8.2 Mold clamp Units (Hydraulic,Toggle,and Hydromechanical)
There are three types of clamp units
1. Fully hydraulic. These provide very accurate control of clamping tonnage coupled with precise speed control during the opening and closing phases. Platen support is centrally located, offering very rigid assembly and platen parallelism. The main disadvantage is the relatively slow clamping speed due to the time required to reach full tonnage.
2. Toggle system. The toggle system utilizes a single, small hydraulic cylinder that opens and closes the mold through a set of mechanical linkages. Full clamping tonnage is accomplished when the linkage is in the closed position-arrived at more rapidly since the single, small diameter hydraulic cylinder operates much faster.
3. Hydromechanical. The hydromechanical system take advantage of the rapid moving smaller hydraulic cylinder to move the larger clamping piston utilizing a mechanical blocking device or shutter. The size of the hydraulic column is substantially reduced as compared to the column used with the fully hydraulic system.