SMART MATERIAL COUPLINGS

Abstract

The following invention relates to smart material couplings, particularly to shape memory alloy suspension systems to mitigate against shock or blast. There is provided A land vehicle comprising: an armoured v shaped hull; at least one wheel set with a hub, and at least one suspension device comprising a shape memory material operably connecting the hull to the wheel set.

Claims

1. A land vehicle comprising: an armoured V-shaped hull; a wheel set with a hub; and a suspension device comprising a shape memory material operably connecting the V-shaped hull to the wheel set.

2. The vehicle according to claim 1, wherein the suspension device operably connects the V-shaped hull to the hub of the wheel set.

3. The vehicle according to claim 1, wherein the suspension device is in the form of a passive spring suspension.

4. The vehicle according to claim 3, wherein the passive spring suspension is a shape memory alloy in the form of at least one elongate rod, spring, leaf spring, plurality of thin elongate plates, or torsion bar.

5. The vehicle according to claim 1, wherein the suspension device is external to the vehicle.

6. The vehicle according to claim 1, wherein the shape memory material is a shape memory alloy.

7. The vehicle according to claim 6, wherein the suspension device consists only of one or more shape memory alloys.

8. The vehicle according to claim 4, wherein the suspension device includes a plurality of elongate rods of shape memory alloy operably which extend and connect the V-shaped hull to a hub of the wheel set.

9. The vehicle according to claim 1, wherein the suspension device is in a wishbone configuration.

10. The vehicle according to claim 1, wherein there are two or more wheel sets.

11. The vehicle according to claim 1, further comprising: a power plant; and a drive shaft comprising a shape memory alloy, wherein said drive shaft is located between and operably connected via drive couplings to said power plant and the hub of the wheel set, to provide drive to said at least one wheel set.

12. The vehicle according to claim 1, wherein the shape memory material is a shape memory alloy selected from CuAlNi, NiTi, FeMnSi, CuZnAl, CuAlNi, and alloys of zinc, copper, gold and iron.

13. The vehicle according to claim 1, wherein the suspension device is in the form of a passive spring suspension, the passive spring suspension being a shape memory alloy in the form of a plurality of elongate rods, and the plurality of elongate rods are arranged such that the spacing of rod fixings to the V-shaped hull are at a greater distance apart than rod fixings on the hub of the wheel set.

14. A land vehicle comprising a suspension device, said suspension device comprising a shape memory alloy.

15. The land vehicle according to claim 14 wherein the suspension device includes an elongate rod, spring, leaf spring, plurality of thin elongate plates, or torsion bar.

16. A land vehicle comprising: an armoured V-shaped hull; a first wheel set including two wheels, each with a hub; a second wheel set including two wheels, each with a hub; and a first suspension device comprising a shape memory material operably connecting the V-shaped hull to the first wheel set; and a second suspension device comprising the shape memory material operably connecting the V-shaped hull to the second wheel set; wherein each of the first and second suspension devices comprises a shape memory alloy in the form of an elongate rod, spring, leaf spring, plurality of thin elongate plates, and/or torsion bar, the memory shape memory alloy comprising at least one of CuAlNi, NiTi, FeMnSi, CuZnAl, CuAlNi, and alloys of zinc, copper, gold and iron.

17. The vehicle according to claim 16, wherein the first suspension device operably connects the V-shaped hull to one of the hubs of the first wheel set, and the second suspension device operably connects the V-shaped hull to one of the hubs of the second wheel set.

18. The vehicle according to claim 16, wherein the first and second suspension devices each includes a plurality of elongate rods of shape memory alloy which extend and connect the V-shaped hull to a respective hub of the first and second wheel sets.

19. The vehicle according to claim 16, wherein the first and second suspension devices are part of a wishbone configuration.

20. The vehicle according to claim 16, further comprising: a power plant; and a drive shaft comprising a shape memory alloy, wherein said drive shaft is located between and operably connected via drive couplings to said power plant and the respective hubs of the first and second wheel sets, to provide drive to said first and second wheel sets.

