Retractable pen

A retractable pen, comprising a first barrel (1), an ink cartridge (2), a second barrel (3), a clamping component (5) and a spring (4);

• a main body of the ink cartridge (2), the spring (4) and the clamping component (5) are all located inside the first barrel (1) and the second barrel (3), the spring (4) is wound on a portion, close to the nib, of the ink cartridge (2), and the nib in a front portion of the ink cartridge (2) can be extended and exposed out of the first barrel (1);
• a mounting portion, muff-coupled to the first barrel (1), is arranged on the clamping component (5), and the clamping component (5) is rotatable with respect to the first barrel (1);
• when the first barrel (1) is muff-coupled to the second barrel (3), a polygonal neck (51) is formed on a surface where an outer surface of the clamping component (5) comes into contact with the second barrel (3), and a limiting stopper (52) is arranged in the polygonal neck (51);
• fence-like extension bars (30) are arranged in the front portion of the second barrel (3), and the fence-like extension bars (30) are all extended outward in a length direction and enclosed to form a cylindrical shape;
• and ribs (11), matched with the fence-like extension bars (30), are arranged on the periphery of the front portion of the first barrel (1), and the adjacent ribs (11) are clamped between adjacent extension bars (30) so that the first barrel (1) and the second barrel (3) are limited to do relative movement in the length direction;
• a bulge (31) is arranged on an inner sidewall of the second barrel (3), and the bulge (31) is received in the polygonal neck (51) and cannot get out of the polygonal neck;
• and when the second barrel (3) and the first barrel (1) do relative movement in an axial direction, the bulge (31) can slide around the limiting stopper (52) within the polygonal neck (51);
• the limiting stopper (52) is located in a middle region of the polygonal neck (51), and the bulge (31) is clamped into the limiting stopper (52) when the second barrel (3) and the first barrel (1) do relative movement in the axial direction;
• and the ink cartridge (2) is exposed in a first stage in which the second barrel (3) and the first barrel (1) approach each other in the axial direction;
• and
• the nib (2) is hidden in a second stage in which the bulge (31) is separated from the limiting stopper (52) and the second barrel (3) and the first barrel (1) get away from each other in the axial direction.