Ball striking cue with self-locking conical joint

A ball striking cue comprising a butt section, a shaft section, and a self-locking joint for removably interconnecting the butt and shaft sections end to end along a longitudinal geometrical axis, said joint comprising:

• a proximate end of one of the butt and shaft sections having an axial hole defining a bottom and an uniformly widening-out inner surface;
• a proximate end of the other of said butt and shaft sections having an axial extension including a free end and an uniformly tapering outer surface;
• wherein the inner and outer surfaces have complementary shapes and the inner surface has smaller radial dimensions than the outer surface whereby when the outer surface is inserted in the inner surface a gap exists between said bottom and free end, and wherein the degree of widening-out of the inner surface and of tapering of the outer surface is function of the nature of the material forming the inner and outer surfaces to enable (a) press fit of the outer surface in the inner surface by forcing the outer surface axially in the inner surface and (b) retention of the outer surface in the inner surface while enabling separation of the inner and outer surfaces by forcing said surfaces axially apart from each other;
• and
• wherein the proximate end of one of said butt and shaft sections comprises an outer threaded axial cylindrical surface on which an internally threaded sleeve is mounted, and wherein the other of said butt and shaft sections comprises an annular abutment surface facing one end of said sleeve, whereby rotation of the internally threaded sleeve on the threaded cylindrical surface causes axial displacement of the internally threaded sleeve on the threaded cylindrical surface and abutment of said one end of the internally threaded sleeve against said annular surface and then axial spreading apart of the inner and outer surfaces.