Clamping unit with double crank drive

A clamping unit for an injection molding machine, comprising:

• a fixed platen;
• a support platen;
• a moving platen arranged between the fixed platen and the support platen;
• an opening and closing mechanism for back and forth movement of the moving platen in relation to the support platen, said opening and closing mechanism being constructed as crank drive having two crank disks which are arranged in parallel side-by-side disposition and connected in fixed rotative engagement, with each of the crank disks linked by first connecting rods to the support platen and by second connecting rods to the moving platen, a drive mechanism for rotating the crank disks wherein at least one of the first and second connecting rods is articulated in eccentric relationship to the crank disks;
• a gear arranged between and connected to the crank disks, said gear being in engagement with the drive mechanism;
• and
• a pulling means extending between the support platen and the fixed platen to allow a buildup of a clamping force between the fixed platen and the moving platen.