WO2010002327A1

WO2010002327A1 - Whiplash protection arrangement

Info

Publication number: WO2010002327A1
Application number: PCT/SE2009/050714
Authority: WO
Inventors: Peter Axelsson
Original assignee: Autoliv Development Ab
Priority date: 2008-07-04
Filing date: 2009-06-11
Publication date: 2010-01-07
Also published as: KR20110028474A; CN102076520A; DE112009001411T5

Abstract

The present invention relates to a whiplash protection arrangement, arranged to be used in a vehicle seat 1 comprising a squab 2 configured to be attached to a vehicle structure 4 and a seat back 3 supported by the squab 2 via a recliner mechanism 5 for adjustment of a seat back 3 angle in relation to the squab 2 about a recliner pivotal axis A. The whiplash protection arrangement comprises two interacting pivotal members 11, 12 arranged to pivot in relation to each other about an pivotal axis when a force acting on the seat back 3 is in excess of a predetermined threshold value as a result of a rear impact crash and said whiplash protection arrangement is arranged between the recliner mechanism 5 adjusting the seat back and the seat back 3. Further said pivotal members 11, 12 pivotal axis can be arranged to coincide with said recliner pivotal axis.

Description

Whiplash protection arrangement

FIELD OF THE INVENTION

The present invention relates to a whiplash protection arrangement, arranged to be used in a vehicle seat and vehicle seat provided with a whiplash protection arrangement. More specifically the invention relates to a whiplash protection arrangement, arranged to be used in a vehicle seat comprising a squab and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab about a recliner pivotal axis.

BACKGROUND OF THE INVENTION One type of whiplash protection arrangements allow the seat back of a vehicle seat to "yield", at least to a predetermined extent, in case of a rear impact, whereby the torso and head of a person (also referred to as an occupant) sitting in the seat will be accelerated in a less aggressive way than would be the case if the seatback were rigid and accelerated together with the vehicle structure, to which the seat is attached. Different approaches to facilitate this yielding seat back have been suggested.

One is to allow the whole seat to tilt backwards, by providing a fractural impression in the seat support, which fractural impression in a rear impact situation will be activated by the instantaneously-operating force from an occupant's torso against the seat back to render a controlled shear fracture in the seat support allowing a tilting of the whole seat backwards. An other approach is to provide mechanical arrangements between the seat support and a recliner mechanism, to allow for the recliner mechanism and the seat back it carries to yield/tilt backwards when a predetermined force is reached against the seat back from an occupant as a result of a rear impact. Suggested such mechanical arrangements show a large number of components and movable parts, which drives cost in production and complexity in services. Such arrangements can also be relatively bulky and protrude outside the seat, which consumes space inside a vehicle. The number of mechanical parts in the arrangement also implies that it is heavy, which is against a general auto industry trend towards smaller and lighter vehicles to reduce cost and to reduce fuel consumption. OBJECT AND SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a whiplash protection arrangement as is first mentioned above and that solves or at least alleviates to some extent some of the abovementioned challenges. This object is achieved by the present invention as it is defined in the attached independent claims.

It is now suggested a whiplash protection arrangement arranged to be used in a vehicle seat, comprising a squab configured to be attached to a vehicle structure and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab about a recliner pivotal axis, wherein said whiplash protection arrangement comprises two interacting pivotal members arranged to pivot in relation to each other about an pivotal axis when a force acting on the seat back is in excess of a predetermined threshold value as a result of a rear impact crash, and said whiplash protection arrangement is arranged between the recliner mechanism adjusting the seat back and the seat back. By positioning the whiplash protection arrangement in this way it can utilize the seat back volume and will therefore not need to increase the outer size of a vehicle seat.

The whiplash protection arrangements pivotal axis can also be arranged to coincide with said recliner pivotal axis. Said recliner pivotal axis is usually chosen to provide an ergonomically positive adjustment of the seat back and it can be favourably to use the same axis for the whiplash protection arrangement.

Further, the whiplash protection arrangement can be provided with means for energy absorption arranged to absorb energy when the two pivotal members are pivoting in relation to each other. Such means for energy absorption makes it possible to further reduce the potentially harmful influence on a person in the seat from a rear impact.

Such an energy absorption means can comprise deformation elements, which can be arranged for plastic deformation to absorb kinetic energy when the seat back yields.

The deformation elements can also be realisably attached to the pivotal members, whereby they can be replaced, e.g. due to a plastic deformation or a need or desire to change the energy absorption characteristics.

