GB2339145A

GB2339145A - A vehicle seat

Info

Publication number: GB2339145A
Application number: GB9814759A
Authority: GB
Inventors: Martin Lindstrom
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1998-07-07
Filing date: 1998-07-07
Publication date: 2000-01-19
Anticipated expiration: 2018-07-07
Also published as: GB9814759D0; GB2339145B

Description

2339145 PATENTS ACT 1977 P12504GB-NF/isd DESCRIPTION OF INVENTION

"IMPROVEMENTS IN OR RELATING TO A VEHICLE SEAT" THE PRESENT INVENTION relates to a vehicle seat, and more particularly relates to a vehicle seat in which a retractor reel for a safety-belt is mounted in the back-portion of the seat.

It has been proposed previously to provide a vehicle seat with the retractor reel for a safety-belt mounted in the back-portion of the seat, the retractor reel being located at a position just above the shoulder of an occupant of the seat.

When such a seat is in use, and a vehicle in which the seat is mounted is involved in an accident, a substantial forwardly directed force is applied to the retractor mechanism, and consequently this force is applied to the back-portion of the seat. Thus, seats of this type have been designed with the back-portion having a very strong vertical members in which the retractor reel may be mounted.

It is, of course, expensive to fabricate a seat with a very strong member, and the very strong member typically occupies a relatively large space. Also the resultant seat is heavy. Various attempts have been made to overcome this 2 problem, for example by reinforcing the frame of the back-portion of the seat with wires. However, these prior seats are still relatively heavy and space consuming.

The present invention seeks to provide an improved seat.

According to this invention there is provided a vehicle seat the vehicle seat comprising a squab and a back, the squab of the seat being mounted on a carriage, the carriage being slidably mounted on a rail, locking means being provided adapted to lock the carriage in at least one position on the rail, the locking means being adapted to be released in the event that an accident should occur to penrnit the carriage to move forwardly along the rail, the seat-back incorporating a rigid member on which a retractor for a safety-belt is mounted at an elevated position, said member having means mounted thereon also at an elevated position receiving an end portion of an elongate flexible member, the flexible element passing guide means located at a position beneath said elevated positions and fixed relative to said rail, the other end of the flexible element being connected to the seat or carriage.

It will be understood that in the event that an accident arises the carriage, and the seat, will move forwardly along the rail. The flexible element remains in engagement with the guide means. The entire seat back moves forwardly. The end of the flexible element connected to the seat or carriage moves forwardly, applying tension to the flexible element. Because the entire seat is moved forwardly relative to the guide means, the flexible element now makes an angle with the rigid element within the back of the seat. Tension applied to the seat belt will tend to place the rigid element in the back of the seat in compression, while applying tension to the flexible element.

Preferably the said locking means are adapted to be released by the breaking of a frangible element forming part of the locking means.

In an alternative embodiment of the invention the locking means are adapted to be released in response to a signal from a sensor responsive to an accident.

Preferably the means receiving an end portion of the flexible element comprise means which resiliently retain the end of the flexible element and clamping means, response to an accident, to clamp the flexible element in position.

Conveniently the means receiving an end portion of the flexible element comprise a clamping element through which the flexible element passes, and a compression spring being provided between the clamping means and an engagement element provided at the end of the flexible element adapted to apply tension to the flexible element, the clamping means being adapted, in response to an accident, to clamp the flexible element against axial movement.

Advantageously the clamping means comprise an outer housing and an inner housing with pyrotechnic material therebetween, means being provided to ignite the pyrotechnic material in response to an accident in order to deform the inner housing to a position in which it clamps the flexible element.

Preferably wherein the carriage of the seat is adjustably mounted on the rail, manually operable means being provided adapted to release the locking means, said manually operable means being adapted simultaneously to release a releasable clamp, which engages an element extending substantially parallel with the rail, to permit movement of the clamp simultaneously with the 4 adjustment of the seat the clamp carrying the guide means for the flexible element.

