GB2335844A

GB2335844A - Seat assembly providing adjustable lumbar support

Info

Publication number: GB2335844A
Application number: GB9806636A
Authority: GB
Inventors: Stefaan Deceuninck
Original assignee: Youngflex AG
Current assignee: L&P Swiss Holding GmbH
Priority date: 1998-03-27
Filing date: 1998-03-27
Publication date: 1999-10-06
Also published as: GB9806636D0

Abstract

A seat assembly providing adjustable lumbar support comprises a pair of, preferably elastic, flexible supporting elements (2) each of which is anchored to a corresponding side of a seat frame (1, fig. 1). Inner ends of the flexible elements (2) that extend towards one another are linked by means of a Bowden cable mechanism (5,6,7) that enables the ends of the flexible elements (2) to be tensioned towards one another to give an increasingly tight feel to a seat in the lumbar region. The elements (2) together with additional supporting elements not shown underlie the conventional seat upholstery that extends over the frame (1, fig. 1).

Description

2335844 1 SEAT ASSEMBLY PROVIDING ADJUSTABLE LUMPAR 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 that 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.

It has hitherto been proposed to provide for lumbar adjustment either of a complete supporting element, or of a discrete element such as the abovementioned strap or belt, by providing means for 1 2 variably tensioning the supporting platform or other element in a transverse direction.

Most hitherto known arrangements of this kind provide for simultaneous and symmetrical tensioning of any lumbar support means between opposite lateral sides of the seat frame. Such an arrangement is, however, relatively complex and expensive, and thus an arrangement has been proposed that enables use of only a single tensioning mechanism provided between the lumbar support and one side of the seat frame. Such an arrangement suffers from the disadvantage, however, that tensioning of an element from only one side of the seat is asymmetrical and places limitations upon the form of lumbar support that can be utilised.

It is accordingly an object of the present invention to provide an improved lumbar adjusting mechanism for a seat that allows a more versatile form of adjustment to be achieved whilst utilising only a single adjustment mechanism.

In accordance with the present invention, means intended to provide support in the lumbar region of a backrest is divided approximately at the centre point of its transverse dimension, to provide two supporting elements margins of which are spaced apart in the said transverse dimension, and an adjusting mechanism provided in the seat frame is adapted to provide variable tensioning of the said spaced margins towards one another for adjustment of the lumbar support thereby provided.

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 rear view in diagrammatic form of a backrest portion of a vehicle seat frame provided with a lumbar adjusting mechanism in accordance with the invention; and Fig.2 is a plan view taken in section on the line II-II of Fig.i.

3 Referring to the drawings, the frame of a vehicle backrest is illustrated diagrammatically by the reference numeral 1, and, in the lumbar region of the backrest, there is provided a support comprising a pair of symmetrically arranged flexible elements 2, each of which is anchored to a corresponding side of the frame 1 by means of wire links 3. The use of such wire links 3 to retain upholstery support in a seat frame is well known, and thus the form of the links is not illustrated in more detail.

Each of the flexible support elements 2 has an inner margin 4, to which is anchored in an appropriate manner, not illustrated in detail, a bracket 5 for attachment to a Bowden cable mechanism. As seen more clearly in Fig.2, one of the brackets 5 is anchored to the inner core 6 of a Bowden cable, whereas the other bracket 5 is anchored to the outer sheath 7. The Bowden cable is linked to an actuating mechanism 8 that is operable in known manner by means of a rotary hand wheel 9 at one side of the seat frame 1.

Thus, by means of the hand wheel 9, the Bowden cable can be actuated to tension the two brackets 5 towards one another, thus reducing the tranverse dimension of the lumbar support arrangement provided by the two elements 2, the outer margins of which are fixed by means of the wire links 3. Tensioning of the Bowden cable mechanism thus causes the two margins 4 of the elements 2 to be tensioned forwardly in the direction of the arrow X as shown in Fig.2. Thus, the transverse profile of the lumbar support can be varied from a generally concave profile as shown in Fig.2, to a profile wherein the elements 2 extend approximately linearly between the links 3 anchored to the seat frame 1. Additionally, if the two supporting elements 2 are of elastic material, or otherwise resiliently extensible, the seat can be given an increasingly tight lumbar feel as the elastic elements are tensioned.

It will be appreciated that although the frame 1 is shown as providing support only in the lumbar region by means of the 4 elements 2, the support provided for upholstery of the seat can be supplemented by conventional supporting elements.

Furthermore, although the elements 2 are shown as being in the form of straps or belts of flexible and/or elastic material, other forms of upholstery supporting elements could be used, such as a wire grid of the kind known under the Trade Mark FLEXOLATOR. As will be well known to one skilled in the art such pads may be constructed in a form that enables them to be transversely resiliently extensible.

Thus, it will be seen that an arrangement in accordance with the invention can provide lumbar adjustment utilising only a single relatively simple manually actuatable mechanism in a system that can be applied to a variety of lumbar support arrangements, in a versatile manner.

Claims

1. A seat arrangement provided with an adjustable lumbar supporú, said support comprising a pair of support members each anchored to a lateral frame portion of a back rest of the seat and extending towards the centre of the back rest to provide support for upholstery of the seat in a lumbar region thereof, inner ends of the respective support members terminating in spaced relation from one another in a central region of said back rest and being linked by means for adjustably tensioning said ends towards one another to enable variation of the degree of lumbar support provided by said support members.

2. An arrangement according to claim 1, wherein said means linking said support members comprises a Bowden cable mechanism of which the sheath of the cable is anchored to the said inner end of one support member and the inner cable is anchored to the said inner end of the other support member.

3. An arrangement according to claim 1 or 2, wherein said support members comprise flexible or elastic belts or straps.

4. An arrangement according to any one of claims 1 to 3 wherein an actuating mechanism for said tensioning means is mounted on a said lateral frame portion of said backrest.

5. A seat arrangement provided with a lumbar adjusting mechanism substantially as described herein with reference to the accompanying drawings.