIER AUTOMATICALLY OR SEMI-AUTOMATICALLY AT HIGH PRODUCTION RATES.

The present invention relates to a suspension element for seat or bed base achievable automatically or semi-automatically at high production rates.

In general, it is known that many seats or bed bases involve suspension elements comprising springs arranged side by side which support a padding intended to receive a part of the body of a user.

These springs are usually connected to each other by means of connecting elements which may, for example, consist of cords, wire, or even plastic links.

It has been found that, in order to meet the requirements of volume, weight, cost and industrialization, in certain types of seats, in particular car seats, suspension elements are frequently used, using flat springs made by wires. of steel bent so as to have a sinuous or crenellated form, for example of the NOSAG type. These springs have, at their ends, hooks intended to be fixed on the fixed frame of the seat part concerned, for example the backrest.

mm if These springs are connected to each other by connecting elements to form a flat or curved suspension web on which is fixed a padding.

In order to produce industrially, with production costs as low as possible, it has been proposed to produce plastic connecting elements by overmolding, on the springs constituting the web. This solution which leads to a product of good quality, volume reduced to the bare minimum and at an acceptable cost, has the advantage of effectively solving the problems relating to the securing of the son to the connecting elements.

However, it nevertheless has the disadvantage of requiring the use of injection molds in which the springs must be arranged one by one before proceeding with the inj ection.

In addition, this solution does not lend itself easily to recycling because the plastic connecting elements are difficult to separate from the springs and therefore it can not easily perform a plastic / steel selective sorting. However, the possibility of recycling materials becomes an essential parameter in the choice of an industrial solution in view of the regulation which becomes more and more constraining.

The object of the invention is therefore more particularly to eliminate these disadvantages.

For this purpose, it proposes a suspension element comprising a planar support grid and a series of flat springs having a sinuous or crenellated shape, preferably parallel to each other, each of these springs being fixed on one of the faces of the grid by means of easily disconnectable fasteners. Preferably, these fixing means may consist of elastic clamps in which the metal son constituting the springs snap.

Advantageously, the direction of insertion of the spring wires into the elastic grippers located in the central part of the grid is perpendicular to the plane of said grid so that the spring wires can snap into them at the end of a displacement. normal to this plan.

On the other hand, the direction of insertion of the elastic grippers located in certain ribs of the grid for example in the lateral edges of the grid may be parallel to said plane so as to ensure axial locking of the wires in at least one direction.

The ends of the wires constituting the springs may be shaped so as to form hooks intended to engage the fixed frame of the seat.

Alternatively, these hooks can be hooked under prestressing on the uprights and / or the rails of a rigid or semi-rigid frame, the assembly forming a slab intended to be fixed on the frame of the seat. This solution considerably simplifies the factory assembly of the seat. In addition, it ensures a perfect control of the prestress in tension exerted on the springs thus providing a better consistency of the depression of the suspension ply. The frame may also be equipped with means for adjusting the tension of one or more springs located in a given area, for example to adapt the lumbar support of the driver on the seat. Similarly, the grid may be designed so as to be elastically deformable in its plane, in at least one direction and be fixed under prestress in said frame.

Embodiments of the invention will be described below, by way of non-limiting examples, with reference to the accompanying drawings in which:

Figure 1 is a top view of a seat frame fraction on which is mounted a suspension member;

Figures 2 and 3 are schematic sectional views respectively according to A / A ', B / B' of Figure 1;

Figure 4 is a schematic top view of a seat fraction according to an alternative embodiment of the invention;

Figure 5 is a cross-section along Y / Y 'of Figure 4.

In the example illustrated in Figures 1 to 3, the frame fraction consists of a tabular element 1 used to stiffen the back of a motor vehicle seat. This tabular element 1, the lower part of which has not been represented, is shaped so as to have a substantially U-shaped inverted shape presenting two substantially parallel uprights 2, 3 interconnected by a bent upper part 4.

