GB2173397A

GB2173397A - Flexible webs for seat backs

Info

Publication number: GB2173397A
Application number: GB08607811A
Authority: GB
Inventors: Bernard Boisset
Original assignee: Bertrand Faure SA; Industrielle Bertrand Faure SA
Current assignee: Faurecia Sieges dAutomobile SAS
Priority date: 1985-04-11
Filing date: 1986-03-27
Publication date: 1986-10-15
Also published as: FR2580160A1; GB2173397B; GB8607811D0; ES296637Y; BE904584A; DE3611355C2; DE3611355A1; FR2580160B1; ES296637U

Abstract

Flexible webs intended to be fitted on the rigid tubular frame (1) of a motor vehicle seat back and to receive the person sitting in the seat with interpositioning of a cushion itself covered with facing are made from a flexible plastic material, and comprise a central grid (2) and side uprights (3) connected to said grid by horizontal metal straps (5) which are mounted for sliding on this grid and on the uprights by means of lugs formed in these elements. The assembly formed by the web, the cushion which it supports and the covering forms an independent seat cover for the frame and is easy to fit thereover in the manner of a sleeve. <IMAGE>

Description

SPECIFICATION Improvements to flexible webs for seat backs and to assemblies comprising such webs The invention relates to flexible webs for mounting on rigid frames of seat backs and for comfortably receiving the persons sitting in these seats with interpositioning of cushions, generally made from foam.

It also relates to the assemb!ies (coverings, seat backs, seats) equipped with such flexible webs.

It concerns more particularly, because it is in their case that its application seems to offer the most interest, but not exclusively, among these flexible webs and assemblies, those relative to the seat backs of motor vehicle seats.

In most known embodiments, the flexible web is generally formed by flat metal springs, more particularly of the wavy zig-zag type.

These springs do not lend themselves perfectly to supporting intermediate cushions directly because of their deformability and their small lift area.

To overcome these drawbacks, it has already been proposed in constituting the flexible web in question by at least one perforated flexible panel made from a plastic material attached to the rigid frame and connecting springs interposed between the different panels if more than one is provided and/or between the rigid frame and the panel (or paneis), these springs serving, in this latter case, for providing panel(s)-frame attachment.

Known embodiments of these seat backs have further drawbacks in particular that of not lending themselves to automatic fitting of the springs, these then working under traction and attachment of their ends to the corresponding support having to be made manually.

In addition, with these embodiments, the flexible webs must be fitted on the rigid frames before being covered with their cushions and coverings.

The purpose of the invention is, especially, to overcome these drawbacks by proposing a flexible web which incorporates resilient elements working under flexion and which lends itself to automatic manufacture, this web then being completed by addition of the corresponding cushion and covering independently of the rigid frame of the seat back to be covered, so as to form an independent covering able then to be fitted in an extremely simple way on this frame.

For this, the flexible webs of the above kind according to the invention are essentially characterized in that they further comprise two side uprights adapted for being readily mounted on the rigid framework by straddling, which provides attachment of the web to the framework, and in that the connection springs are elongate metal straps which extend along the web transversely with respect to the seat, are resiliently flexible perpendicularly to the mean surface of the web and are incompressible lengthwise.

In advantageous embodiments, recourse is further had to one and/or other of the following arrangements: -each of the side uprights is separated from the flexible portion of the web by a vertical slot of variable width and each strap comprises a central section carried by this flexible portion and two ends mounted for sliding respectively on the two uprights, -the web further comprises an upper horizontal cross piece adapted for covering the seat back frame and integral both with the uprights and with the flexible portion of the web, -the flexible web is formed of half panels each integral with a side upright, separated from each other by a vertical median slit of variable width and joined together by straps, which are mounted for sliding along at least one of them, -the straps are elongate strips, -the straps are made from steel and have a thickness of about 1 mum and a width of about lOmm, -each strap is held applied against a face of the flexible web by lugs formed in this web, each lug ending in a hook so as to jointingly surround the corresponding strap over the whole of its periphery except for the portion, of this strap, disposed opposite the recess freed by formation of the lug, -in a web according to the preceding paragraph, each lug hook is shaped so as to make it possible to fit each strap on the web by simply presenting this strap at the mouth of the gap between the lug and the web, then by transversely pushing said strap inwardly of this gap and as far as the end thereof, -the flexible portion of the web is formed by a grid and each strap extends along a transverse bar of the grid, -each above lug is recessed in a widened zone of the grid, which zone surrounds an intersection point of a cross bar and a longitudinal bar of this grid, -bearing surfaces integrally molded with the uprights are provided opposite each strap end for limiting sliding thereof, -each upright has the general form of an angle iron bordered by a pad, -the lower ends of the uprights are connected together by a lower cross piece, -the assembly formed by the flexible web, the cushions supported by this web and the facing of this cushion form a covering produced independently of the rigid framework of the seat back and which may be readily fitted thereon in the manner of a sleeve or thereastride.

