GB2351016A

GB2351016A - Seat with adjustable profile seat back.

Info

Publication number: GB2351016A
Application number: GB9913929A
Authority: GB
Inventors: Guy Lariviere
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1999-06-15
Filing date: 1999-06-15
Publication date: 2000-12-20
Anticipated expiration: 2019-06-15
Also published as: GB9913929D0; GB2351016B

Abstract

A seat back comprises a rigid main frame 7 and first 13 and second 16 sub-frames located within the main frame. The main frame is formed with two side members 8, 9 and an upper cross arm 10. The upper part of the first sub-frame 13 is pivotally connected 11, 12 to the cross arm 10 and the upper part of the second sub-frame 16 is pivotally connected 14, 15 to the lower part of the first sub-frame 13. Adjustment means 20 are provided to adjust the inclination of the sub-frames relative to the main frame, and in this way the profile of the seat back is altered. The lower part of the second sub-frame may be retained by guide means 18, 19 so that it slides substantially parallel to the side members. The seat provides enhanced safety because there is a non-articulated rigid main frame.

Description

2351016 PATENTS ACT 1977 P13411QB-NF/jsd DESCRIPTION OF INVENTION

"IMPROVEMENTS IN OR RELATING TO A SEAT" THIS INVENTION relates to a seat, and more particularly relates to a vehicle seat such as a seat intended for use in a vehicle such as a motor car.

It has been proposed to provide seats for use in motor vehicles, such as motor cars, which have adjustable back-rests.

US-A-5,104,189 discloses an arrangement in which the back-rest is constituted by an upper section and a lower section which are interconnected by a pivotal link, so that the two sections can adopt different inclinations relative to each other.

A disadvantage of the prior art arrangement is that, in the event that an accident should occur, when a substantial force may be applied to the back-rest of the vehicle, the interconnection between the frames may be damaged, or even disintegrate, substantially weakening the back-rest of the seat. This could lead to the occupant of the seat being injured.

According to this invention there is provided a seat, the seat comprising a squab and a back-rest, the back-rest incorporating a substantially rigid m 2 frame having two side arms and an upper cross arm, there being a first subframe substantially contained between the side arms, the upper part of the first sub-frame being pivotally connected to the upper cross-arm of the main frame and there being a second sub-frame, the upper part of the second sub-frame being pivotally connected to the lower part of the first sub-frame, the second sub-frame also being substantially contained between the side arms of the main frame, means being provided to adjust the inclination of the sub-frames relative to the main frame.

Preferably the lower part of the lower sub-frame is retained by guide means provided at the lower part of the main frame.

Conveniently the guide means comprise a backing plate and a plurality of tongues located forwardly of the backing plate defining recesses which accommodate the lower edge of the lower sub-frame as a sliding fit.

Advantageously a control knob is provided accessible from the exterior of the seat, the control knob being connected to a guide rod, the guide rod being connected to the upper sub-frame in order to adjust the position of the upper sub-frame on rotation of the central knob.

In a preferred embodiment clamping means are provided to lock the subframes in position.

The seat may be provided with a head-rest at the top of the back-rest. The back-rest may be connected to the squab of the seat by means of a recliner mechanism.

3 In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a side view of a seat showing operative parts of the back of the seat in section, showing the seat in a first condition, FIGURE 2 is a view corresponding to Figure 1 showing the seat in a second condition, FIGURE 3 is a front view of a frame present in the back of the seat, and two sub-frames also present in the back of the seat, FIGURE 4 is a side view of the frame showing the sub-frames in the position that they occupy in Figure 1, and FIGURE 5 is a side view of the frame showing the sub-frames in the position that they occupy in Figure 2.

Referring initially to Figure 1 of the drawings, a vehicle seat 1 is illustrated. The seat comprises a squab 2 which is slidably mounted on a rail 3. The rear of the squab supports a back-rest 4. The back-rest carries a headrest 5.

The back-rest 4 is connected to the squab 2 by means of a recliner mechanism 6. The recliner mechanism is connected to the lower part of an inverted "U'-shaped main frame 7. The "U"-shaped main frame 7 is relatively strong, and is located entirely within the back-rest 4.

4 As can be seen in Figure 3, the main frame 7 consists of two side arms 8, 9, the upper ends of which are interconnected by a transverse bar 10. The lower ends of the side arms may also be inter-connected by a transverse bar, to make the frame square or rectangular. Pivotally connected to the lower side of the transverse bar 10, by means of hinges 11, 12, is an upper cross-arm constituted by a first sub-frame 13. The first sub-frame 13 comprises a rectangular frame which is contained between the arms 8 and 9 of the main frame 7. Pivotally connected, by means of pivots 14, 15, to the lower part of the first sub-frame 13 is the upper part of a second sub-frame 16. The subframe 16 is again a rectangular frame which is totally contained between the arms 8 and 9 of the main frame 7. The lower edge of the sub-frame 16 is trapped as a sliding fit between a back plate 17 which extends between the lower ends of the arms 8 and 9 of the main frame 7, and two tongues 18, 19 which are located slightly forwardly of the back plate 17.

