Opening and closing mechanism for portfolio blowing and blowing-stretching mold

An opening and closing mechanism for a portfolio blowing or stretching-blowing mold used for the manufacture of plastic containers such as bottles and flasks, said mold comprising two half-molds pressed against each other in the closed position of the mold, said mechanism comprising:

• a) a stationary common swivel pin (4) supporting the two half-molds (3) in free rotation,
• b) two control arms (9) connected in free rotation at one of their ends to the two half-molds (3) at points on the half-molds located on opposite sides of the swivel pin,
• c) cam means comprising at least one follower roller (16) loosely mounted on a roller-support shaft substantially parallel to said swivel pin (4), and at least one guide cam (17) for causing the roller to move in a direction substantially perpendicular to said swivel pin, towards and away therefrom, and which intersects the pin, and
• d) connection means for joining said roller to the other ends of the two control arms, wherein said connection means comprises two superposed connection rods (13, 14) joined together by coupling means (18-20), said two connection rods supporting, respectively, at one of their ends, the roller-support shaft (16a) and a coupling shaft (10) which joins the other ends of the control arms (9), said rods being mounted so as to rotate freely, at their other ends, on a common pin (15) substantially parallel to the swivel pin supporting the half-molds, and said connection rods extending approximately transversely to a plane (M) containing the swivel pin and the coupling shaft (10).