Conveniently the guide means comprise a horizontally extending axle extending from the clamp supporting a rotary pulley wheel, the flexible element engaging the rotary pulley wheel.

Preferably the clamp engages a serrated bar, the serrated bar having downturned end portions engaging the floor of the vehicle.

In a preferred embodiment a deformable energy absorbing element is provided connected between the said clamp and a point on the said carriage, the deformable element being adapted to deform on forward movement of the carriage in an accident situation.

Conveniently the said other end of the flexible element is connected to the seat or carriage by a device which is adapted to yield when a predetermined tension is present in the flexible element, permitting the seat to move forwardly, while maintaining tension in the flexible element.

Preferably the said device comprises a substantially arcuate deformable element connected between the flexible element and the seat or carriage one end of the element being connected to the seat or carriage, the other end of the element being connected to the flexible element.

The flexible element may be a cable, a wire, a strap or a chain.

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 I is a diagrammatic side view of a vehicle seat in a first or cc ordinary" condition, FIGURE 2 is an enlarged view of part of the seat of Figure 1, FIGURE 3 is a view corTesponding to Figure I showing the seat in a second condition following a frontal impact of a motor vehicle in which the seat is fitted, and FIGURE 4 is an enlarged view of the part of the seat shown in Figure 2 when in the condition illustrated in Figure 3.

Referring initially to the drawings, a vehicle floor I supports, by means of support legs 2,3, a pair of substantially horizontal parallel rails 3. A pair of parallel carriages 4 is provided adapted to slide along the rails. The carriages 4 support, by means of support arms 5,6 the squab 7 of a seat. The seat has a back-portion 8 which incorporates a substantially vertically extending rigid member 9. Mounted at an elevated position in the upper region 10 of the vertical member 9 is a retractor mechanism (not shown) for a seat-belt 11. The seat-belt I I has a first portion 12 which extends from the upper part 10 of the vertical member 9 across the chest or thorax of an occupant 13 of the seat. The safety-belt also includes a lap portion 14 which extends across the lap of the occupant of the seat, the lap portion 14 being secured to the carTiage 4 by an anchor point 15.

6 A locking mechanism (not shown) is provided to lock each carriage 4 to the rail 3. The locking mechanism is adapted to be released upon actuation of a lever 16. The locking mechanism incorporates one or more frangible elements so that, if a substantial force is applied to the carriage 4 acting in the forward direction, part of the locking mechanism breaks, pennitting the carriage to move forwardly even though the lever 16 has not been actuated to move the locking arrangement to the "unlocking" position. Thus the locking mechanism is released in the event that an accident should occur. In an alternative embodiment the locking means may be released in response to a signal from a sensor responsive to an accident.

The lever 16 is also connected, by means of a Bowden flexible element 17, to a releasable clamp 18. The clamp engages a serrated clamping bar 19 which has cranked end portions 20,21 which secure the serrated bar 19 in position above the floor 1. The bar 19 thus, extends parallel with the rails 3.

The releasable clamp 18 is connected to the anchor point 15 on the carnage 4 by means of a strap 22. The strap 22 is made of a relatively strong material, such as metal, and is adapted to deform only if a very substantial force is applied to the strap. The strap 22 may thus present energy absorbing properties.

The clamp 18 carries a horizontally extending shaft 23 which is provided with a rotary pulley wheel 24. The clamp is located beneath the elevated position at which the retractor mechanism is mounted on the vertical member 9.

