GB2220137A

GB2220137A - A motor vehicle seat with a spring core resting on a subframe

Info

Publication number: GB2220137A
Application number: GB8914487A
Authority: GB
Inventors: Jurgen Schaffke; Reiner Renz; Adolf Honegg; Heinz Bossert
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1988-06-29
Filing date: 1989-06-23
Publication date: 1990-01-04
Anticipated expiration: 2009-06-23
Also published as: FR2633565B1; JPH0736783B2; JPH0241112A; GB2220137B; DE3914851A1; GB8914487D0; FR2633565A1; IT1231606B; DE3914851C2; IT8948097A0

Description

A motor vehicle seat with a spring core resting on a subframe 2ri 2o 137 4

The invention relates to a motor-vehicle seat with a spring core resting on a subframe and surrounded by a topframe, each topframe portion extending in the longitudinal direction of the vehicle being supported relative to the subframe via a stay preventing floating movements and limiting lateral compression movements.

A motor-vehicle seat of this type, in which the stay is designed respectively as a stabilizing wire, can be taken as known from German Patent Specification 3,442,734. The stabilizing wire is formed as an extension of a spring turn and can therefore be produced in a simple way by mechanical means. However, it is not possible for seats without a stay to be retrofitted with the stabilizing wire. Also, although the known stay affords sufficient lateral support, but relatively high forces are imparted to the topframe under the associated compression movements.

The present invention seeks to provide a stay which can easily be adapted to meet different requirements and with which even motor-vehicle seats without a stay can also be equipped subsequently, and which exerts no reaction on the topframe under compression movements taking place at the edge.

According to the present invention there is provided a motor vehicle seat with a spring core resting on the subframe and surrounded by a topframe, each topframe portion extending in the longitudinal direction of the vehicle being supported relative to the subframe via a stay preventing floating movements and limiting lateral compression movements, wherein the stay comprises a foam block which is fixed to the frame and which is inserted between two springs stretched from the subframe to the 2 topframe and at least partially surrounds these positively.

A simple fixing to the subframe, in interaction with the two stretched springs, may be obtained if the foam block is supported on the raised edge of the subframe.

The properties of the foam block which have a stabilizing effect are enhanced if the latter initially projects beyond the contour of the topframe, the foam block being compressed and being pressed with prestress against the stretched springs by the tensioning of the seat covering during assembly of the seat.

An even better lateral hold as a result of less compression is obtained if the top of the foam block serves as a rest for a seat spring aligned essentially in the transverse direction of the vehicle and fastened to the topframe.

In a further embodiment of the invention, it is possible to equip the underside and/or top of the foam block with projecting webs formed during the operation of foaming the foam block. It is thereby possible to provide a foam block, the spring characteristic of which is such that the supporting effect of the foam block is fully utilized only at a load above that occurring during normal motoring.

A tilting movement of the webs is counteracted if these intersect one another with the effect of forming a wafer pattern. The pattern can be. regular or also irregular. Furthermore, the web height can differ over the extent of the pattern, so that depressions of differing depth are obtained next to one another.

Simple foaming moulds can be used and an easy mouldremoval operation is achieved if the webs have a trapezoidal cross-section giving spring characteristic and with towards one another.

rise to a progressive sides tapering outwards An embodiment of the invention will now be described by way of example with reference to the drawing. In this:

Figure 1 shows a spring-box portion of a motor- 3 vehicle seat with a foam block helical compression springs, and Figure 2 shows a section along the line II-II of Figure 1.

According to Figure 1, a motor-vehicle seat not shown in detail consists of a subframe 2 having a raised edge 1 and with a spring core 3 which is elevated above it and which is surrounded by a topframe 4. The topframe 4, in its portions which are aligned in the longitudinal direction of the vehicle is supported on the subframe 2 via front springs 5, 6 designed as helical compression springs and via springs 7 - 9 adjacent to these and wound in meander form.

