PROTECTIVE HELMET

1 . A protective helmet comprising:

an outer shell;

at least one bladder, coupled to the outer shell, that provides shock absorption in at least one zone or protection, the at least one bladder holding a fluid and having a relief valve for relieving pressure on the at least one bladder when the pressure on the at least one bladder is greater than a pressure threshold.

2 . The protective helmet of claim 1 wherein the relief valve releases the fluid from the at least one bladder to the exterior to the protective helmet.

3 . The protective helmet of claim 1 wherein the relief valve releases the fluid from a first bladder of the at least one bladder to a second bladder of the at least one bladder.

4 . The protective helmet of claim 1 further comprising:

a sensor, coupled to the at least one bladder, that generates sensor data in response to a release of pressure by the relief valve.

5 . The protective helmet of claim 1 further comprising:

at least one inflatable element coupled to at least one of: the at least one bladder and the outer shell, the at least one inflatable element being selectively inflatable to improve the fit between the protective helmet and a wearer of the protective helmet,

6 . The protective helmet of claim 1 wherein the at least one bladder holds an absorption pack containing a plurality of absorption particles.

7 . The protective helmet of claim 6 wherein the plurality of absorption particles include a plurality of beads of different sizes.

8 . The protective helmet of claim 6 wherein the plurality of absorption particles include a plurality of beads of different shapes.

9 . The protective helmet of claim 6 wherein the plurality of absorption particles include a plurality of frangible beads that are fluid-filled.

10 . The protective helmet of claim 6 wherein the plurality of absorption particles include a plurality of beads of different frictional characteristics.

11 . A protective helmet comprising:

an outer shell; and

at least one bladder, coupled to the outer shell, that provides shock absorption in at least one zone or protection, wherein the at least one bladder holds an absorption pack that contains a plurality of absorption particles.

12 . The protective helmet of claim 11 further comprising:

at least one inflatable element coupled to at least one of: the at least one bladder and the outer shell, the at least one inflatable element being selectively inflatable to improve the fit between the protective helmet and a wearer of the protective helmet.

13 . The protective helmet of claim 11 wherein the plurality of absorption particles include a plurality of beads of different sizes.

14 . The protective helmet of claim 11 wherein the plurality of absorption particles include a plurality of beads of different shapes.

15 . The protective helmet of claim 11 wherein the plurality of absorption particles include a plurality of frangible beads that are fluid-filled.

16 . The protective helmet of claim 11 wherein the plurality of absorption particles include a plurality of beads of different frictional characteristics.

17 . The protective helmet of claim 11 wherein the at least one bladder further holds a fluid that at least partially fills the interstitial spaces between the absorption particles and includes a relief valve for relieving pressure on the at least one bladder when the pressure on the at least one bladder is greater than a pressure threshold.

18 . The protective helmet of claim 11 wherein the relief valve releases the fluid from the at least one bladder to the exterior of the at least one bladder.

19 . The protective helmet of claim 11 wherein the relief valve releases the fluid from a first bladder of the at least one bladder to a second bladder of the at least one bladder to distribute force of an impact event.

20 . The protective helmet of claim 11 further comprising:

a sensor, coupled to the at least one bladder, that generates sensor data in response to a release of pressure in the bladder.