WO1999047385A1

WO1999047385A1 - A bolster arrangement

Info

Publication number: WO1999047385A1
Application number: PCT/GB1999/000477
Authority: WO
Inventors: Andrew Leask
Original assignee: Rover Group Limited
Priority date: 1998-03-13
Filing date: 1999-02-16
Publication date: 1999-09-23
Also published as: GB9805703D0; GB2335171A

Abstract

A bolster arrangement in which a panel interference element (5) and a mounting interference element (4) are arranged to allow progressive and uni-directional engagement therebetween as panel (1) is subjected to a percussive deformation force. Thus, any rebound due to shape memory within the panel (1) is inhibited by the interference engagement between the panel interference element (5) and the mounting interference element (4). The bolster arrangement is typically associated with a crushable bracket (3) in order to retain the bolster panel (1) relative to a mounting surface (2).

Description

- 1 - A BOLSTER ARRANGEMENT

The present invention relates to a bolster arrangement and more

particularly to a bolster arrangement for panels, such as in the knee area of

a motor vehicle, which may come into percussive contact with an occupant

during an accident.

Safety is always of paramount importance within a motor vehicle.

Thus, most motor vehicles include collapsible or crushable compartments

and panels in order to mitigate the effects of collision either with external

objects or with occupants of that vehicle. One area of a motor vehicle that

includes such collapsible or deformable panels is the so-called knee bolster

panel.

Essentially, these panels are mounted on crushable brackets such that

the panel collapses with an occupant on percussive contact for example with

that occupant's knee. Typically, these panels are made from a plastics

material and extend for cosmetic reasons about the vehicle such as

substantially above the footwell for a knee bolster panel. Thus, during

collision with an occupant's knee, the panel collapses absorbing percussive

energy and so reducing injury to the occupant.

Unfortunately, with plastics materials there is typically a 'rebound'

effect due to inherent plastics materials performance, i.e. within the elastic - 2 -

deformation range and so shape memory return. This rebound of the bolster

panel can be relatively forceful and may in itself create an injury along with

inhibiting occupant escape by trapping for example the occupant's legs

between the bolster panel and a seat base, etc.

It is an object of the present invention to provide a bolster arrangement

for panel within a motor vehicle which substantially relieves the above-

mentioned problems.

In accordance with the present invention there is provided a bolster

arrangement for motor vehicle, the arrangement including a bolster panel

being associated with mounting means by retainer means comprising a

panel interference element secured to the bolster panel and a mounting

interference element secured to the mounting means, the panel interference

element and the mounting interference element being at least adjacent

when the bolster panel is in association with the mounting means such that

said panel interference element and said mounting interference element

both progressively and uni-directionally engaging each other upon a

percussive deformation to said panel in order to retain such deformation.

Further in accordance with the present invention there is provided a

bolster mounting arrangement comprising a panel interference element for

securing to a bolster panel and a mounting interference element for coupling - 3 -

to a mounting, the panel interference element and the mounting

interference element being coupled to retain, in use, a bolster panel, relative

to a mounting whilst said panel interference element and said mounting

interference element progressively and uni-directionally engage with

respect to each other when subjected to a percussive force.

The panel and/or mounting interference element may comprise

reciprocal combinations of the following:

respective serrated surfaces or edges; or

a respective serrated surface or edge with reciprocal tooth element; or

respective friction interference surfaces; or

a respective plurality of spaced apertures with reciprocal engagement

toothed elements; or

a one-way valve arrangement with a hydraulic and/or pneumatic fluid

passing therethrough.

Preferably, the uni-directional engagement between the respective

panel and mounting interference elements is progressive and normally

increasing with extent of percussive deformation of the panel. Such - 4 -

progressive increase in interference engagement between the panel

interference element and the mounting interference element may be

achieved by altering the spacing, configuration or angle of serrations or

other means of progressive engagement.

The bolster arrangement may include a frangible flange between the

panel and the mounting interference elements to facilitate installation

within a motor vehicle.