A stay 10, which prevents not only floating movements, but also excessive lateral compression, consists of a foam block 11, the basic hardness of which can easily be adapted to meet different requirements, for example by changing the material composition. and the density. The foam block 11 is inserted between the two and at least partially surrounds these positively, whilst its top 12 is supported on the topframe 4. The raised edge 1 of the subframe 2 fixes the foam block 11 in this region in interaction with the two springs 5 and 6.

As is evident from Figure 1, the foam block 11 initially projects beyond the contour of the topframe 4 and only after the operation of tensioning the seat covering (not shown) after the upholstering is it brought by the latter into an externally flush form generating a prestress. Under forces acting horizontally, the two foam blocks 11, only one of which is shown, prevent an excessive inclination of the two springs 5 and 6 and thus forestall the unpleasant phenomenon of floating movements.

The foam blocks 11 also prevent excessive lateral compression, such as can occur, for example, during cornering and when a person sits down on and gets up from the seat cushion, and in order to increase the effective supporting surface it is advantageous to extend each foam inserted between two and only one of which is shown, front springs 5 and 6 4 block 11 beyond the two springs 5 and 6 towards the longitudinal mid-axis of the seat and to support over a specific length on its top 12 at least one seat spring 13 aligned essentially in the transverse direction of the seat. Under local overloading of the middle region of the seat spring 13 or of a spring 15 placed in front of it, a mat 14 bridging the gap between the foam blocks 11 and fastened to the subframe 2 prevents a knocking against the subframe 2 which is associated with noise.

The foam block 11, which, contrary to the illustration in Figure 1, can also be made wedge-shaped, is equipped on its top 12 and on its underside 16 with webs 17 which consist of the material of the foam block 11 and are formed during the operation of foaming the foam block 11 and which intersect to provide a wafer pattern evident from Figure 1. In addition to the pattern illustrated, a plurality of also irregular pattern designs is possible, and, as can be taken from Figure 2, the height of the webs 17 can also vary.

To afford specific compression conditions, it is also possible for the webs 17 to be offset relative to one another in terms of height, so that all the webs 17 come to bear only with an increasing compression movement.

It is evident from Figure 2 that the webs 17 have a trapezoidal crosssection with sides 18 and 19 tapering outwards towards one another. This, whilst ensuring that the foam block 11 can easily be removed from the mould, at the same time makes it possible to obtain a progressive characteristic variable within wide limits. Depressions 20 of differing depth can be delimited from one another by means of the webs 17, the depressions 20 ensuring a reduction in volume of approximately 10% with a corresponding weight reduction.

1

Claims

1. A motor vehicle seat with a spring core resting on the subframe and surrounded by a topframe, each topframe portion extending in the longitudinal direction of the vehicle being supported relative to the subframe via a and limiting lateral stay'comprises a foam block which is fixed to the frame and which is inserted between two springs stretched from the subframe to the topframe and at least partially surrounds these positively.

stay preventing floating movements compression movements wherein the

2. A motor vehicle seat the foam block is supported subframe.

according to Claim 1, wherein on the raised edge of the

3. A motor vehicle seat according to Claims 1 and 2, wherein the foam block in the unstressed condition the topframe, and is compressed and pressed with prestress against the stretched springs by the tensioning of a seat covering.

projects beyond the contour of

4. A motor vehicle seat according to any one or more of the preceding claims, wherein the top of the foam block serves as a rest for a seat spring aligned essentially in the transverse direction of the vehicle and fastened to the topframe.

5. A motor vehicle seat according to any one or more of the preceding claims, wherein the underside and/or top of the foam block has projecting webs formed during the operation of foaming the foam block.

6. A motor vehicle seat according to Claim 5, wherein the webs intersect one another with the effect of forming a wafer pattern.

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7. A motor vehicle seat according to Claims 5 and 6, wherein the webs have a trapezoidal cross-section with sides tapering outwards towards one another.

8. A motor vehicle seat with a spring core resting on the subframe and surrounded by a topframe, substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

Published 1989 atThe Patent Office, State House, 66-171 High Holborn. London WCIR 4TP. FUrther copies maybe obtained from The Patent Office. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques RAI, St Mary Cray, Rent, Con. 1/87