AU738414B2 - Moulded motor vehicle safety screen having a controlled deformation characteristic - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

*t o* Name of Applicant: REES OPERATIONS PTY LTD Actual Inventor: JAMES DEANE COOGAN Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention title: MOULDED MOTOR VEHICLE SAFETY SCREEN HAVING A CONTROLLED DEFORMATION CHARACTERISTIC Details of Associated Provisional Application No: PO 6934 dated 22 May 1997 The following statement is a full description of this invention, including the best method of performing it known to us.

This invention relates to improvements in and relating to moulded safety screens of the type described and illustrated in our International PCT application PCT/AU95/00562 filed 31st August 1995 and entitled "Luggage Safety Barrier", and more particularly to a unitary thermoformed safety panel which is designed having a controlled deformation characteristic when a load impacts thereagainst.

Safety standard requirements require that motor vehicle safety screens be designed so that they do not deform by more than 350mm (measured from the plane of the screen) under a minimum impact load of 60kg travelling at 60kph. In the event of the vehicle coming to a sudden halt, and a load impacts against the safety screen or barrier, it is necessary to ensure that the screen does not deform to an extent %:i where it will penetrate into the passenger seat and impact against a passenger seated in either the front or rear seat of the vehicle. It is for this reason that well-known ooo° safety screens made of metal mesh incorporate one or more stiffening frame .15 members as a means of reducing the extent of deformation suffered by the screen.

With moulded plastics safety screens of the type described in the applicant's aforesaid international PCT application, due to the flexible nature of the plastics material, under significant impact loading forces, there are instances where the 20 screen is deflected forwardly by an amount more than that allowed by the safety regulations. While this can be remedied by using suitable energy absorbing mountings for the screen, this adds to the overall cost of the product. There is a need therefore for a moulded safety screen to be designed in such a manner that it will satisfy the appropriate safety regulations applicable to the maximum deformation allowed under minimum impact load, without having to make use of elaborate energy absorbing securing devices which secure the corner regions of the screen to the floor and roof of the vehicle.

It is the main object of the present invention therefore to provide a moulded plastics panel for a motor vehicle safety screen or barrier designed to withstand severe impact forces imparted thereagainst by a forwardly moving load in the vehicle, by undergoing controlled deformation which is within allowable safety limits, thereby ensuring that the panel will not plastically deform to an undesirable extent.

It is a further object of the present invention to provide a moulded plastics panel for a motor vehicle safety screen assembly wherein the panel has a predetermined deformation characteristic under impact load.

Broadly according to this invention therefore, a safety screen for a motor vehicle comprises a unitary thermoformed yieldable transparent panel of tough impact resistant thermoplastics material adapted to be mounted within the vehicle so as to extend transversely from side to side and from top to bottom of the vehicle so as to separate the load carrying area from occupants within the vehicle, characterised in that said moulded panel comprises an approximately central portion having stiffening formations formed therein, and a pair of preferential bending regions or 15 zones which are located on opposite sides of said central portion and which extend over at least part of the height (ie vertical dimension) of the panel, whereby under impact load, the panel will bend preferentially at said preferential bending zones on either side of said stiffened central portion.

20 Desirably the stiffening formations comprise a plurality of forwardly opening recessed pockets or ribs which extend horizontally across the central portion of the panel in a lower region thereof, and which protrude or project from its rear surface.

Desirably the preferential bending regions or zones are formed by "nonstiffened" wall portions of the body of the panel extending uninterruptedly between the upper and lower edges thereof.

Desirably the body of the panel is forwardly bowed or arched (in side elevation).

The panel can be vacuum formed or injection moulded from polycarbonate sheet material.

From practical tests carried out by the applicant, it has been found that a safety screen assembly produced in accordance with the present invention will consistently deform substantially less in its centre region due to the feature of having the preferential bending regions or zones formed in the panel. The tests have shown that the stiffened centre portion of the panel functions as a rigid beam which resists plastic deformation under impact load and remains largely unbent, while the opposite side portions of the panel, ie those portions between a respective said preferential bending zone or region and its corresponding panel side edge, plastically deform to a greater extent.

S:i •In order to further explain the present invention, a preferred embodiment thereof is described hereunder in some further detail with reference to and as illustrated in the accompanying drawings wherein: o Fig 1 is a rear plan view of a moulded plastics safety screen made in accordance with the present invention; Fig 2 is an isometric view of the moulded panel shown in Fig 1; Fig 3 is a vertical sectional view of the panel shown in Fig 1; 20 Fig 4 is a horizontal sectional view of the panel shown in Fig 1; while Fig 5 is a schematic sectional view of the panel after deformation by an impact load.

