GB2307852A

GB2307852A - Reinforced Frame for a Vehicle Seat

Info

Publication number: GB2307852A
Application number: GB9525159A
Authority: GB
Inventors: Martin Lindstrom; Lennart Haglund
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1995-12-08
Filing date: 1995-12-08
Publication date: 1997-06-11
Anticipated expiration: 2015-12-08
Also published as: GB2307852A8; GB9525159D0; DE19650503A1; GB2307852A9; GB2307852B

Description

A - I-

DESCRIPTION OF INVENTION

2307852 clIXPROVEXENTS IN OR RELATING TO A FRAXE FOR A VEHICLE SEAT" THE PRESENT INVENTION relates to a frame for a vehicle seat, such as a seat intended for use in an automobile or the like.

It has been proposed to mount, on part of a vehicle seat, a seat belt retractor, such that the seat belt emerges from an appropriate point on the seat just above the shoulder of a person sitting on the seat. This provides the advantage that regardless of the adjustment of the seat, the seat belt is always in the correct position relative to the occupant of the seat.

When a vehicle is involved in an accidentf an occupant of the vehicle may apply substantial force to the seat belt. The seat belt must be able to withstand this force, and consequently where a seat belt retractor is mounted on the seat, it is necessary to provide a frame with a strengthened portion to withstand the forces that arise when an accident occurs. It has thus been proposed to provide a seat where one side of the generally rectangular frame forming the back of the seat is constituted as a relatively strong "tower", the tower carrying the seat belt retractor mechanism. The remaining parts of the frame are weaker than the tower.

In such an arrangement the frame has been reinforced by a rigid diagonally extending reinforcing J element. The reinforcing element minimises any risk of the frame Illozenging11 if the frame is subjected to substantial forces in an accident situation. The rigid reinforcing element, however, can prove to be uncomfortable, not only for the occupant of the seat, since the spine of the occupant of the seat may engage the reinforcing element, but also for people sitting behind the seat, whose knees may engage the reinforcing element.

The present invention seeks to provide an improved seat frame.

According to this invention there is provided a frame for a vehicle seat, the frame comprising two side elements interconnected by a top crosspiece to form the frame, one side element being relatively strong and having an upwardly extending portion extending above the level of the top cross-piece, the upwardly extending portion defining means through which a seat belt passes, the seat belt being stored on a retractor mechanism that is connected to the said one side element, the frame being reinforced by a flexible substantially inextensible wire which acts to prevent the frame Illozenging11 if a force is applied to the seat belt, the wire not presenting a rigid obstruction in the central part of the frame between the two side elements and beneath the cross-piece.

Preferably the wire extends substantially diagonally across the frame from a point adjacent the corner of the frame defined by the top piece and the second side element to the opposed lower diagonal corner of the frame.

Preferably the said one side element is f ormed as a hollow element, the retractor mechanism being contained within the hollow element.

In order that the invention may be more readily understood, the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a perspective illustrative view of the driver of a motor vehicle sitting on a seat provided with a seat belt which is mounted within the seat, FIGURE 2 is a perspective view of a prior-art frame of a type that might be used in the seat as illustrated in Figure 1, and FIGURE 3 is a view corresponding to Figure 2, but illustrating a frame in accordance with the invention which might be used in a seat as illustrated in Figure 1.

Referring initially to Figure 1 of the accompanying drawings, a seat 1 is shown to be occupied by the driver of a motor vehicle. The seat 1 comprises a squab 2 which may be mounted for forward and rearward adjustment. Pivotally connected to the squab 2 is a back 3, which can move, about a horizontal pivot axis, to adjust the "rake" or angle of inclination of the torso of the driver.

Mounted at the top of the back 3 is a head-rest 4. Mounted within the seat is a retractor mechanism (not shown) for a seat belt 5. The seat belt emerges from an aperture which is located at a position 6 just above one -shoulder of the occupant of the vehicle. The seat belt is intended to pass across the chest of the occupant of the vehicle, through a tongue 7 which is adapted to be received in a buckle 8 which is carried by a plate 9 secured to the squab 2 of the seat by a bolt 10, and thence across the lap of the occupant to a further anchor point (not shown) where the free end of the belt is secured to the squab 2 of the seat.

Figure 2 illustrates a frame that is present within the back 3 of the seat illustrated in Figure 1. The frame comprises a first side element 12 which extends vertically, and a second side element 13 which also extends vertically. The lower ends of the side elements define apertures 14, 15, which receive a shaft 16 on which the back 3 of the seat is pivotally mounted to effect the adjustment of "rake" described above.

