Abstract: A caster may include a shaft, a first elastic ring, a C-shaped ring, and a second elastic ring. The shaft has one end inserted and secured in a wheel, and a first rod is extended from the other end of the shaft, and a second rod protrudes from an end of the first rod. The diameter of the first rod is larger than that of the second rod, and an end of the second rod comprises a flexible portion. The shaft only needs to be processed to form the second rod and the flexible portion, and the first elastic ring and the second elastic ring which are identical are adapted to be formed through the same mold so as to save the manufacturing cost.

Abstract: A caster may include a shaft, a first elastic ring, a C-shaped ring, and a second elastic ring. The shaft has one end inserted and secured in a wheel, and a first rod is extended from the other end of the shaft, and a second rod protrudes from an end of the first rod. The diameter of the first rod is larger than that of the second rod, and an end of the second rod comprises a flexible portion. The shaft only needs to be processed to form the second rod and the flexible portion, and the first elastic ring and the second elastic ring which are identical are adapted to be formed through the same mold so as to save the manufacturing cost.

Abstract: A chair covering includes a main frame and a mesh-like support member. The chair covering is a seat covering, backrest covering, or head covering. The main frame includes a first frame and a second frame, wherein the material of the first frame is softer than that of the second frame. The periphery of the mesh-like support member is mounted between the connection portions of the first frame and the second frame, an appropriated portion of the first frame, or an appropriated portion of the second frame.

Abstract: Provided is a plastic fastening mechanism including an intermediate main body having an axial, shouldered first through hole, two wings each having an axial, shouldered second through hole, and two flexible interconnections each formed between the wing and the main body; and elastomeric first and second elements each shaped to conform to the rear of either the first or second member. The main body is threadedly secured to a chair J-bar and the wings are threadedly secured to chair backrest. The main body of each of another two plastic fastening mechanisms is threadedly secured to the J-bar, and the wings thereof are threadedly secured to chair headrest. Moreover, there are provided two elastomeric mechanisms shaped to conform to the rears of the fastening mechanisms. The elastomeric mechanism includes an intermediate, hollow member, two side receptacles, and second interconnections each formed between the hollow member and either receptacle.