Patent ID: 7398561

Claim:
A device for opening-closing jaw guard of a helmet fitted on the helmet body which is provided with an opening portion for the face in front to protect the jaw of the wearer by blocking part of the opening portion by a hinge means, said hinge means comprising: fixed plates which are fixed on both the left and right sides of the helmet body and each of which has a long hole, an arc-shaped guide hole formed away from the long hole at a predetermined interval, and a fixed plate having a wheel hole formed between these holes and; operating plates which are fixed on the inside of the left and right extending portions of said jaw guard and each of which has an arc-shaped internal gear, an upward guide protuberance formed on the outside of the internal gear, and a main boss formed in the central position of the arc of the internal gear; a planetary gear which is engaged with the internal gear of said operating plate, and has a protuberance formed on either side, and a cutaway portion formed on the outer circumference; and a pivoting lever which has a shaft protuberance of front end inserted into the cutaway portion of said planetary gear and a penetration hole of rear end inserted into the main boss of said operating plate.