Connected to a forward part of the carriage 4, by means of a pin 27, is a force-absorbing member 28, constituted by an arcuate element formed of a 7 deformable material, such as an appropriate metal. The other end of the arcuate element is connected, 29, to one end of an elongate flexible element in the form of a wire or flexible element 30. The wire or flexible element 30 passes round the pulley wheel 24 carried on the shaft 23, and then extends upwardly closely adjacent to and substantially parallel with the vertical member 9 within the back of the seat. The upper end of the flexible element 30 terminates, at an elevated position adjacent the top of the vertical member 9 present in the backportion 8 of the seat with an enlarged washer 3 1. Trapped between the washer 31 and a clamping arrangement 32 is a helical compression spring 33. The clamping arrangement 32 is secured in position on the vertical member 9 present in the back-portion 8 of the seat and is initially in a position in which the flexible element 30 may pass freely through the clamping arrangement 32. The clamping arrangement 32 is located above the clamp 18 which carries the shaft 23 and the pulley wheel 24.

The back-portion 8 of the seat is connected to the squab 7 of the seat by means of a recliner mechanism 34. The recliner mechanism 34 may be operated to increase or decrease the angle of rake of the back-portion 8 of the seat. Depending upon the direction of movement of the back-portion of the seat the compression spring 3 expands or contracts to maintain a substantially constant tension within the wire or flexible element 30.

If the position of the seat needs to be adjusted axially of the vehicle, the lever 16 may be actuated, thus releasing the locking mechanism between the carriage 4 and the rail 3, and also releasing the clamp 18. The seat may thus be slid axially to the desired position, with the carriages 4 moving along the rails 3, and at the same time the clamp 18 will be moved along the serrated bar 19 by the strap 22, since no substantial force is applied to the strap 22. The lever 16 is then returned to its initial position, thus re-engaging the clamp 18 at an 8 appropriate position on the serrated bar 19, and re-securing the locking connection between the carriages 4 and the rails 3.

Figure 2 shows the clamping arrangement 32 and the associated spring 33 to enlarged scale. The clamping arrangement 32 comprises a cylindrical housing 35 having, within it, a waisted tubular housing 36. The space between the outer housing 35 and the inner waisted housing 36 is filled with a pyrotechnic material 37. The waisted housing 36 defines a through passage 37 through which the flexible element 30 passes freely.

In the event that an accident should occur involving a frontal impact of the vehicle in which the seat is fitted, the occupant 13 of the seat will move forwardly, relative to the rest of the vehicle, imparting a substantial force to the safety-belt 11. As a consequence, the entire seat will tend to move forwardly. The frangible element in the locking mechanism provided in each carriage 4 which locks the carriage 4 in position on the rail 3 will break, and the carriages 4, carrying with them the squab 7 of the seat, will move forwardly relative of the rails 3. However, the clamp 18, which is secured to the serrated bar 19 will be retained in its initial position.

As the seat moves forwardly, the forward movement of the seat may be resisted by the deformation of the strap 22 connected between the anchor point 15 on the carriage 4, and the clamp 18.

In response to the sensing of the accident the pyrotechnic charge 37 between the inner waisted housing 36 and the outer housing 35 of the clamping arrangement 32 will be ignited, thus deforming the inner waisted housing 36 to the condition illustrated in Figure 4 in which the flexible element 330 is securely 9 gripped. It is to be appreciated, however, that various other types of clamping arrangement may be used in the place of that specifically described.

As the caniage moves forwardly, the end of the flexible element 30 which is connected by the connection 29 to the defor-mable element 28, tends to move forwardly. Thus a substantial tension is applied to the flexible element 30. Of course, the upper end of the flexible element 30 is now securely clamped in position. The releasable clamp 18 is fixed in position on the serrated bar 19 and thus the shaft 23 and the associated wheel 24 are retained in position. As the carriage moves forwardly, the end of the flexible element 30 connected 29 to the force absorbing member 28 moves forwardly, thus substantially increasing the tension in the flexible element 30. The deformable element 28 is deformed, with the arcuate element becoming substantially straightened, when the tension within the flexible element 30 reaches a predetermined limit. Thus, a very high tension, equivalent to the predetermined limit necessary, to institute deformation of the deformable member 28, is maintained within the flexible element 30. Because the lower part of the back portion 8 of the seat has moved forwardly relative to the clamp 18 the cable 30 is no longer parallel with the vertical member 9 in the back portion 8 of the seat, but instead makes an, acute angle with the vertical member 9. The vertical member 9 thus bisects the angle between the direction of the force applied to the vertical member 9 by the seat belt I I and the axis of the cable 30. Thus the vertical member 9 is placed in compression while forces tend to extend the cable 30. The risk of the vertical member 9 bending or buckling is thus substantially reduced. Thus the flexible element 30 substantially reinforces the back of the seat.

