WO2006068567A1

WO2006068567A1 - Force-limiting seat mounting means

Info

Publication number: WO2006068567A1
Application number: PCT/SE2005/000299
Authority: WO
Inventors: Glenn Johansson; Alf HÅKANSSON
Original assignee: Volvo Lastvagnar Ab
Priority date: 2004-12-22
Filing date: 2005-03-02
Publication date: 2006-06-29
Also published as: SE0403155D0

Abstract

The present invention provides a seat mounting means for a vehicle seat. The seat mounting means comprises a first member which is arranged to be immovably fixed to the seat, and a second member which is arranged to be immovably fixed to the floor of the vehicle. The first member is joined to said second member such that the first member can be displaced rearward with respect to the second member in a substantially horizontal plane. The seat mounting means of the present invention further comprises a force-limiting means which acts to limit the force which can be applied to the first member, thereby reducing the risk of injury to the seat occupant.

Description

Title

Force-limiting seat mounting means.

Technical field The present invention relates to improvements in the safety of vehicle seats, particularly seats in trucks, buses, minibuses, vans and the like.

Background to the invention

Vehicle manufacturers have made serious efforts in recent years to reduce the numbers of injuries and deaths to vehicle occupants. Airbags, seatbelts and crumple-zones are all improvements which are aimed at improving the safety of occupants and other persons involved in an accident.

US2002/0053820 describes a device for guiding a seat of a vehicle, comprising at least one guide rail arranged on the seat, and at least one sliding rail fastened to the vehicle. The device further comprises at least one arresting element which arrests the seat in a desired position on the sliding rail and at least one deformation element which absorbs energy in the event of a crash. Only the deformation element is deformed in the event of a collision, so only this element needs replacement after the vehicle has been involved in an accident.

EP 1201490 describes a vehicle occupant-protecting apparatus, comprising a seat, lower and upper rails and an acceleration device integrated with the seat. The acceleration device includes a cylinder and a piston. Through the use of such an apparatus, the deceleration of a vehicle body and a seat and the deceleration of an occupant can be made equal to each other at an earlier timing.

It has been discovered that injury to vehicle occupants may occur when a vehicle component situated directly in front of the occupant (e.g. the instrument panel) is pushed towards them during a frontal collision. The component often makes contact with the occupant's legs, trapping the occupant between the seat and the vehicle component. This can lead to serious injuries, such as broken legs. Occupants who are trapped in this way are also in serious danger of further injury (e.g. if a fire starts) and the structure of the vehicle must often be cut away to release them. This is a particular problem in large commercial vehicles such as trucks, buses minibuses and vans, in which the driver and other occupants usually sit in an elevated, more upright position than in cars. The instrument panel in such vehicles is usually situated at a level close to the legs of the occupants, which may increase the risk for injury to the leg region during an accident.

To minimize this problem, certain vehicle manufacturers have concentrated on making the instrument panel as yielding as possible. Instrument panels often have a pre-determined "force corridor" along which they collapse, which helps to avoid or minimize occupant injuries. However, when the instrument panel collapses to its maximum point, or the instrument panel is deformed by incoming objects, forces on the occupant can reach unacceptable levels. Furthermore, if the path of a collision is not aligned with the "force corridor", the benefits of such a system are limited.

There is a need for further safety features in a vehicle which are able to avoid this problem.

Summary of the invention

The current invention addresses the problems associated with accidents in which vehicle occupants become trapped or injured between the seat and vehicle components such as the instrument panel.

Specifically, the invention provides a seat mounting means for a vehicle seat, said seat mounting means comprising a first member which is adapted to be immovably fixed to the seat, and a second member which is adapted to be immovably fixed to the floor of the vehicle, said first member being joined to said second member such that the first member can be displaced rearward with respect to the second member in a substantially horizontal plane. The invention is characterised in that said seat mounting means further comprises a force-limiting means which, in a first condition, prevents relative displacement of the first member and the second member, and, in a second condition corresponding to a collision, said force limiting means is arranged such that, upon application of a predetermined force in said horizontal plane by a vehicle component rearwardly to the first member via the seat occupant, displacement of the first member relative to the second member is effected, thereby reducing the risk of injury to the seat occupant by the vehicle component. During a collision, the present invention allows the seat mounting means to yield to the forces which may be exerted by vehicle components (such as the instrument panel) which are forced inwards in the vehicle. The rearward displacement of the seat upon application of a certain predetermined force moves the occupant away from the component and thereby reduces the forces experienced by the occupant. This in turn reduces the chances of serious injury or breakage of the occupant's legs and the risk of the occupant being trapped between the seat and the instrument panel. Furthermore, rearward displacement of the seat means that the entire body of the occupant is moved away from the site of the collision, reducing the chances of injury to other parts of the occupant's body, e.g. the head.