The deformation elements can comprise two coaxially arranged and interconnected pieces positioned at least partly one inside the other, a first one of said two interconnected pieces is attached with torsion rigidity to one of the two pivotal members and the other one of said two interconnected pieces is attached with torsion rigidity to the other of the two pivotal members. Further, the axis of the two coaxially arranged and interconnected pieces can be arranged to coincide with the pivotal axis of the two interacting pivotal members. Hench, the backwards tilting movement of the seat back as a result of a rear impact will be around the same pivotal axis as the comfort adjustment of the same.

Further, a releasable locking means can be arranged to interlock the two pivotal members and said locking means can comprise a release means configured to be activated in case of a rear impact crash, hence releasing said locking means allows the two interacting pivotal members to pivot in relation to each other. Hereby, some other irrelevant forces acting on the seat back in other situations can be prevented from causing the seat back to yield even if the magnitude and direction of the force on the seat back is above said threshold value. Such an irrelevant situation is e.g. if a heavy person in a seat behind is using the seat back to move around. The release means can be actuated by a pyrotechnic device, which in turn is initiated by a signal from a pre-crash or in-crash censor arrangement. Such pyrotechnic devices and censor arrangements are well known in the industry and will therefore not be further explained. The release means can alternatively be actuated by a mechanical link arrangement eg. arranged inside the seat back, whereby a force on the seat back from a person sitting in the seat at a rear impact crash is picked up and linked or transferred to activate and power the release means. Hereby a fully mechanical system can be achieved that is integrated in the seat back without need for electrical or pyrotechnic technology. The releasable locking means can comprise a retractable bolt, which in its normal position cooperates with the two pivotal members to interlock them and in its retracted position allow the two interacting pivotal members to pivot in relation to each other. The bolt can e.g. in its normal position run through complementary configured holes in the two pivotal members. This invention also comprise a vehicle seat configured to be attached to a vehicle, said seat comprises a squab and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab, wherein a whiplash protection arrangement comprising two interacting pivotal members arranged to pivot in relation to each other about an pivotal axis when a force in excess of a predetermined threshold value as a result of a rear impact crash is acting on the seat back allowing the seat back to yield and wherein said whiplash protection arrangement is arranged between the recliner mechanism and the seat back.

In addition this invention comprises a vehicle seat configured to be attached to a vehicle, said seat comprises a squab and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab about a recliner pivotal axis, wherein a whiplash protection arrangement comprising two interacting pivotal members arranged to pivot in relation to each other about an pivotal axis when a force in excess of a predetermined threshold value as a result of a rear impact crash is acting on the seat back allowing the seat back to yield and that said two pivotal members pivotal axis is arranged to coincide with said recliner pivotal axis.

In order that the invention may be 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 drawing, in which:

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view schematically showing a vehicle seat provided with a whiplash protection arrangement according to an embodiment of the present invention. Figure 2 is a perspective view of a whiplash protection arrangement according to figure 1 in a normal state.

Figure 3 is an exploded perspective view of components in the embodiment of figure 2. Figure 4 schematically shows a top view of a seat provided with a whiplash protection arrangement according to an embodiment of the present invention in a rear impact situation.

Figure 5a shows a detail view of an embodiment according to the present invention in a resting/normal position and 5b shows he same in a situation where the yielding of a seat back is initiated

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Fig. 1 , a vehicle seat 1 is schematically illustrated. The seat 1 comprises a squab 2 for a person to sit on and a seat back 3 for said person to rest his/hers back against when sitting in the seat facing forward in the vehicles longitudinal direction. The squab is further attached to a vehicle structure 4. Such attachments are well known in the art and will therefore not be further explained.

To facilitate comfort adjustment of the seat backs 3 angle in relation to the squab 2, a recliner mechanism 5 is arranged between the structure of the squab 2 and the structure of the seatback 3. Usually, as in this example, there are two recliner mechanisms for one seat, arranged one at each side of the seat (the right hand side and the left hand side). It is of course possible to have only one or more than two recliner mechanisms depending on how the seat back and the squab are interconnected. The recliner mechanism provides the possibility to adjust the seat back angle about a recliner pivotal axis A, that typically is arranged orthogonally to the vehicles longitudinal direction. A recliner mechanism 5 typically show a first bracket 6 arranged to be firmly attached to the structure of the squab 2 and a second bracket 7 arranged to be firmly attached to the structure of seat back 3. Recliner mechanisms as such are well known in the art and will therefore not be explained in further detail.

According to an embodiment of the present invention, a whiplash protection arrangement 10 is arranged between the recliner mechanism 5 and the seatback 3, one at each side portion (right hand side and left hand side) of the seat.

