Knife with replaceable blade

A knife with a replaceable blade, comprising a housing,

• a cover arranged on the housing and a blade carrier arranged between the housing and the cover and slidable relative to the housing to move a blade between an extended position and a retracted position, and a blade cartridge carrier arranged adjacent and parallel to the blade carrier having a perimeter extending around a periphery of a position adjacent to the retracted position of the blade, the blade cartridge carrier having an internal space to receive spare blades,
• wherein the cover can be connected with the housing in an open type to fix the blade carrier between the cover and the housing;
• a switch mechanism is arranged on the cover to control opening and closing of the cover and the housing, the switch mechanism comprising a trigger member located at an outside of the cover and a contacting member connected with the trigger member;
• a through hole is arranged on the cover, and the trigger member is arranged in an interior of the through hole;
• the trigger member comprising one pushing face and an axis pin, the pushing face capable of rotating around the axis pin, a front portion of the pushing face is provided with a blocking portion and a stopping member is arranged in the through hole of the cover;
• and when no force is exerted on the pushing face, the blocking portion is located at a position of the stopping member and the stopping member stops forward movement of the trigger member;
• and actuating the pushing face to overcome an elasticity of a pressure spring permits the pushing face to rotate around the axis pin and the blocking portion to rotate to a position above the stopping member to allow the trigger member to move forward.