A HELMET FOR IMPACT PROTECTION
A helmet for protecting a wearer's head has a protective layer configured to, when the helmet is impacted by a force, absorb the normal component thereof by compression and rupture when the tangential component of the force exceeds a predefined threshold.
1 .- 15 . (canceled)
16 . A helmet for protecting a wearer's head comprising:
a protective layer configured to, when the helmet is impacted by a force, absorb the normal component thereof by compression and rupture when the tangential component of the force exceeds a predefined threshold.
17 . The helmet according to claim 16 wherein the protective layer comprises closed-cell foam configured to perform said absorbing and said rupturing.
18 . The helmet according to claim 17 wherein the closed-cell foam comprises expanded beads.
19 . The helmet according to claim 16 , wherein the protective layer comprises:
a first layer; and
protuberances extending from the first layer; and
wherein the protuberances are configured to rupture from the first layer when exceeding the predefined threshold.
20 . The helmet according to claim 19 , wherein the protective layer further comprises:
a second layer covering the protuberances.
21 . The helmet according to claim 20 , wherein the second layer also comprises protuberances configured to rupture from the second layer when exceeding the predefined threshold.
22 . The helmet according to claim 21 wherein the protuberances of the first layer and the protuberances of the second layer face towards each other.
23 . The helmet according to claim 20 wherein the first and second layer are connected with each other by the protuberances.
24 . The helmet according to claim 22 wherein the protuberances of the first layer are interlinked with the protuberances of the second layer.
25 . The helmet according to claim 20 , wherein the protuberances comprise at least one of the group of:
a tubular protuberance;
a beam-shaped protuberance;
a conical protuberance with an elliptic or polygonal base.
26 . The helmet according to claim 18 , wherein the protective layer comprises a mixture of the beads and second granules.
27 . The helmet according to claim 26 wherein the protective layer is further arranged such that the rupturing initiates at a border between the beads and the granules.
28 . The helmet according to claim 26 wherein the beads and granules have a diameter of around 0.5 mm to around 5 mm.
29 . The helmet according to claim 26 , wherein the beads have a first density between 50 and 70 m −3 ·kg; and
the granules correspond to second beads having a second density between 90 and 110 m −3 ·kg.
30 . The helmet according to claim 26 , wherein the mixture comprises between 25 and 75 weight percent of the beads with the first density.