Rubber injection molds are provided. A rubber injection mold includes a binary form-stripping mold, a trinary form-stripping mold, and a quadruple form-stripping mold. The binary form-stripping mold can include an upper mold and a bottom mold movably connected to each other via a guide post. The trinary form-stripping mold can include an upper mold, a bottom mold, and a middle plate positioned between the upper mold and the bottom mold. The upper mold and the bottom mold movably connected to each other via a guide post welded to the bottom mold. The quadruple form-stripping mold can include an upper mold, a bottom mold, a middle plate, and a middle frame. A guide post is welded to the bottom mold. Side rails can be respectively arranged at two ends of the upper mold and the bottom mold. Upper mold handles are fixedly mounted in the side rails of the upper mold.

It is described a method and an apparatus for injection co-mould and assemble plastic material objects having a first part provided with a hinge pin, and a second part provided with an annular element suitable to be coupled in an articulated manner. The apparatus includes a mould having separated moulding impressions for the two parts to be moulded; a first moulding pin element defining the pin impression and a second moulding pin element defining the annular element impression are provided. The apparatus includes cooling means; particularly the first pin element is internally provided with a channel and a tubular element, being coaxially arranged and defining a cooling gap. A cooling fluid flows through the tubular element and the gap. Cams are provided which axially move the pin elements to cause the automatic assembly of the object during the mould opening and then to allow extracting the moulded object.