Dropper separating and positioning mechanism

A dropper positioning mechanism for positioning a dropper suspended by a supporting bar and constituted by a thin plate having an upper end portion, a center portion and a lower end portion, first and second side edges, said upper end portion of said dropper having a through bore through which said supporting bar passes, said center portion of said dropper having a threading bore which is positioned on a predetermined threading path and through which a thread is to be passed during a threading operation, said lower portion having first and second side edges, said threading path being in a perpendicular relationship with the axis of said threading bore, said dropper positioning mechanism comprising:

• first and second positioning members facing said first side edge and said second side edge, respectively, of said lower end portion of said suspended dropper, said first and second positioning members being movable toward and away from each other in a horizontal direction, said first positioning member having a guide portion and a stop portion, said guide portion of said first positioning member being inclined at a predetermined angle with respect to said threading path and engageable with said first side edge of said lower end portion of said dropper, said stop portion of said first positioning member extending from one end of said guide portion of said first positioning member toward said second positioning member and being engageable with said first side edge of said lower end portion of said dropper, said second positioning member having a guide portion and a stop portion, said guide portion of said second positioning member being inclined at a predetermined angle with respect to said threading path and engageable with said second side edge of said lower end portion of said dropper, and said stop portion of said second positioning member extending from one end of said guide portion of said second positioning member toward said first positioning member and being engageable with said second side edge of said lower end portion of said dropper;
• and
• moving means for moving said first and second positioning members toward and away from each other,
• wherein said dropper is twisted by said guide portions of said first and second positioning members and positioned by both said guide portions and said stop portions of said first and second positioning members when said first and second positioning members are moved toward each other by said moving means, and wherein said thread is passed through said threading bore of said dropper when said dropper is twisted and positioned by said first and second positioning members.