WO2010041086A1

WO2010041086A1 - Mine-resistant vehicle

Info

Publication number: WO2010041086A1
Application number: PCT/GB2009/051357
Authority: WO
Inventors: Nicholas James Baird
Original assignee: Permali Gloucester Limited
Priority date: 2008-10-11
Filing date: 2009-10-09
Publication date: 2010-04-15
Also published as: GB0818694D0

Abstract

A mine-resistant vehicle (100, 300) which comprises a vehicle body having a separate or integral chassis and a shielded underside,a plurality of structural support members (231, 232, 310, 320, 330) having an upper part and a lower part, the support members (231, 232, 310, 320, 330) being connected at their lower part to the vehicle body and extend upwards towards their upper part to define a support frame, and a crew carrying pod (240) which is suspended from the support frame so that there is a vertical clearance between a base of the pod (240) and any structural parts of the vehicle body below the base of the crew carrying pod, the crew carrying pod providing at its base a support for one or more crew members and the crew carrying pod (240) further being rigidly connected to the frame such that in use an upwardly directed force applied to the shielded underside of the vehicle in the event of an explosion below the vehicle is transferred indirectly to the crew in the pod (240) after having flowed upwards through the support members (231, 232, 310, 320,330) and then downwards through the pod such that both the members and the pod assist in absorbing the force of the explosion.

Description

MINE-RESISTANT VEHICLE

This invention relates to improvements in mine-resistant vehicles especially but not exclusively for military use.

It is known to provide mine-resistant vehicles which are provided with protection against attack from mines and roadside improvised explosive devices. In a typical attack a mine is triggered as the vehicle rolls onto it or an explosive device is detonated remotely when a vehicle passes an explosive device. The explosive force of the mine radiates upwards towards the underside of the vehicle and can rupture the underside or throw the vehicle upwards violently. The impact of these forces on the underside can cause severe injury to any person in the vehicle even if the integrity of the interior is maintained due to the high accelerations that can be produced.

There are two key elements in protecting the occupants of vehicles from mine attack. One is to prevent the mine blast from rupturing or penetrating the hull of the vehicle, and the other is to manage and reduce the acceleration forces experienced by the occupants.

Blasts can be prevented from rupturing the vehicle by making the flat underside or hull of the vehicle extremely solid and thick, using heavy armour plating. This can ensure that any fragments from the explosion do not penetrate the underside. However, the force must still be absorbed by the vehicle and the vehicle can still be accelerated violently or even thrown in the air with enough force to injure any occupants. This solution, whilst protecting against penetration, does nothing to help reduce the forces on the occupants. Several techniques are known for reducing accelerations. One technique is disclosed in United States Patent 7357062 and consists of providing an underside which takes the form of a V-shaped hull. The upwards forces from an explosion are deflected around the vehicle by the flanks of the hull, protecting the occupants of the vehicle. This solution is lighter and more efficient than flat armour and so allows better protection within a given weight limit. A problem with this design, however, is that the centre of gravity of the vehicle is higher than a similar vehicle with a flat underside. This could make it unstable. Also it is still possible for the forces applied to the underside to cause damage to the occupants as the forces jolt the vehicle.

Other previous techniques for reducing accelerations concern modifications to the inside of the vehicle such as mounting seats on crushable mounts or suspending the seats and floor from the wall or ceiling of the vehicle to introduce some compliance. A problem with these solutions that is hard to avoid is that there can only ever be a relatively small distance between the floor and the seat squab which limits the amount of absorption of forces that can be provided. Increasing this distance may push the crew's heads too close to the ceiling of the vehicle which would introduce new risks.

