Patent ID: 7288221

Claim:
A mold clamping apparatus for clamping a fixed die and a movable die on a base, comprising: a fixed die plate fixed on the base and holding the fixed die; a movable die plate holding the movable die and provided in the opening or closing direction on the base movably; a tie bar having a piston and a coupled section; a cylinder for mold clamping equipped in either of the fixed die plate or the movable die plate, having a cylinder chamber accommodating the piston of the tie bar and at least two driving liquid supply ports supplying pressurized driving liquid for generating mold clamping force to the cylinder chamber; a coupling section being equipped in the other of the fixed die plate or the movable die plate and enabling to unite or release for the coupled section of the tie bar; a die plate position detection sensor for detecting a position of the movable die plate on the base: a position detector for detecting a position of the tie bar in a moving direction of the tie bar; a direction change valve coupled with each of the driving liquid supply ports for changing a supply of the driving liquid between a first cylinder chamber and a second cylinder chamber zoned by the piston of the cylinder for mold clamping, and a control unit for specifying a position of the tie bar where the coupling section and the coupled section are to be coupled based on the position of the movable die plate detected by the die plate position detection sensor, and controlling the tie bar at the specified position by controlling the direction change valve in response to the position of the tie bar detected by the position detector in a state where the movable die and the fixed die are contacted and a molding material is provided to a sleeve coupled with a cavity formed by the fixed die and the movable die, wherein said specifying a position of the tie bar and said controlling the tie bar at the specified position is performed for every molding cycle.