GB2347621A

GB2347621A - A vehicle seat

Info

Publication number: GB2347621A
Application number: GB9905520A
Authority: GB
Inventors: Karl-Gunnar Lindblad; Anders Svantesson
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1999-03-10
Filing date: 1999-03-10
Publication date: 2000-09-13
Anticipated expiration: 2019-03-10
Also published as: GB9905520D0; GB2347621B; WO2000053452A1

Abstract

A vehicle seat 1 has a support in the form of a carriage 5 which is located beneath a sub-frame 7 incorporated in the squab of the seat. The sub-frame is supported on the support towards the rear by means of a lever 13 which is associated with a linkage 16, 18, which connects the lever to one end of a kinetic energy absorber 21. The front part of the sub-frame 7 is mounted at support 5 by means of two interconnected links 22, 25, one of these links being connected to the other end of the kinetic energy absorbing element 21. The seat, in a rear impact, initially moves rearwardly, with the links 13, 25 pivoting in a rearward sense, and then the seat tilts about a pivot axis 14 defined at the upper end of the link 13. These movements are effected in such a way that energy is absorbed by the kinetic energy absorbing element 21.

Description

2347621 DESCRIPTION OF INVENTION "IMPROVEMENTS IN OR RELATING TO A VEHICLE

SEAT" THE PRESENT INVENTION relates to a vehicle seat, and more particularly relates to a vehicle seat intended for use in a motor vehicle, such as a motor car.

It has been proposed previously to provide a vehicle seat which, in the event of a rear impact, moves towards the rear of the vehicle, preferably with a pivoting or tilting action.

GB-A-1,228,657 discloses a seat of this type in which the main body of the seat is pivotally connected to the floor of the vehicle, and the front part of the seat is connected to the floor of the vehicle by a device arranged to absorb kinetic energy. The arrangement is such that, in the event of a rear impact, the seat pivots in a rearward direction about the pivotal connection between the seat and the floor of the vehicle, whilst the device that absorbs kinetic energy becomes extended.

It is believed that the risk of a passenger being injured in an accident involving a rear impact may be reduced if a seat of this general type is utilised, and the present invention seeks to provide an improved vehicle seat.

2 The device shown in GB-A- 1,228,657 that absorbs kinetic energy extends from the front part of the seat towards the floor of the vehicle just in front of the seat, and consequently may well obstruct the legs of a person sitting in the seat. Additionally, the illustrated device has to have a substantial length in order to permit a desired degree of tilting.

According to this invention there is provided a vehicle seat, the vehicle seat comprising a support structure located beneath the seat, the seat having a squab mounted above the support structure, the seat including a back-rest extending generally upwardly from a rear part of the squab of the seat, there being a first connection between the squab and the support structure towards the rear of the squab adapted to pennit an initial rearward movement of the squab of the seat relative to the support, and a subsequently pivotal movement of the squab relative to the support, there also being a second connection between the squab and the support structure adjacent the front of the support structure adapted to permit an initial rearward movement of the squab, and a subsequent pivoting of the squab, there being a kinetic energy absorbing element associated with the first connection adapted to resist said rearward movement, and a kinetic energy absorbing element associated with the second connection adapted to resist the pivoting motion, the or each kinetic energy absorbing element being located beneath the squab of the seat.

Preferably a single kinetic energy absorbing element is provided associated with both connections.

Conveniently the support structure comprises a carriage slidably mounted on a rail.

3 Advantageously the first connection comprises a first lever having one end pivotally connected to the support structure, and the other end pivotally connected to the squab of the seat, the lever being adapted to pivot about the pivotal connection thereof to the support structure on rearward movement of the squab, the kinetic energy absorbing element being adapted to resist such movement.

Preferably the point of pivotal connection between the first lever and the squab of the seat is connected by a second lever to one end of a third lever, the third lever being adapted to pivot substantially about its centre point, the other end of the third lever being connected to the kinetic energy absorbing device.