According to a first aspect the invention provides a mine-resistant vehicle which comprises a vehicle body having a separate or integral chassis and a shielded underside, a plurality of structural support members having an upper part and a lower part, the support members being connected at their lower part to the vehicle body and extend upwards towards their upper part to define a support frame, and a crew carrying pod which is suspended from the support frame so that there is a vertical clearance between a base of the pod and any structural parts of the vehicle body below the base of the crew carrying pod, the crew carrying pod providing at its base a support for one or more crew members and the crew carrying pod further being rigidly connected to the frame such that in use an upwardly directed force applied to the shielded underside of the vehicle in the event of an explosion below the vehicle is transferred indirectly to the crew in the pod after having flowed upwards through the support members and then downwards through the pod such that both the members and the pod assist in absorbing the force of the explosion.

By hanging a crew carrying pod from a support frame and rigidly connecting the two together the path through which the forces flow to reach the passengers is much greater than it would be if the passengers were in direct contact with the underside of the vehicle. Because the underside of the vehicle is shielded the blast forces are prevented from directly reaching the base of the passenger compartment which may otherwise impart dangerous forces on the occupants. Since both the support members and the crew pod are able to absorb the blast energy by deformation the force and acceleration applied to the crew in the pod is greatly reduced.

To help absorb the blast energy the support members of the support frame may include one or more bends between the upper part and the lower part. Thus, as the forces flow through the uprights the frame may distort at the bends which dissipates energy. For example, the frame may initially bow outwards away from the lower part before bending back inwards towards the upper part. The or each bend may subtend an angle of at least 45 degrees. The support members may be bent so that the path along which force flows from the lower part to the upper part has to change direction at least twice.

The support members and crew carrying pod may be so constructed and arranged as to provide a substantially optimal absorption of the energy through deformation at multiple spaced location over substantially the whole of the path along which energy passes to reach the crew. Each part of the path may be carefully considered to see if it can contribute to the dissipation of energy, and if it can then preferably the shape, and material used for, each part may be selected so as to provide a degree of energy dissipation. By providing a distributed absorption of energy the applicant has appreciated that a maximum benefit of the relatively long path length can be attained.

For instance, the design may be such that at least 10 percent, or 20 percent, or at least 30 percent of the energy is absorbed by deformation of the path defined by the crew carrying pod between the rigid connection to the support members and the support for the crew, the rest dissipated by the support members and other parts of the vehicle.

The path along which forces flow from the underside of the vehicle to the base of the crew carrying support may be substantially free of predominantly elastic elements. Such elastic elements, for example metal or rubber compression springs, may appear useful in isolating the crew from the blast but the applicant believes they are detrimental in that, generally, all they would do is store the energy and then re-release that energy back into the rest of the path. Such storage and re-release of energy is undesirable in an application where a sudden extremely high amount of energy is applied to the system.

The crew carrying pod may comprise a base and side walls, and perhaps also a roof, forming a volume which can accommodate a crew member such as a driver or a gunner or a navigator on the support. It may accommodate all occupants of the vehicle. The side walls of the pod may include one or more bends along their length to assist in reducing accelerations as the forces instead cause parts of the walls to bend more or to straighten out (depending on the direction of the bend and its location) .

The crew carrying pod may be provided with one or more supports for crew which comprise seats such as chairs or benches which are secured to the base. As previously mentioned this again lengthens the path that forces travel to reach the passengers, as the force must flow down the side walls of the compartment from the part where it is connected to the support member to the base to reach the seats.

The support members of the frame may be arranged in two or more groups along the length of the vehicle, each group comprising at least two uprights, one each side of a longitudinal central axis of the vehicle which are interconnected at their upper part by at least one top rail. The top rail may be substantially horizontal. Each upright may include one or more defined bends. Each group therefore forms a hoop or partial hoop from which the pod is suspended.

The crew carrying pod may be totally isolated from the underside and/or the chassis and from the support members except for its connection through the structural support members. Alternatively, there may be non- load bearing members in the space between the bottom of the pod and the vehicle underside such as pipes and hoses. A gap of at least 10cm or at least 20cm or more than 30cm may be provided between any part of the pod and any structural part of the vehicle below it such as chassis rails or the hull of the vehicle or drivetrain components.

