GB2339385A

GB2339385A - Vehicle seat with inflating headrest

Info

Publication number: GB2339385A
Application number: GB9815057A
Authority: GB
Inventors: Yngve Haland; Martin Lindstrom
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1998-07-10
Filing date: 1998-07-10
Publication date: 2000-01-26
Anticipated expiration: 2018-07-10
Also published as: GB9815057D0; GB2339385B

Description

2339385 PATENTS ACT 1977 P12557GB-NF/jsd DESCRIPTION OF INVENTION

"EWPROVEMENTS IN OR RELATING TO A VEHICLE SEAT"' THE PRESENT INVENTION relates to a vehicle seat but more particularly relates to a vehicle seat which provides the vehicle seat with an enhanced performance in the event that a rear impact should occur.

It has been appreciated that if a motor vehicle, such as a motor car, is involved in a rear-end collision, or rear impact - that is to say if a following vehicle runs into the back of the car - the occupants of the struck car may often sustain neck injuries.

It is to be understood that during a rear-end collision of this type, the vehicle that is struck is subjected to a forward acceleration. This imparts a forward acceleration to the seats of the vehicle. The squab and the back of each occupied seat engage the posterior and torso of the occupant of the seat and impart a substantial acceleration to the posterior and torso of the occupant. However, no corresponding acceleration is immediately imparted to the head of the occupant. The head is a part of the body that has substantial mass, and consequently the head has substantial inertia.

Thus, whilst the posterior and torso of the occupant of the vehicle are accelerated forwardly as a result of the rear-end collision, the head of the occupant of the vehicle initially remains stationary. This causes the neck initially to adopt a "S"-shaped configuration as the lower part of the neck moves forwardly relatively 2 to the head of the occupant whilst remaining vertical, and the upper part of the neck remains in its initial position. Subsequently, the head begins to rotate, and the neck then occupies a curved configuration. The head subsequently moves forwardly. Research has shown that "whiplash" injuries may be sustained when the neck passes the "S"-shaped configuration, if the head is moving, relative to the torso, at a substantial speed.

The present invention seeks to provide an improved vehicle seat.

According to one aspect of this invention there is provided a vehicle seat the seat comprising a squab and a back, the back of the seat being provided with a headrest, the back of the seat incorporating two substantially airtight compartments, namely a first lower compartment located in the lower region of the back and a second compartment located in an upper part of the back, there being a further substantially airtight compartment provided on the headrest, the two compartments in the back of the seat being initially inflated, and the further compartment provided on the headrest being un-inflated, there being a flow passage for air extending from at least the first lower compartment to the further compartment provided on the headrest, that flow passage being provided with a one-way valve, the arrangement being such that on the application of pressure to the lower compartment gas passes from the lower compartment to the said further compartment to inflate the further compartment the said second compartment resisting rearward movement of the torso of an occupant of the seat relative to the seat in the event that a rear impact should arise.

Preferably the second compartment is also connected to the further compartment by means of a flow passage and an associated non-retum valve.

3 Advantageously said associated non-return valve is adapted to permit a flow of air only when a predetermined pressure is exceeded.

Conveniently the first compartment is filled with a resilient material or resilient element which acts to maintain the compartment in an initial "inflated" condition.

Advantageously the said resilient material is a resilient foam.

Preferably the first compartment is formed of a fabric which is substantially impervious to air but which possesses porous properties.

Conveniently the second compartment provided in the back of the seat is filled with a resilient material or resilient element which acts to maintain the compartment in an "inflated" condition.

Advantageously said resilient material is a resilient foam.

Preferably the second compartment is formed of a fabric which is substantially impervious to air but which possesses porous properties.

According to another aspect of this invention there is provided a vehicle seat the seat comprising a squab and a back, the back of the seat being provided with a headrest, the back of the seat incorporating at least one substantially airtight compartment, there being a finther substantially airtight compartment mounted on the headrest the or each compartment in the back of the seat being filled with a resilient material or element which acts to maintain the compartment in an initial "inflated" condition, there being a flow passage from said at least one compartment to the further compartment provided on the 4 headrest, the flow passage incorporating a one-way valve, the arrangement being such that on the application of pressure to said at least one compartment gas flows from said at least one compartment to the further compartment.

Preferably the resilient material comprises a resilient foam.

Conveniently each said compartment is formed as a fabric which is substantially impervious to air but which possesses porous properties.