The invention comprises, apart from these main arrangements, certain other arrangements which are preferably used at the same time and which will be more explicitly discussed hereafter.

In what follows, a preferred embodiment of the invention will be described with reference to the accompanying drawings in a way which is of course in no wise limitative.

Figure 1 of these drawings shows a front view of the right hand half of a flexible web for a vehicle seat back constructed in accordance with the invention, Figure 2 is a cross section of this web half through II of Fig. 1, Figure 3 is a partial section of this same half through III of Fig. 1, Figures 4 and 5 show respectively in a cross section through IV of Fig. 1 and in a vertical longitudinal section, the covering formed by the same half web equiped with its cushion and facing, Figure 6 is an enlarged detail of a portion of Fig. 5.

The rigid seat back frame considered here is formed by a metal tube 1 curved in the form of an upturned U.

This tube 1 is mounted on a sitting portion frame in a way known per se, and not shown, particularly by means of a hinged device allowing the user to modify the slope of the seat back at will.

It is the whole of the covering of tube 1 which is prepared, in accordance with the invention, independently of this tube, in the general form of an upturned stocking which is very easy to fit on the tube in the manner of a sleeve.

For this a flexible web is provided formed from a plastic material both mechanically resistant and slightly deformable, such as polypropylene, which web comprises a central grid 2, two side uprights 3 separated by this grid and an upper cross piece 4 integral both with the grid and with the uprights.

Grid 2 is formed by a criss cross pattern of horizontal or cross bars 21 and vertical or longitudinal bars 22.

The uprights 3 are in the general form of angle irons one flange 31 of which, or front flange, is in the extension of the grid at rest and the other flange 32 of which extends rearwardly of the seat back.

Grid 2 is connected to uprights 3 by horizontal metal straps 5 whose central portion is mounted for sliding on the grid and whose ends are mounted for sliding on the front flanges of the uprights.

Each strap 5 is elongate in the horizontal direction, flexible in the directions perpendicular to the mean surface of the grid and incompressible in the lengthwise direction.

The straps 5, which play the role of "flexure beams", may be formed by a round wire.

But it is preferable to form them by strips or ribs, preferably made from steel, having more particularly a thickness of about 1 mum and a width of about 10mum.

Strips or straps 5 run preferably alongside the horizontal bars 21 of the grid.

They are applied against this grid and against the front flanges of the uprights by lugs 6 formed by stamping said grid and said flanges, the stamped portion of the grid being preferably provided in widened portions 7 of this grid situated at certain intersection points of its bars.

The recesses provided by formation of lugs 6 are shown at 8 on the drawings.

Each lug 6 ends in a hook or nose 9 projecting in the direction of the mean surface of grid 2 or flange 31 and the whole of this lug and its hook is shaped so that after fitting of the corresponding strap 5, it surrounds this strap jointingly over the whole of its periphery except for its portion situated opposite recess 8.

The portionof nose 9 turned towards the side of the free end of the lug has an oblique ramp 10 (Fig. 6) adapted for coacting with the facing side or "front" side of the corresponding strap 5 during fitting thereof. The simple thrust exerted by this front edge on this ramp 10 resiliently pushes lug 6 away from the mean plane of grid 2 or flange 31 and then lets the tip of nose 9 slide against the strap during its transverse advance to the bottom of the housing defined by the lug.

Just at the moment when said front side reaches said bottom, the opposite side of the strap or "rear" side goes beyond the level of nose 9 and lug 6 snaps resiliently back against the strap: nose 9 is then disposed opposite the rear side of the strap and ensures efficient locking of the assembly.

It should be noted that such an assembly relies on a simple transverse translation of the strap 5 to be fitted along the grid 2 and flanges 31, the resilient deformations of the different lugs 6 which serve for fitting the same strap (seven lugs in the example illustrated in the Figures) being identical and simultaneous.

Such a translational movement may be controlled automatically.

This automatic assembly of the straps forms an important advantage of the invention, the different straps being manufactured automatically on the spot by cutting from a continuous strip.

It should be noted that after assembly thereof on the grid 2 and flanges 31 straps 5 may slide slightly with respect thereto, during deformation of the grid, while themselves bending so as to follow these deformations, the play between grid 2 and each upright 3 being then itself variable.

