Anti-bottom-falling swivel glide

A swivel glide, comprising a metal screw stem (1), a hemispherical plastic connecting seat (3) and a hemispherical plastic base (6), wherein a lower end of the metal screw stem (1) is connected to a top of the hemispherical plastic connecting seat (3);

• wherein the hemispherical plastic connecting seat (3) is formed by injection molding of plastic parts, wherein a bottom of the hemispherical plastic connecting seat (3) is provided with a cavity (9), wherein a side wall of the cavity (9) is provided with a concave arc-shaped spherical surface (4), wherein an outer side wall of the hemispherical plastic base (6) is provided with a convex arc-shaped spherical surface (7), wherein the convex arc-shaped spherical surface (7) is clamped in the concave arc-shaped spherical surface (4), and wherein a diameter of the concave arc-shaped spherical surface (4) is 1 mm larger than a diameter of the convex arc-shaped spherical surface (7);
• wherein a top of the concave arc-shaped spherical surface (4) is provided with a concave central arc-shaped spherical surface (5) in the center, wherein a top of the convex arc-shaped spherical surface (7) is provided with a convex central arc-shaped spherical surface (8) in the center, and wherein the convex central arc-shaped spherical surface (8) is clamped in the concave central arc-shaped spherical surface (5);
• wherein a circle between the concave arc-shaped spherical surface (4) and the concave central arc-shaped spherical surface (5) is provided with an inclined platform (12) with an upward tilt angle of +/−22 degrees, and wherein a circle between the convex arc-shaped spherical surface (7) and the convex central arc-shaped spherical surface (8) is provided with a horizontal platform (11).