As mentioned, the support members may comprise a set of complete or partial hoops, each having two opposed uprights, a top rail and a lower rail. The pod may be hung from the top rail of the or each hoop. It may hang from the upper most part of the hoop and the lower part of the hoop may include a part of the chassis.

The vehicle may have a long axis extending from front to rear and the hoops may extend transverse to this axis. There may be at least two, or three or four or more hoops.

The support members of the frame may provide structural support for an outer skin of the vehicle comprising one or more of: side panels, rear panels, roof panels, front panels. They may be rigid members. Alternatively the hoops may isolated from the outer surface of the vehicle, with panels being supported by the chassis. This would provide a vehicle with an outer shell and an isolated inner compartment. The outer shell may be at least partially armoured.

The crew carrying pod may be hung from the support frame by one or more rigid couplings or connectors. These may be located closer to a line passing vertically through the longitudinal central axis of the vehicle than the lower parts of the frame. The crew carrying pod may be suspended from the top part of the support members by one or more rigid connectors, which may have one or more bends to help manage the dissipation of forces. The connectors may themselves not make a substantial contribution to the dissipation of energy, the energy being dissipated largely through lots of small contributions made by many different parts of the support members and crew carrying pod through which force flows. The applicant feels that any attempt to dissipate the bulk of the energy in a small region, such as the connector, would not provide as effective a solution as a design in which the whole of the path is designed to provide many smaller contributions to energy dissipation. The crew carrying pod may completely enclose one or more crew members, or may simply provide structural support for them whilst they may be at least partially protruding from the pod. For instance, the head of a crew member may be raised above the top of the pod.

The upper part of the support frame may be located towards the top of the vehicle above the head of at least one crew member seated in the crew carrying pod. Placing it at the top again increases the path length for acceleration forces, as they must travel from the hull right to a point above the crew almost at the top of the vehicle and then down to below the crew member.

The chassis may comprises a separate structural metal chassis, such as a ladder frame including at least one elongate chassis rail extending along at least part of the length of the vehicle. The bodywork of the vehicle and other parts such as the engine and suspension may fixed to this separate chassis as well as the support frame.

Alternatively the vehicle may have a monocoque or unibody construction in which the chassis comprises an integral part of the body so that no separate chassis can be identified. The term chassis within the meaning of this invention encompasses both types of vehicle chassis structure. In this case the frame may also be formed as an integral part of the uni-body. In that case, the support frame may provide the main structural integrity of the vehicle and act as a structural space frame chassis.

The support members may be metal members or composite or a combination of both. They may be secured to the chassis by any suitable means such as welding or bolting in place. The crew carrying pod may be a monocoque structure. It may have a base section to which one or more seats are affixed. Again this ensures that the force path from the hull to the crew must pass down the structure from the point where it joins the hoops to reach the seats.

The underside of the vehicle may comprise a v-shaped hull. This helps dissipate the forces as is known in the art.

The vehicle may be provided with two or more axles, each supporting at least one pair of wheels. It may include or more tracked wheelsets. It may comprise two or more tracked wheel sets. It may comprise a 4 x 4 or 6 x

6 vehicle for example, although other configurations are within the scope of the invention. It may include an engine such as a diesel engine which is fixed to the chassis in such a manner that it can be easily broken away in the event that the vehicle is subject to high acceleration forces without striking the crew pod.

There will now be described, by way of example only, one embodiment of the present invention with reference to the accompanying drawings of which:

Figure 1 is a perspective view of a vehicle in accordance with the invention;

Figure 2 is a cross section through the vehicle of Figure 1 ;

Figure 3 is a cross section through an alternative embodiment of a vehicle in accordance with the invention; and

Figure 4 illustrates the location of the parts of the support frame of the vehicle of Figure 1 which form a space frame chassis for the vehicle. As shown in Figure 1 , a mine resistant vehicle 100 comprises a body which is supported above a road surface by three pairs of wheels 110, 120, 130 supported by respective axles. All three sets of wheels may be driven by a drivetrain 140 connected to an engine (not shown) , typically a diesel engine, contained within a forward part 155 of the body of the vehicle 100. The body 150 comprises an armoured outer shell that surrounds a crew carrying pod within which various crew members including a driver and perhaps a navigator may be seated. The hull which is slung from the underside of the body comprises an optional V-shaped deflector 160 which helps to deflect energy from a blast underneath the vehicle around the body rather than directly into the crew compartment.