For limiting such longitudinal sliding of straps 5, bearing surfaces 11 are provided on uprights 3 disposed opposite the ends of the straps and forming stops.

These bearing surfaces are advantageously formed by the bases of the flanges 32 connected to the front flanges 31 of said uprights.

These uprights 3 as well as the upper cross piece 4 are adapted so as to be readily and accurately fitted to the tube 1 by being simply fitted vertically thereon in the manner of a sleeve.

For this they have different bearing surfaces adapted to be applied jointingly against the different faces of tube 1: at 13, 14 and 15 (Figs. 2, 3 and 4) such bearing surfaces of uprights 3 can be seen applied respectively against the external front, rear and side faces of the vertical legs of said tube and at 16 and 17 (Fig. 5) such bearing surfaces of cross piece 4, applied respectively against the front and upper faces of the upper horizontal section of tube 1.

Some of these bearing surfaces are advantageously reinforced by flanges or gussets 18 (Figs. 1 and 3) which extend perpendicularly to said bearing surfaces.

The flanges 32 end at their rear end in a rim or beading 19 formed longitudinally with a groove 20.

This beading 19- defines the rear contour of the seat and, because of its rounded profile, it may be directly covered either by the covering or facing 21 (Fig. 4) which covers the cushion 22 made from foam or a similar material supported directly by the flexible web, or by this cushion 22 itself (Fig. 5).

The periphery of grid 2 may, in a way known per se, be formed and/or reinforced by forwardly sloping sections of the seat back, which sections are sometimes called "seagulls wings".

Such sections have been shown by the dot dash lines 23 in Fig. 4 and when they are provided cushion 22 extends only in front of these sections and beside them, and not behind them, as in said Fig. 4.

The upper portion of grid 2 is connected to cross piece 4 by slanting fan or other shaped sections, forming pentagonal or trapezoidal mesh, as illustrated in Fig. 1.

As can also be seen in Fig. 1, the base of grid 2 is advantageously connected to the bases of uprights 3 by flexible V shaped lugs 29 integrally molded with the grid-upright assembly, which limits the mutual moving apart of said bases before the straps 5 are fitted.

The covering formed by grid 2, uprights 3, cross piece 4, cushion 22 and facing 21 forms a sort of seat cover or upturned stocking if, of course, said facing is provided not only on the front face of the cushion but also on the rear face of the seat back.

For joining together the bases of uprights 3 and at the same time defining the lower opening of the seat cover, to the lower ends of the beadings 19 extending along these uprights a flexible cross piece 25 is added which may have the same U section as the beadings 19.

The seat cover considered may be formed as an independent cover, i.e. quite independent of tube 1.

Once finished, it may be very simply fitted on this tube by simply fitting it vertically in the manner of a sleeve; the seat back is then covered.

For holding this cover in place, metal clips or similar means (not shown) are positioned through the open base of the cover for attaching the bases of uprights 3 to the bases of the vertical legs of tube 1.

Finally, for completing the seat back and preventing any introduction of foreign bodies thereinside, the base of the cover is closed.

For this, on the lower cross piece 25 are removably fixed two plastic material strips 26 and 27 previously sewn to the front and to the rear of the cover, these strips comprising a portion 28 adapted for clipping to the groove of said cross piece and flaps serving for the mutual assembly of the two strips.

Following which, and whatever the embodiment adopted, flexible webs, coverings and seat backs are finally obtained whose construction follows sufficiently from the foregoing.

In operation, the slight deformations of the grid due to the application of the back of the user to the seat back are resiliently absorbed by the reversible bending and sliding of the metal straps 5, which are accompanied with slight variations of thickness of the gaps or slits i between the grid 2 and the uprights 3.

These assemblies and subassemblies have numerous advantages with respect to those at present known and in particular the following: -their cost price is very low because more particularly of the possibility of manufacturing them automatically and so by mass production methods, the coverings being very easily fitted on the frames, -the separation between the manufacture of the frames and that of the coverings increases the overall flexibility in manufacturing the seat concerned, -the comfort of these seats is excellent, more particularly because of adjusting at will the flexibility of each zone of the flexible web by adjusting not only the curve and the local thickness of the grid but also by adjusting the sections and distribution of the metal straps 5, these latter being advantageously closer to the base of the seat backs, -the seats considered have a very long lifespan, because of the resistance to deterioration of the plastic materials used and the long life of the metal straps, which may be made from a rust proof material or may be at least appropriately surface treated.

