Vehicles for travelling over a surface

Claim 1

A VEHICLE FOR TRAVELLING OVER A SURFACE AND WHICH IS SUPPORTED ABOVE THAT SURFACE, AT LEAST IN PART, BY A CUSHION OF PRESSURIZED GAS FORMED AND CONTAINED IN A SPACE BENEATH THE VEHICLE WHEREIN THE SPACE IS BOUNDED FOR AT LEAST PART OF ITS PERIPHERY BY CONTAINING MEANS COMPRISING A DOWNWARDLY EXTENDING WALL MEMBER, FLEXIBLY ATTACHED AT ITS UPPER END TO A PART OF THE VEHICLE BODY, A TIE FLEXIBLY ATTACHED AT ONE END TO THE WALL MEMBER AT A POSITION INTERMEDIATE BETWEEN THE ENDS OF THE MEMBER AND FLEXIBLY ATTACHED AT ITS OTHER END TO THE LOWER PART OF THE VEHICLE INBOARD OF THE POINT OF ATTACHMENT OF THE UPPER END OF THE WALL MEMBER, AND A HINGE IN THE WALL MEMBER AT A POSITION ABOVE THE POINT OF ATTACHMENT OF THE TIE, THE WALL MEMBER AT LEAST FOR ITS LENGTH BELOW THE HINGE HAVING SUFFICIENT STIFFNESS TO PREVENT SUBSTANTIAL BENDING THEREOF AT LEAST WHEN UNDER LOAD IN A DIRECTION OUTWARD FROM THE CUSHION SPACE, WHEREBY ON CONTACT WITH THE SURFACE SUCH THAT THE CONTACT LOAD IS IN THE SAME DIRECTION AS THE CUSHION LOAD THE LOWER PART OF THE WALL MEMBER IS DEFLECTED OUTWARDS AWAY FROM THE CUSHION SPACE PIVOTING ABOUT THE POINT OF ATTACHMENT OF THE TIE, THE WALL MEMBER FOLDING INWARDS AT THE HINGE TOWARDS THE CUSHION SPACE SO THAT THE LOWER PART OF THE WALL MEMBER DEFLECTS UPWARDS TOWARDS THE LOWER PART THE VEHICLE.