Abstract: A bobbin winding device has a switching motor and a switching lever connected to the switching motor. The switching motor is driven by the control unit, and the switching lever is rotated, so that the intermediate position of the detection lever is changed to one side in the rotation direction of the detection lever. This allows changing the winding diameter of the bobbin thread wound on different bobbin diameters. Here, the bobbin winding device has a color sensor which detects the outer diameter of the bobbin mounted on the spool shaft. The control unit drives the switching motor to rotate the switching lever based on the detected outer diameter of the bobbin. Therefore, the user can wind the bobbin thread around the bobbins having different outer diameters without rotating the switching lever from the initial position based on the outer diameter of the bobbins to be mounted.

Abstract: A thread winder includes a thread winding shaft into which a bobbin shaft is inserted so that a bobbin is detachably attached to the thread winding shaft, a rotating mechanism rotating the thread winding shaft to wind a thread on the bobbin, a thread winding shaft switching mechanism switching the thread winding shaft between a preparatory position and a winding position, a guiding member guiding the thread from a thread spool to the bobbin, a guiding member position switching mechanism switching the guiding member between a guide position and a retreat position, and a link mechanism links both switching mechanisms so that the guiding member is located at the guide position when the thread winding shaft assumes the preparatory position and so that the guide member is located at the retreat position when the thread winding shaft assumes the winding position.