GB2414442A

GB2414442A - Three point seat belt with additional fixed two point belt

Info

Publication number: GB2414442A
Application number: GB0411912A
Authority: GB
Inventors: Ola Bostroem
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2004-05-27
Filing date: 2004-05-27
Publication date: 2005-11-30
Anticipated expiration: 2024-05-27
Also published as: GB2414442B; GB0411912D0

Abstract

A seat belt arrangement, the seat belt arrangement includes a three-point seat belt (5) mounted on one side of the seat and a two-point seat belt (12) mounted on the other side of the seat. The two-point seat belt passes through a shoulder guide (15) and extends to a permanent anchorage (16) located adjacent the side of the seat. The two-point seat belt does not inconvenience the seat occupant when the belt is not in use. The two-point seat belt does not include a buckle arrangement.

Description

24 1 4442

DESCRIPTION OF INVENTION

"IMPROVEMENTS IN OR RELATING TO A SEAT BELT ARRANGEMENT" THE PRESENT INVENTION relates to a seat belt arrangement, and more particularly relates to a seat belt arrangement to provide protection for an occupant of a seat in a vehicle in the event that an accident should occur.

Seats belts have now been in use for many years in vehicles to restrain seat occupants in the event that an accident should occur. A typical seat belt, which provides a good restraining characteristic in connection with frontal impacts, is the so-called three-point seat belt. A typical threepoint seat belt has a retractor which may be mounted on the vehicle or which may be mounted on the seat. A seat belt is wound on a spring-biased spool within the retractor.

The seat belt passes from the retractor to a guide, which is located above the shoulder of the seat occupant which is the shoulder closest to the side of the vehicle. The guide may be mounted on a pillar of the vehicle or may be integrally formed in the seat, depending upon the position of the retractor.

The seat belt initially extends from the guide to an anchorage which is provided substantially at floor level, still on the same side of the seat. A tongue is slideably mounted on the belt and the tongue can be engaged with a buckle, the buckle being provided on the other side of the seat.

When the tongue is inserted in the buckle the three-point belt forms a lap strap extending from the anchored end of the belt to the buckle and diagonal portion which extends from the buckle to the guide mounted adjacent the shoulder of the vehicle occupant.

It has now been found that when a seat occupant is utilising a threepoint belt of this type, while good protection is provided in frontal impacts and some side impacts, there is a risk of injury occurring if the vehicle is involved in a so- called "far side" impact. In such an impact, a further vehicle, such as vehicle emerging from a side turning, impacts with the side of the vehicle which is furthest away from the seat occupant. The body of the vehicle is thus accelerated in such a way that the upper torso of the seat occupant, which tends to remain stationary as a consequence of inertia, becomes withdrawn from the part of the three-point belt which extends over the shoulder of the seat occupant. The seat belt thus effectively becomes disengaged from the upper torso of the seat occupant, and as a consequence injuries can arise. It has also been found that a seat occupant may become disengaged from a conventional three-point seat belt during a roll-over situation.

In order to enhance the level of safety provided by the seat belt arrangement it has been proposed to incorporate, into the seat belt arrangement, an additional seat belt which will engage the other shoulder of the seat occupant. Thus, with such an additional belt, both shoulders of the seat occupant are engaged and the risk of injury occurring in a side impact or roll- over may be reduced.

The present invention seeks to provide an improved safety belt arrangement, which will not inconvenience an occupant of the seat.

According to this invention there is provided a seat belt arrangement, the seat belt arrangement incorporating a seat, three-point seat belt and a two-point seat belt, the three-point seat belt having a retractor on which the belt is wound, the belt from the retractor passing through a shoulder guide located to one side of the centreline of the backrest of the seat, the safety belt being anchored on that side of the seat and having a tongue thereon for engagement with a buckle on the other side of the seat, the two-point seat belt being located on the said other side of the seat and extending to an anchorage on the said other side of the seat, the two-point seat belt being permanently connected to the said anchorage on the said other side of the seat.

Preferably the two-point seat belt has the end thereof remote from the anchorage mounted to a retractor, the seat belt extending through a shoulder guide provided on or adjacent the said other side of the seat.

Conveniently the two-point seat belt is associated with a force limiter having a minimum force limiting level of 1 kN and a maximum force limiting effect of 3kN.

Advantageously at least one of the seat belts is provided with a pretensioning arrangement.

Preferably there is a supplementary side restraint provided on the said other side of the seat.

Conveniently the supplementary restraint is in the form of an inflatable air-bag initially stored within the backrest of the seat.

Advantageously the shoulder guide for the two-point seat belt is located closer to the centreline of the seat than the shoulder guide for the three-point seat belt.

Preferably the shoulder guide for the two-point seat belt is spaced from the centreline of the seat by a distance of between 5 ems and 10 ems.