Description

[0059] An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings of which:

[0060] FIG. 1 shows a side view of a remote control blast protected vehicle

[0061] FIG. 2 shows the wheel hub arrangement of a vehicle defined herein

[0062] FIG. 3a, 3b shows a split hull arrangement at maximum and minimum displacements

[0063] FIG. 4 shows a configuration of the spring and damper system for the split hull

[0064] FIG. 5 shows a configuration of a split hull on an APC

[0065] FIG. 6 shows a remote control split hull vehicle with roll cage

[0066] FIG. 7 shows a cross section of FIG. 6, along axis A-A.

[0067] Turning to FIG. 1, there is provided a man portable (50 Kg) remote controlled blast protected vehicle 1. The RC vehicle comprising an upper hull 2 and lower V-sectioned hull 3. A plurality of shape memory alloy suspension elongate rods 4a,4b,4c and 4d, connect the V-hull 3, to the wheel sets 5, via the internal hub 6. Further there is provided a shape memory allow drive train 8, affixed by upper drive coupling 7a and lower drive coupling 7b, which may also be selected from shape memory alloy materials. A cowling 9, is located over the upper drive coupling 7a to mitigate against over deflection of the shape memory allow drive train 8. A plurality of arm supports, affix the external roll cage (shown in FIG. 6) to the upper hull 2.

[0068] In normal use the first pair of elongate suspension rods 4a, 4b and the second pair of elongate suspension rods 4c, 4d are spaced further apart than at the hub 6, such that in use, the wheel set 5 may not readily travel laterally along the major axis of the vehicle, such that travel of each wheel set is substantially limited to vertical displacement. The bending and flexing of the elongate rods allows for travel over rough terrain, and provides suspension without the need for traditional suspension and chassis systems.

The drivetrain could be replaced, such that the motor may located such that it forms part of the hub, (not shown).

[0069] During a shock event the force from an explosive event may in part be dissipated by the V shaped hull 3. Further the plurality of shape memory alloy suspension elongate rods 4a, 4b, 4c and 4d, as they are not encased, a large proportion of any blast will have a lower cross section across which to act, and any force that is exerted onto the rods, allow ready displacement and further attenuation of the blast. The SMA rods 4a, 4b, 4c and 4d, are able to undergo large deflections due to its super elastic properties.

[0070] Turning to FIG. 2, there is provided a RC vehicle 1, as shown in FIG. 1, where the wheel set 15 has an integral hub 16. The hub 16 comprises a plurality of SMA rods 14a, 14b, 14c and 14d, which forms the suspension device 10, when connected to the hull 13 via connecting block 12. The connecting block 12, allows ready removal of a plurality of elongate rods 14a, and 14b, such that the wheel set 15 and hub 16 can be readily replaced as an entire unit. The SMA rods 14a-d, are preferably terminated with a bend radii 11, to provide further rigidity to hub 16.

[0071] The hub 16 is operably connected to the lower drive coupling 17b, which may also be selected from a shape memory alloy material. The lower drive coupling 17b, is operably connected to the shape memory alloy drivetrain 18, and, at the end distal to the hub 16, is operably connected via upper drive coupling 17b, which may also be selected from a shape memory alloy material, to a motor. The deflection of the drivetrain 18, may be mitigated by a cowling 19, to prevent excess movement, in the event of a blast hazard.

[0072] Turing to FIGS. 3a and 3b, there is provided a split hull 20, with an upper hull 21 and a lower hull 22. The upper and lower hulls are able slidably engaged such that the upper hull 21 is able to displace vertically within lower hull 22. The alternative arrangement where the upper hull 21 is able to displace vertically externally with respect to the lower hull 22 is readily achievable. The lower hull 22 comprises a V-shaped portion 23, which may provide enhanced blast deflection in the event of a shock impulse. A plurality of biased resilient member 25 are located between said upper hull 21 and lower hull 22, to reduce the travel between said upper and lower hulls in the event of a shock event The biased resilient member 25 may be a damper with an external spring and as shown in FIG. 4. The biased resilient member 25 may be affixed via piston and spring portion 28, to the upper hull 21, via an upper connection support 26, which support may be distanced from the upper hull 21 by a plurality of struts 29. The struts 29 may dissipate the shock impulse over a wider area of the upper hull. The distal end of the biased resilient member 25 may be located on a lower connection support ledge 27.