As is evident, and as it follows moreover already from what has gone before, the invention is in no wise limited to those of its modes of application and embodiments which have been more especially considered; it embraces, on the contrary, all variants thereof, particularly: -those where the central flexible panel made from plastic material is formed not by a grid but by a perforated sheet, -those where the central flexible panel is formed not by a single block, but by two half panels symmetrical with each other with respect to a median longitudinal vertical plane and connected to each other, at least partially, by the central portions of the metal straps, in which case each half panel may be integral with the adjacent upright, the above variable lateral vertical gaps i being then replaced by a single central variable vertical gap, -those where the single panel or the above two half panels are replaced by a plurality of flexible panels, in number at least equal to three, separated from each other by lateral or oblique slits of a variable width themselves having the flexible connecting- straps passing therethrough, -those where the variable spacing connection between the above grid 2 and each side upright 3 before fitting of the metal straps 5, is provided by other means than the upper cross piece 4, for example by means of V shaped flexible lugs integrally molded with the grid-upright assembly.

Claims

1. A flexible web intended for mounting on a rigid seat back frame (1) and comfortably receiving the person sitting in this seat with interpositioning of a cushion (22) and comprising at least one perforated plastic material flexible panel (2) attached to the rigid frame and connecting springs interposed between the different panels if several are provided and/or between the rigid frame and the panel (or the panels), characterized in that it further comprises two side uprights (3) adapted so as to be readily fitted on the rigid frame in the manner of a sleeve, and in that the connecting springs are elongate metal straps (5) which extend along the web transversely with respect to the seat, are resiliently flexible perpendicularly to the mean surface of the web and are incompressible in their lengthwise direction.

2. Flexible web according to claim 1, characterized in that each of the side uprights (3) is separated from the flexible portion of the web by a vertical slit of variable width (i) and in that each strap (5) comprises a central section carried by this flexible portion and two ends mounted for sliding respectively on the two uprights.

3. Flexible web according to claim 2, characterized in that it further comprises an upper horizontal cross piece (4) adapted so as to cover the seat back frame (1) and integral both with the uprights (3) and with the flexible portion (2) of the web.

4. Flexible web according to claim 1, characterized in that it is formed of half panels each integral with a side upright, seprated from each other by a median vertical slit of variable width and joined together by the- straps, which are mounted for sliding along at least one of them.

5. Flexible web according to any one of preceding claims, characterized in that the straps (5) are elongate strips.

6. Flexible web according to claim 5, characterized in that the straps (5) are made from steel and have a thickness of about 1 mum and a width of about 10mum.

7. Flexible web according to any one of the preceding claims, characterized in that each strap (5) is held applied against a face of the web by lugs (16) stamped out from this web each web ending in a hook (9) so as to jointingly surround the corresponding strap over the whole of its periphery except for the portion, of this strap, disposed opposite the recess (8) freed by formation of the lug.

8. Flexible web according to claim 7, characterized in that the hook (9) of each lug (6) is shaped so as to make it possible to fit each strap (5) on the web by simply presenting this strap at the mouth of. the gap between the lug (6) and the web, then by..

transversely pushing said strap inwardly of this gap and as far as the end thereof.

9. Flexible web according to any one of the preceding claims, characterized in.that the flexible portion (2) of the web is formed by a grid and in that each strap (5) extends along a transverse bar of this grid.

10. Flexible web according to claim 9, characterized in that each grid lug (6) is recessed in a widened zone (7) of the grid (2), which zone surrounds an intersection point of a transverse bar (21) and a longitudinal bar (22) of this grid.

11. Flexible web according to any one of the preceding claims, characterized in that bearing surfaces (11) integrally molded with the uprights (3) are provided opposite each strap end for limiting sliding thereof.

12. Flexible web according to any one of the preceding claims, charcterized in- that each upright (3) has the general form of an angle iron edged with beading (19).

13. Flexible web according to any one of the preceding claims, characterized in that the lower ends of the uprights (3) are joined together by a lower cross piece (25).

14. Covering comprising flexible reinforced web (2, 3, 5) according to any one of the preceding claims, the cushion (22) supported by this web and the facing (21) of this cushion, charcterized in that it forms a sort of seat cover or upturned stocking independent of the frame (1) to be covered and easy to fiton this frame in the manner of a sleeve.

15. A flexible web intended for mounting on a rigid seat back frame, substantially as hereinbefore described with reference to the accompanying drawings.

16. A covering for a seat substantially as hereinbefore described with reference to the accompanying drawings.

17. Any novel feature or combination of features described herein.