Embodiments of the present invention will now be described by way of

example only with reference to the accompanying drawing, in which:

Figure 1 is a schematic plan view of a first, basic, embodiment of a

bolster arrangement;

Figure 2 is a schematic plan view of a second embodiment of a bolster

arrangement;

Figure 3 is a schematic plan view of a third embodiment of a bolster

arrangement; and

Figure 4 is a schematic plan view of a fourth embodiment of a bolster

arrangement. - o

Referring to Figure 1 in which a first basic embodiment of a bolster

arrangement in accordance with the present invention is depicted, a bolster

panel 1 is located at a displaced position in relative association with a

mounting surface 2. The panel 1 is held or mounted in association with the

surface 2 using a crushable bracket 3 which upon a percussive deformation

in the direction of arrow head A collapses in that direction. The bolster

panel 1 is typically made from a plastics material and moulded with a

degree of shaped memory retention. Thus, after removal of the percussive

force associated with such deformation in the direction of arrow head A,

there is a degree of rebound or bounce back bias within the panel 1 to return

the panel 1 to its shaped memory configuration. This rebound bias, as

described above, can be detrimental in terms of supplemental or secondary

injury to a motor vehicle occupant adjacent the panel 1 and, furthermore,

may hinder rescue or escape of an occupant through a pinning effect with

other structures of the vehicle.

In accordance with the present invention there is provided a bolster

arrangement 4 essentially comprising a panel interference element 5 and a

mounting interference element 6. The bolster arrangement 4 is adjacent

the crushable bracket 3 such that upon crushing of the bracket 3 any

bounce-back or rebound bias of the bolster panel 1 is inhibited by

interference between the respective elements 5, 6. Engagement between the

panel interference element 5 and the mounting interference element 6 is - 6 -

both progressive and uni-directional in that there is substantially no return

so that the deformation of the panel 1 is retained.

In the embodiment depicted in Figure 1, the panel interference element

5 is secured at one end to the bolster panel 1 whilst the other end includes a

toothed element 7. This toothed element 7 engages serrations, grooves or

indentations in the mounting interference element 6. Thus, upon

application of a percussive force, typical of an occupant to panel impact in a

vehicle accident, in the direction of arrow head A, it will be appreciated that

the toothed element 7 progresses along the serrations of the mounting

interference element 6 and return of the toothed element 7, and so the panel

interference element 5, is prevented by engagement with the serrations. It

will also be appreciated, as the panel 1 is secured to the element 5 it too is

prevented from return or bounce-back after percussive shock deformation in

the direction A.

Normally, the interference elements 5, 6 are made from a suitable

plastics material. Furthermore, the interference elements 5, 6 may be

respectively secured to the panel 1 or a mounting surface 2 as discrete

elements or produced as integral constructions within panel 1 or surface 2

during their manufacture. - 7 -

Inherently, a single toothed element 7 only provides limited resistance

to rebound due to the limited, single, engagement between the toothed

element 7 and the serrations of the interference element 6. Furthermore,

such limited interference may make the arrangement relatively susceptible

to deformation other than as a result of violent percussive action as it will

be relatively easy to push the toothed element 7 into the serrations of the

interference element 6. Thus, installation of the panel 1 relative to the

mounting surface 2 may result in such inadvertent deformation which, due

to the nature of the invention, i.e. progressive and uni-directional, will be

retained by the engagement between the element 7 and serrations. In order

to prevent such low force deformation, a frangible flange 8 is normally

provided to achieve low impact strength and so accommodate the use of

necessary installation forces without rendering the panel 1 unacceptable for

cosmetic reasons. Alternatively, it will be appreciated that the serrations in

mounting interference element 6 could be made in the form of a screw

thread, which provides the necessary serrations, with the toothed element 7

screwed onto that thread to achieve installation adjustment but retaining

the inventive progressive uni-directional engagement upon violent

percussive deformation by 'jumping' those threads .

In order to achieve balance in a practical construction of the present

invention, it may be that a crushable bracket 3 is provided either side of the

bolster arrangement 4 or a bolster arrangement 4 provided either side of a - 8 -

crushable bracket 3. Furthermore, those skilled in the art will appreciate

that, the panel interference element 5 and the mounting interference

element 6 could be presented as indicated in Figure 1 or vice versa between

the mounting surface 2 and the bolster panel 1. Finally, it will also be

understood that, although particularly advantageous with regard to knee

bolster panels, that the bolster panel 1 could constitute any surface within a

motor vehicle which may be subjected to occupant collision.

Within the scope of the present invention which essentially provides for

progressive uni-directional interference between a bolster panel 1 and a

mounting surface 2 through an appropriate bolster arrangement, it will be

appreciated that it is generally desirable to provide for progressive increase

in interference with extent of deformation depth and to inhibit inadvertent

installation deformation. Within serration embodiments of the present

invention, it will be appreciated that the configuration in terms of pitch,

spacing and angling of each serration may be altered along with reciprocal

engagement toothed elements 7 to tune and achieve desired results.