It is to be appreciated that the seat may be used in the ordinary way, with the angle of rake of the back of the seat and the longitudinal position of the seat readi - ly being adjusted. However, the seat may be fabricated to be relatively light and may also be fabricated to be not very bulky. Nevertheless, a substantial tension is applied to the flexible element 30 when a frontal impact accident situation occurs, which provides a sufficient reinforcing effect for the seat to be able to withstand the forces applied to it.

I

Claims

I I CLAIMS:

1. A vehicle seat, the vehicle seat comprising a squab and a back, the squab of the seat being mounted on a carriage, the carriage being slidably mounted on a rail, locking means being provided adapted to lock the carriage in at least one position on the rail, the locking means being adapted to be released in the event that an accident should occur to permit the carriage to move forwardly along the rail, the seat-back incorporating a rigid member on which a retractor for a safety-belt is mounted at an elevated position, said member having means mounted thereon also at an elevated position receiving an end portion of an elongate flexible member, the flexible element passing guide means located at a position beneath said elevated positions and fixed relative to said rail, the other end of the flexible element being connected to the seat or carriage.

2. A seat according to Claim I wherein the said locking means are adapted to be released by the breaking of a frangible element forming part of the locking means.

3. A seat according to Claim I wherein the locking means are adapted to be released in response to a signal from a sensor responsive to an accident.

4. A seat according to any one of the preceding claims wherein the means receiving an end portion of the flexible element comprise means which resiliently retain the end of the flexible element and clamping means, responsive to an accident, to clamp the flexible element in position.

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5. A seat according to any one of Claims I to 3 wherein the means receiving an end portion of the flexible element comprise a clamping element through which the flexible element passes, and a compression spring being provided between the clamping means and an engagement element provided at the end of the flexible element adapted to apply tension to the flexible element, the clamping means being adapted, in response to an accident, to clamp the flexible element against axial movement.

6. A seat according to Claim 5 wherein the clamping means comprise an outer housing and an inner housing with pyrotechnic material therebetween, means being provided to ignite the pyrotechnic material in response to an accident in order to deform the inner housing to a position in which it clamps the flexible element.

7. A seat according to any one of the preceding Claims wherein the carriage of the seat is adjustably mounted on the rail, manually operable means being provided adapted to release the locking means, said manually operable means being adapted simultaneously to release a releasable clamp, which engages an element extending substantially parallel with the rail, to permit movement of the clamp simultaneously with the adjustment of the seat the clamp carrying the guide means for the flexible element.

8. A seat according to Claim 7 wherein the guide means comprise a horizontally extending axle extending from the clamp supporting a rotary pulley wheel, the flexible element engaging the rotary pulley wheel.

9. A seat according to any one of Claims 7 to 8 wherein the clamp engages a serrated bar, the serrated bar having down-turned end portions engaging the floor of the vehicle.

13

10. A seat according to any one of Claims 7 to 9 wherein a deformable energy absorbing element is provided connected between the said clamp and a point on the said carriage, the defor-mable element being adapted to deforTn on forward movement of the carriage in an accident situation.

11. A seat according to any one of the preceding claims wherein the said other end of the flexible element is connected to the seat or carriage by a device which is adapted to yield when a predetermined tension is present in the flexible element, permitting the seat to move forwardly, while maintaining tension in the flexible element.

12. A seat according to Claim I I wherein the said device comprises a substantially arcuate deformable element connected between the flexible element and the seat or carriage one end of the element being connected to the seat or carriage, the other end of the element being connected to the flexible element.

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

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