[0073] The upper hull 21, may further comprise at least one stop 24, which may prevent over displacement of the upper and lower hull such that when the maximum travel of the lower hull is reached and the biased resilient member 25 has been fully compressed, that the lower hull 22 is prevented from further travel by the stop 24. The use of a plurality of individual stops or a projection which extends around the entire periphery of the upper hull, may prevent excess damage to the hull and spread the shock impulse force around a larger section of the upper and lower hulls. Further the stop 24 may be located on the lower hull 22, or a combination of both upper and lower stops.

[0074] In FIG. 3b, biased resilient member 25 has been fully depressed and the maximum travel between the upper and lower has been reached such that the lower hull 22 has been prevented from further travel in a vertical position by the biased resilient member 25 and stops 24.

[0075] FIG. 4 shows a side view of biased resilient member 35, which extends between and upper connection point 36 and lower connection point 37. The biased resilient member comprises an internal damper or shock absorber 38, with an externally located spring 30. The spring and damper will have different spring constants depending on the mass of the vehicle, however the spring constant per unit mass is selected to provide minimal travel some 50 mm to dissipate the load from the impulse shock.

[0076] FIG. 5 shows a section of an armoured personnel vehicle 40. The APV comprises a split hull with an upper hull 41 and a lower hull 42. The upper and lower hulls are able slidably engaged such that the upper hull 41 is able to displace vertically within lower hull 42. The alternative arrangement where the upper hull 41 is able to displace vertically externally with respect to the lower hull 42 is readily achievable. The lower hull 42 comprises a V-shaped portion 43, which may provide enhanced blast deflection in the event of a shock impulse. A plurality of biased resilient member (one shown as dotted line) 45 are located between said upper hull 41 and lower hull 42, to reduce the travel between said upper and lower hulls in the event of a shock event The biased resilient member 45 may be a damper with an external spring and as shown in FIG. 4, with a significantly uprated spring constant. The biased resilient member 45 may be affixed via piston and spring portion 48, to the upper hull 41, via an upper connection support 46, which support may be distanced from the upper hull 41 by a plurality of struts 49. The struts 49 may dissipate the shock impulse over a wider area of the upper hull. The distal end of the biased resilient member 45 may be located on a lower connection support ledge 47.

[0077] The upper hull 41, may further comprise at least one stop 44, which may prevent over displacement of the upper and lower hull such that when the maximum travel of the lower hull is reached and the biased resilient member 45 has been fully compressed, that the lower hull 42 is prevented from further travel by the stop 44. The use of a plurality of individual stops or a projection which extends around the entire periphery of the upper hull, may prevent excess damage to the hull and spread the shock impulse force around a larger section of the upper and lower hulls. Further the stop 44 may be located on the lower hull 42, or a combination of both upper and lower hulls 41,42.

[0078] The upper hull 41 may comprise a floor panel 52, in the form of a spall liner, to provide further blast attenuation protection. The APC 40 may be fitted with blast attenuating seats 46 which are mounted to the walls 53 of the upper hull.

[0079] The lower hull may ride on a conventional chassis with axles 50, and wheels 51, with standard APC suspension systems and steering assemblies, (not shown).

[0080] FIG. 6 shows a man portable (50 Kg) remote controlled blast protected vehicle 60, with an external roll cage 61 fitted thereto. The roll cage 61 provides external protection to the upper hull, and a simple means of lifting the vehicle from a deployment platform. A section along line A-A is shown in FIG. 7

[0081] FIG. 7 shows a section along A-A, of the RC vehicle 60. There are two biased resilient member 65, located either end of the vehicle 60. A battery power pack 66, is in electrical connection with a motor 67 which via a drive belt 64 provides drive via gearboxes (not shown) to each wheel set 63, via the shape memory alloy drivetrain 69. In the RC vehicle 60, the preferred arrangement is to have each side of the vehicle powered by a separate motor, such that skid steer may be used to control direction of travel, this removes the need for separate steering

[0082] In an alternative arrangement each drivetrain 69, may have an individual motor, wherein the motors are centrally operated such that skid steering may be effected. The use of a plurality of motors provides redundancy after a shock hazard event.