Patent ID: 6250905
Filing Date: 2001-06-26
Classification: B29C

Abstract:
A closing unit of an injection molding machine comprising a fixed injection plate with injection opening and a movable closure plate which form clamping plates for an injection mold, a displacement device for the movable closure plate for the positioning of the movable closure plate relative to the fixed injection plate, a plurality of hydraulic force cylinders on the fixed injection plate to produce a closing force, the closure plate having one connecting rod per cylinder for transmitting the closing force from a piston of the force cylinder to the movable closure plate, wherein locking bushings are provided on the injection plate which are turnable around their axes and which are in each case connected with the piston of a respective one of the hydraulic force cylinders, the connecting rods passing axially through the hydraulic force cylinders and the locking bushings, an actuator for turning the locking bushings into a first and a second angular position, first locking means along a rod section A on the connecting rods and second locking means in the locking bushing, said first and second locking means registering with each other in such a manner that in the first angular position, they permit an axial passage of the connecting rods through the hydraulic force cylinders and the locking bushings, and that in the second angular position the first locking means in the rod section A on the connecting rods cooperates with the second locking means of the locking bushings for the transmission of the required closing force; and,the piston of the hydraulic force cylinder is connected via a screw thread to the locking bushing, the piston being secured against rotation, so that by the turning of the locking bushing around an angle .gamma. from the first angular position into the second angular position, the connecting rod is advanced relative to the piston.