Heat shielding composite cloth

1. A heat shielding composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) comprising at least one pair of layers made up of an upper layer ( 12 ) and a lower layer ( 11 ) that are made of a thermal insulating material and are movably connected to one another by one or more shape memory alloy (SMA) wires ( 103 , 113 , 123 ),

for which, at a temperature equal to or above the Austenite phase temperature (Af) of the shape memory alloy of which the wires ( 103 , 113 , 123 ) are made, the following relationship is satisfied:

the ratio Lu/Ll is comprised between 0.1 and 10,

where:

Lu is the sum of lengths of the portions of shape memory alloy wires ( 103 , 113 , 123 ) that are restrained to the upper layer ( 12 ) over an area of 3 cm 2 of the composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ),

Ll is the sum of lengths of the portions of shape memory alloy wires ( 103 , 113 , 123 ) that are restrained to the lower layer ( 11 ) over said area of 3 cm 2 of the composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ),

the shape memory alloy wires ( 103 , 113 , 123 ) being arranged parallel to each other ( 70 ; 90 ) or disposed according to a grid pattern ( 80 ), wherein the number of shape memory alloy wires ( 103 , 113 , 123 ) portions over a square area of 10 cm 2 of the composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) is comprised between 1 and 200,

characterized in that also the following relationship is satisfied:

the ratio (Lu+Ll)/H is comprised between 0.1 and 10;

where:

H is the sum of lengths of the portions of shape memory alloy wires ( 103 , 113 , 123 ) that are arranged between the upper layer ( 12 ) and the lower layer ( 11 ) and are not restrained thereto over said area of 3 cm 2 of the composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ),

the overall configuration of the heat shielding composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) being such that, at a temperature equal to or above the Austenite phase temperature (Af), the distance between the upper ( 12 ) and lower ( 11 ) layers is increased starting from a minimal distance comprised between 0 and 5 mm by an amount comprised between 1 and 40 mm.

2. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein the ratio between (Lu+Ll)/H is comprised between 0.6 and 4 and the ratio between Lu/Ll is comprised between 0.5 and 2 over said area of 3 cm 2 of the composite cloth ( 100 ; 110 ; 70 : 80 ; 90 ).

3. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein the shape memory alloy wires ( 103 , 113 , 123 ) are disposed according to a grid pattern ( 80 ) with 90° angles between crossing wires.

4. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein the diameters of the shape memory alloy wires ( 103 , 113 , 123 ) are comprised between 50 and 250 μm.

5. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein the Martensite phase temperature (Mf) of the shape memory alloy of which the wires ( 103 , 113 , 123 ) are made is equal to or lower than 40° C. and the Austenite phase temperature (Af) of said shape memory alloy is equal to or higher than 60° C.

6. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein a thermally insulating gas is present between the upper layer ( 12 ) and the lower layer ( 11 ), and wherein the minimal distance between the upper layer ( 12 ) and the lower layer ( 11 ) at a temperature lower than the Martensite phase temperature (Mf) is determined by the diameter of the shape memory alloy wires ( 103 , 113 , 123 ).

7. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein a thermally insulating solid material is arranged between the upper layer ( 12 ) and the lower layer ( 11 ).

8. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein the upper layer ( 12 ) and the lower layer ( 11 ) are movably connected to each other by a plurality of shape memory alloy wires ( 103 , 113 , 123 ) and wherein at least one of said shape memory alloy wires ( 103 , 113 , 123 ) has a diameter different from the diameters of the other shape memory alloy wires ( 103 , 113 , 123 ) by at least 10%.

9. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , wherein the upper layer ( 12 ) and the lower layer ( 11 ) are movably connected to each other by a plurality of shape memory alloy wires ( 103 , 113 , 123 ) and wherein at least one of said shape memory alloy wires ( 103 , 113 , 123 ) has a difference of at least ±10° C., in Martensite phase temperature (Mf) and/or in Austenite phase temperature (Af) with respect to the other shape memory alloy wires ( 103 , 113 , 123 ).

10. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , comprising two or more pairs of upper layers ( 12 ) and lower layers ( 11 ) superimposed to each other and wherein an upper layer ( 12 ) of a pair of layers ( 11 , 12 ) is joined to a lower layer ( 11 ) of an adjacent pair of layers ( 11 , 12 ).

11. The composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 , comprising two or more pairs of upper layers ( 12 ) and lower layers ( 11 ) superimposed to each other and wherein the upper layer ( 12 ) of one pair of layers ( 11 , 12 ) is also the lower layer ( 11 ) of an adjacent pair of layers ( 11 , 12 ).

12. A garment comprising the heat shielding composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 1 .

13. The garment according to claim 12 , wherein said garment is a gauntlet.

14. The garment according to claim 12 , wherein said garment is a part of a fire fighter vest.

15. A composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 2 , wherein the shape memory alloy wires ( 103 , 113 , 123 ) are disposed according to a grid pattern ( 80 ) with 90° angles between crossing wires.

16. A composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 2 , wherein the diameters of the shape memory alloy wires ( 103 , 113 , 123 ) are comprised between 50 and 250 μm.

17. A composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 3 , wherein the diameters of the shape memory alloy wires ( 103 , 113 , 123 ) are comprised between 50 and 250 μm.

18. A composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 2 , wherein the Martensite phase temperature (Mf) of the shape memory alloy of which the wires ( 103 , 113 , 123 ) are made is equal to or lower than 40° C. and the Austenite phase temperature (Af) of said shape memory alloy is equal to or higher than 60° C.

19. A composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 3 , wherein the Martensite phase temperature (Mf) of the shape memory alloy of which the wires ( 103 , 113 , 123 ) are made is equal to or lower than 40° C. and the Austenite phase temperature (Af) of said shape memory alloy is equal to or higher than 60° C.

20. A composite cloth ( 100 ; 110 ; 120 ; 70 ; 80 ; 90 ) according to claim 4 , wherein the Martensite phase temperature (Mf) of the shape memory alloy of which the wires ( 103 , 113 , 123 ) are made is equal to or lower than 40° C. and the Austenite phase temperature (Af) of said shape memory alloy is equal to or higher than 60° C.