But telescopic tube

The utility model provides a but telescopic tube, includes 4 sleeve pipe arcs, support connecting rod and 1 cylindrical thread connecting rod and U type connecting plate and circular connecting plate, support the connecting rod and go up bracing piece and 4 under bracing connecting rods including 4 symmetrical of setting up, the sleeve pipe arc includes interior sleeve pipe arc and outer tube arc, interior sleeve pipe arc and the stack of outer tube arc form complete circular closed sleeve pipe, the concave underrun screw fixed mounting of U type connecting plate is on the inner wall of sleeve pipe arc, every sleeve pipe arc passes through U type connecting plate and goes up bracing piece and 1 lower support rod swing joint with 1 simultaneously, the cylindrical thread connecting rod passes the screw of upper and lower circular connecting plate in proper order, under the user state, thereby contained angle alpha's size changes the size by the but telescopic tube diameter D of 4 sleeve pipe arcs formation on changing through positive reverse rotating cylindrical thread connecting rod, between the lower support rod. This but telescopic tube simple structure, construction convenience, repeatedly usable.