Pre-loadable spring roller blind

A pre-loadable spring roller blind, comprising a spring bar (11), a limiting spring (12) sleeved on an outer side of the spring bar (11), a spring tail plug (13) and a limiting pipe plug sleeve (14), wherein the spring tail plug (13) comprises a first rotating plug (131), a first adjusting core (132) and a holding spring (133);

• the first rotating plug (131) is sleeved at a tail of the spring bar (11);
• the first rotating plug (131) is fixedly connected with a tail of the limiting spring (12);
• the spring bar (11) and the first rotating plug (131) are provided with limiting structures for preventing the first rotating plug (131) from sliding toward a head of the spring bar (11);
• and inner wall of the first rotating plug (131) is transversely provided with a first positioning component (1311);
• a cavity with an opening that faces the tail of the spring bar (11) is located between the first rotating plug (131) and the spring bar (11);
• and the first rotating plug (131) has a degree of freedom for rotation relative to the spring bar (11);
• the holding spring (133) is sleeved on the spring bar (11);
• the holding spring (133) and the spring bar (11) are in interference fit;
• the holding spring (133) is located in the cavity;
• ends of the holding spring (133) are each provided with a lead-out part;
• the first positioning component (1311) is transversely arranged between the lead-out parts;
• one of the lead-out parts on a left of the first positioning component (1311) has a degree of freedom for holding with the spring bar (11) in a counterclockwise direction;
• and the other of the lead-out parts on a right of the first positioning component (1311) has a degree of freedom for holding with the spring bar (11) in a clockwise direction;
• the first adjusting core (132) comprises a second limiting part (1322), and a toggle part (1321) connected with the second limiting part (1322);
• the second limiting part (1322) is sleeved at the tail of the spring bar (11);
• the toggle part (1321) is transversely inserted between the two lead-out parts of the holding spring (133);
• the lead-out part on a left of the toggle part has a degree of freedom for driving the holding spring (133) to spin off the spring bar (11) in the clockwise direction;
• and the lead-out part on a right of the toggle part has a degree of freedom for driving the holding spring (133) to spin off the spring bar (11) in the counterclockwise direction;
• the second limiting part (1322) and the toggle part (1321) have a degree of freedom of rotation relative to the spring bar (11);
• the head of the spring bar (11) is fixedly connected with a screw rod (111) arranged coaxially;
• the limiting pipe plug sleeve (14) is sleeved on an outer side of the screw rod (111), and is fixedly connected with a head of the limiting spring (12);
• an adjusting nut (15) is arranged between the limiting pipe plug sleeve (14) and the screw rod (111);
• the adjusting nut (15) is in threaded connection with the screw rod (111);
• and the adjusting nut (15) moves along an axial direction of the limiting pipe plug sleeve (14) and being rotatable synchronously with the limiting pipe plug sleeve (14).