The suspension element here involves three flat springs Ri, R ₂ , R ₃ made of steel wires, oriented perpendicularly to the uprights 2, 3, namely:

- two springs R _1, R ₂ crenellated shape, - a spring R ₃ having a straight portion followed at each of its ends a portion 5, 6 folded to a right angle. Each of these springs R ₁ to R ₃ is extended at its ends by two straight portions 7 which extend obliquely with respect to the plane of the spring and are terminated by hooks 8 which engage under tension in the orifices of the tabular uprights 2 , 3.

These springs R ₁ to R ₃ are also temporarily fixed by fastening means distributed over a substantially rectangular support grid G.

This support grid G, which is made of injection-molded plastic material inside a mold, here comprises five parallel longitudinal strips L ₁ to L ₅ interconnected by three transverse strips T ₁ to T ₃ .

The width of the gate G substantially corresponds to the length of the springs R ₁ to R ₃ , while its length substantially corresponds to the maximum distance between the springs R ₁ and R ₃ .

In this example, the gate G comprises two types of fasteners F ₁ , F ₂ , respectively shown in Figures 2 and 3.

The first type of fastening element F ₁ (FIG. 2) consists of a resilient clip formed by a substantially U-shaped protuberance delimiting a prismatic cavity C ₁ whose inlet orifice comprises a narrowing R of smaller width. the diameter of a wire constituting the springs R ₁ to R ₃ . The wire can therefore engage inside the cavity C ₁ by exerting a force to separate the two wings of the U at the narrowing R, until the width of this narrowing reaches the value the diameter of the wire. Once the wire has passed beyond the narrowing, it returns to its original position by trapping the wire. Extraction of the wire can not be obtained than by exerting on the wire an effort in the opposite direction of the preceding one, so as to obtain a reverse process.

The opening of the son of fasteners F ₁ is oriented perpendicular to the plane of the grid G and the prismatic cavity is oriented parallel to the longitudinal axis XX 'of the springs R ₁ to R ₃ .

The fixing elements F ₁ are arranged in the central part of the grid G, so as to receive sections of wires oriented parallel to said longitudinal axis XX '.

The second type of fixing elements F ₂ involves a fastening tab P integral with an outer longitudinal strip L ₁ , L ₅ , at one of its ends and extending towards the center of the grid G, parallel thereto, delimiting therewith a prismatic space E s opening towards said center. Starting from its opening O, this space E has a portion P ₁ narrowing to a width less than the diameter of a wire, then a portion P ₂ , whose width is at least equal to said diameter.

Furthermore, the upper face of the tab P comprises, in the vicinity of said opening, a chamfered portion PC.

These fixing elements are intended to receive portions of wire PF extending perpendicularly to the longitudinal axis XX 'of the springs R ₁ to R ₃ , at the end of an operating sequence comprising the following phases:

- A first phase in which the thread portions PF are applied under stress against the chamfered face PC of the leg P: during this phase, the wire slides on the chamfer by deforming elastically. - A second phase in which, once the PC chamfered face passed, the wire is in front of the opening O and tends to return to its original shape by engaging in the space E.

- A third phase during which, returning to its original shape, the wire passes in force in the portion P ₁ causing an elastic deformation of the leg P, then engages in the P ₂ portion of greater width of the said space E where it is held prisoner because of the return of the leg P to its original shape. Here, too, the yarn can be extracted from the fastener by an inverse process.

An important advantage of the solution described above is that the establishment of the springs R ₁ to R _{3 is} effected after the realization of the gate G by a simple stress engagement exerted perpendicularly to the plane of the gate G. The tooling used to automatically perform this operation is greatly simplified.

In the example described above, the suspension element is directly attached to the frame of the seat on the seat mounting site.

Of course, the invention is not limited to this solution.

Indeed, these suspension elements can be previously mounted on frames C as shown in Figure 4, before being mounted on the frame S, S 'of the seat (thanks to MF attachment means between the frame C and the frame S, S 'of the seat).

