A string collecting device, comprising a rotating part and a string winding part configured to wind a string, wherein the rotating part is provided with at least one movable part that can be moved, and each movable part is configured to be engaged with the string winding part when the rotating part is rotated towards a string collecting direction, wherein when the movable part is engaged with the string winding part , the rotating part , the at least one movable part and the string winding part are connected to be in synchronous rotation, wherein the rotating part is provided with a toggle portion configured to drive the at least one movable part to move in a radial direction of the rotating part , wherein each movable part comprises a pull-out surface interacting with the toggle portion; the toggle portion comprises a pull-out structure , and the pull-out structure is configured to press the pull-out surface , when the rotating part is rotated towards the string collecting direction, so as to drive the movable part to be engaged with the string winding part ; the pull-out structure is provided on a central axis of the rotating part ; the pull-out structure comprises at least one pressing portion which is in one-to-one correspondence with the at least one movable part , and each pressing portion is configured to press against the respective pull-out surface ; the toggle portion further comprises a pull-back structure , and the movable part comprises a pull-back surface arranged opposite to the pull-out surface ; the pull-back structure is configured to push and press the pull-back surface , when the rotating part is rotated towards a direction opposite to the string collecting direction, so as to drive the at least one movable part to be separated from the string winding part ; and the pull-back structure comprises at least one pull-back block, which is in one-to-one correspondence with the movable part . wherein the rotating part is provided with at least one movable part that can be moved, and each movable part is configured to be engaged with the string winding part when the rotating part is rotated towards a string collecting direction, wherein when the movable part is engaged with the string winding part , the rotating part , the at least one movable part and the string winding part are connected to be in synchronous rotation, wherein the rotating part is provided with a toggle portion configured to drive the at least one movable part to move in a radial direction of the rotating part , wherein each movable part comprises a pull-out surface interacting with the toggle portion; the toggle portion comprises a pull-out structure , and the pull-out structure is configured to press the pull-out surface , when the rotating part is rotated towards the string collecting direction, so as to drive the movable part to be engaged with the string winding part ; the pull-out structure is provided on a central axis of the rotating part ; the pull-out structure comprises at least one pressing portion which is in one-to-one correspondence with the at least one movable part , and each pressing portion is configured to press against the respective pull-out surface ; the toggle portion further comprises a pull-back structure , and the movable part comprises a pull-back surface arranged opposite to the pull-out surface ; the pull-back structure is configured to push and press the pull-back surface , when the rotating part is rotated towards a direction opposite to the string collecting direction, so as to drive the at least one movable part to be separated from the string winding part ; and the pull-back structure comprises at least one pull-back block, which is in one-to-one correspondence with the movable part . <EOS>