Now also referring to figure 2. Said whiplash protection arrangement 10 comprises a first interacting pivotal member 1 1 , attached to the recliners back rest bracket 7, and a second interacting pivotal member 12 attached to the structure of the seat back 3. Said two interacting pivotal members 11 and 12 are arranged to pivot in relation to each other in a rear impact situation about a pivotal axis arranged orthogonally to the vehicles longitudinal direction. O

Now also referring to figure 3. The first interacting pivotal member 11 further comprises a recliner bracket 11.1 that is intended to be firmly attached to the recliners back rest bracket 7 or, in an alternative embodiment of this invention, can be an integral part thereof. The first interacting pivotal member 1 1 also comprises a circular tubular portion 1 1.2 protruding from the recliner bracket 1 1.1 with its centre axis coinciding with the joint pivotal axis of the interacting pivotal members 1 1 and 12.

The second interacting pivotal member 12 comprises a back rest bracket 12.1 that is intended to be firmly attached to the structure of the seat back 3, or in an alternative embodiment of this invention, can be an integral part thereof.

The second interacting pivotal member 12 further comprises an aperture arranged to receive the tubular portion 11.2 protruding from the recliner bracket 11.1 to form the pivotal joint between the two pivotal members 1 1 and 12.

In some of today's seats, as in this example seat, a physical connection is provided between the right hand side and the left hand side recliner mechanisms 5 to ensure that the two sides are synchronized when changing the seat back angle. This connection is often provided for by a rod extending between the respective recliner mechanisms. That rod is therefore often coinciding with the recliner pivotal axis.

By arranging the first interacting pivotal member 11 so that the synchronizing rod between the two recliner mechanisms freely can extend through its circular tubular portion 11.2, the pivotal axis of the pivotal interconnection between the two pivotal members 11 and 12 will coincide with the pivotal axis of the recliner mechanism.

To prevent the two pivotal members 11 ;12 from pivot in relation to each other in situations other than intended, a releasable locking means is provided to interlock the two pivotal members in normal situations. Said locking means in this embodiment is a retractable bolt 13, extending with close running fit through both the pivotal members 11 ; 12 and preferably at a distance from there joint pivotal axis to reduce the shearing force that act on the bolt 13.

To release the two pivotal members in case of a rear impact, the bolt 13 is arranged to be retracted in such a situation. In this embodiment this retraction is performed by arranging a wire 14 between the bolt 13 at the right hand side of the seat and the bolt 13 at the left hand side of the seat. That wire 14 is arranged inside the seat back 3 and is arranged and dimensioned together with the back rest padding so that a compression of the seat back by an occupants torso as a result of a rear impact, will dislocate the centre portion of the wire in a direction backwards thus (since the wire is not tensile) withdraw the bolts 13 attached at the ends of the wire allowing the two interacting pivotal members 11 ; 12 to pivot in relation to each other. Such release of the bolt 13 or other physical locking means can also in other embodiments be provided by means of other actuators known in the industry, such as pyrotechnical devices, electromagnetic devices, etc. Such actuators can be initiated by a signal from any in-crash or a pre-crash detection system. Such actuators and detection systems are well known in the industry and will therefore not be further explained.

Means for energy absorption is preferably arranged to absorb energy when the two pivotal members 1 1 ; 12 are pivoting in relation to each other as a result of a rear impact.

Such energy absorbing means can comprise two coaxially arranged and interconnected pieces positioned at least partly one inside the other and arranged with torsion rigidity at one each of the two pivotal members 11 ;12.

In the present embodiment, the inner one of said interconnected pieces is said circular tubular portion 1 1.2 of the first interacting pivotal member 11. The outer one of said interconnected pieces is a circular tubular portion 12.2 protruding from the back rest bracket 12.1 with its centre axis coinciding with the joint pivotal axis of the interacting pivotal members 11 and 12. The inner diameter of the outer tubular portion 12.2 is larger than the outer diameter of the inner tubular portion 1 1.2. To avoid play, the dimensions need to be adapted to each other and can be provided with a low friction device or treatment. Some type of a bearing can be considered.

To provide for the energy absorption, the two tubular portions can be interconnected to form a torsion type fitting causing a deformation of the pipes or part of the pipes as a result of the pivoting movement between said two pivotal members 1 1 ; 12.

With reference to figure 5a and 5b, in the present embodiment, to control the energy absorption and yielding event, the outer tubular portion 12.2 is provided with a weakening in the form of a slightly curved lip 12.3 formed in a wall portion of the tubular piece. A rivet 15 is arranged at the free end of said lip 12.3 and extending through said tubular portion 11.2 interconnecting the two tubular portions.

