Abstract: Testable, redundant pneumatic control assemblies and related systems and methods are described herein. An example pneumatic control assembly described herein includes first, second, and third parallel supply channels between a compressed air supply and valve header, first, second, and third parallel vent channels between a vent and the valve header, and first, second, third, fourth, fifth, and sixth logic valves. The first and sixth logic valves are disposed in the first parallel supply channel and the first parallel vent channel, the second and third logic valves are disposed in the second parallel supply channel and second parallel vent channel, and the fourth and fifth logic valves are disposed in the third parallel supply channel and third parallel vent channel. The pneumatic control assembly also includes a first, second, and third solenoid valves to control certain ones of the logic valves.

Abstract: Testable, redundant pneumatic control assemblies and related systems and methods are described herein. An example pneumatic control assembly described herein includes first, second, and third parallel supply channels between a compressed air supply and valve header, first, second, and third parallel vent channels between a vent and the valve header, and first, second, third, fourth, fifth, and sixth logic valves. The first and sixth logic valves are disposed in the first parallel supply channel and the first parallel vent channel, the second and third logic valves are disposed in the second parallel supply channel and second parallel vent channel, and the fourth and fifth logic valves are disposed in the third parallel supply channel and third parallel vent channel. The pneumatic control assembly also includes a first, second, and third solenoid valves to control certain ones of the logic valves.

Abstract: A helmet includes a shell having a lower edge, and an edge support extending around the lower edge of the shell. The edge support has a greater structural rigidity than the shell. The helmet can further include a retention strap system, and the edge support can include at least one attachment to attach the retention strap system to the helmet. The attachment can, for example, include a seating, and the helmet can, for example, further include an abutment member removably seatable within the seating. The abutment member can be attachable to a strap of the retention strap system.