Conveniently a second compartment is provided in the upper part of the back of the seat provided with a resilient material or a resilient element to maintain the compartment in an initial inflated condition, the said second compartment being vented to permit air within the compartment to escape from the compartment in a predetermined manner when the compartment is compressed.

According to a further aspect of the invention there is provided a vehicle seat comprising a squab and a back, at least the upper part of the back being provided with a compartment, the compartment being provided with a resilient material or resilient element which acts to maintain the compartment in an initial inflated condition, the compartment being vented to permit air within the compartment to escape from the compartment in a predetermined manner when the compartment is compressed.

Advantageously the said second compartment in the upper part of the back of the seat is formed of a fabric having at least one aperture therein to provide the venting of the compartment.

Conveniently other resilient material comprises a resilient foam within the compartment.

In one embodiment a lower substantially air-fight compartment is located in the lower region of the back of the seat there being a further substantially air-fight compartment provided in the head rest and a flow passage for air extending from the lower compartment to the further compartment on the head rest the arrangement being such that on the application of pressure to the lower compartment air passes from the lower compartment to the further compartment to inflate the further compartment.

Preferably said compartment in the upper part of the back is vented by also being connected to the further compartment by means of a flow passage and an associated non-return valve which is adapted to permit a flow of air only when a predetermined pressure is exceeded.

In order that the invention may be more readily understood and so that ftu-ther 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 view comprising four illustrations showing the condition of the head and neck of an occupant of the vehicle in a rear collision situation where a conventional seat is used, FIGURE 2 is a view of a seat in accordance with the invention, with part thereof cut away to illustrate the interior of the seat FIGURE 3 is a view corTesponding to Figure 2 illustrating the seat in the condition that would exist following a rear impact and 6 FIGURE 4 is a view corresponding to Figure 2 showing a further embodiment of the invention with part of the foam filling of the upper compartment cut away.

Referring initially to Figure I of the accompanying drawings, illustration A shows the position of the head I and neck 2 of the occupant of a motor vehicle during ordinary conditions. The head and neck would occupy this position it for example, the vehicle were stationary.

Assuming that the vehicle was then subjected to a rear impact the posterior and torso of the 'Occupant of the vehicle would be moved forwardly, as a consequence of the forward movement of the vehicle and the forward movement of the seat mounted in the vehicle. The head I of the occupant would tend to remain stationary. A neck 2 of the occupant would then have the condition shown in illustration B. The neck here has a "S" configuration. Subsequently, as shown in illustration C, the head I moves rearwardly, thus giving the neck 2 an arcuate configuration and, if the head does not impinge on the headrest the head can move to the tilted back position shown in illustration D where the neck 2 is bent back (hyperextension) with a very significant degree of curvature. The head may then spring forwardly. This sequence of movements provides the "whiplash" effect.

It is believed that if the neck is subject to the distortions shown in illustrations A to D, the hydro-dynamic pressure of the fluid within the spine can rise suddenly, when the neck adopts the "S"-shaped configuration, thus imparting pressure shocks to parts of the central nervous system in contact with that fluid. Also, injuries may well be imparted to the ganglia. It is believed that this is why patients with socalled "whiplash" injuries may suffer from the effects of those injuries for a long time. Even though a typical rear impact collision occurs with a 7 relatively low impact speed, these collisions are responsible for a large number of relatively serious injuries each year.

A vehicle seat in accordance with the present invention is intended to reduce the "whiplash" effect as described above.

Referring now to Figure 2 of the accompanying drawings, a vehicle seat in accordance with the invention comprises a squab I I of conventional design and a back 12. The back 12 is provided with a protruding headrest 13 provided at the uppermost part of the back 12.

The interior of the back 12 contains a first substantially airtight compartment defiried by a bag 14 formed of a fabric which is substantially impermeable to gas. The bag 14 is filled with a resilient element such as a porous resilient foam material, which keeps the bag in an "inflated" condition. A duct 15 leads from the bag 14 and contains a non-return valve 16. The duct leads to a further compartment defmed by a substantially airtight bag 17 which is located on the front part of the headrest 13.

The back 12 of the seat contains a third compartrnent defted by a substantially airtight bag 18, which again may be made of a material which is slightly pervious to gas. The bag 18 may be maintained in an "inflated" condition by a resilient element, such as a resilient porous foam material within the bag. The bag 18 is located in an upper part of the seat back at a position above the first bag 14.