Now with reference to fig. 4 and 5. If a rear impact crash situation occurs, the torso 21 of a person sitting in the seat will exert a force against the seat back 3 as a result of the acceleration generated by the impact. That force will compress the seat back and penetrate enough to actuate the wire 14 so that it will withdraw the bolts 13 freeing the pivotal members 1 1 ;12. The only thing now holding the two pivotal members in place is the energy absorbing means constituted here by the lip 12.3 that is attached to the tubular portion 11.2 via the rivet 15.

When the force against the seat back 3 exceeds a predetermines value, the lip 12.3 starts to deform thus transforming kinetic energy from the pivotal movement of the pivotal members 1 1 ;12 to heat energy. This also means that the energy absorption can be controlled by the design and dimensioning of energy absorbing means, in this embodiment the lip 12.3.

In the claims, any reference signs placed between parentheses shall not be constructed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Claims

1. Whiplash protection arrangement, arranged to be used in a vehicle seat comprising a squab configured to be attached to a vehicle structure and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab about a recliner pivotal axis, wherein said whiplash protection arrangement comprises a first interacting pivotal member (1 1 ) comprising a protruding circular tubular portion (11.2) and a second interacting pivotal member (12) comprising an aperture arranged to receive the protruding tubular portion (11.2) to form a joint between the two pivotal members (1 1 , 12), the pivotal members (1 1 , 12) being arranged to pivot in relation to each other about the pivotal axis when a force acting on the seat back is in excess of a predetermined threshold value as a result of a rear impact crash, and said whiplash protection arrangement is arranged between the recliner mechanism adjusting the seat back and the seat back.

2. Whiplash protection arrangement, according to claim 1 , wherein its pivotal axis is arranged to coincide with said recliner pivotal axis.

3. Whiplash protection arrangement according to anyone of the claims 1 or 2, wherein means for energy absorption is arranged to absorb energy when the two pivotal members are pivoting in relation to each other.

4. Whiplash protection arrangement according to claim 3, wherein the energy absorption means comprises deformation elements.

5. Whiplash protection arrangement according to claim 4, wherein the deformation elements is arranged for plastic deformation.

6. Whiplash protection arrangement according to anyone of the claims 4-5, wherein the deformation elements is realisably attached to the pivotal members.

7. Whiplash protection arrangement according to anyone of the claims 4-6, wherein the deformation elements comprises; two coaxially arranged and interconnected pieces positioned at least partly one inside the other, a first one of said two interconnected pieces is attached with torsion rigidity to one of the two pivotal members and the other one of said two interconnected pieces is attached with torsion rigidity to the other of the two pivotal members, and wherein the two coaxially arranged pieces axis coincides with the pivotal axis of the two interacting pivotal members.

8. Whiplash protection arrangement according to anyone of the claims 1-7, wherein a releasable locking means is arranged to interlock the two pivotal members and said locking means further comprise a release means configured to be activated in case of a rear impact realising said locking means allowing the two interacting pivotal members to pivot in relation to each other.

9. Whiplash protection arrangements according to claim 8, wherein the release means is actuated by a pyrotechnic device.

10. Whiplash protection arrangement according to anyone of the claims 8 to 9, wherein the release means is actuated by a mechanical link arrangement inside the seat back, whereby a force on the seat back from a person sitting in the seat at a rear impact is transferred to activate and power the release means.

1 1. Whiplash protection arrangement according to anyone of the claims 8 to 9, wherein the releasable locking means comprises a retractable bolt, which in its normal position cooperates with the two pivotal members to interlock them and in its retracted position allow the two interacting pivotal members to pivot in relation to each other.

12. A vehicle seat configured to be attached to a vehicle, comprising a squab and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab, wherein a whiplash protection arrangement comprising two interacting pivotal members arranged to pivot in relation to each other about an pivotal axis when a force in excess of a predetermined threshold value as a result of a rear impact is acting on the seat back allowing the seat back to yield and wherein said whiplash protection arrangement is arranged between the recliner mechanism and the seat back.

13. A vehicle seat configured to be attached to a vehicle, comprising a squab and a seat back supported by the squab via a recliner mechanism for adjustment of a seat back angle in relation to the squab about a recliner pivotal axis, wherein a whiplash protection arrangement comprising two interacting pivotal members arranged to pivot in relation to each other about an pivotal axis when a force in excess of a predetermined threshold value as a result of a rear impact is acting on the seat back allowing the seat back to yield and that said two pivotal members pivotal axis is arranged to coincide with said recliner pivotal axis.