Furthermore, as depicted in Figure 2, a plurality of toothed elements 27 in a

panel interference element 25 can be provided to engage the serrations of a

mounting interference element 26. Thus, the general configuration of the

bolster arrangement is consistent with that depicted in Figure 1 but,

additional interference between the elements 25, 26 is provided by the

plurality of toothed elements 27 and so there is both a compounded increase - 9 -

in deformation resistance in the direction of arrow head B along with an

increase in rebound resistance through a similar increase in the number

and range of interference engagement contacts between the elements 27 and

serrations of the interference element 26.

A frangible flange 28 is provided again to facilitate installation

resistance to inadvertent deformation. However, a shock absorber washer

element 29 is also provided to reinforce the flange 28 and so improve

resistance to such installation deformation. Typically, the washer 29 will be

made from a rubber or foam material with appropriate elastomeric

performance.

As depicted in Figure 3, a bolster panel 31 can be located in association

but with a spaced relationship relative to a mounting surface 32 using a

panel interference element 35 and a mounting interference element 36.

However, in its normal retained state, there is no interaction between

serrations of the interference element 36 with a toothed element 37 of the

interference element 35 but rather retention is achieved by a frangible

flange 38 in association with a washer 39 and a retention collet 40. The

association of flange 38, washer 39 and collet 40 may be achieved in situ as

appropriate and possible using adhesives. Upon application of a percussive

force in the direction C, it will be appreciated that the toothed element 39

will engage serrations of the mounting interference element 36 in order to - 10 -

resist rebound whilst the collet/washer 39 can be arranged to be either fixed

in their relative position as depicted in Figure 3 or displaceable with the

interference element 35. When the collet and the washer 39 are fixed, it

will be appreciated that supplemental tooth elements 41 of the panel

interference element 35 may engage these components 39, 40. Thus, in such

an embodiment, the washer 39 and collet 40 may be made from a robust

elastomeric material such that the supplemental toothed elements 41

become embedded in such material of the washer 39/collet 40 as

deformation progresses. If the collet 40/washer 39 are moveable in the

direction C, it will be appreciated that the serrations of the interference

element 36 will engage the collet 40 and washer 39 again to resist rebound

in the direction opposite to C.

It will be noted that a consistent feature between the embodiments

depicted in Figures 1, 2 or 3 is that there is a substantial enclosed volume

within the mounting interference element 6; 26; 36 bounded by the walls of

that element 6; 26; 36 and the mounting surface 32 in association with the

panel interference element 5; 25; 35. Without ventilation this enclosed

volume may become pressurised and give inconsistent progressive uni¬

directional engagement with deformation depth particularly, when it will be

understood that a plurality of arrangements may be distributed about a

panel which provide^' a compound effect upon that panel. Thus, ventilation

apertures may be provided in the interference element 6; 26; 36 or, as - 11 -

depicted in Figure 4, a mounting interference element 46 can be provided

with apertures rather than serrations for engagement with toothed

elements 47 of the panel interference element 45. Thus, upon percussive

deformation in the direction of arrow head D, the toothed elements 47

engage apertures in the interference element 46 in order to provide

progressive uni-directional deformation whilst preventing rebound of a

bolster panel 41 coupled to the panel interference element 45. In the

embodiment depicted in Figure 4, it will be appreciated that the area

bounded by the mounting surface 42, the mounting interference element 46

and the panel interference element 45 is fully vented through the apertures

in the interference element 46 and so there is no pressurisation.

Although interference between serration or apertures with toothed

elements is the preferred approach in accordance with the present

invention, it will be appreciated that alternative interference between the

panel interference element and the mounting interference could be achieved

through simple friction contact or using a hydraulic/pneumatic fluid and a

one-way valve/flow mechanism. With a friction surface embodiment,

progressively and uni-directionally greater friction contact would be made

between respective surfaces of the two interference elements with

deformation depth. In a hydraulic embodiment upon the application of the

percussive deformation force, hydraulic fluid is forced from one side of the - 12 -

port valve to the other with no return and so no rebound of the panel is

allowed.

