Helmet designs utilizing an outer slip layer

Abstract

Disclosed herein is a helmet structure for reducing kinetic energy transmission. The helmet receives contact of an object that transfers kinetic energy to a first layer having material that displaces in response to applied shearing force. The helmet uses a second layer having material that displaces in response to applied shearing force and uses a third layer having material that does not displace in response to applied shearing force to transfer kinetic energy laterally with respect to the skull. Helmet layers can have material with different mechanical responses, including elastic or rubbery elastic. The outer slip layer may also contain reinforcement particles such as metal, glass and ceramic. In one embodiment, each layer in the structure has a different shear modulus and each layer has a higher shear modulus than the immediately preceding layer. The shear modulus of each layer is modified by adding rigid reinforcement to the layer.

Dependencies are inferred from the claim text.