Linear cutting stapler

A linear cutting stapler, comprising:

• an upper jaw and a lower jaw capable of being closed or open relative to each other, wherein the upper jaw comprises an anvil and the lower jaw comprises a staple cartridge frame and wherein the upper jaw is removably attached to the lower jaw through an engaging unit, wherein:
• the engaging unit comprises a positioning pin and a pin slot, wherein the positioning pin and the pin slot are respectively located at a proximal end of the anvil and a proximal end of the staple cartridge frame or respectively located at the proximal end of the staple cartridge frame and the proximal end of the anvil,
• the positioning pin is configured to engage the pin slot when the upper jaw and the lower jaw rotate about the positioning pin, such that the positioning pin works as a support shaft when the upper jaw and the lower jaw rotate,
• when the linear cutting stapler is in an open state, the positioning pin is in a first slot position of the pin slot and when the linear cutting stapler is in a closed state, the positioning pin is in a second slot position, and
• the second slot position is arranged in an angle with respect to the first slot position, such that when the upper jaw and the lower jaw rotate from the closed state to the open state, the positioning pin is held in the second slot position, causing the upper jaw to remain attached to the lower jaw.