Abstract: A helmet adjustment mechanism is adapted to adjust the size of a helmet having first and second retention members (e.g., plastic straps) movable with respect to each other. The adjustment mechanism includes an actuating member (e.g., a pinion) coupled to at least one of the retention members and movable (e.g., rotatable) in two directions to move at least one of the retention members relative to the other. A clutch mechanism is coupled to the actuating member and includes at least one locking member (e.g., two locking members) that inhibits movement of the actuating member in both of the two directions. The adjustment mechanism also includes a release mechanism (e.g., including a rotary dial) adapted to move the locking member from a locked position to an unlocked position to allow movement of the actuating member. When the actuating member is being moved, the adjustment mechanism also provides a ratcheting detent.

Abstract: A bicycle rear derailleur guard assembly for use with a bicycle having a derailleur mounted to a frame of the bicycle by a derailleur mounting bolt. The derailleur guard assembly preferably includes a body supportable by an axle assembly of the bicycle. The body is configured to extend from an axis of the axle assembly to a space adjacent the mounting bolt of the derailleur and defines an inner surface facing the frame when the guard assembly is mounted to the bicycle. A support is configured to support the derailleur when the guard assembly is mounted to the bicycle and, in at least one arrangement, the body is positioned outwardly of the derailleur mounting bolt within the space adjacent the mounting bolt.