APPARECCHIATURA PER LA FORMATURA A COMPRESSIONE DI PREFORME PER CONTENITORI IN RESINA SINTETICA.

摘要

The apparatus is for compression moulding synthetic resin preforms by pressure-inserting a mould punch (15) into a die cavity (20a) loaded with a charge (8). The preforms (9) comprise an upper neck (91) provided with projections and a hollow body (92) positioned below the neck (91). The apparatus is characterized in that each die comprises a first tubular element (51) which is axially fixed during the charge loading and moulding stage, and a second tubular element (52) which is axially movable telescopically relative to the first tubular element (51), to assume a first position in which it projects out of the first tubular element (51) to a maximum extent in order to increase the axial dimension of the die cavity (20a), and a second position in which it is retracted into the first tubular element (51) to a maximum extent in order to define the die cavity (20a) provided for the final moulding stage, and thrust means (80) to normally maintain said second tubular element (52) in its first position, the action of said thrust means (80) being overcome during the moulding stage.