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 1 5 which: FIGURE 1 is a diagrammatic perspective view of a vehicle seat illustrating one form of seat belt arrangement in accordance with the present invention, and FIGURE 2 is a view corresponding to Figure 1 illustrating a modified embodiment of the invention.

Referring initially to Figure 1, a vehicle seat 1 is illustrated, the vehicle seat having a squab 2 and a backrest 3. The backrest 3 carries a headrest 4.

The seat is provided with an integral three-point seat belt 5. The threepoint safety belt 5 incorporates a retractor 6 which is located towards the top of the backrest of the seat, within the interior of the backrest. The retractor 6 incorporates a spool. Wound on the spool of the retractor 6 is a webbing belt 7.

The belt 7 emerges from the retractor and passes through a shoulder guide 8 which is provided at the top of the backrest, a substantial distance, measured horizontally, from the centreline C of the backrest. The distance from the centreline C to the guide is typically in excess of 12 cm. The belt 7 extends from the guide 8 to an anchorage 9 provided at the side of the seat below the guide 8. The anchorage 9 may secure the end of the belt 7 to the seat or to the floor of a vehicle in which the seat is mounted.

A tongue 10 is slidably mounted on the belt 7, the tongue 10 being configured to co-operate with a buckle 1 1 which is provided at the other side of the seat. The buckle 11 may be secured to the seat or to the floor.

In an initial condition of the seat belt 5, a substantial length of the belt 7 is wound onto the spool of the retractor 6, and the belt 7 extends directly from the guide 8 to the anchorage 9, with the tongue 10 being slideable on the belt.

When the belt is to be used the tongue 10 is grasped and is pulled across the lap of the seat occupant and is engaged in the buckle 11. The seat belt 5 then forms a conventional three-point seat belt 5, with a lap strap and a diagonal portion.

The upper end of the diagonal portion is held in position on the shoulder of the seat occupant by the shoulder guide 8.

The vehicle seat 1 is provided with an additional two-point seat belt 12.

The two-point seat belt 12 incorporates a retractor 13 which is embedded within the upper part of the backrest 3 of the seat 1. A webbing belt 14 is wound on the spool of the retractor 13, and the belt 14, after emerging from the retractor 13, passes through a shoulder guide 15 provided at the upper part of the backrest of the scat. The guide 15 is closer to the centreline C than the guide 8 of the 3-point seat belt 5, but on the opposite side of the centreline. The distance between the guide 15 and the centreline C, measured horizontally, is between 5 and 10 cm. The guide 15 is thus located very much towards the centre of the seat, immediately adjacent the headrest 4. The belt 14 extends from the guide 15 to an anchorage 16 provided at the side of the seat in the region of a buckle 11. The anchorage 16 may be on the seat or on the floor.

The end of the seat belt 14 is permanently fixed to the anchorage 16.

It is to be appreciated that a seat occupant may choose to use the two point seat belt 12 in addition to the previously described three-point seat belt 5.

If the two-point seat belt 12 is to be utilised the seat occupant will, initially, pull a length of the belt 14 from the retractor 13 through the guide 15, and slide one arm between the seat 14 and the backrest 3 of the seat 1, thus applying the belt 14 in a manner similar to that in which a strap of a rucksack is applied to a shoulder. The shoulder guide 15 holds the upper end of the belt 14 in position on the shoulder of the seat occupant.

Once the two-point seat belt 12 has been engaged with a shoulder in this way the thrcc-point seat belt 5 can be utilised in the conventional manner.

Because only a relatively small length of belt 14 has to be paid out from the retractor 13 the retractor 13 may be much smaller than the retractor 6. The end of the two-point seat belt 12 remote from the retractor is permanently secured to the anchorage 16, and so it is not necessary for the seat occupant to use a buckle for the two-point seat belt 12. The twopoint belt 12 is thus not an inconvenience for the seat occupant, even when the belt is not in use. There is no loose tongue in the region of the shoulder guide 15 when the belt is not in use. Also, when the belt is not in use, it is held, by the effect of the retractor 13, against the seat back and does not provide any discomfort to the seat occupant.

It is prctcrred for the seat 1 to have an additional "in-board" side restraint in the form of an inflatable air-bag 17 which is stored within the side part of the backrest of the seat. The air-bag 17 is provided on the same side of the set as the two-point seat-belt 12.

In the event of a side impact, such as a "far side" impact, the air-bag 17 will inflate and extend forwardly from the side of the backrest, thus being located adjacent the side of the upper torso of the seat occupant, to help prevent the torso moving laterally relative to the seat back. The presence of the air 10bag 17, in conjunction with the two-point seat belt 12, will help minimise any risk that the seat occupant will become disengaged from the seat belt arrangement. In a far-side side impact the two-point seat belt 12 and the air bag 17 will each tend to impart an acceleration to the upper torso of the seat occupant which is closely related to the acceleration imparted to the actual seat 15as a consequence of the side impact.

