GB2287171A

GB2287171A - Ensuring the safety of occupants in a compact vehicle

Info

Publication number: GB2287171A
Application number: GB9503985A
Authority: GB
Inventors: Johann Tomforde; Anton Reichel; Berthold Klein; Karl-Heinz Baumann
Original assignee: Daimler Benz AG; Mercedes Benz AG
Current assignee: Daimler Benz AG
Priority date: 1994-03-04
Filing date: 1995-02-28
Publication date: 1995-09-13
Anticipated expiration: 2015-02-28
Also published as: GB9503985D0; IT1277855B1; DE4407129A1; ITRM950065A0; GB2287171B; FR2716848B1; FR2716848A1; DE4407129C2; ITRM950065A1

Description

2287171 1 Device for ensuring the safety of vehicle occupants The

invention relates to an arrangement f or ensuring the safety of vehicle occupants, particularly but not exclusively, of the front seat passenger, in a compact vehicle with a relatively short front and rear deformation length.

In vehicles of this type with front and rear parts which are cut off relatively linearly and with wheels which extend almost up to the respective terminating edge, in the case of an impact an early rise in the acceleration of the vehicle occurs which permits an equally early triggering of existing restraining systems for the vehicle occupants. In order to obtain a maximum degree of energy absorption within the small deformation length available, the wheels are selectively used as deformation elements in that they become deformed, while the absorption of energy takes place, between the acting impact f ace and lateral longitudinal carriers which are pressure resistant in design. Despite these measures, the impact can be designated as hard and dissipates within a short time period, an additional factor being that because of the type of impact an amplified rebound of the vehicle occurs.

The present invention seeks to indicate a way of protecting the occupant against injuries in the best possible way in the event of an impact of the type described above.

According to the present invention there is provided an arrangement for ensuring the safety of vehicle occupants in a compact vehicle with relatively short f ront and rear deformation lengths, wherein a seat for a vehicle occupant has a large distance up to the dashboard, even when the seat is located in the most forward position, the seat having an automatic three-point belt whose lap belt section ends are fixed to the seat and whose shoulder belt section end is held fixed to the vehicle with the intermediate connection of a deformation element, the shoulder belt 2 end is retracted by a pretensioning device in the event of an early rise in the acceleration of the vehicle brought about by the f ront part of the vehicle, by means of which belt pretensioning device the belt is pressed against the body of the vehicle occupant with a pretensioning f orce which is just still bearabie, and wherein the shoulder beit section is guided by a backrest-side, vertically adjustable mounting, a seat carrier is fixed with respect to the vehicle body in such a way that starting from a predetermined degree of loading it becomes displaced counter to the impact direction accompanied by the absorption of energy and a foot rest which supports the feet of the vehicle occupant in an energy-absorbing manner is connected in front of the splashboard on a passenger compartment side of the vehicle.

By means of this arrangement it becomes possible in particular for the front seat passenger to move forwards selectively in the event of a headon collision without the geometry of the belt being changed and without the risk of so-called "submarining" arising. The large free space towards the dashboard is utilized in a selective fashion in order to enlarge the braking distance of the vehicle occupant specifically in vehicles with a very short crush zone and thus to reduce the stress on the vehicle occupant in the event of a head-on collision. The f orward movement of the seats acts here as a limitation on the force of the lap belt. The risk of the braking distance being wasted is minimized by the effect of the pretensioning device which presses the belt against the body of the vehicle occupant in excess of the degree which has been customary hitherto.

If the backrest and/or the headrest is supported on the vehicle body side, weight advantages are obtained since the design of the backrest no longer has to fulf il any particularly high rigidity requirements.

If, in this context, the angle of inclination of the backrest can be varied and/or the seat is longitudinally displaceable, it is to be ensured that the supporting ef f ect a f 3 of the backrest and/or of the headrest only becomes operative in the case of a predetermined rise in acceleration of the dimensionally rigid passenger cell brought about by an impact.

In order to provide better protection in particular for the front seat pasenger who sits relatively near to the rear part of the vehicle in the event of a rear-end impact, the seat carrier is connected to the rearside deformation zone via a slide rod which is preferably telescopically guided and is blocked against being pushed in in the event of impact loading.

If a saf ety steering column with an airbag which can be triggered by a sensor and which supports the upper body of the vehicle occupant is provided on the driver's side, the disadvantages caused by the smaller distance between the vehicle occupant and the dashboard are compens ated.