The seat mounting means of the present invention may be additional to any seat- adjustment means. Alternatively, it may be comprised in any seat-adjustment means.

The predetermined force applied to the first member is at least 2kN, preferably at least 3kN, more preferably at least 4kN. Is this suitable? Preferably, the force- limiting means limits the force experienced by the first member during a collision to below 6kN.

The force-limiting means may comprise a series of teeth arranged substantially linearly in the direction of travel of the vehicle, each tooth being substantially square in shape in its uppermost portions, such that - upon application of the predetermined force - the uppermost portions shear, allowing the first member to be displaced rearward with respect to the second member. Alternatively, it may comprise one or more bolts which are arranged so as to connect said first and second members and which shear upon application of the predetermined force. Alternatively, it may comprise a spring arranged so as to resist displacement of the first member with respect to the second member. Such a spring may be a helical spring arranged such that one end of the spring is connected to the first member and the other end of the spring is connected to the second member.

The force-limiting means may comprise an S-shaped piece of metal, one end of which is connected to the first member, the other end of which is connected to the second member, and which deforms under application of the predetermined force. Alternatively, the force-limiting means may comprise a tube having a weakened section in at least one portion of its circumference which yields upon application of the predetermined force. In this embodiment, one end of the tube is connected to the first member and the other end of the metal tube is connected to the second member. The tube may be thinner at the weakened section; alternatively it is indented at the weakened section.

The force-limiting means may comprise two tubes arranged inside one another such that there is contact between the inner surface of the outer tube and the outer surface of the inner tube, such that relative displacement is effected upon application of the predetermined force.

The force-limiting means may alternatively comprise at least one electric pyrotechnic bolt in conjunction with at least one electronic sensor and a control unit. Upon detection of a predetermined force by the sensor(s), the control unit causes the electric pyrotechnic bolt(s) to shear.

The force-limiting means may alternatively comprise a hydraulic system arranged so as to resist displacement of the first member with respect to the second member until application of the predetermined force.

The first and second members of the seat mounting means are displaceable by an amount of between YY and YYcm, such as, e.g. between YY and YY cm or between YY and YYcm. Please complete.

The invention also relates to a seat comprising a seat mounting means according to the present invention in which the first member is immovably fixed to the seat. The invention further relates to a vehicle comprising a seat mounting means as described herein. The vehicle may be a bus, truck, minibus or van.

Brief Description of the Figures

The invention will the described in the following by way of example only, and with reference to the drawings, in which: Figure Ia shows a seat mounting means according to the present invention in an initial position before a collision has occurred;

Figure Ib shows the seat mounting means according to the present invention in a second position during a collision;

Figure 2 shows an embodiment in which the force-limiting means is a series of teeth;

Figures 3a-3d show an embodiment in which the force-limiting means are one or more bolts;

Figure 4a and 4b show an embodiment in which the force-limiting means is a tube;

Figures 5a-5d show embodiments in which the force-limiting means is two tubes arranged inside one another;

Figures 6a and 6b show an embodiment in which the force-limiting means is an electric pyrotechnic bolt in conjunction with a sensor and control unit;

Figure 7a and 7b show an embodiment in which the force-limiting means is a spring;

Figure 8a and 8b show an embodiment in which the force-limiting means is an S- shaped piece of metal;

Figure 9a and 9b show embodiments in which the force-limiting means comprises a hydraulic system;

Figure 10 shows a vehicle comprising a seat which comprises the seat mounting means according to the invention; and

Figure 11 is a graph showing the variation of force in kN with distance during a collision.

Detailed description In the following text, the term "instrument panel" is used broadly to describe the part of a passenger compartment which lies directly in front of a vehicle occupant with regard to the direction of travel of the vehicle. The phase "instrument panel" includes components such as the steering wheel, airbag unit, display unit, storage units or may simply be the bulkhead of the passenger compartment.

