Folding knife with positioning mechanism and elastic bar

A folding knife, comprising:

• a handle, comprising:
• a first plate, wherein an inner side of the first plate is concavely formed with a groove;
• and
• a second plate formed with a through hole corresponding in position to the groove, wherein the first plate or the second plate is formed with a first positioning groove;
• a blade configured to be located between the first plate and the second plate and having:
• a pivotal connection end configured to be pivotally connected to a position of the handle that is adjacent to a first end of the handle, wherein the blade is configured to be rotated out of the handle and rotated into the handle around the position where the handle and the blade are pivotally connected;
• a blade tip end;
• a passage-allowing groove configured to correspond in position to the groove of the first plate when the blade is fully stored in the handle, wherein a protruding tip is defined between and connected both to the passage-allowing groove and a side surface of the blade that faces the handle when the blade is stored in the handle;
• and
• a second positioning groove configured to correspond to the first positioning groove when the blade is rotated out of the handle and in an unfolded state;
• an elastic bar having a first end located at a position of the handle that is adjacent to a second end of the handle, and a second end at a position adjacent to the position where the handle and the blade are pivotally connected, and configured to, when the blade is fully stored in the handle, press against the protruding tip defined between and connected both to the passage-allowing groove and the side surface of the blade and apply a rotating force to the blade that pushes the blade along a direction out of the handle;
• a positioning portion configured to be disposed in the first positioning groove and, when the second positioning groove corresponds to the first positioning groove, be extended into the second positioning groove and prevent the blade from rebounding because of a reaction force;
• and
• an engaging portion comprising:
• an engaging post comprising:
• a pressing portion configured to be extended into the through hole from an inner side of the second plate and be exposed from an outer side of the second plate;
• a position-limiting portion, wherein a greatest length of the position-limiting portion in a transverse direction is greater than a hole diameter of the through hole, so as to prevent the engaging post from separating from the through hole;
• an engaging portion configured to be extended into the groove of the first plate and, when the pressing portion is pressed, be disengaged from the blade and prevented from being pressed against an outer edge of the blade, so that the blade is pushed by the elastic bar and rotated out of the handle till the positioning portion is extended into the second positioning groove, and a portion of the outer edge of the blade passes through an area corresponding to the groove of the first plate while the blade is being rotated outward;
• and
• a passage-allowing portion, wherein a greatest length of the passage-allowing portion in the transverse direction is less than a greatest length of the engaging portion in the transverse direction;
• and
• an elastic element located in the groove of the first plate and configured to:
• push the engaging portion in a direction away from the groove of the first plate;
• and
• when the blade is stored in the handle and the pressing portion is not pressed, push the engaging portion and press the engaging portion against the outer edge of the blade, so that the blade is blocked by the engaging portion and prevented from being rotated outward.