Patent ID: 6722875
Filing Date: 2004-04-20
Classification: B29C

Abstract:
An injection molding machine comprising:a) a stationary base platen upon which a lower mold half is mounted; b) a vertically moveable platen on the bottom side of which is mounted an upper mold half in confronting relation to said bottom mold half; c) an advance mechanism for raising and lowering said moveable platen relative to said stationary platen; d) an injection unit for injecting molding material into one of said mold halves when said mold halves have been moved into a molding relationship; e) a plurality of vertically extending locking rods positioned to straddle said mold halves, each locking rod being attached at one end thereof to said lower stationary platen, extending through a locking rod opening in said moveable platen, and having a plurality of longitudinally spaced annular locking grooves extending over a distance adjacent the opposite locking rod end to a position at least adjacent said moveable platen; f) a locking device having a locked and an unlocked position on the top surface of said moveable platen for locking said moveable platen at a set distance from said stationary platen, said locking device including; i) a caliper for each locking rod having inboard and outboard caliper halves, each caliper half having a generally semi-circular, radially inward protruding lock ring adapted to fit within a locking groove when said inboard and outboard caliper halves are moved together to form a generally circular locking ring; ii) first and second actuating rods, said first rod secured to said inboard caliper half of a first caliper at one end thereof and to said outboard caliper half of a second caliper at its opposite end, said second actuating rod secured to said outboard caliper half of said second caliper at one end thereof and to said inboard caliper half of said first caliper at its opposite end; iii) a piston rod connector plate and a cylinder connector plate, said piston rod connector plate secured to said first actuating rod at a first distance between the ends of said first actuating rod and through which said first actuating rod extends, said piston rod connector plate having a first opening slidably receiving said second actuating rod; said cylinder connector plate fixed to said second actuating rod at a second distance between the ends of said second actuating rod and through which said second actuating rod extends, said cylinder connector plate having an opening slidably receiving said first actuating rod; iv) a compression spring between said piston rod connector plate and said cylinder connector plate simultaneously biasing said inboard and outboard caliper halves of said first and second calipers to a closed position; and, v) an opening mechanism attached to said piston rod connector plate and to said cylinder connector plate for drawing said connector plates towards one another to simultaneously open said inboard and outboard caliper halves of said first and second calipers against the bias of said compression spring.