A control knob 20 is provided which is accessible from the outside of the back-rest 4 of the seat 1, the control knob being located part way up the side of the back-rest 4. The control knob 20 is mounted on a shaft 21 which extends through the side arm 8 of the main frame 7. The shaft 21 is rotatable by means of the knob 20. On the interior of the frame, the shaft 21 carries a radially directed lug 22, the end of which is connected to a rigid control rod 23. The control rod 23 extends to the free end of a lug 24 which extends radially from a shaft 25 which is secured firmly to, and which extends horizontally from, the side of the upper sub-frame 13.

It is to be appreciated that in an initial condition of the back-rest the two sub-frames 13 and 16 are substantially aligned, and are thus totally contained within the envelope defffied by the main frame 7 forming the back-rest of the seat. This is the condition illustrated in Figures 1, 3 and 4.

However, the condition of the back-rest of the seat may be adjusted by rotating the control knob 20 in the anti-clockwise direction as shown in the accompanying drawings. This has the effect of pivoting the upper subframe about the hinges 11 and 12, so that the lower edge of the sub-frame moves rearwardly, out of the envelope defined by the main frame 7. This has the effect of moving the hinges 14 and 15 rearwardly, consequently moving the upper part of the lower sub-frame 16 rearwardly. This draws the lower part of the lower sub-frame 16 upwardly, so that the lower part of the lower sub-frame rises, although the lower part of the sub-frame is still trapped between the backing plate 17 and the tongues 18, 19.

A clamping mechanism (not shown) is provided to lock the sub-frames in a selected position. The clamping mechanism may be associated with the control knob 20. For example, the control knob 20 may form one-half of a dog clutch, which is spring-biased into contact with a fixed part of the dog clutch. The control knob would have to be moved, by moving the knob against the spring bias, away from the fixed part of the dog clutch before the knob could be rotated.

A driver or occupant of a motor vehicle will be able to adjust the backrest, by adjusting the positions of the sub-frames 13 and 16, so that the driver or occupant is in a comfortable position. It is to be appreciated when the backrest if adjusted as shown in Figures 2 and 5, the back of the occupant of the seat will sink deeply into the back-rest, thus bringing the head of the occupant into a position immediately adjacent the head of the head-rest. It is known that the risk of iruries occurring, especially during a rear impact, are minimised if 6 the head of an occupant is very close to the head-rest of the seat. It is also believed that if the back of the occupant has sunk deeply into the back-rest of the seat, the risk of injury is reduced, especially in a side impact situation.

It is to be noted, however, that although the back-rest of the seat is adjustable, to provide enhanced safety and comfort for the occupant of the seat, the back-rest is still strong since the integrity of the main frame 7 has not been prejudiced in any way. It is the main frame 7 that provides the inherent strength in the back-rest of the scat.

In this Specification the word "comprising" is used to mean "consisting of or includinj and the word "comprises" is used to mean "consists of or includes".

Claims

7 CLAIMS:

1. A seat, the seat comprising a squab and a back-rest, the back-rest incorporating a substantially rigid main frame having two side arms and an upper cross arm, there being a first sub-frame substantially contained between the side arms, the upper part of the first sub-frame being pivotally connected to the upper cross-arm of the main frame and there being a second sub-frame, the upper part of the second sub-frame being pivotally connected to the lower part of the first sub-frame, the second sub-frame also being substantially contained between the side arms of the main frame, means being provided to adjust the inclination of the subframes relative to the main frame.

2. A seat according to Claim 1 wherein the lower part of the lower subframe is retained by guide means provided at the lower part of the main frame.

3. A seat according to Claim 2 wherein the guide means comprise a backing plate and a plurality of tongues located forwardly of the backing plate defining recesses which accommodate the lower edge of the lower sub-frame as a sliding fit.

4. A seat according to any one of the preceding Claims wherein a control knob is provided accessible from the exterior of the seat, the control knob being connected to a guide rod, the guide rod being connected to the upper sub-frame in order to adjust the position of the upper sub-frame on rotation of the central knob.

8

5. A seat according to any one of the preceding Claims wherein clamping means are provided to lock the sub-frames in position.

6. A seat according to any one of the preceding Claims provided with a head-rest at the top of the back-rest.

7. A seat according to any one of the preceding Claims wherein the backrest is connected to the squab of the seat by means of a recliner mechanism.

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

9. Any novel feature or combination of features disclosed herein.