The term "rearward" as used in the present case refers to a force or displacement which is directed towards the rear of a vehicle (i.e. contrary to the normal direction of travel of a vehicle). The term "forward" refers to the direction which is the normal direction of travel of the vehicle.

When two components are described as "immovably fixed" it is meant to mean that they are joined to one another in such a way that they cannot be readily removed or moved with respect to one another. The components are fixed to one another by, for example, welding or bolting, and cannot usually be separated without using tools.

The invention will now be more closely described with reference to the figures.

Figure Ia shows a seat mounting means 10 for a vehicle seat according to the present invention.

Reference 10 in Figure Ia refers to a seat mounting means for a vehicle seat 60. The seat mounting means 10 forms the primary means for connecting the vehicle seat 30 to the floor 74 of the vehicle 70. The seat mounting means may comprise seat-adjustment means (shown schematically as 58) which, when released, allows the seat to be adjusted and, when locked, holds the seat in the desired position for occupant comfort. Seat adjustment may be possible in any plane.

The seat mounting means 10 comprises a first member (designated by reference 12) which is adapted to be immovably fixed to the seat. The first member 12 is shown schematically in Figs Ia and Ib, but it is to be understood that it may comprise one or more plates, rods, rails or tubes and is made of a stiff material such as metal, preferably steel. To allow fixing to the seat 60, the first member 12 may comprise threaded sections, or holes for bolts, screws or other such fastening means. The first member 12 may also comprise areas which can be welded to the seat. The seat mounting means 10 further comprises a second member 14 which is adapted to be immovably fixed to the floor 74 of the vehicle. The second member 14 is shown schematically in Figs Ia and Ib, but it is to be understood that it may comprise one or more plates, rods, rails or tubes and is made of a stiff material such as metal, preferably steel. As above, the second member 14 may comprise threaded sections, or holes for bolts, pins, screws or other such fastening means to allow fixing to the floor. The second member 14 may also comprise areas which can be welded to the floor of the vehicle.

The first member 12 is joined to the second member 14. The joining is such that, under specific circumstances, the first member can be displaced rearward with respect to the second member in a substantially horizontal plane. Joining is such that displacement outside this substantially horizontal plane, or in a direction other than rearward is not possible. For example, the first member can comprise rails or runners while the second member comprises one or more wheels or protrusions which run in such rails or runners so as to permit rearward displacement of the first member. The opposite arrangement of rails/runners and wheels/protrusions may also exist. Alternatively, both the first and second members can comprise rails which are adapted so as to engage each other and permit rearward displacement of the first member. The first and second members may be joined through a system of arms and levers which allows rearward displacement of the first member. Any further examples?

In accordance with the invention, the seat mounting means 10 further comprises a force-limiting means 16, which is shown schematically in Figs Ia and Ib. In a first condition (shown in Fig. Ia), which corresponds to normal use of the vehicle prior to collision, the force-limiting means 16 prevents relative displacement of the first member and the second member. Relative movement of the first and second member is th.us prevented under normal use of the seat.

In a second condition, corresponding to a collision (shown in Fig. Ib), the force- limiting means 16 is arranged such that, upon application of a predetermined force in said horizontal plane by a vehicle component rearwardly to the first member via the seat occupant, displacement of the first member relative to the second member, is effected, thereby reducing the risk of injury to the seat occupant by the vehicle component.

Upon application of a predetermined force (during a collision), the occupant and seat are displaced rearwards as the force-limiting means yields, and the seat is allowed to move backwards. This will limit the force which is exerted on the legs of the occupant by a vehicle component. Under impact, it is often the instrument panel 76 which is pushed towards the occupant, and makes contact with the occupant's legs.

When the predetermined force is applied, displacement between the first and second members is effected and the occupant and seat are displaced rearwards (as shown by the arrow in Fig. Ib). The forces exerted on the legs of the occupant are reduced, thereby reducing the risk of injury to the seat occupant.

The force-limiting means 16 of the present invention may take a variety of forms, which are described in Figures 2-8 and in the following text.