This solution has the advantage of being able to make the entire frame / suspension element (slab) in a site separate from that of the mounting of the seat. In addition, it makes it possible to deliver assemblies in which the prestressing of the springs R ₅ to R ₉ , which is generated when they are fastened to the C frame is perfectly controlled, so that we obtain the same prestressing from one set to another.

In addition, the frame C may be equipped with means for adjusting the tension of the springs R ₈ , R ₉ in a specific region of the suspension element. These means may comprise, for example, an electric screw jack V pulling a rudder PA, on which are fixed the springs R ₈ , R ₉ .

Thanks to the particularities of the suspension elements described above, two methods of manufacturing these elements are conceivable.

According to a first method of manufacture, the support grids G are produced by injection molding, for example on a first site.

In parallel, the springs R ₁ to R _3, which require very different techniques, are produced on a second site.

The spring construction R ₁ to R ₃ of the gates G may be achieved by means of an automatic machine in which the gates G are arranged flat and springs are engaged perpendicularly to the plane of the gate G.

The grid / spring assembly may be mounted on C frames before being taken to the seat assembly site.

According to the second method of manufacture, the grids G are obtained continuously by calendering a thermoformable plastic strip. The springs are then assembled on the grids G formed by the calender which are then cut in a cutting station in order to be separated from each other. The invention is not limited to the embodiment of the previously described fasteners. For example, these fastening elements could include attaching members, easily disconnectable such as, for example, rivets snap.

Claims

claims

1. A suspension element for a seat or bed base comprising a planar support grid (G) and a series of flat springs (R ₁ to R ₃ ) having a sinuous or crenellated shape, preferably oriented parallel to one another, each of these springs (R ₁ to R ₃ ) being fixed on one of the faces of the grid (G) by means of easily disconnectable fastening elements (F ₁ , F ₂ ) consisting of elastic clamps in which the metal wires constituting the springs (R ₁ to R ₃ ), engage snap, characterized in that it comprises in the central portion of the grid (G) a first type of elastic grippers whose direction of insertion of the metal son is perpendicular to the plane of the grid (G), so that the spring wires can snap thereon after a normal displacement to said plane and at least one elastic clamp of a second type provided in a rib of the grid ( G) and whose direction of introduction of the thread It is parallel to the plane of the grid (G), so as to ensure axial locking of the wire in at least one direction.

2. Suspension element according to claim 1, characterized in that the ends of the son constituting the springs (R ₁ to R ₃ ) are shaped so as to form hooks (8) intended to be hooked to a frame (C ) removable adapted to be fixed on said frame (S,

S ¹ ) -

3. A suspension element according to claim 2, characterized in that the attachment of the springs (R ₅ to R ₉ ) is performed under prestressing so that the springs are under tension.

4. A suspension element according to claim 2, characterized in that the frame (C) is equipped with means (V, PA) for adjusting the tension of one or more springs (Rg, R ₉ ) in a specific area.

5. A suspension element according to claim 2, characterized in that the grid (G) is designed to be elastically deformable in its plane in at least one direction and is fixed under prestressing on said frame (C).

6. A suspension element according to claim 1, characterized in that the resilient clamps (F ₁ ) of the first type are formed by a protuberance of the grid (G) U-shaped defining a prismatic cavity (C ₁ ) of which inlet comprises a constriction (R) of width less than the wire diameter, the passage opening of the son of the clamp (F ₁₎ being oriented perpendicularly to the plane of the grid (G).

7. A suspension element according to one of the preceding claims, characterized in that the elastic clamp of the second type comprises a fastening lug secured to the grid by one of its ends and which extends parallel thereto. defining a prismatic space (E) having, at its opening (O), a portion (P ₁ ) narrowing to a width less than that of a wire, this portion being followed by a second portion (P ₂ ) of greater width.

8. A suspension element according to claim 7, characterized in that, in the vicinity of said aperture, the upper face of the tab (P) comprises a chamfered portion (PC).