GB2201087A

GB2201087A - Motor vehicle seat

Info

Publication number: GB2201087A
Application number: GB08802824A
Authority: GB
Inventors: Johann Tomforde; Steffen Kohl; Mathias Diebold; Frieder Lang; Peter Fassbender
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1987-02-13
Filing date: 1988-02-08
Publication date: 1988-08-24
Anticipated expiration: 2008-02-08
Also published as: DE3704489C2; DE3704489A1; FR2610880B1; GB8802824D0; IT8819139A0; GB2201087B; FR2610880A1; IT1215744B

Abstract

A motor vehicle seat has an upwardly movable back cushion portion 5 and a lower stationary back cushion portion 4 forming a lumbar support. Adjusting means 15 for the movement of the back cushion 5 may comprise a rack 14 and pinion 21 driven either manually or by an electric motor 16 via worm gearing 17, 19. There is a gap between the movable and fixed cushion portions 5, 4. <IMAGE>

Description

Motor Vehicle Seat The invention relates to a motor vehicle seat comprising a first supporting body for a seat cushion and a second supporting body non-positively connected with it, for supporting a back cushion separate from the seat cushion, the back cushion being arranged to be upwardly movable along guides to enable adjustment of the height of the seat back.

A seat constructed in this manner is known from DE OS 15 30 970, its back being easily adaptable to differing sizes of the upper part of the body of the users of the seat. Such a possibility of adaptation affords special advantages also with the modern day seats with head rests and with belt sections associated with the back. A drawback of the known seat -is the great gap present already in the lower most position of the back between it and the seat cushion, this gap increasing when the back is pushed upwards, so that sitting without growing tired over a particularly long distance is not afforded. In addition, it is visually disturbing to see the adjustment arrangement.

The present invention, while retaining the advantages which can be achieved with a vertically adjustable seat back, seeks to construct the driver's seat in such a manner that a maximum degree of sitting comfort is afforded even over long distances, and to accommodate the adjustment arrangement in an advantageous position which improves the overall stylistic impression.

According to the present invention there is provided a motor vehicle seat comprising a first supporting member for a seat cushion and a second supporting member nonpositively connected with the first member and supporting an upper back cushion separate from the seat cushion, the back cushion being arranged to be upwardly movable along guides, wherein onto the seat cushion there connects a lower back cushion portion which is fixed in position-and forms a lumbar support, and is disposed in the accommodation region of adjusting means for the movement of the back cushion, being followed by the upper back which is vertically adjustable and separated by a dividing gap from the lower back cushion.

It has been found to be particularly advantageous to let the upper side of the stationary back cushion portion extend upwards at least 140 mm from the upper side of the seat cushion when a person sits on the latter - in terms of a body weight of some 75 kg.

In an embodiment particularly advantageous in terms of favorable introduction of force there stands out of every guide a. toothed rack receiving the upper back cushion portion, into which rack a stationarily mounted toothed wheel engages, fitted with a drive.

The entry of dust and foreign bodies is prevented if each toothed rack is covered by bellows in the gap region between the stationary back cushion portion and the vertically-adjustable back cushion portion.

In another embodiment of the invention the.---guides are cpnstructed as longitudinal slots drilled into each supporting rod, into which head bolts protruding from the associated support member engage, and each support rod is fitted with a supporting rod portion with which a drivable toothed wheel is in engagement.

In a further construction of the invention there is provided, to save space, on the same axis as the toothed wheel, a worm wheel rotatable by means of a worm shaft end driven by an electric motor or manually.

A simplification of the drive may be achieved if the two toothed wheels engage into each other. Thus the drive motion of one -toothed wheel can be transmitted in the direc-tion of rotation to the other toothed wheel.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings wherein: Fig lis a simplified front view of a motor vehicle seat divided according to the invention; Fig 2 is the magnified rear view of the division region of the seat back with driving arrangement according to Fig. 1; Fig 3 is a perspective view of the two support members according to another example of embodiment with a motor-driven adjustment arrangement, and Fig 4is a possibility of another, preferably manually-actuated, adjustment arrangement.

The motor vehicle seat 1 shown in contour lines only in Fig. -1 has a seat cushion 2 onto which the back cushion 3 connects, the latter consisting of a lower stationary back cushion portion 4 and an upper upwardly movably constructed back cushion portion 5. Between the two portions a dividing gap 6 is provided the lower delimitation of which is formed by the upper side 7 of the lower back cushion portion 4. Here, the upper side 7related to the depressed upper side-8 of the seat cushion 2 on which a person weighing about 75 kg is seated - has a minimum distance of 14Q mm. This dimension is sufficient, as tests have shown, for a very extensive number of persons because, in spite of differing body sizes, the pelvic height measurement changes only within relatively narrow limits.Laterally, the gap area 9 formed by the dividing gap 6 is covered in each case by bellows 10.