The side elements 12 and 13 are inter -connected, at the top of the frame, by a cross-piece 17. The crosspiece 17 may carry the head-rest 4 illustrated in Figure 1.

It is to be observed that the first side element 12 is substantially bigger and substantially stronger than the second element 13. Also the first side element 12 has a portion 18 which extends upwardly above the cross-piece 17. The portion 18 defines an aperture 19.

The first side element 12 forms a relatively strong "tower" which contains a retractor mechanism for a safety belt. The safety belt from the retractor mechanism emerges through the aperture 19 which is effectively located at the position 6 as shown in Figure 1.

Should an accident arise, a substantial force will be applied to the portion 18 of the first side element 12 defining the aperture 19, since such a force will be imparted to the saf ety belt 5 by the torso of the driver of the vehicle. Consequently, the frame is reinforced by means of a substantially rigid diagonally extending reinforcing element 20 which extends from the corner of the frame defined between the first side element 12 and the cross- piece 17, and the lower diagonally opposite corner.

The reinforcing element 20 reduces the risk of the frame Illozenging11 in an accident situation. If a substantial force is applied to the portion 18 of the first side element 12 there is a risk that the upper right-hand corner of the frame may move towards the lower left-hand corner, as seen in Figure 3. This is Illozenging11. The reinforcing element is intended to prevent this occurring.

The rigid reinforcing element 20 may prove to be inconvenient. The spine of the driver of the vehicle may engage the reinforcing element 20, especially if the driver is heavy and the padding provided on the back 3 of the seat is not very thick. Also, if a person sitting behind the illustrated seat 1 has relatively long legs, the knees of the person sitting behind the seat may also engage the rigid reinforcing element 20.

Consequently, it is to be appreciated that the rigid reinforcing element 20 is undesirable, but serves a very important purpose of minimising the risk of the frame Illozenging11 in the event that an accident should arise and substantial force are applied to the safety belt 5.

Figure 3 is a view corresponding to Figure 2 illustrating an embodiment of the invention. The parts of this figure which correspond with the arrangement described with reference to Figure 2 carry the same reference numerals and will consequently not be re-described.

It is to be observed that in the embodiment of Figure 3, the diagonally extending rigid reinforcing element 20 is omitted and has been replaced by a reinforcing wire 21 which extends from the upper corner of the frame defined by the second side element 13 which does not carry the projection defining the aperture 19, and the opposed lower corner of the frame, that is to say, the corner of the frame adjacent the lower end of the first vertical element 12 that carries the extending portion 18 that defines the aperture 19. The wire 21 is a substantially inextensible flexible element.

The wire 21 may initially be slightly loose, or not under substantial tension. It is to be appreciated that should the frame tend to lozenge, due to a substantial force applied to the portion 18, of the first side element 12, the corners of the frame to which the ends of the wire are connected will tend to move apart, and thus the wire will be tensioned and will provide the desired reinforcing effect. The wire will prevent the corners to which it is attached from moving apart, thus preventing the Illozenging11 of the frame.

consequently, since in ordinary circumstances the wire 21 is relatively "slack" the disadvantages exhibited by the stiff reinforcing element 20 will not be present in this embodiment of the invention. Also, the amount of force an element can withstand in extension is much greater than the force it can withstand in compression, since in compression the element will tend to buckle. Thus, the wire 21 needs only have a relatively small diameter, in comparison with the thickness of the rigid reinforcing element 20, to provide the same reinforcing effect. Thus, the total mass of the wire 21 is less than the mass of the reinforcing element 20. This leads to a saving in raw 0 material costs, and a redirection in the weight of the complete vehicle, helping to conserve fuel.

1

Claims

CLAIMS:

1. A frame for a vehicle seat, the frame comprising two side elements interconnected by a top cross-piece to form the frame, one side element being relatively strong and having an upwardly extending portion extending above the level of the top cross-piece, the upwardly extending portion defining means through which a seat belt passes, the seat belt being stored on a retractor mechanism that is connected to the said one side element, the frame being reinforced by a flexible substantially inextensible wire which acts to prevent the frame Illozenging11 if a force is applied to the seat belt, the wire not presenting a rigid obstruction in the central part of the frame between the two side elements and beneath the cross-piece.

2. A frame according to Claim 1 wherein the wire extends substantially diagonally across the frame from a point adjacent the corner of the frame defined by the top piece and the second side element to the opposed lower diagonal corner of the frame.

3. A frame according to any one of the preceding Claims wherein the said one side element is formed as a hollow element, the retractor mechanism being contained within the hollow element.

4. A frame for a vehicle seat substantially as herein described with reference to and as shown in Figure 3 of the accompanying drawings.