The present invention provides a protective headgear having a multi-layered shell to attenuate amplitude of incident mechanical waves of a blunt trauma to a human head by inducing destructive interference with the incident mechanical waves through phase reversal of reflected mechanical waves reflecting off a boundary between two adjacent layers of the protective headgear, and by coaxially converging the phase-reversed reflected mechanical waves with the incident mechanical waves. The multi-layered shell is configured to equally protect people having a similar size of head but with a range of body weight.

A helmet for tracking impact including at least one sensor, a processor in communication with the sensor and a storage file in communication with the processor, the at least one sensor measures a force applied to the helmet and sends a signal to the processor indicative of the measured force. The processor receives the signal indicative of the measured force and compares the measured force to a predetermined value, wherein if the measured force exceeds the predetermined value data is sent to the storage file to record the measured force. The helmet can include an alarm system and/or an Injury tracking system.

A helmet including a body, an outer shell having an inner surface and an outer surface and a plurality of shock absorbers, the shock absorbers being positioned internal of the outer shell. A first set of shock absorbers has a first shock absorption characteristic and a second set of shock absorbers has a second shock absorption characteristic, the second shock absorption characteristic being different than the first shock absorber.

A helmet body with an outer shell and at least two energy management liners may include an elastomeric shaft, a fixed retainer, and an adjustable retainer. The elastomeric shaft has a head, a tail, and a plurality of frustoconical ridges disposed along the elastomeric shaft between the head and the tail, the elastomeric shaft being narrower at the tail than at the head. The fixed retainer has first opening large enough to receive both the head, but a second opening is smaller than a size of the head. The adjustable retainer may have an aperture sized to receive the tail and part of the elastomeric shaft. The inner liner and the outer liner are coupled together with the fixed retainer on one side, the elastomeric shaft extending through the fixed retainer, the inner liner, and the outer liner and the adjustable retainer around the elastomeric shaft on the other side.

An impact reducing headgear is disclosed which utilizes dynamically responsive materials which undergo physical changes during exposure to impact forces, such that physical changes or phase changes absorb energy. The helmet may be constructed with a dual shell structure and a bladder, where the dynamically responsive materials may be contained.

A football helmet has a rigid plastic football helmet shell with a raised plateau of the shell extending from the front portion, over the crown portion, toward the back portion. This raised plateau is the only raised plateau of the shell which begins in the front portion, extends over the crown portion, and ends in the back portion. The raised plateau has a left border and a right border. The left border is composed of a plurality of segments and extends continuously from the front portion, over the crown portion, toward the back portion. The segments of the left border including at least a first segment and second segment, which meet to form an angle. A non-circular first ventilation hole through the shell has at least a first side, a second side, and a third side, and is positioned at the angle, such that the first side is adjacent to the first segment and the second side is adjacent to the second segment. The first segment extends beyond the first ventilation hole by a first distance at least as long as the first side and the second segment extending beyond the first ventilation hole by a second distance at least as long as the second side.

Composite structures include composite cellular or foam structures and more specifically composite cellular or foam structures used for protective head liner structures (e.g. in helmet liners).

A protective helmet can include an outer shell and a multi-layer liner disposed within the outer shell and sized for receiving a wearer's head. The multi-layer liner can include and inner-layer, a middle-layer, and an outer-layer. The inner-layer can include an inner surface oriented towards an inner area of a helmet for receiving a wearer's head. The inner-layer can comprise a mid-energy management material with a density in a range of 40-70 g/L. The middle-layer can be disposed adjacent an outer surface of the inner-layer, wherein the middle-layer comprises a low-energy management material with a density in a range of 10-20 g/L. The outer-layer can be disposed adjacent an outer surface of the middle-layer, the outer-layer comprising an outer surface oriented towards the outer shell, wherein the outer-layer comprises a high-energy management material with a density in a range of 20-50 grams g/L.

A football helmet has a rigid plastic football helmet shell with a raised plateau of the shell extending from the front portion, over the crown portion, toward the back portion. This raised plateau is the only raised plateau of the shell which begins in the front portion, extends over the crown portion, and ends in the back portion. The raised plateau has a left border and a right border. The left border is composed of a plurality of segments and extends continuously from the front portion, over the crown portion, toward the back portion. The segments of the left border including at least a first segment and second segment, which meet to form an angle. A non-circular first ventilation hole through the shell has at least a first side, a second side, and a third side, and is positioned at the angle, such that the first side is adjacent to the first segment and the second side is adjacent to the second segment. The first segment extends beyond the first ventilation hole by a first distance at least as long as the first side and the second segment extending beyond the first ventilation hole by a second distance at least as long as the second side.

An impact reducing headgear is disclosed which utilizes dynamically responsive materials which undergo physical changes during exposure to impact forces, such that physical changes or phase changes absorb energy. The helmet may be constructed with a dual shell structure and a bladder, where the dynamically responsive materials may be contained. A embodiment for a comfortable fit which remains tight to the wearer's head is disclosed.