Conveniently the connection provided at the front of the seat comprises a pivot linkage including a connecting plate which is pivotally connected to the support structure, and which is also pivotally connected to a lever arm, the lever arm being pivotally connected to the squab of the seat, the lever arm being adapted to pivot from an initial position to a further position on rearward movement of the squab of the seat, the lever arm presenting a surface cooperating with a catch, the catch acting to prevent upward movement of the lever arm, with a consequent pivotal movement of the connecting plate, until the lever arm has pivoted to a predetermined extend as a consequence of rearward movement of the squab of the seat.

Advantageously the connecting plate has a third pivotal connection point which is connected to the kinetic energy absorbing element.

Preferably the points of connection of the squab of the seat to the support are adjustable to pen-nit adjustment of the orientation of the squab of the seat.

4 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 which:

FIGURE I is a side view of a seat in accordance with the invention, illustrating the occupant of the seat, the seat being shown in an initial position, FIGURE 2 is an enlarged view of part of the seat of Figure I in a first position, FIGURE 3 is a view corresponding to Figure 2 illustrating the position of the components irnmediately following a rear impact, and FIGURE 4 is a view, corresponding to Figure 3, showing the position of the illustrated components a few moments later.

Referring initially to Figure I of the accompanying drawings, a vehicle seat I is provided which is mounted on a rail 2, the rail 2 having lugs 3, 4 by means of which the rail may be mounted to the floor of the motor vehicle. A carriage 5 is provided which is mounted on the rail 2 so as to be slidable along the rail 2. The carriage 5 acts as a support structure for the seat 1.

The seat I has a squab 6 which incorporates a sub-frame 7 which is supported by the carriage 5, as will be described in greater detail below. The seat I also has a back 9 having a head-rest 9. The back 9 extends upwardly from the rear of the squab 6. The seat I is shown, in Figure 1, with an occupant 10.

Referring now to Figure 2, it can be seen that the carriage 5 is provided, towards its rear end, with an upstanding support plate 11. Pivotally connected by means of a pivot 12, to the support plate 11, is a first substantially vertical lever 13 of a linkage. The other end of the lever 13 is provided with a pivot pin 14. The pivot pin 14 serves pivotally to connect the lever 13 to the subframe 7 of the squab of the seat. The pivot pin 14 actually passes through an elongate vertical slot or aperture 15 provided in the sub-frame 7. The position of the pivot pin 14 within the elongate slot or aperture 15 is adjustable by means of a mechanism (not shown) to permit the orientation of the squab of the seat to be adjusted.

The pivot pin 14 also serves to connect one end of a second lever 16 to the upper end of the first lever 13. The second lever 16 extends substantially horizontally, and the other end of the lever is connected by means of a pivot pin 17 to the upper end of a third substantially vertical lever 18, the central point of which is pivotally connected by means of a pivot 19 to the support plate 11. The lower end of the third lever 18 is pivotally connected, by means of a pivot 20, to part of a kinetic energy absorbing element 21 which will be described in greater detail hereinafter.

Towards the front part of the carriage 5, a connecting plate 22 is provided which, as will become clear, has three pivot points located substantially at the comers of a triangle. The connecting plate 22 is pivotally connected by means of a first pivot point 23 to the carriage 5. This pivot poit is located, in the embodiment illustrated, towards the bottom right-hand comer of the connecting plate 22. The connecting plate 22 has a further pivot point 24 at the bottom left-hand comer as illustrated, this pivot point 24 being pivotally connected to the lower end of a substantially vertical lever arm 25. The lever 6 arm is of generallv elongate form, and the upper end of the lever arm 25 is provided with a pivot 26 which pivotally connects the upper end of the lever arm to the sub-frame 7 of the squab of the seat. The pivot 26 is received within a vertical elongate slot or aperture 27 formed in the sub-frame 7. A mechanism (not shown) is provided for adjusting the position of the pivot 26 within the vertical slot or aperture 27, thus enabling the orientation of the squab of the seat to be adjusted.