As Figure 2 shows, a first supporting member 11 is provided, securing the back cushion portion 4, with which a second supporting member 12, receiving the upper back cushion portion 5, is non-positively associated. Each supporting member 12 is provided with a guide 13 from which there protrudes a toothed rack 14 receiving, in a manner not represented, the vertically-movable back cushion portion 5. Adjusting means 15 consisting in a motorised drive 16 which drives by means of a worm 17 a worm wheel 19 fixed rotationally fast on a shaft 18, set in rotary motion two toothed wheels 20 and 21 taken up by the ends of the shaft 18, and engaging with the respectively associated toothed rack 14, whereupondepending on the direction of rotation - the back cushion portion 5, and with it a head rest which may be provided and an upper belt deflection point moves up or down.

All the adjustment means 15 are advantageously concentrated in the stationary bottom back cushion portion 4 and can be covered in the manner indicated by a piece of lining material 22, while the still unprotected area of the toothed racks 14 and the associated portion of the supporting members 12 can be covered in each instance by bellows 10 represented in Fig. 1.

In a manner not shown the described vertical adjustment device can be fitted also with a seat back with slant adjustment, in which case a toothed rack of elastic material is used to compensate the pivoting movements.

In the example of embodiment of Figure 3 the second supporting member 12 connected with the first supporting member- 11 receives supporting rods 23 into which longitudinal slots 24 have been drilled as guides 13.

Head bolts 25 protruding from the supporting member 12 engages into these. Furthermore, each supporting rod 23 has a toothed rack portion 26 with which in each instance a toothed wheel 27 or 28 engages. The two toothed wheels 27 have associated along the same axis a worm wheel 29 or 30 which is in each case impinged upon by a worm shaft end of the drive 16. The above-mentioned adjusting means 15 are stationarily mounted on the supporting member 12 in the region of the lower back cushion portion not represented.

According to Figure 4 the toothed wheels 27 and 28 are dimensioned in such a manner that they engage mutually and at the same time engage into the toothed rod portion 26 of the supporting rod 23. The drive is effected through the worm wheel 29 associated with the toothed wheel 27 with which a worm 32, associated at its end with flexible shaft 31 rotatable by hand, is in engagement. As with the embodiment according to Figure 3 there takes place, depending on the direction of rotation of the two toothed wheels 27 and 28, either an upward or downward movement of the two supporting rods 23 of the upper back cushion portion not represented.

Claims

1. A motor vehicle seat comprising a first supporting member for a seat cushion and a second supporting member non-positively connected with the first member and supporting an upper back cushion separate from the seat cushion, the upper back cushion being arranged to be upwardly movable along guides, wherein onto the seat cushion there connects a lower back cushion portion which is fixed in position and forms a lumbar support, and is disposed in the accommodation region of adjusting means for the movement of tHe back cushion, being followed by the upper back cushion which is vertically adjustable and separated by a dividing gap from the lower back cushion.

2. A motor vehicle seat according to Claim 1 wherein the upper side of the fixed back cushion portion extends upwards at least 140 mm from the upper side of the seat cushion when a person of average size having a body weight of approximately j5 kg is sitting thereon.

3. A motor vehicle seat according to Claim 1 or 2, wherein, out of each guide a tooth-ed rack receiving the upper back cushion portion emerges, and a toothed wheel mounted on a fixed part of the seat and provided with a drive, engages with it.

4. A motor vehicle according to Claim 3, wherein each toothed rack is covered by bellows in the gap region between the fixed back cushion portion and the upwardly movable back cushion.

5. A motor vehicle seat according to Claim 1, wherein the guides comprise longitudinal slots drilled into each supporting rod, the head bolts protruding. from the associated supporting member engaging thereinto, and wherein each supporting rod is-fitted with a toothed rack portion with which a drivable toothed wheel is in engagement.

6. t motor-vehicle seat according to Claim 1, wherein coaxially with the toothed wheel a worm wheel is arranged which movable by a worm wheel end in rotation by means of an electric motor or manually.

7. A motor vehicle seat according to Claim 5 or 6, wherein the two toothed wheels mutually engage.

8. A motor vehicle seat substantially as described herein with reference to and as illustrated in the accompanying drawings.