Rotary looptaker and bobbin case with magnetic repulsive force therebetween

In a rotary looptaker being of the type accommodating a bobbin case therein, said bobbin case having an annular rib in the shape of an outward flange having a radially outermost surfaces and upper and lower axially facing surfaces formed on an outer peripheral portion of said bobbin case, and said looptaker having an annular groove formed on an inner peripheral portion thereof having a radially innermost surface and upper and lower axially facing surfaces and being driven for rotation about an axis of rotation with said annular rib fitted into said annular groove, the improvement comprising:

• at least one first permanent magnet forming at least part of said annular rib of said bobbin case, said at least one first permanent magnet being magnetized in an axial direction with respect to said axis of rotation and having a surface thereof of one polarity forming at least part of one of said axially facing surfaces of said annular rib;
• and
• at least one second permanent magnet forming at least part of said annular groove of said looptaker and said at least one second permanent magnet being magnetized in said axial direction and having a surface thereof of said one polarity forming at least part of one of said axially facing surfaces of said annular groove facing said axially facing surface of said annular rib formed at least in part by said surface of said one polarity of said at least one first permanent magnet, whereby a magnetic repulsive force is generated between said annular rib and said annular groove.