Patent ID: 6966075

Claim:
An adjustable helmet comprising: a first shell having smooth interference-free sliding surfaces and at least one anchoring hole; a second shell having smooth interference-free sliding surfaces and a series of at least two anchoring holes, said second shell being adjustably connected to said first shell so that said smooth interference-free sliding surfaces of said two shells fit together in an overlapping relationship; and a manually operable locking device comprising at least one tooth, said locking device being movable between a locked position and a release position so that: a) in said locked position, said at least one tooth engages said at least one anchoring hole of said first shell, as well as at least one hole of said series of at least two anchoring holes of said second shell thereby locking said first and second shells together; and b) in said release position, said at least one tooth does not engage said series of at least two anchoring holes of said second shell, thereby allowing said first shell and said second shell to move in relation to each other along their smooth, interference-free sliding surfaces.