The bag 18 may also be connected by a duct 19, to the further compartment 17 provided in the headrest. A non-return valve 20 is provided within the duct 19.

8 It is preferred that bag 14 and/or bag 18 is filled with a resilient porous foam material which is equivalent to or which has equivalent properties to, that used for the padding or upholstery of the seat 10 as being described, so that the back of the seat provides in ordinary use, an appropriate "feel".

In the event that a rear impact should occur, the lower torso of the occupant of the seat will impart a substantial force, as indicated by the arrow A, on the first bag 14 provided in the lower part of the back of the seat. The effect of the force applied to the lower part of the back of the seat in the direction of the arrow A would be to pressurise the gas within the bag 14, whilst simultaneously compressing the foam material that is present within the bag 14. The gas will move through the duct 15, past the non-return valve 16 and will inflate the bag 17 that is formed integrally with the headrest 13 of the seat, the bag 17 formed integrally with the headrest of the seat thus having the inflated condition illustrated in Figure 3. The inflated bag 17 will engage the rear part of the head of the occupant of the seat, thus minimising the risk of whiplash injury.

The second bag provided in the back of the seat, that is to say the bag 18 which is located towards the upper part of the back of the seat, provides a force-absorbing effect. Gas from this particular airbag may also be supplied to the further compartment 17 mounted on the headrest of the seat in order to enhance the inflation of that second airbag, but, in a preferred embodiment, only when the pressure of gas within the bag 19 exceeds a predetermined threshold determined by the non-return valve 20. Thus the air is vented from the bag 18 in a predetermined manner.

9 It is to be appreciated, therefore, that in the event that a rear impact should occur, initially the torso of the occupant of the seat will move rearwardly relative to the seat, thus compressing the lower bag 14, and consequently inflating the upper bag 17 formed on the headrest 13 of the seat. The upper bag 17 will thus contact the rear part of the head of the occupant of the seat, thus minimising the risk of "whiplash" occurring. Also the second bag 18 provided in the rear of the seat will absorb energy as the torso of the occupant of the seat moves rearwardly, and air will be vented from the bag in a predetermined manner.

The bags 14 and 18 are filled with a foam material and the bags are formed of a slightly porous fabric. Following a rear impact the foam within the lower bag 14 and within the upper bag 18 provided in the back 12 of the seat will tend to expand to restore the bags to their initial condition. During this process air will pass through the porous fabric to the interior of each bag. Also the further compartment 17 provided on the headrest 13 will gradually deflate, thus returning to its initial condition. It is to be appreciated, however, that whilst a certain degree of porosity of the fabric is desirable nevertheless the fabric should still be sufficiently impervious to air that, in the event that a rear impact should arise, the further compartment 17 will be sufficiently inflated and will remain inflated for a sufficiently long period to provide the desired degree of protection to the head of the occupant of the seat.

Referring now to Figure 4 of the accompanying drawings, in a modified embodiment of the invention, the upper compartment 18 provided in the back 12 of the seat which is initially filled with foam to maintain the compartment in an inflated condition, is provided with a plurality of apertures 21 formed in the fabric constituting the compartment. The compartment is not connected to the further compartment 17 provided in the headrest of the seat.

The upper compartment 18 in this embodiment of the seat provides a very desirable characteristic in that if the upper compartment is compressed, air is vented from the compartment through the apertures 21 in a predetermined manner. The upper compartment 18 provides a very desirable characteristic when compressed by the torso of an occupant of slight build having a weight for example, of less than 100 lbs.

As can be seen in Figure 4, the lower compartment 14 is connected to the further compartment 17 in the manner described with regard to the embodiment of Figures 2 and 3.

VVhilst, in the embodiments described above, reference has been made to the use of a foam material present within the airbags, it is to be appreciated that the foam material may be replaced by any resilient compressible material or element which serve to maintain the airbag initially in a "inflated" condition in which the bag contains gas, but which permits the airbag to be compressed or reduced in volume, thus compressing the gas within the bag and forcing that gas into the further compartment 17 provided on the headrest 13 of the seat.

It is to be appreciated that the invention is being described above with reference to an embodiment incorporated in a rear seat of a motor vehicle. However, the invention may also be embodied in a front seat of a motor vehicle.