As shown in Fig. 2, the force-limiting means 16 may comprise a first series of teeth 18 arranged substantially linearly in the direction of travel of the vehicle. The teeth are asymmetric, so that the incline of each tooth on its forward edge 20 is lower than on the rearward edge 22, as shown in Fig. 2. On their uppermost portions 24, each tooth is substantially square in shape. The first series of teeth 18 is immovably fixed to one of the first or second members (12, 14), while a bar or a corresponding series of teeth is immovably fixed to the other of the first or second members and arranged so as to engage the first series of teeth 18. In the event of a collision, the uppermost portions of the teeth 24 shear, allowing the first member to be displaced rearward with respect to the second member. This embodiment may be used in the case where the seat mounting means 10 of the present invention forms part of the seat-adjustment means 58.

In a second embodiment, the force-limiting means 16 comprises one or more bolts 26 which are arranged so as to connect said first and second members (12, 14) and which shear upon application of the predetermined force. Possible arrangements for these bolts are shown in plan view in Figs. 3a, 3b and 3d. Fig. 3c shows a side view of the arrangement of Fig. 3a. Either the first member or the second member comprises at least one slot 28 in which the bolts 26 can move. At one end, the bolts are fastened to either the first or second members, and arranged so that they project through the slot 28 in the other of the first or second member. The bolts are tightened so that displacement of the first and second members is prevented in a first condition. In the event of a collision, however, sufficient force applied to the first member via the seat occupant causes the bolts to shear, allowing the first member to be displaced rearwards. Relative displacement of the two members is stopped by one of the bolts.

In a third embodiment (Figures 4a, 4b), the force-limiting means 16 comprises a tube 30 having at least one weakened section 32 in at least one portion of its circumference which yields upon application of the predetermined force. The weakened section 32 may be a thinner section of the tube 30; alternatively, the tube

30 may be indented at the weakened section such that it yields at the indentations.

The axis of the tube 30 is aligned with the normal direction of travel of the vehicle. One end of the tube is connected to the first member and the other end of the tube is connected to the second member. In this first condition, relative displacement of the two members is prevented. However, application of a force to the first member during a collision causes the tube to collapse, thereby effecting displacement of the first member relative to the second member. The tube 30 is made from a strong material which yields at high forces, such as metal.

In a further embodiment (Figures 5a-d), the force-limiting means 16 comprises two tubes (34, 36) arranged inside one another such that there is contact between the inner surface 38 of the outer tube 34 and the outer surface 40 of the inner tube 36. One tube is connected to the first member, which the other tube is connected to the second member. The central axis of the two tubes is substantially aligned with the normal direction of travel of the vehicle (in a forward-rearward axis). The tubes are arranged such that relative displacement of the two tubes is prevented under normal use by the friction which exists between the surfaces 38,40 of the two tubes. However, upon application of the predetermined force, relative displacement of the two tubes is effected. The two tubes may have parallel walls (Fig. 5a, 5b). Alternatively, the inner tube 36 may be narrower at the end inside the outer tube 34 and wider at the other. Upon application of a force to the first member during a collision, the inner tube 36 is forced into the outer tube 34, and that the force required to displace the two tubes relative to one another increases with displacement distance (Fig, 5c, 5d).

In a fifth embodiment, (Figures 6a, 6b) the force-limiting means comprises at least one electric pyrotechnic bolt 42 in conjunction with at least one electronic sensor 44 and a control unit 46. The bolt 42 holds the first and second members relative to one another in a first condition, preventing their relative displacement. The electronic sensor(s) 44 may be placed in the seat, in the first member or in the vehicle component, or may be present in an airbag mechanism. If the sensors register a force on the first member at or above the predetermined force, the control unit 46 causes the electric pyrotechnic bolt 42 to shear, allowing the first member to be displaced.

In a further embodiment, (Figures 7a, 7b) the force-limiting means comprises a spring 48 arranged so as to resist displacement of the first member with respect to the second member. The spring 48 may be a helical spring arranged such that one end of the spring is connected to the first member and the other end of the spring is connected to the second member. The inherent stiffness of the spring prevents relative displacement of the first and second members in the first condition (under normal use). In the event of a collision, however, sufficient force applied to the first member via the seat occupant causes the spring to compress, allowing the first member to be displaced rearwards.

