Apparatus and lower thread winding-spool for detecting the ending region of lower thread of sewing machine

A lower thread ending region detection apparatus (LTERDA) comprising:

• a light control unit (LCU), which carries out at least one of the functions of emitting light, reflecting light, passing or penetrating light and blocking light, and is constructed so that it rotates during the usage of a part of lower thread due to the effect of the physical bearing power (PBP) of the lower thread if the lower thread of the ending region is still left, while it does not rotate despite the continual usage of the lower thread if the physical bearing power (PBP) becomes less than a certain level as the lower thread of the ending region is unwound;
• a light receiving unit (LRU), which receives the light transferred out by the light control unit (LCU) and outputs a detection signal;
• and a control and notification unit (CNU), which determines whether a sewing machine motor (SMM) rotates by analyzing at least one of the detection signals between the light receiving unit (LRU)'s output signal and a motor rotation sensing output signal, whether the light control unit (LCU) rotates by analyzing the detection signal output from the light receiving unit (LRU), and whether the lower thread has reached the ending region based on determinations of both the sewing machine motor (SMM)'s rotation and the light control unit (LCU)'s rotation, and outputs the result to the user.

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A lower thread winding-spool, which composes a thread bobbin used in a lower thread ending region detection apparatus (LTERDA), comprising:

• a cylindrical body formed with a bobbin spindle hole (BSH),
• wherein on the inner surface of the bobbin spindle hole (BSH) of the cylindrical body, a parking part insertion structure (PPIS) is formed to allow a thread bobbin parking part (TBPP), which is installed on a rotating plate (RTPL) that composes the lower thread ending region detection apparatus (LTERDA) and supports the function of detecting whether a part of lower thread wound on the thread bobbin has reached its ending region or the lower thread has been broken, to be easily inserted.