Referring to the drawings, a moulded plastics protective panel 10 for a motor vehicle safety screen assembly is arranged to be mounted between the load carrying area of a vehicle and its rear passenger seat and extends transversely from side to side and from the roof to the floor of the vehicle. A pair of upper mounting devices (not shown) are used to releasably fix the upper corners of the panel 10 to respective anchorage points in the vehicle roof, while a pair of lower mounting devices (not shown) releasably attach lower corner regions of the panel 10 to respective anchorage points in the floor of the vehicle. The upper and lower mounting devices do not form part of this invention.

In this embodiment, the panel 10 is produced from sheet polycarbonate material by a vacuum forming process polycarbonate being particularly advantageous on account of its extremely high impact strength and its transparency.

The unitary panel 10 is formed to have a slightly bowed or concave configuration and comprises a forwardly inclined upper panel portion 12 and a near vertical or rearwardly inclined lower panel portion 14. A rearwardly directed peripheral flange extends continuously around the periphery of the panel The lower panel portion 14 is provided in a centre region 16 thereof with a plurality of spaced apart stiffening formations in the form of rearwardly projecting recessed ribs or pockets 17, 17'. The ribs or pockets 17, 17' extend horizontally across the panel 10 and thereby serve to stiffen the panel against bending about a vertical axis.

The stiffened centre region 16 of the lower panel portion 14 is flanked on opposite sides thereof with a pair of preferential bending regions or zones 20 which, in this embodiment, are defined by approximately planar wall sections of the panel "which extend between the top and bottom edges 21, 22 respectively of the panel 20 and are free of any stiffening formations. In this embodiment, the wall thickness of the panel 10 is uniform throughout, however, in some instances, the wall thickness in S the region of the zones 20 may be reduced.

The opposite side regions 23, 24 of the panel 10, ie those portions of the panel between the zones 20 and their respective panel sides 26, 27, can also be stiffened by means of strengthening ribs or pockets 29, 30 which extend into the upper region 12 of the panel 10. It will of course be appreciated that the shape and configuration of the stiffening ribs/pockets 29, 30 can vary widely.

In the event of an impact load impacting against the rear face of the panel when installed in a vehicle, the panel will bend preferentially about the lines B, B' formed by the regions or zones 20, which in turn causes the opposite side regions 23, 24 to plastically deform to a far greater extent than the central region 16 which remains largely unbent. The degree of stiffness of the central region 16 of the panel is such that, under impact load, the region 16 will suffer very little plastic deformation, in comparison to the side regions 23, 24, and as a result the amount of forward deflection of the centre region 16 is reduced.

It should be appreciated that the number and configuration of the preferential bending zones or regions may vary and, for example, need not extend the entire height of the panel 10. In addition the shape and configuration of the stiffening formations can also vary widely; however, variations of this nature are intended to fall within the scope of the present invention.

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Claims (8)

1. A safety screen for a motor vehicle comprising a unitary thermoformed yieldable transparent panel of tough impact resistant theromoplastics material adapted to be mounted within the vehicle so as to extend transversely from side-to- side and from top-to-bottom thereof so as to separate the load carrying area from occupants within the vehicle, characterised in that said panel comprises an approximately central portion having stiffening formations formed therein, and a pair of preferential bending regions or zones located on opposite sides of said central portion and which extend over at least part of the height of the panel, whereby under impact load, the panel will bend preferentially at said preferential bending zones on either side of said stiffened central portion. 15

2. A safety screen for a motor vehicle according to claim 1 wherein said preferential bending regions or zones are formed by planar wall portions of the panel S" which extend between the upper and lower ends of the panel and which lie in the plane containing the front face of the panel. S 20

3. A safety screen for a motor vehicle according to either claim 1 or claim 2 wherein said stiffening formations comprise one or more forwardly opening recessed S.pockets or ribs which extend horizontally across the central portion of the panel in a lower region thereof, said pockets or ribs projecting rearwardly of the plane of the panel.

4. A safety screen for a motor vehicle according to any one of the preceding claims wherein the panel is forwardly bowed or arched (in side elevation) so as to form a forwardly inclined upward panel portion and a near vertical lower panel portion.

A safety screen for a motor vehicle according to any one of the preceding claims wherein the panel is vacuum formed from polycarbonate sheet material.

6. A safety screen for a motor vehicle according to any one of the preceding claims further comprising additional stiffening rib formations between said central portion of the panel and respective side edges of the panel, said additional stiffening rib formations having inner extremities horizontally spaced from the outer ends of respective said stiffening formations in the central portion of the panel.

7. A safety screen for a motor vehicle according to any one of the preceding claims wherein said thermoformed panel has a uniform wall thickness.

8. A safety screen for a motor vehicle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. Dated this 24 th day of July 2001 REES OPERATIONS PTY LTD S By its Patent Attorneys MADDERNS S o *oo *o•