Knife configured to receive blade securely and safely

A knife configured to receive a blade securely and safely, comprising:

• the blade, having a side provided with an engaging hole adjacent to a first end of the blade;
• a handle, wherein a portion of the blade that is adjacent to the first end of the blade is pivotally provided, via a pivot pin, in a portion in the handle that is adjacent to an end of the handle, in order for the blade to rotate with respect to the handle, thereby allowing a blade tip at an opposite second end of the blade to be rotated out of the handle or received in a receiving space in the handle;
• the handle is assembled at least from a first plate, a second plate, and a third plate;
• the first plate has an inner side provided with a switch groove adjacent to an end of the first plate, and the switch groove extends in a front-rear direction;
• the second plate is mounted on the inner side of the first plate and is formed with a positioning hole corresponding in position to a first end of the switch groove, and the positioning hole has a top end and a bottom end, which are in communication with the first end of the switch groove and the engaging hole respectively while the blade is received in the handle;
• and the third plate is spaced from the second plate by a predetermined distance to form the receiving space;
• a positioning member movably engaged in the positioning hole, wherein the positioning member has a thickness greater than a depth of the positioning hole in order for a top portion of the positioning member to extend into the first end of the switch groove or a bottom portion of the positioning member to extend into the engaging hole;
• and
• a locking switch movably engaged in the switch groove, wherein once the blade is rotated out of the handle, the bottom portion of the positioning member is pushed by the side of the blade because the positioning hole does not correspond in position to the engaging hole, and consequently the top portion of the positioning member extends into the first end of the switch groove to prevent the locking switch from displacement along the switch groove;
• and when the blade is received in the handle, the positioning hole corresponds to and is in communication with the engaging hole such that the locking switch is displaceable to the first end of the switch groove to push the top portion of the positioning member, thereby displacing the bottom portion of the positioning member downward into the engaging hole to prevent the blade from rotation.