The third pivot point 28 provided on the connecting plate 22 is connected to the other end 21 of the kinetic energy absorbing device.

The kinetic energy absorbing device 2 1, in this embodiment, comprises a cylinder 29 and an associated piston having the piston shaft 30. The cylinder 29 is connected to the pivot point 28, and the piston shaft 30 is connected to the pivot point 20. The cylinder may contain a viscous fluid, and the piston may be provided with a plurality of small apertures. Of course, it is to be appreciated that many altemative forms of energy absorbing device may be utilised.

The lever arm 25, whilst being of generally elongate form, does present, to one side of the lever arm (as can be seen most clearly in Figure 4), an outwardly extending projection 31 which presents a first upper surface part 32 which extends generally perpendicularly to a line extending between the pivot points 24 and 26, and a second upper surface part 33 which is downwardly inclined relative to the perpendicular.

As can also be seen most clearly in Figure 4, the carriage 5 is provided with a recess 34 adapted to receive the lower part of the lever arm 25 when the components described above are in the position illustrated in Figure 2.

7 Adjacent the recess 34 is a spring biased catch 35. The catch incorporates a spring 36 which biases a detent member 37 so that the detent extends across part of the top of the recess 34.

When the components are in the initial position, as illustrated in Figure 2, the detent 37 of the spring catch 35 engages the portion 32 of the upper surface of the projection 31 provided on the lever arm 25, thus retaining the lower part of the lever arin 25 within the recess 34 and consequently preventing upward movement of the front part of the squab 6 of the seat. This is the position of the components as shown in Figure 2.

In the event that a rear impact occurs, the floor of the vehicle and thus the rail 2 and consequently also the carriage 5 will be moved forwardly thus tending to impart a forward motion to the sub-frame 7 and to the remaining components of the seat. The torso of the occupant of the seat, however, will present substantial inertia, thus resisting the forward movement of the subframe 7. The sub-frame 7 will thus tend to move rearwardly relative to the carriage 5, especially since the catch 35 effectively prevents any upward movement of the front part of the subframe 7.

As can be seen from Figure 3, the sub-frame 7 may move rearwardly, which causes a clockwise pivoting of the first lever 13 about the pivot point 12, which, because the upper end of the first lever 13 is connected to the upper end of the third lever 18 by means of tile second lever 16, causes the third lever 18 to pivot about its mid point 19, thus moving the point of pivotal connection 20 between the third lever 18 and the kinetic energy absorbing element 21 towards the left, as shown in Figure 3. This tends to compress the kinetic energy absorbing element 21 which thus absorbs kinetic energy. Consequently, whilst 8 the rearward movement of the sub-frame 7 is permitted, it is resisted, with an absorption of energy.

As the sub-frame 7 moves rearwardly, so the upper end of the lever arm 25 is moved rearwardly, because the upper end of the lever arm 25 is pivotally connected to the sub-frame 7 by the pivot 26. The lever 25 thus pivots about its pivotal coruiection 24 with the connecting plate 22. This movement of the lever arm 25 moves the projection 31 away from the detent member 37 of the catch mechanism 35. In particular, the detent member 37 becomes disengaged from the first upper surface part 32 of the upper edge of the projection 3 1, and instead engages the second or inclined upper surface part 33. The inclined portion 33 is then positioned to effect a cam action on the spring biased detent 37. Any continuing force applied to the seat by the torso of the occupant of the seat, as a consequence of the inertia of the torso of the occupant of the seat, now tends to apply a force to the seat leading to a pivoting action about the pivot point 14 where the first lever 13 is connected to the rear part of the sub-frame 7 of the squab of the seat. The configuration of the inclined upper surface part 33 of the edge of the projection 31 provided on the lever arm 25 is such that the spring biased detent is forced toward the left, as shown in Figure 4, against the bias of the spring 36, thus releasing the lever arm 25, and permitting the front part of the squab 6 of the seat to move upwardly as the sub-frame 7 executes a pivotal motion about the axis defmed by the pivot pin 14.

