Patent ID: 6402998
Filing Date: 2002-06-11
Classification: B29C

Abstract:
A motor-driven mold clamping device comprising:a servo motor; a movable platen; a toggle mechanism driven by said servo motor to advance and retract said movable platen for clamping a mold, said toggle mechanism having a crosshead associated with said movable platen; a setting unit for setting a position of said movable platen; a position detector for detecting a position of said crosshead; and a control unit for approximating a correlation between the position of said crosshead and the position of said movable platen by using at least one mathematical function of a quadratic or higher order, said control unit calculating a calculated position of said crosshead by the at least one mathematical function with the position of said movable platen set by using said setting unit to control the position of said crosshead for the control of mold opening and mold closing positions, the control of the position being made in accordance with the detected position supplied from said position detector and the calculated crosshead position, wherein said control unit being configured to divide a movable range where said movable platen travels into a plurality of regions and said control unit also approximates a correlation between the position of said crosshead and the position of said movable platen for each of the divided regions by using the mathematical function.