It will be appreciated that a variety of cross-sections for the bolster

arrangement could be achieved. However, it is preferred that a cross-

section between the panel interference element and the mounting

interference element is either rectilinear or circular in order to achieve the

most appropriate interference interaction between the panel interference

element and the mounting interference element.

The frangible flanges 8, 28, 38, 48 are made frangible by including

appropriate lines of weakness through indentations or scoring.

As depicted in the drawing, a collapsible bracket 3, 23, 33, 43 is

generally provided to achieve the major mounting connection to retain

association between a bolster panel 1, 21, 31, 41 and a mounting surface 2,

22, 32, 42 in normal use prior to a deformation impact. However, it will be

appreciated that, provided the potential problems of inadvertent

deformation, from installation or normal wear and tear, can be avoided then

this collapsible bracket 3, 23, 33, 43 could be dispensed with. Furthermore,

the bolster arrangement in accordance with the present invention could be

incorporated within a collapsible bracket 3, 23, 33, 43 in a concentric

configuration provided there was no functional interference therebetween. - 13 -

Where an interference interaction between serrations and toothed

elements is required, it will be appreciated that it is preferable for the

toothed element and the serrations to have a substantial perpendicular

component to the direction of percussive deformation in order to provide for

good interference engagement. Thus, as depicted in the drawing, typically

the serrations and the toothed element will have a saw-toothed

configuration in the direction of deformation. Furthermore, as indicated

above, the spacing, pitch and configuration of each of these serrations/tooth

elements can be altered in order to provide for progressive increase in

deformation resistance. Furthermore, the depth of serrations may be

increased by providing a degree of ramped inclination between opposed

serration surfaces. Essentially, as the panel interference element slides

relative to the mounting interference element with such an increase in

serration depth, it will be appreciated it will become increasingly difficult to

progress.

Claims

- 14 - CLAIMS

1. A bolster arrangement for a motor vehicle, the arrangement including a

bolster panel associated with mounting means by retaining means

comprising a panel interference element secured to the bolster panel

and a mounting interference element secured to the mounting means,

the panel interference element and the mounting interference element

being at least adjacent when the bolster panel is in association with the

mounting means such that said panel interference element and said

mounting interference element both progressively and uni-directionally

engaging each other upon a percussive deformation to said panel in

order to retain said deformation.

2. A bolster mounting arrangement comprising a panel interference

element for securing to a bolster panel and a mounting interference

element for coupling to a mounting, the panel interference element and

the mounting interference element being coupled to retain, in use, a

bolster panel, relative to a mounting whilst said panel interference

element and said mounting interference element progressively and uni-

directionally engage with respect to each other when subjected to a

percussive force.

3. An arrangement as claimed in Claim 1 or Claim 2, wherein the panel

interference element and the mounting interference element - 15 -

reciprocally include serrated surfaces in order to provide progressive

and uni-directional engagement therebetween.

4. An arrangement as claimed in any of Claims 1, 2 or 3, wherein the

panel interference element and/or the mounting interference element

include toothed means to facilitate progressive and uni-directional

engagement between said elements.

5. An arrangement as claimed in Claim 1 or Claim 2, wherein the panel

interference element and said mounting interference arrangement

provide progressive and uni-directional engagement therebetween

through contact of friction surfaces therebetween.

6. An arrangement as claimed in Claim 1 or Claim 2, wherein said panel

interference element and/or said mounting interference elements

includes apertures to facilitate progressive and uni-directional

engagement therebetween.

7. An arrangement as claimed in Claim 1 or Claim 2, wherein said panel

interference element and said mounting interference element constitute

a reciprocal one-way valve arrangement for hydraulic or pneumatic flow

therethrough to provide progressive and uni-directional engagement

therebetween. - 16 -

8. An arrangement as claimed in any preceding claim, wherein said panel

interference element and said mounting interference element are

configured to provide increased resistance to progressive and uni┬¼

directional engagement therebetween upon percussive deformation.

9. An arrangement as claimed in any preceding claim, wherein between

said panel interference element and said mounting interference element

there is provided a frangible flange to resist progressive and uni┬¼

directional engagement therebetween until a predetermined level of

percussive deformation force is presented therebetween.

10. An arrangement as claimed in Claim 1 or Claim 2, wherein said panel

interference element and/or said mounting interference element include

reciprocal screw threads engaging with respect to each other and

subject to respective interactive deformation upon progressive and uni┬¼

directional engagement therebetween.