Abstract: An injection molding system for a material vulcanizable by heat comprises a mould (13, 113, 213) with molding impressions (14, 114, 214) fed from material-feeding channels (17, 19, 117, 119, 217, 219). The mould is separable into a first portion (16, 116, 216) containing first sections (17, 117, 217) of the feeding channels and a second portion (18, 118, 218) containing end sections (19, 119, 219) of the feeding channels and the molding impressions (14, 114, 214).

Abstract: An injection molding machine comprises: a body (12) provided with a rectilinear cavity having a first end which is open and a second end (20a) opposite to the first one in which a nozzle (21) for injection into the mould (16) is disposed; a floating punch (15) that is slidable within the cavity in the hollow body (12) between said first and second ends to define an injection chamber (20) with said second end (20a), said punch being provided with a passage (15c) to supply a way for access to the chamber (20); feeding means (13) adapted to be received in the first open end of the hollow body, to feed the injection chamber (20) with the material through the passage (15c) in the floating punch (15); thrust means (14) adapted to be received in the first open end of the hollow body (12) as an alternative to the feeding means (13), to make the floating punch (15) slide towards the injection nozzle (21), thereby causing injection into the mould of the material previously fed to the chamber (20).

Abstract: An open mill or mixer for the processing of rubber and plastics comprises an additional or third roll for a higher productivity and, when upstream of the open mill a closed mixer is provided, for a readier cooling of the mixture. The two usual rolls are not placed at the same level, but one is slightly upper, while the third additional roll engages the lower one in the bottom part thereof. The angle formed by the lines joining the center of this latter with the centers of the other two rolls is comprised between 60.degree. and 120.degree. and is preferably of 80.degree.-90.degree.. Also the third roll is motor-driven, as well as the other two and has a higher peripheral speed than the roll which is wrapped up by the mix sheet and has the lower speed.