Figure 2 shows the structure of the vehicle in more detail. It is a cross section taken along a plane that passes vertically through the centre of the vehicle orthogonal to its main front to rear axis. As can be seen the vehicle includes a ladder chassis comprising two main beams 210,220 running from the front to the rear of the vehicle. These are connected by two or three cross members (not shown) . Extending upwards from the chassis rails 210,220 are a set of support frames. One frame 230 is visible in Figure 2 as it lies in the centre of the vehicle but in this example there are in fact three frames, one also at the front and one at the rear of the crew carrying pod each spaced from the others between the ends of the chassis rails.

The frame 230 comprises two tubular uprights 231 ,232, one on each side of the vehicle, connected at a lower part to a respective chassis rail 210,220. Each of the uprights 231 ,232 bends outwards from the rails 210,220 and then returns inwards where they are connected to a horizontal top rail 233 which together with the uprights forms an inverted U-shaped frame. The top rail 233 forms an upper part of the frame and provides a mount for two rigid connector blocks 234,235 which are located inboard of the chassis rails (when considering a vertical line extended down from the connector to the ground the line will pass between the two chassis rails) . A crew carrying pod 240 is suspended from the connectors.

The pod 240 comprises a monocoque hollow structure of sheet metal or fibre-reinforced plastic composite, although it could equally comprise a lattice structure of rods or beams forming a space frame. The pod 240 has side walls 241 ,242 that extend downwards from the connectors to a base or floor 243, and the chairs which the crew members will occupy when driving the vehicle are mounted on the floor of the pod. In Figure 2 only one chair 250 is shown but in practice the pod 240 may hold as many as ten or more crew and have ten or more chairs. The bottom of the pod is held clear of the hull of the vehicle by at least d of at least 10cm or more. As with the uprights of the frame, the sides of the pod similarly bend out from the connectors and then back in to form the floor.

Mounted between the chassis rails and the support frame is a blast deflector in the form of a v-shaped hull 160 which forms the external base of the vehicle 100. This is shown as a shallow V shape but in practice the angled flanks may be more steeply raked. The running gear of the vehicle will therefore lie below and between the chassis rails and below the deflector.

The support frame 230 also provides a mounting structure for external vehicle armour 260,270 which is fastened to the frame uprights by multiple connecting bolts 271. The V-shaped hull 160 and external armour 260,270 are, however, optional, and embodiments within the scope of the invention are possible which omit one or both of those features to provide a lighter weight vehicle.

The provision of the support frame structure 230 and the pod that is suspended from it and which supports the crew ensures that the path along which acceleration forces must travel from initially accelerating the hull 160 upwards to the seats is relatively long. The forces must flow upwards through the chassis rails to the uprights, then down the sides of the cell and finally up through the seat base. Because there are several bends along this path, combined with substantial linear path lengths, a large part of the acceleration energy can be dissipated reducing greatly the acceleration of the crew members. These forces are shown by arrows in Figure 2.

An alternative embodiment of a mine resistant vehicle 300 is illustrated in Figures 3 and 4 of the accompanying drawings. Many parts are the same as they are for the embodiment of Figures 1 and 2 and so for clarity these are indicated with like reference numerals.

