AU2004208699A1 - Impact absorbing seat - Google Patents

Description

I

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s) G AND J LEWIS ENTERPRISES PTY LTD A.C.N. 002 263 121 Invention Title: IMPACT ABSORBING SEAT The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 IMPACT ABSORBING SEAT Field of the Invention The present invention relates to a seat which is arranged to absorb energy from impacts and, particularly, but not exclusively, to a vehicle seat which is arranged to absorb relatively high energy impacts such as may be produced by explosions.

Background of the Invention There are vehicles which are at risk of receiving impacts to the underside of the vehicle. Military vehicles, in particular, are at significant risk of receiving underside-impacts from mine blasts, as they may be travelling in areas where explosive mines have been laid. Even non-military vehicles may be at risk of underside-impact if they are travelling in mined areas.

Such underside-impacts from high energy explosions can result in serious injury and death to vehicle occupants. It is not necessarily heat or flame from a mine explosion that causes injury to the occupants.

Instead, the energy from the impact to the underside of the vehicle is transmitted to the vehicle occupant, resulting in crash-type injuries from the energy applied to the occupant. Even where the underside of the vehicle is blast resistant e.g. armoured, blast energy can still be transmitted to a vehicle occupant via the vehicle body and seating.

Summary of the Invention The present invention provides an impact resistant seat arrangement, comprising a seat base and a damping arrangement mounted to the seat base and being arranged to absorb impact energy from an impact below the seat.

3 Preferably, the seat arrangement is arranged to be mounted in a vehicle, and the damping arrangement is arranged to absorb impact energy from an impact to the underside of the vehicle.

In the case of a mine blast or other high energy impact to the underside of a vehicle, therefore, an occupant of the seat arrangement preferably receives at least some protection from transmission of the energy of the impact.

Preferably, the damping arrangement includes a damper unit mounted between the seat base and a floor with respect to which the seat is mounted. Where the seat is mounted in a vehicle, the damper unit is mounted between the seat base and floor of the vehicle.

Preferably, the damper unit comprises a unit arranged to progressively collapse in response to a impact to the underside of the unit, absorbing energy as it progressively collapses.

Preferably, the damper unit is an elongate element having an irregular shape cross section.

Preferably, the damper unit is mounted under a rear portion of the seat base, the rear portion being arranged to bear the majority of the weight of a seat occupant.

Preferably, the seat base includes one or more damper elements mounted within the seat base. These damper elements may be in the form of brackets and are preferably arranged to reduce a rebound affect of the seat material following an impact.

The seat material is preferably a foam. In one embodiment, the seat material includes lower density foam for supporting the seat occupant, for comfort, and a higher density foam underneath the lower density foam, the higher density foam being provided to reduce impact energy transmitted to the seat occupant.

Preferably, a securing element is provided arranged to stabilise the seat base during an impact. Preferably, the securing element is arranged to secure the front 4 portion of the seat base to reduce twisting of the front portion due to impact. The securing element preferably comprises a bracket mounted between the front portion of the seat and the floor. The bracket preferably extends underneath across the front portion of the seat.

Preferably, lateral support members are provided at a front portion of the seat and preferably operate to retain a seat occupiers legs during an impact.

Brief Description of the Drawings Features and advantages of the present invention will become apparent from the following description of an embodiment thereof, by way of example only, with reference to the accompanying drawings, in which; Figure 1 is a side view of a seat arrangement in accordance with an embodiment of the present invention; Figure 2 is a side view of the seat arrangement of Figure 1, shown as it may be positioned after an impact to the underside of the seat, and Figure 3 is a diagram illustrating progressive collapse of a damping unit of a damping arrangement of the seat arrangement of Figure 1.

Description of Preferred Embodiment Figures 1 and 2 illustrate a seat arrangement generally designated by reference numeral 1. The seat arrangement includes a seat base 2 and a damping arrangement generally designated by reference numeral 3.

