Abstract: A plastic housing comprises a top wall, a plurality of sidewalls extending from the top wall, each sidewall having a first end adjoining the top wall and an opposite second end, the sidewalls cooperatively defining an opening at the second ends thereof; the top wall has a uniform thickness, and a thickness of each of the sidewalls gradually decreases from the first end to the second end. Because of the shrinkage rate of the second ends of the sidewalls is much greater than the first ends of the sidewalls, the thickness of each sidewall is decreasing from the first end to the second end, therefore, the shrinkage deformation of the sidewalls can be even with the gradient thickness. The warping of the sidewalls is alleviated or is avoided.

Abstract: A rotary connection apparatus comprising a bottom bracket, a top bracket rotatably connected to the bottom bracket, an annular spacer and a plurality of balls. The spacer and the balls are received between the bottom bracket and the top bracket. A thickness of the spacer is less than a diameter of the balls, and the spacer includes a plurality of holding holes, each holding hole has two openings exposed at opposite surfaces of the spacer, and a diameter of each of the openings is less than that of the balls, and a diameter of a central portion of each holding hole is equal to the diameter of the balls; each of the holding holes accommodates one corresponding ball, and each ball has opposite end portions protruding out of the spacer. A spacer is also provided.

Abstract: A demolding mechanism for demolding a molded article with internal thread is provided. The demolding mechanism includes an outer sleeve and a core. The sleeve includes a number of spring legs and a body. Each spring leg has an external thread. The core includes an end portion and a cylindrical shank. The end portion includes a central portion and a number of evenly spaced ribs. The diameter of the core is smaller than that of the sleeve. The sleeve is slidable along the core. When the spring legs move away and disengage from the ribs, the spring legs are configured to deflect inwardly, thereby enabling the external thread thereof to disengage from the inner thread of the molded article.

Abstract: A plastic housing includes a plastic substrate and a decorative pattern layer attached on the plastic substrate. The decorative pattern layer includes an primer layer of a predetermined pattern formed on the plastic substrate and a colored pattern layer printed on the primer layer. The colored pattern layer is impervious to the color of the background color of the color layer, thus enabling housings with different colors to have substantially the same visual effects.