GB2335843A - Seat assembly providing adjustable lumbar support - Google Patents

Abstract

A support element for incorporation in a seat frame in order to provide support for upholstery comprises a pair of spaced transverse wires 1,2 between which are tensioned a plurality of spaced linear wires 3 to form a wire grid. The linear wires 3 are arranged to support a resilient belt 4 which is formed of a resilient, preferably elastic or elastomeric material, and is penetrated by the linear wires 3 that pass through the material of the belt. The belt ends have hooks 5 which attach to lever members 8 on a spindle 7 mounted on the seat frame. A pulley 9 mounted on each spindle (7,fig.2) carries a Bowden cable mechanism 10,11 which enables the two belt ends to be tensioned simultaneously by a common adjusting mechanism.

Description

2335843 1 SEAT ASSEMBLY PROVIDING ADJUSTABLE LUMBAR SUPPORT This invention

concerns a seat assembly of the kind providing adjustable lumbar support, and a suspension element for use therein.

Recently, increased demand for versatile means of adjustment of seating by an occupant, more especially in the field of motor vehicle seating, has led to many attempts to provide improved lumbar adjustment in the backrest of a seat.

Such adjustment is conventionally provided by means enabling the upholstery of the seat to be moved forwardly or rearwardly in the lumbar region of a backrest, in order that the vertical profile of the backrest can be adjusted to suit the spinal curvature of the occupant of the seat.

In the construction of motor vehicle seats, it is conventional to provide a supporting platform, that is suspended from the seat frame and underlies the seat upholstery and associated cushioning material, usually a pad of foamed plastic.

Hitherto, known lumbar adjustment mechanisms either provide for variation of the vertical profile of such a supporting platform, or provide a discrete lumbar supporting element thad is of limited vertical dimension and can thus be moved forwardly and rearwardly independently of other upholstery supports. One such known lumbar supporting element is in the form of a transverse strap or belt the ends of which can be tensioned outwardly to give increased support in the lumbar region and thus vary the effective vertical profile of a seat back when placed under load by the occupant of the seat.

Such hitherto known arrangements suffer from the disadvantages that to form a complete platform assembly with a construction that allows variation of its vertical profile to provide lumbar 2 adjustment is relatively complex and expensive, whereas the provision of an independent lumbar adjusting element also involves additional expense and has the disadvantage that the lumbar adjustment is not fully integrated with the means supporting the remainder of the backrest.

It is therefore one object of the present invention to provide an improved arrangement wherein lumbar adjustment can be integrated with a supporting platform for the upholstery of the seat, in a simple and inexpensive manner.

In accordance with the invention this object is achieved by providing a platform arrangement for incorporation in the frame of a seat which comprises spaced transverse supporting elements between which extend a plurality of wires spaced apart in order to provide support for upholstery of a seat, the said wires being linked in at least one region of the platform arrangement by means of a transversely extending web or belt with respect to which each of the wires is anchored, and the ends of said web or belt being adapted for connection to an adjustment mechanism provided in a seat frame, in order to enable variable tension-ing of said web or belt.

Further preferred features and advantages of the invention will become apparent from the following description taken in conjunction with the drawings, in which:

Fig.1 is a front elevation of one embodiment of a platform arrangment in accordance with the invention, for incorporation in the backrest of a seat and showing the attachment of theplatform to adjusting means located in a seat frame; Fig. 2 is a fragmentary perspective view illustrating in more detail an adjusting mechanism of the arrangement shown in Fig.1; Fig.3 is a plan view taken in section on the line III-III of Fig.2; and 3 Figs.4 and 5 are respectively plan views of a platform arrangement as shown in Fig.1, illustrating diagrammatically the method of providing lumbar adjustment.

Referring to Fig.1 of the drawings, there is shown a platform arrangement for incorporation in a seat assembly and comprising upper and lower transverse wires 1 and 2, between which are tensioned a plurality of vertical, linear wires 3 in order to provide a supporting platform in the form of a wire grid.

Platforms of this construction are well known in the automotive industry and are generally formed by wires or cords 1 and 2 of heavier gauge steel that are provided with an outer sheath in the form of a wound paper wrapping or coating of synthetic plastics material, the wires 3 being of smaller diameter spring steel and being anchored to the wires or cords 1 and 2 by being wound around the latter to form a locked wire knot that causes an indentation in the sheathing of the wires 1 and 2, thus locating the wires 3 relatively to their longitudinal axes.

In this well known conventional construction, the wires 3 are normally held in their relative spacing at one or more points intermediate the wires 1 and 2 by means of cords of paper or plastic material that extend parallel to the wires 1 and 2 and are penetrated by the wires 3. This arrangement is very well known to those skilled in the art of automobile seating and will not therefore be described in more detail. Suffice it to say, however, that when such a platform element is normally incorporated in the backrest of a vehicle seat, the wires 1 and 2 would be suspended from the two opposite sides of the frame of a seat backrest, with the wires 3 extending tranversely acrossthe back of the seat. In accordance with the arrancrement according to the invention, on the other hand, the wires 1 and 2 are located tranversely across the frame of the seat, and the conventional cords that are penetrated by the wires 3 are OMItted. In this case, the wires 3 penetrate a tranverse web or 4 strap 4 that may be formed of suitable material that is preferably elastic or elastomeric, and the ends of which are anchored to substantially rigid hook elements 5 as illustrated in more detail in Figs. 2 and 3.