In yet another embodiment, (Figures 8a, 8b) the force-limiting means comprises an S-shaped piece of metal 50, one end of which is connected to the first member, the other end of which is connected to the second member, and which deforms under application of the predetermined force. In a similar way to the spring described above, the inherent stiffness of the S-shaped piece of metal prevents relative displacement of the first and second members in the first condition. In the event of a collision, however, sufficient force applied to the first member via the seat occupant causes the S-shaped piece of metal to deform, allowing the first member to be displaced rearwards.

In a final embodiment, (Figures 9a, 9b) the force-limiting means comprises a hydraulic system 52 arranged so as to resist displacement of the first member with respect to the second member until application of the predetermined force. The hydraulic system generally comprises a piston 54 which is movable inside a cylinder 56. Usually, one end of a hydraulic piston and cylinder system is fixed to the first member while the opposite end of the hydraulic system is fixed to the second member. Relative displacement of the first and second members is not possible until the predetermined force has been reached, after which point, the hydraulic system yields, effecting displacement of the first member relative to the second member.

The seat mounting means according to the present invention may be additional to any seat-adjustment means 58 (see Figs. Ia, Ib). In this case, the seat mounting means acts independently from any seat-adjustment means 58. It is however desirable that it is the seat mounting means of the present invention rather than the seat adjustment means which is the point of weakness in the seat mounting means. In the event of a collision, it is the seat mounting means which yields first.

Alternatively, the seat mounting means of the present invention may form part of any seat-adjustment means 58. For instance, the seat-adjustment means may incorporate a force-limiting means (such as a bolt) which yields under the application of the predetermined force.

Generally, the first and second members are displaceable by an amount of between YY and YYcm, such as, e.g. between YY and YY cm or between YY and YYcm. Please complete.

The present invention also relates to a seat 60 comprising a seat mounting means 10 described herein. The first member 12 is immovably fixed to the seat 60. The seat 60 comprises a seat cushion 62, a backrest 64, optionally a headrest 66 which may be adjusted relative to one another so that the seat provides comfort and support to an occupant. The first member 12 may comprise one or more plates, rods, rails or tubes and is made of a stiff material such as metal, preferably steel. So as to be fixed to the seat, the first member 12 may comprise threaded sections, or holes for bolts, screws or other such fastening means. The first member 12 may also be welded to the seat. The present invention further relates to a vehicle 70 comprising a seat mounting means as described herein (Figure 10). The vehicle may comprise a passenger compartment 72, said passenger compartment comprising a floor 74 which defines the base of the passenger compartment, an instrument panel 76 which defines the front of the passenger compartment, and a seat 60 as defined herein, in which the second member 14 of the seat mounting means is immovably fixed to the floor 74 of the vehicle. As described above, the force applied to the first member 12 is a result of contact between the instrument panel 76 and the seat 60 via the occupant.

The present invention is particularly of relevance in large commercial vehicles in which the driver and other occupants usually sit in an elevated, more upright position than in cars. Such a vehicle may be a bus, truck, minibus, van or the like.

The present invention aims to reduce or eliminate injury to the occupant of the seat. The magnitude of the force which is applied to the occupant (particularly in the leg region) is therefore significant. A certain amount of force may be applied to the first member without effecting displacement of the first and second members. This prevents undesired relative slippage or movement of the first and second members during normal use of the seat. Over a certain force value (such as those experienced during a collision) the force-limiting means takes effect, and prevents the force from increasing further. The predetermined force may vary from vehicle to vehicle, but is usually at least 2kN, preferably at least 3kN, more preferably at least 4kN. Is this suitable?

Figure 11 shows the variation of force in kl\! with distance during a collision. Please explain this graph - what exactly is the distance on the x-axis, and where is the force measured?

The force-limiting means allows the force applied to the first member (via the occupant and the seat) to increase to a certain predetermined level, at which point displacement is effected between the first and second members, and the force does not increase above this level. Above a force of 6kN, it is likely that the occupant will suffer serious injury, such as broken legs. In one embodiment, therefore, the force- limiting means limits the force applied to the first member during a collision to below 6kN. The present invention should not be limited to the examples and embodiments described above, but may be varied within the scope of the appended claims. In particular, the force-limiting means can be connected either way round in the seat- mounting means, such that elements which are stated or shown as connected to the first member may equally be connected to the second member and vice versa, provided that the function of the force-limiting means is not lost.