Figure 3 is a cross section similar to Figure 2 (the vehicle outwardly appearing the same as that shown in Figure 1) and Figure 4 shows only the vehicle support frame structure. The vehicle 300 differs from the first embodiment in that no chassis rails are provided. Instead the framework supporting the suspended crew cell is made more rigid and, together with a lattice of interconnecting bars and beams that join the framework at intervals along the length of the vehicle, sufficient rigidity of the vehicle is provided. As shown in Figure 3, the frame work comprises a set of hooped frames 310, 320 and 330 of unitary construction. Figure 4 shows that there are three hoops although more or less could be used. The hoops 310, 320, 330 are connected by beams that run longitudinally. Each hoop is of metal and may be formed by rough casting and then machining to form two spaced uprights 311 , 312 and a top rail 313 but also an integral bottom rail 314 which closes the U-shaped frame and provides increased rigidity. As with the frame of Figure 2 the uprights are bent to help dissipate forces. A crew carrying pod 250 is suspended from the frame which may be the same as the pod of the vehicle of Figure 1. The bottom rail is hollowed out to provide space through which the vehicle drivetrain (driveshafts, gearbox etc) can pass.

As with the first embodiment the pod 250 is suspended from the top of the frame which includes multiple bends and substantial linear path lengths in the uprights of the frame and the walls of the cell. These help dissipate energy and reduce accelerations of any crew members in the vehicle. The v-shaped hull is bolted directly onto the bottom rail of the support hoops and can form part of the chassis if desired contributing to the structural rigidity of the vehicle by holding the hoops in position relative to one another.

Claims

1. A mine-resistant vehicle (100, 300) which comprises a vehicle body having a separate or integral chassis and a shielded underside, a plurality of structural support members (231 ,232,310,320, 330) having an upper part and a lower part, the support members (231 ,232, 310, 320, 330) being connected at their lower part to the vehicle body and extend upwards towards their upper part to define a support frame, and a crew carrying pod (240) which is suspended from the support frame so that there is a vertical clearance between a base of the pod (240) and any structural parts of the vehicle body below the base of the crew carrying pod, the crew carrying pod providing at its base a support for one or more crew members and the crew carrying pod (240) further being rigidly connected to the frame such that in use an upwardly directed force applied to the shielded underside of the vehicle in the event of an explosion below the vehicle is transferred indirectly to the crew in the pod (240) after having flowed upwards through the support members (231 ,232, 310, 320, 330)and then downwards through the pod such that both the members and the pod assist in absorbing the force of the explosion.

2. A mine resistant vehicle according to claim 1 in which one or more of the support members (231 ,232, 310, 320, 330) of the support frame and the crew carrying pod (240) include one or more bends between the upper part and the lower part so that force flowing from the lower part to the upper part has to change direction at least twice.

3. A mine resistant vehicle according to claim 1 or claim 2 in which the support members (231 ,232, 310, 320, 330) of the frame are arranged in two or more groups along the length of the vehicle, each group comprising at least two uprights, one each side of a longitudinal central axis of the vehicle which are interconnected at their upper part by at least one top rail (233) so that each group forms a hoop or partial hoop from which the pod is suspended.

4. A mine resistant vehicle according to claim 3 in which the vehicle has a long axis extending from front to rear and the hoops extend substantially transverse to this axis.

5. A mine resistant vehicle according to any preceding claim in which the crew carrying pod (240) is totally isolated from the underside except for its connection through the structural support members.

6. A mine resistant vehicle according to any preceding claim in which a gap of at least 10cm or at least 20cm or more than 30cm is provided between any part of the pod (240) and any structural part of the vehicle below the pod (240) .

7. A mine resistant vehicle according to any preceding claim in which the crew carrying pod (240) comprises a base (243) and side walls (241 ,242) forming a volume which can accommodate a passenger such as a driver or a gunner or a navigator.

8. A mine resistant vehicle according to any preceding claim in which the crew carrying pod (240) is provided with a support (250) comprising one or chairs or benches which are secured to the base.

9. A mine resistant vehicle according to any preceding claim in which the support members of the frame provide structural support for an outer skin of the vehicle comprising one or more of: side panels, rear panels, roof panels, front panels.

10. A mine resistant vehicle according to any preceding claim in which the underside of the vehicle comprises a v-shaped hull (160) .

11. A mine resistant vehicle substantially as described herein with reference to and as illustrated in the accompanying drawings.