Claims

1. A vehicle seat, the seat comprising a squab and a back, the back of the seat being provided with a headrest, the back of the seat incorporating two substantially airtight compartments, namely a first lower compartment located in the lower region of the back and a second compartment located in an upper part of the back, there being a further substantially airtight compartment provided on the headrest, the two compartments in the back of the seat being initially inflated, and the further compartment provided on the headrest being un-inflated, there being a flow passage for air extending from at least the first lower compartment to the further compartment provided on the headrest, that flow passage being provided with a one-way valve, the arrangement being such that on the application of pressure to the lower compartment air passes from the lower compartment to the said further compartment to inflate the further compartment, the said second compartment resisting rearward movement of the torso of an occupant of the seat relative to the seat in the event that a rear impact should arise.

2. A vehicle seat according to Claim I when the second compartment is also connected to the further compartment by means of a flow passage and an associated non-return valve.

3. A vehicle seat according to Claim 2 wherein said associated non-return valve is adapted to perrait a flow of air only when a predetermined pressure is exceeded.

4. A vehicle seat according to any one of the preceding claims wherein the first compartment is filled with a resilient material or resilient element which acts to maintain the compartment in an initial "inflated" condition.

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5. A vehicle seat according to Claim 3 wherein the said resilient material is a resilient foam.

6. A vehicle seat according to Claim 3 or 5 wherein the first compartment is formed of a fabric which is substantially impervious to air but which possesses porous properties.

7. A vehicle seat according to any one of the preceding claims wherein the second compartment provided in the back of the seat is filled with a resilient material or resilient element which acts to maintain the compartment in an "inflated" condition.

8. A vehicle seat according to Claim 7 wherein said resilient material is a resilient foam.

9. A vehicle seat according Claim 7 or 8 wherein the second compartment is formed of a fabric which is substantially impervious to air but which possesses porous properties.

10. A vehicle seat the seat comprising a squab and a back, the back of the seat being provided with a headrest, the back of the seat incorporating at least one substantially airtight compartment, there being a further substantially airtight compartment mounted on the headrest, the compartment in the back of the seat being filled with a resilient material or element which acts to maintain the compartment in an initial "inflated" condition, there being a flow passage from said at least one compartment to the further compartment provided on the headrest the flow passage incorporating a one-way valve, the arrangement 13 being such that on the application of pressure to said at least one compartment gas flows from said at least one compartment to the further compartment.

11. A vehicle seat according to Claim 10 wherein the resilient material comprises a resilient foam.

12. A vehicle seat according to Claim 10 or 11 wherein each said compartment is formed as a fabric which is substantially impervious to air but which possesses porous properties.

13. A vehicle seat according to any one of Claims 10 to 12 wherein a second compartment is provided in the upper part of the back of the seat, provided with a resilient material or a resilient element to maintain the compartment in an initial inflated condition, the said second compartment being vented to permit air within the compartment to escape from the compartment in a predetermined manner when the compartment is compressed.

14. A vehicle seat comprising a squab and a back, at least the upper part of the back being provided with a compartment, the compartment being provided with a resilient material or resilient element which acts to maintain the compartment in an initial inflated condition, the compartment being vented to permit air within the compartment to escape from the compartment in a predetermined manner when the compartment is compressed.

15. A vehicle seat according to Claim 13 or 14 wherein the said second compartment in the upper part of the back of the seat is formed of a fabric having at least one aperture therein to provide the venting of the compartment.

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16. A vehicle seat according to Claims 13, 14 or 15 wherein the resilient material comprises a resilient foam within the compartment.

17. A vehicle seat according to Claim 14 or any Claim dependent thereon wherein the seat has a head rest and wherein a lower substantially airfight compartment is located in the lower region of the back of the seat, there being a further substantially air-fight compartment provided in the head rest and a flow passage for air extending from the lower compartment to the further compartment on the head rest, the arrangement being such that on the application of pressure to the lower compartment, air passes from the lower compartment to the further compartment to inflate the further compartment.

18. A vehicle seat according to Claim 17 as dependent upon Claim 14 wherein said compartment in the upper part of the back is vented by also being connected to the further compartment by means of a flow passage, and an associated non-retum valve which is adapted to perrnit a flow of air only when a predetermined pressure is exceeded.

19. A vehicle seat substantially as herein described with reference to and as shown in Figures 2 and 3 of the accompanying drawings.

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

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