As the front part of the seat moves upwardly, the lever arm 25 will move upwardly with the front part of the sub-frame and cause the connection plate 22 to pivot upwardly about the pivotal connection 23 between the connecting plate 22 and the carriage 5. This will tend to move the pivotal connection 28 between the connecting plate 22 and the kinetic energy absorbing element 21 9 generally towards the pivotal connection 20 between the kinetic energy absorbing element 21 and the third lever 18. Thus, the kinetic energy absorbing device is further compressed, with the consequent absorption of further kinetic energy.

It is to be appreciated that the seat described above is provided with a kinetic energy absorbing element which is located beneath the squab of the seat.

In the described embodiment of the invention there is a first connection between the carriage 5 and the sub-frame 7 towards the rear of the seat which is adapted to permit an initial rearward movement of the squab of the seat relative to the support, and a subsequently pivotal movement of the squab relative to the support. There is also a second connection, located towards the front of the carriage, between the carriage and the squab which is adapted to permit an initial rearward movement of the squab and the subsequent pivoting of the squab. In the described embodiment there is a single kinetic energy absorbing element having opposed ends associated with the two connections identified above. However, it is to be appreciated that in a modified embodiment of the invention, two separate kinetic energy absorbing elements are provided, with one kinetic energy absorbing element being connected, for example, to the linkage constituted by the levers 13, 16 and 18, and with a separate kinetic energy absorbing element being connected to the connection plate 22.

Claims

CLAIMS:

1. A vehicle seat, the vehicle seat comprising a support structure located beneath the seat, the seat having a squab mounted above the support structure, the seat including a back-rest extending generally upwardly from a rear part of the squab of the seat, there being a first connection between the squab and the support structure towards the rear of the squab adapted to permit an initial rearward movement of the squab of the seat relative to the support, and a subsequently pivotal movement of the squab relative to the support, there also being a second connection between the squab and the support structure adjacent the front of the support structure adapted to permit an initial rearward movement of the squab, and a subsequent pivoting of the squab, there being a kinetic energy absorbing element associated with the first connection adapted to resist said rearward movement, and a kinetic energy absorbing element associated with the second connection adapted to resist the pivoting motion, the or each kinetic energy absorbing element being located beneath the squab of the seat.

2. A seat according to Claim I wherein a single kinetic energy absorbing element is provided associated with both connections.

3. A seat according to Claim I or 2 wherein the support structure comprises a carriage slidably mounted on a rail.

4. A seat according to any one of the preceding Claims wherein the first connection comprises a first lever having one end pivotally connected to the support structure, and the other end pivotally connected to the squab of the I I seat, the lever being adapted to pivot about the pivotal connection thereof to the support structure on rearward movement of the squab, the kinetic energy absorbing element being adapted to resist such movement.

5. A seat according to Claim 4 wherein the point of pivotal connection between the first lever and the squab of the seat is connected by a second lever to one end of a third lever, the third lever being adapted to pivot substantially about its centre point, the other end of the third lever being connected to the kinetic energy absorbing device.

6. A seat according to any one of the preceding Claims wherein the connection provided at the front of the seat comprises a pivot linkage including a connecting plate which is pivotally connected to the support structure, and which is also pivotally connected to a lever arm, the lever arm being pivotally connected to the squab of the seat, the lever arm being adapted to pivot from an initial position to a further position on rearward movement of the squab of the seat, the lever arm presenting a surface co-operating with a catch, the catch acting to prevent upward movement of the lever arm, with a consequent pivotal movement of the connecting plate, until the lever arm has pivoted to a predetermined extend as a consequence of rearward movement of the squab of the seat.

7. A seat according to Claim 6 wherein the connecting plate has a third pivotal connection point which is connected to the kinetic energy absorbing element.

8. A seat according to any one of the preceding Claims wherein the points of connection of the squab of the seat to the support are adjustable to permit adjustment of the orientation of the squab of the seat.

12

9. A seat substantially as herein described with reference to and as shown in the accompanying drawings.

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