In order to avoid an excessive slipping down of the vehicle occupant, which adversely affects the belt geometry, in the event of an impact, the seat upholstery of the seat cushion is supported on a seat wedge which is constructed as a deformation element.

So that excessively high contact pressing forces of the belt and undesired forward movement of the vehicle occupant do not occur during the course of the accident, the forward movement brought about by the shoulder belt-side deformation element corresponds at least to that of the seat carrier.

In a particularly simple embodiment, the shoulder belt-side deformation element can be constructed as at least one belt rupture joint.

An easily achievable, automatically self-adjusting upper belt deflection means is provided if the eyelet through which the shoulder belt section passes is incorporated in a vertically adjustable headrest.

For the selective forward movement of the seat in the event of an impact, it is proposed that the seat carrier should rest, secured against lifting off, on at least one 4 rail which is f ixed to the vehicle body and has a top hat cross sectional profile, and using at least one screw shaft which projects away from it enters a hole in the rail which is adjoined in the direction of the splashboard by a slot which can be widened by the screw shaft.

If the width of the slot is varied over its length, the force necessary for displacing the seat carrier can be selectively influenced.

An exemplary embodiment of the invention is explained in greater detail below with reference to the drawing, in which:

Fig. 1 shows a side view of a compact vehicle which is represented in simplified form, Fig. 2 shows a top view of the illustration according to Fig. 1 with the roof part and side part removed, Fig. 3 shows a belt-side deformation element which is formed by rupture joints and Fig. 4 shows a rail which is secured on the vehicle body side and has a device for energy-absorbing dis- placement of a seat carrier (not illustrated in greater detail) mounted on it.

According to Figs. 1 and 2, the vehicle body 1 of a compact vehicle which is illustrated in simplified form is provided with a particularly dimensionally rigid passenger cell 2 which receives two seats 3 and 4 in its enclosed space, the seat 4 which constitutes a front passenger seat being set back with respect to the seat 3 and as a result being at a larger distance from the dashboard 5 and the splashboard 6.

The seat 3 which is conceived as a driver's seat is adjustable at least in the longitudinal direction in a manner which is not illustrated but is known. The driver has a safety steering column 7 which can be shortened in the axial direction with the absorption of energy and whose steering wheel 8 conceals a covered airbag 9.

The seat 4 receives a vehicle occupant 10 who is held by means of an automatic three-point belt 11 whose lap 1 0 belt ends 12 are guided on the seat side and whose shoulder belt end 13 is guided with the intermediate connection of a deformation element 14 to an indicated belt roller 15 which is fixed to the vehicle body and has a pretensioning device 16. Each seat 3 and 4 has a cushion 17 and a backrest 18 with headrest 19, the latter being assigned an eyelet 20 through which the shoulder belt section 21 passes. As a result, together with the vertical adaptation of the headrest 19, a vertical adjustment of the upper belt deflection point which is formed by the eyelet 20 also takes place.

As is indicated in Fig. 1 with respect to seat 3 only, the seat upholstery 22 is supported on a seat wedge 23 which deforms plastically under heavy loading and at the same time ensures that the lap of the vehicle occupant 10 does not slip down too far thereby changing the belt geometry. In particular, the seat 4 is supported by means of a seat carrier 24 on fixed rails 25 whose design is apparent in particular from Fig. 4. The rail 25 is equipped with a hat-shaped profile and is attached to the vehicle floor 26. At one or more attachment points along the rail, a screw shaft 27 which projects away from the seat carrier (not illustrated) penetrates a hole 28 which is let in to the upper side of the rail 25 and thus secures the seat carrier to a threaded plate 30 on the underside over a plurality of attachment points which are of identical design, in each case with the intermediate connection of a bracing plate 29. Starting from the hole 28 and extending in the direction of the splashboard 6, indicated in Fig. 1, in front of which splashboard a foot rest 32 which consists e.g. of rigid expanded polyurethane is arranged to support the feet 31 of the vehicle occupant 10 in an energy absorbing fashion, there is a slot 33 of constant or varying width, which slot is widened by the respectively assigned screw shaft 27 with the absorption of energy when a predetermined longitudinal loading occurs at the attachment points.