Figs.2 and 3 also show in more detail an adjusting mechanism comprising a bracket 6 attached to a vertical side member of the seat frame (not shown) and supporting a rotary shaft 7 upon which is anchored a lever member 8 shaped to receive the hook element 5, as shown in Fig.3. Such an adjusting mechanism is provided at each side of the seat, and each spindle 7 carries a pulley 9 around which is wound an inner core 10 of a Bowden cable mechanism of which the outer sheath 11 is anchored to the seat frame and coupled to a known adjusting mechanism. The core 10 of the Bowden cable can thus be tensioned for the purpose of rotating the pulley 9.

As can be seen from Fig.1, two identical and antisymmetrical mechanisms are provided of which the respective Bowden cables 10, 11, are coupled for simultaneous actuation to a common adjusting mechanism (not shown) that is of conventional construction.

As shown in Ficr.4, the belt 4 when in the relaxed state is supported between the respective levers 8 by means of the hook elements 5 engaging therewith, the elements 5 being retained in engagement with the levers 8 under the inherent resilience of the strap 4. The resilience of the strap 4 also enables it to be displaced rearwardly in the direction of the arrow X of Fig.4 so that the central portion thereof can extend rearwardly of the general plane of the platform element as indicated at 12 in Fig. 4.

Upon actuation of the Bowden cable mechanisms in order to rotate the pulleys 9, the levers 8 and the associated hook elements 5 are rotated symmetrically in opposite directions as indicated diagrammatically in Fig. 5, whereby the belt 4 is tensioned forwardly in the direction of the arrow Y in order to provide increased lumbar support. The belt 4 is correspondingly stretched and tensioned forwardly of the plane 12 of the platform element, as indicated. The belt 4 carries with it the wires penetrating the belt, in order that the vertical profile of the platform element is likewise adjusted in an integrated manner.

It will thus be seen that by virtue of the interaction of the transverse belt 4 providing lumbar adjustment, and the wire grid provided by the wires 1, 2 and 3, it is not only possible to provide adjustable lumbar support in a simple manner, but such support is also integrated with the overall support provided by the platform suspended in the seat frame.

Although the arrangement according to the invention has been illustrated diagrammatically in the accompanying drawings, it will be appreciated that various developments and modifications may be made to the arrangement illustrated, by one skilled in the art, without departing from the scope of the invention as defined in the claims.

Thus, also the means by which the platform formed by the wire grid is itself suspended in the seat frame are not illustrated, one skilled in the art will have no difficulty in devising appropriate means of connection of the wire grid to the seat frame, for example by means of helical tension springs, or wire links, in known manner.

If desired, the belt 4 penetrated by the wires 3 and providing the lumbar adjustment, may be supplemented by one or more further transverse belts 40 that can be anchored directly to the seat frame in order to provide added support for the upholstery. Alternatively, in place of the additional belt 40 illustrated in Fig.1, the wires 3 could be interconnected by the conventional paper or plastic cords.

Furthermore, in place of the linear wires 3 tensioned between the wire cords 1 and 2 as illustrated, there could be used wires of non-linear configuration, as will also be apparent to one familar 6 with constructions of this kind.

it will be appreciated that the tranverse belt 4 or 40 may be constructed of any suitable material, and the wires 3 may be caused to penetrate the material during formation of the wire grid. Alternatively, the belt 4 may be pre-formed of suitable material hasving a configuration such that it can receive and locate the wires 3 by interlocking with a pre-formed platform or grid.

other modifications may be apparent to one skilled in the art within the scope of the claims.

Also, although devised for lumbar adjustment, an adjustable platform element as described could also be provided in other areas of the seat, for example in a seat base adapted to provide adjustable thigh support. A single platform element may, moreover be provided with more than one transverse belt, the belts each being adjustable either in synchronism or independently of one another.

Claims (9)

Claims:

1. A platform arrangement for incorporation in the frame of a seat said arrangement comprising spaced transverse supporting elements between which extend a plurality of wires spaced apart in order to provide support for upholstery of a seat, the said wires being linked in at least one region of the platform arrangement by means of a transversely extending web or belt with respect to which each of the wires is anchored, and the ends of said web or belt being adapted for connection to an adjustment mechanism provided in a seat frame, in order to enable variable tensioning of said web or belt.

2. A platform arrangement according to Claim 1 wherein the said web or belt is formed of elastic or elastomeric material, and the said wires linked by said web or belt are arranged to penetrate the material of the web or belt, whereby the spacing of the wires is maintained by the material of the web or belt in which the wires are embedded.

3. A platform arrangement according to Claim 1 wherein the said web or belt has a configuration such that it can receive and locate the said plurality of spaced wires by interlocking therewith.

4. A platform element according to any one of Claims 1 to 3 wherein the ends of said web or belt are anchored to substantially rigid hook-shaped elements adapted to engage with lever members of a mechanism for tensioning the belt.

5. A platform element according to any one of Claims 1 to 4 wherein the said web or belt is supplemented by at least one further web or belt to which the said plurality of wires are anchored.

6. A platform element as claimed in any one of Claims 1 to 5 in combination with a seat f rame incorporating an adjustment mechanism for tensioning said transversely extending web or belt.

7. A platform element as claimed in Claim 6, wherein the said seat f rame comprises a back rest, and the transversely extending web or belt is provided in the lumbar region of the back rest.

8. A platform arrangement substantially as described herein with reference to Fig. 1 of the drawings.

9. A seat assembly incorporating a platform element, substantially as described herein with reference to Figs. 1 to 5 of the drawings.