Claims

1. A seat mounting means (10) for a vehicle seat, said seat mounting means comprising a first member (12) which is adapted to be immovably fixed to the seat, and a second member (14) which is adapted to be immovably fixed to the floor of the vehicle, said first member (12) being joined to said second member such that the first member can be displaced rearward with respect to the second member in a substantially horizontal plane, characterised in that said seat mounting means (10) further comprises a force-limiting means (16) which, in a first condition, prevents relative displacement of the first member and the second member, and, in a second condition corresponding to a collision, said force limiting means is arranged such that, upon application of a predetermined force in said horizontal plane by a vehicle component rearwardly to the first member via the seat occupant, displacement of the first member relative to the second member is effected, thereby reducing the risk of injury to the seat occupant by the vehicle component.

2. A seat mounting means according to claim 1, in which the seat mounting means (10) is additional to any seat-adjustment means (58).

3. A seat mounting means according to claim 1, in which the seat mounting means (10) is comprised in any seat-adjustment means (58).

4. A seat mounting means according to any of claims 1-3, wherein the predetermined force is at least 2kN, preferably at least 3kN, more preferably at least 4kN. Is this suitable?

5. A seat mounting means according to any of claims 1-4, wherein the force- limiting means (16) limits the force experienced by the first member (12) during a collision to below 6kN.

6. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises a first series of teeth (18) arranged substantially linearly in the direction of travel of the vehicle, each tooth being substantially square in shape in its uppermost portions (24), such that - upon application of the predetermined force - the uppermost portions shear, allowing the first member to be displaced rearward with respect to the second member.

7. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises one or more bolts (26) which are arranged so as to connect said first and second members and which shear upon application of the predetermined force, allowing the first member to be displaced rearward with respect to the second member.

8. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises a tube (30) having at least one weakened section (32) in at least one portion of its circumference which yields upon application of the predetermined force, allowing the first member to be displaced rearward with respect to the second member.

9. A seat mounting means according to claim 8, wherein one end of the tube (30) is connected to the first member (12) and the other end of the tube is connected to the second member (14).

10. A seat mounting means according to any of claims 8-9, wherein the tube (30) is thinner at the weakened section (32).

11. A seat mounting means according to any of claims 8-9, wherein the metal tube (30) is indented at the weakened section (32).

12. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises two tubes (34, 36) arranged inside one another such that there is contact between the inner surface (38) of the outer tube (34) and the outer surface (40) of the inner tube (36) such that relative displacement of the two tubes is effected upon application of the predetermined force.

13. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises at least one electric pyrotechnic bolt (42) in conjunction with at least one electronic sensor (44) and a control unit (46), such that - upon detection of a predetermined force by the sensor(s) (44) - the control unit (46) causes the electric pyrotechnic bolt (42) to shear.

14. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises a spring (48) arranged so as to resist displacement of the first member with respect to the second member.

15. A seat mounting means according to claim 14 wherein the spring (48) is a helical spring arranged such that one end of the spring is connected to the first member (12) and the other end of the spring is connected to the second member (14).

16. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises an S-shaped piece of metal (50), one end of which is connected to the first member, the other end of which is connected to the second member, and which deforms under application of the predetermined force.

17. A seat mounting means according to any of claims 1-5, wherein the force- limiting means (16) comprises a hydraulic system (52) arranged so as to resist displacement of the first member with respect to the second member until application of the predetermined force.

18. A seat mounting means according to any of claims 1-17, wherein the first and second members are displaceable by an amount of between YY and YYcm, such as, e.g. between YY and YY cm or between YY and YYcm. Please complete.

19. A seat (60) comprising a seat mounting means (10) according to any of claims 1-18 in which the first member (12) is immovably fixed to the seat (60).

20. A vehicle (70) comprising a seat mounting means (10) according to any of claims 1-18.

21. A vehicle according to claim 20, said vehicle comprising a passenger compartment (72), said passenger compartment comprising a floor (74) which defines the base of the passenger compartment, an instrument panel (76) which defines the front of the passenger compartment, and seat (60) as defined in claim 19, in which the second member (14) of the seat mounting means (10) is immovably fixed to the floor of the vehicle.

22. A vehicle according to any of claims 20-22, which is a bus, truck, minibus or van.