Collapsible safety helmet

Claim 1

A COLLAPSIBLE SAFETY HELMET COMPRISING A HARD CONVEX SHELL ADAPTED TO FIT OVER THE HEAD AND FORMED FROM THREE INDEPENDENT SUBSTANTIALLY RIGID SECTIONS NORMALLY MOUNTED ON TOP OF ONE ANOTHER, SAID SECTIONS INCLUDING A DOME-LIKE TOP SECTION AND TWO ANNULAR SECTIONS BENEATH IT WITH THE LOWER EDGE OF THE TOP SECTION SEATING ON THE EXTERIOR UPPER PORTION OF THE MIDDLE SECTION AND WITH THE LOWER EDGE OF THE MIDDLE SECTION SEATING ON THE EXTERIOR UPPER PORTION OF THE BOTTOM SECTION TO FORM A SMOOTH OUTER SURFACE FOR THE SHELL, THE MIDDLE AND TOP SECTIONS BEING SMALLER THAN THE INSIDE DIAMETERS OF THE SECTIONS SUPPORTING THEM, THE UPPER PARTS OF THE BOTTOM AND MIDDLE SECTIONS BEING PROVIDED WITH UPWARDLY PROJECTING INWARDLY OFFSET FLANGES ENGAGING THE LOWER PART OF THE INNER SURFACE OF THE SECTIONS RESTING ON SAID BOTTOM AND MIDDLE SECTIONS TO PREVENT RELATIVE LATERAL MOVEMENT OF THE DIFFERENT SECTIONS, THE OUTER SURFACE OF EACH FLANGE BEING PROVIDED WITH A PLURALITY LATERALLY SPACED RECESSES, AND THE INNER SURFACE OF EACH SECTION ADJACENT EACH RECESS BEING PROVIDED WITH PROJECTIONS NORMALLY SEATED IN THE RECESSES IN THAT FLANGE TO LOCK THE SECTIONS TOGETHER, AND SAID SECTIONS HAVING JUST ENOUGH RESILIENCY TO PERMIT SAID PROJECTIONS TO SNAP VERTICALLY OUT OF SAID RECESSES WHEN THE SECTIONS ARE MANUALLY PULLED APART VERTICALLY TO SEPARATE THEM, WHEREUPON THE MIDDLE SECTION CAN BE NESTED IN THE BOTTOM SECTION AND THE TOP SECTION CAN BE NESTED IN THE MIDDLE SECTION TO FORM A COLLAPSIBLE COMPACT UNIT.