Cone: in the bolt ball grid steel ball and thick diameter connection, in order to avoid the pipe head collision (a ball to connect 8 root canal) and the pipe head is made into conical, tapered to the steel pipe welded on the preform is called the cone head.

Sleeve: when a steel tube is connected to a ball, a six angle sleeve is designed to make the bolt of the head of the steel tube be tightly screwed in the hole of the ball.

The cone head is a rotating thick wall shell that receives the pull from the bolt or the axisymmetric pressure acting on the sleeve. The cone head and the bolt are rotational axisymmetric bodies, and the constraint condition of the cone head and the bolt is also axisymmetric.

No nut sleeve commonly known as grid, it has a hole, set to high strength bolts, high strength bolt hole alignment on the keyway, put the top wire screw, so with the wrench nut without thread (sleeve) and high-strength bolt rod which will rotate. The utility model has the advantages of high strength, good corrosion resistance, good decorative beauty, low price and the like.