By means of this selectively displaceable 6 arrangement, in particular of the seat 4, the load level f or the occupant 10 is reduced and at the same time a movable mass is provided which reduces the rebounding of the compact vehicle. Since with this type of loading, as in the case of a rear-end impact, the backrest 18 must absorb large supporting forces which ultimately have to be applied to the vehicle body 1, the backrest 18 is supported, as indicated in Figs. I and 2, on a vehicle body-side rail 35 via a support element 34 so that the rigidity of the backrest 18 and of an associated device for adjusting the angle of inclination does not have to be increased unacceptably, it being at the same time ensured, e. g. by means of a massloaded locking mechanism, that adjustment movements of the backrest 18 or of the entire seat 3 and 4 can be carried out but that a displacement movement during the deflection of the mass-loaded locking mechanism resulting from an impact does'not occur.

Such a blocking effect is also provided by a slide rod 36 cpomprising sections which are guided telescopically in one another, the said slide rod 36 connecting the rearend deformation zone 37 to the seat carrier 24 assigned to the seat 4 so that in the case of intrusions the backrest 18 which is relatively near to an impact is not affected.

It is apparent from Fig. 3 how the deformation element 14 which is only indicated in Fig. 2 and is assigned to the shoulder belt end 13 can be constructed. The belt is folded onto itself in three layers over a specified section and sewed together by means of longitudinal seams which constitute rupture joints 38 which become released with the absorption of energy when a predetermined degree of loading of the belt is exceeded.

f 1 7 claims 1. An arrangement for ensuring the saf ety of vehicle occupants in a compact vehicle with relatively short front and rear deformation lengths, wherein a seat for a vehicle occupant has a large distance up to the dashboard, even when the seat is located in the most forward position, the seat having an automatic three-point belt whose lap belt section ends are fixed to the seat and whose shoulder belt section end is held fixed to the vehicle with the intermediate connection of a deformation element, the shoulder belt end is retracted by a pretensioning device in the event of an early rise in the acceleration of the vehicle brought about by the f ront part of the vehicle, by means of which belt pretensioning device the belt is pressed against the body of the vehicle occupant with a pretensioning f orce which is just still bearable, and wherein the shoulder belt section is guided by a backrest-side, vertically adjustable mounting, a seat carrier is fixed with respect to the vehicle body in such a way that starting from a predetermined degree of loading it becomes displaced counter to the impact direction accompanied by the absorption of energy and a foot rest which supports the feet of the vehicle occupant in an energy-absorbing manner is connected in front of the splashboard on a passenger compartment side of the vehicle.

Claims

2. An arrangement according to Claim 1, wherein the seat backrest and/or

the headrest is supported on the vehicle body side.

3. An arrangement according to Claim 2, wherein the supporting effect of the backrest and/or of the headrest only becomes operative in the case of a predetermined rise in acceleration of the dimensionally rigid passenger cell brought about by an impact.

v 8 4. An arrangement according to any one or more of the preceding claims, wherein the seat carrier is adapted to be connected to a rear-side deformation zone of the vehicle via a slide rod which is telescopically guided and is blocked against being pushed in in the event of impact loading.

5. An arrangement according to any one or more of the preceding claims, wherein the steering column is provided with an airbag adapted to be triggered by a sensor and supports the upper body of the vehicle occupant.

6. An arrangement according to any one or more of the preceding claims, wherein the upholstery of the seat cushion is supported on a seat wedge which is constructed as a deformation element.

7. An arrangement according to any one or more of the preceding claims, wherein the forward movement brought about by the shoulder belt side deformation element corresponds at least to that of the seat carrier.

8. An arrangement according to any one or more of the preceding claims, wherein the shoulder side deformation element is constructed as at least one belt rupture joint.

9. An arrangement according to any one or more of the preceding claims, wherein the mounting through which the shoulder belt section passes is incorporated in a vertically adjustable headrest.

10. An arrangement according to any one or more of the preceding claims, wherein the seat carrier rests, secured against lifting off, on at least one rail which is fixed to the vehicle body and has a top hat profile, and has at least one shaft which projects away from it enters a hole in the rail which hole is adjoined in the direction of the splashboard by a slot which is adapted to be widened by the 9 screw shaft in the event of relative movement between the rail and the seat carrier.

11. An arrangement according to any one or more of the preceding claims, wherein the width of the slot varies over its length.

12. An arrangement for ensuring the safety of 'vehicle occupants in a compact vehicle, substantially as described herein with reference to and as illustrated in the accompanying drawings.