Flexible hinges are not new , and go back many hundreds of years, , I have built suit of armour before, and mostly they use this type of hinge to open and close their helmets, essentially it's two hinges mounted on a ridged plate, one edge of one hinge touching the edge of the other, each hinge is at one end of the plate, one hinge edge fixes to the helmet and the other to the faceplate because of the ridged plate. You have a hinge system which now moves in two directions, upwards and back . All you now need to do is fix a servo and controller plus power supply into your helmet, add flexible joint connectors, to both ends of a pivot rod about 5" long, one end of the rod fixes to the servo (arm) mounted in your helmet and the other end of the rod , with the flexible joint fixing to the faceplate. (( the servos , connecting joints rods etc can all be bought at you local R/C hobby store )) Connect power to your servo , press the controller button , the servo moves the arm , the arm pushes the rod. and your helmet opens and moves up and back.
As there is a spare arm on the servo, you could use another rod to do the same to the lower jaw - now your helmet opens like a clam shell !!
I put this hinge design into public domain over 15 years ago , its nice to see others use it , it is the easiest hinge system to use in the world , I recommend it to ALL !!
