Helmet

A helmet for protecting a wearer's head, the helmet comprising:

• a) an outer shell comprising a first shell member and a second shell member movable relative to one another in a longitudinal direction of the helmet to adjust a size of a cavity for receiving the wearer's head;
• b) an adjustment mechanism configured to control movement of the first shell member and the second shell member relative to one another, the adjustment mechanism comprising:
• i) an actuator movable between a first position in which the first shell member and the second shell member are allowed to move relative to one another and a second position in which the first shell member and the second shell member are precluded from moving relative to one another;
• ii) two points of attachment between the first shell member and the second shell member, the two points of attachment configured to interconnect the first shell member and the second shell member while allowing the first shell member and the second shell member to move relative to one another when the actuator is in the first position;
• and
• iii) a locking recess on an outer surface of the second shell member;
• the actuator comprising a locking projection configured such that, when the cavity is of a first size and the actuator is in the second position, the locking projection extends through the first shell member at a point located between the two points of attachment interconnecting the first shell member and the second shell member and is received by the locking recess to lock the first shell member and the second shell member relative to one another without extending through the second shell member, wherein the locking projection is a first locking projection, the actuator comprising a plurality of locking projections, inclusive of the first locking projection, that extend through the first shell member when the actuator is in the second position, wherein the plurality of locking projections comprises a second locking projection configured such that, when the cavity is of a second size and the actuator is in the second position, the second locking projection extends through the first shell member at a point located between the two points of attachment interconnecting the first shell member and the second shell member and is received by the locking recess to lock the first shell member and the second shell member relative to one another without extending through the second shell member, wherein the first and second locking projections are joined at upper ends thereof by a surface that projects away from the inner face of the actuator and extends between the first and second locking projections in the longitudinal direction of the helmet.