In operation, the damping arrangement operates to damp the energy of an impact from the underside of the seat to an occupant sitting on the seat base 2.

In more detail, the seat base includes a rear portion 4, where the majority of the weight of the seat occupant bears, and a front portion 5 which is arranged to support the seat occupant's legs.

5 The seat base may be formed of a foam material, or any other appropriate cushioning material, such as rubber or latex. An upper part of the seat base is formed of lower density foam 6 for the comfort of the seat occupant.

At the rear portion 4 of the seat base, the lower part of the seat is preferably formed from high density foam 7, which in operation forms part of the damping arrangement 3. The high density foam 7 is arranged to be resistant to impact.

Incorporated within the high density foam 7 of the rear portion 4, are a number of (in the embodiment described herein, three) damping elements 8. In operation, when the high density foam 7 is subject to a high energy impact, the foam 7 is arranged to rebound after the impact. Damping elements 8, which in this example are in the form of energy absorbing brackets (preferably comprised of an appropriate metal) operate to provide extra damping and also to damp the rebound of the high density foam 7. The damping elements 8 form part of the damping arrangement 3.

The seat arrangement 1 may be mounted to a floor 9.

The floor, in this embodiment, is a floor of a vehicle, such as a military vehicle.

At the rear portion 4 of the seat base 2, a damping unit 10 is mounted between the underside of the seat base 2 and the floor 9. The damping unit 10, in this embodiment, forms part of the damping arrangement 3, and comprises an irregular cross section length of metal which extends underneath the seat. The length of the damping unit extends transversely across the underside of the seat in a direction transverse to the length of the seat base 2. The damping unit 10 is arranged to collapse progressively, absorbing impact energy, as will be described later in this description.

The damping elements 3 also extend transversely within the seat base 2.

The front portion 5 of the seat base 2 includes a 6 pair of lateral support wings 11 and 12, which are arranged to provide sideways stability to the seat occupant's legs. A securing element 13, in this example being in the form of a transversely extending section bracket, is mounted between the underside of the seat 2 and the floor 9, at the front portion If the floor of the vehicle receives a high energy impact, such as might be provided by a mine blast, a great deal of force is provided from an underside direction of the seat 2. Without some form of protection from transmission of this high energy to a seat occupant, serious injury and death can result.

The damping arrangement 3 operates to damp the upward energy of the impact of the seat base 2 to the seat occupant. The damping unit 10 is of an irregular cross section and is arranged to progressively collapse in response to a high energy impact, as illustrated in Figure 3. The irregular shaped cross section can be considered to be formed of three parts, comprising a lower part A, a middle part B and an upper part C. On impact, the lower portion A collapses first (collapsing is shown from right to left in Figure This is followed by collapse of the middle portion B and finally compression of the upper portion C. Deformation of the damper unit is non-elastic, so there is no or only limited rebound affect. The high density impact resistant foam provides further energy absorption, as do the damping elements 8. The damping elements 8 reduce any rebound of the foam, further reducing transmission of energy to the seat occupant.

Securing element 13 is provided to maintain stability of the seat 2 in response to an impact, and in particular to prevent or reduce any twisting of the seat which may occur about a longitudinal axis along the length of the seat. Any twisting of the seat could result in injury to the occupant and uneven damping of the impact energy. The wings 11 and 12 assist in retaining the occupant's legs within the seat.

7 Figure 1 illustrates a position of the seat arrangement 1 before impact and Figure 2 illustrates positioning after impact. It can be seen from the Figures that the damping unit 10 has collapsed and the front bracket 13 has remained stable, resulting in a tilt of the seat. Absorption of shock by the damping arrangement will preferably reduce the severity of injury and avoid the death of a seat occupant.

The length of the damping unit 10 and securing element 13 may be varied to "tune" the seat arrangement to the mass of the vehicle and the likely impact force to be received. This would require a knowledge of the type of impacts that the vehicle is likely to face. This knowledge can be obtained what type of mines are known to be used). The weight of the vehicle will also govern the amount of energy that is likely to be transmitted to the seat base from the impact. Varying the length of the damping unit 10 varies the amount of damping that is applied in order to optimise the amount of damping required. The shape, material, width and height can also be varied to vary the damping affect.

