Patent ID: 7346377

Claim:
A folding mechanism comprising: a fixed member having a plurality of fixed cams disposed on a side face of the fixed member; a movable member arranged for rotation with respect to the fixed member having a plurality of movable cams disposed on a side face of the movable member in confronting relation with the fixed cams, the movable cam being formed of a protruded portion and sloped portions extended to the left and right; and a spring for urging the movable member or the fixed member such that the movable cams and the fixed cams are brought into resilient contact with each other; wherein a first set of the movable and fixed cams form an inner camming unit, and a second set of the movable and fixed cams form an outer camming unit positioned circumferentially around the inner camming unit; wherein the movable member and the plurality of movable cams are formed solidly; and wherein, at a position that the movable cam opens over 180° from a closed position, the fixed cam is held in resilient contact with the sloped portion of the movable cam so that a further force is applied to open the movable cam; and wherein each of the plurality of movable cams rotates from a partially open position to a predetermined angle more than 180° from the partially open position without the maximum height of the fixed cams reaching a maximum height of the respective movable cams.