In a roll-over situation, the seat occupant wearing both the two-point seat belt 12 and the three-point seat belt 7 will have a much lower probability of receiving injuries than a corresponding seat occupant wearing only the three 20point seat belt 7.

The three-point seat belt 7 may, as is conventional, be provided with an energy absorber or force limiter. The energy absorber or force limiter may be incorporated within the anchorage 9 or within the retractor 6, or within the 25buckle 11. The anchorage 9 and/or the retractor 6 and/or the buckle 11 may, if desired, be provided with a pretensioner.

Similarly, the two-point seat belt 12 may be provided with a force limiter. The force limiter may be incorporated within the retractor 13 or within the anchorage 16. It is envisaged, however, that the force limiter of the secondary seat belt will have a lower force limiting level than the force limiting level found in a conventional three-point seat belt, and the force limiting level may have a minimum value of lkN and a maximum value 3kN. Again the two point seat belt l 2 may be provided with a pretensioner and the pretensioner may be incorporated within the retractor 13 or within the anchorage 16.

Figure 2 illustrates a modified embodiment of the invention in which like parts are identified by like references. Here, it is to be noted, that the three l O point seat belt 5, instead of being integrated into the seat, is a three-point seat belt of the type in which the retractor 6 is floor mounted adjacent the side of the seat 1, and the shoulder guide 8 is a pillar loop guide which is mounted on a pillar of the vehicle such as, for a front seat occupant, the "B" pillar. It is to be understood that three-point seat belts which are integrated with a seat, as shown in Figure l and three-point seat belts which arc partly mounted to the vehicle, as shown in Figure 2, are both already in use. The present invention relates specifically to the additional two-point seat belt 12, and the two-point seat belt 12 can be used with either of the prior proposed general types of three- point seat belts.

It is to be noted that in both Figure 1 and Figure 2 the guide 8 for the three-point seat belt 7 is located much further, in a horizontal sense, from the centreline of the backrest 3 of the seat than is the guide 15. The reason for this is that the part of the three-point seat belt that is passing through the guide 8 is intended to extend, in use, over the shoulder and substantially diagonally across the torso of the seat occupant to the buckle 11, which is located on the other side of the seat. If the guide 15 for the secondary seat belt 12 were to be located in a position corresponding to the position of the guide 8, the two-point seat belt 12 would extend substantially vertically adjacent the side of the seat, and would not, in an accident situation, firmly engage the shoulder of a seat occupant wearing the two-point seat belt. As a consequence of the guide 15 being located towards the centreline of the vehicle seat, the two-point seat belt 12 does extend at an appropriate angle across the upper torso of the seat occupant, when the two-point belt is in use, to provide a desired restraining effect.

When used in this Specification and Claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following Claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS: 1. A seat belt arrangement, the seat belt arrangement

incorporating a seat, three-point seat belt and a two-point seat belt, the three-point seat belt having a retractor on which the belt is wound, the belt from the retractor passing through a shoulder guide located to one side of the centreline of the backrest of the seat, the safety belt being anchored on that side of the seat and having a tongue lO thereon for engagement with a buckle on the other side of the seat, the two- point seat belt being located on the said other side of the seat and extending to an anchorage on the said other side of the seat, the two- point seat belt being permanently connected to the said anchorage on the said other side of the seat.
2. A seat belt arrangement according to Claim 1 wherein the two-point seat belt has the end thereof remote from the anchorage mounted to a retractor, the seat belt extending through a shoulder guide provided on or adjacent the said other side of the seat.
3. A seat belt arrangement according to Claim l or Claim 2 wherein the two-point seat belt is associated with a force limiter having a minimum force limiting level of l kN and a maximum force limiting effect of 3kN.
4. A seat belt arrangement according to any one of the preceding Claims wherein at least one of the seat belts is provided with a prctensioning arrangement.
5. A seat belt arrangement according to any one of the preceding Claims wherein there is a supplementary side restraint provided on the said other side of the seat.
6. A seat belt arrangement according to Claim 5, wherein the supplementary restraint is in the form of an inflatable air-bag initially stored within the backrest of the seat.
7. A seat belt arrangement according to Claim 2 or any one of the preceding Claims dependent thereon. wherein the shoulder guide for the two- point seat belt is located closer to the centreline of the seat than the shoulder guide for the three-point seat belt.
8. A scat belt arrangement according to Claim 7 wherein the shoulder guide for the two-point seat belt is spaced from the centreline of the seat by a distance of between 5 ems and 10 ems.
9. A seat belt arrangement substantially as herein described with reference to and as shown in the accompanying drawings.
10. Any novel feature or combination of features disclosed herein.