Further, the foam density, shape and thickness can be varied to tune the damping affect, as can be the shape, length, material and height of the damping elements 8 within the foam.

Factors which will determine the amount of damping to be provided by the damping arrangement will include the likely blast force, the mass of the vehicle, the shape of the underbody, and the comfort required for the occupant.

In the above described embodiment, the damping arrangement comprises a combination of the foam material of the seat base, damping elements within the seat base and the damping unit external of the seat base. In other embodiments any one of these alone may provide sufficient damping, and in particular the damping unit may be utilised on its own in some applications. The invention is not limited to the combination of these three 8 components forming the damping arrangement.

The described embodiment includes a single damper unit 10. More than one damper unit may be provided. A plurality of damper units could, for example, be mounted in a direction across the seat. For example, these can be provided several damper units, each damper unit being of relatively short length, and placed adjacent each other in a direction transversely across the seat. Further, two or more damping units may be provided one in front of the other.

In the embodiment described herein, one specific form of the damper unit is described. The damper unit could be of any other shape or material that provides an appropriate damping affect, and the invention is not limited to the shape of the damper unit which is illustrated.

The seat arrangement of the described embodiment is shown only with a seat base 2. It will be appreciated that the seat may also have a seat back.

The seat arrangement in accordance with the present invention is likely to find application in military vehicles. It will be appreciated, however, that the invention is not limited to such an application, and that the seat arrangement may be utilised in other types of vehicles vehicles at risk of mine blasting, politician's vehicles or conventional vehicles).

Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

Claims (14)

1. An impact resistant seat arrangement, comprising a seat base and a damper arrangement mounted to the seat base and being arranged to absorb impact energy from an impact below the seat.

2. A seat arrangement in accordance with claim I, the damper arrangement including a damper unit mounted between the seat base and a floor with respect to which the seat is mounted.

3. A seat arrangement in accordance with claim 2, the damper unit comprising a collapsible element which is arranged to progressively collapse in response to an impact to the underside of the unit, and arranged to absorb absorbing energy transmitted by the input as the element progressively collapses.

4. A seat arrangement in accordance with claim 3, wherein the damper unit is an element having an irregular shape cross section.

A seat arrangement in accordance with claim 2, 3 or 4, the damper unit being mounted under a rear portion of a seat base, the rear portion being arranged to bear the majority of the weight of a seat occupant.

6. A seat arrangement in accordance with any one of claims 1 to 5, the damping arrangement including a damper element mounted within the seat base. 10

7. A seat arrangement in accordance with claim 6, the damper element comprising a non-elastic deformable member and being arranged to reduce a rebound affect of the seat material following an impact.

8. A seat arrangement in accordance with claim 6 or claim 7, a plurality of the damper elements being mounted within the seat base.

9. A seat arrangement in accordance with any one of the preceding claims, the damping arrangement including a high density foam material as part of the seat base.

10. A seat arrangement in accordance with claim 9, the seat base also including a low density foam material for comfort of the seat occupant.

11. A seat arrangement in accordance with any one of the preceding claims, further comprising a securing element mounted between a front part of a seat base and a floor, and being arranged to stabilise the seat base in response to an impact.

12. A seat arrangement in accordance with claim 11 wherein the securing element extends transversely across the seat.

13. A seat arrangement in accordance with claim 11 or claim 12, wherein the securing element is a substantially C-shaped cross section bracket. I I 11

14. A seat arrangement in accordance with any one of the preceding claims, being secured to the floor of the vehicle. A seat arrangement as substantially described herein, with reference to the accompanying drawings. DATED this 2 nd Day of September 2004 G AND J LEWIS ENTERPRISES PTY LTD By their Patent Attorneys GRIFFITH HACK