Patent ID: 6050804
Filing Date: 2000-04-18
Classification: B29C

Abstract:
A clamping apparatus for an injection molding machine, comprising:a stationary platen for holding a stationary mold;a movable platen for holding a movable mold, disposed opposite to the stationary platen;a plurality of tie bars for supporting and guiding the movable platen, each of the tie bars having a first end part fixedly joined to the stationary platen and an opposite second end part with a threaded section;a rear plate supporting the tie bars by their second end parts, the rear plate being disposed such that the movable platen is positioned between the rear plate and the stationary platen;a toggle joint interconnecting the rear plate and the movable platen to drive the movable platen;a threaded shaft supported for rotation on the rear plate and having a threaded section;a first motor for driving the threaded shaft for rotation;a crosshead provided at a link among those forming the toggle joint, the crosshead having a threaded bore engaged with the threaded section of the threaded shaft, the crosshead being capable of moving axially on the threaded shaft to operate the toggle joint when the threaded shaft is rotated;a first bevel gear mounted on the threaded shaft for rotation relatively to the threaded shaft;a second motor for driving the first bevel gear for rotation on the threaded shaft;second bevel gears supported for rotation on the rear plate, each of the second bevel gears having a threaded bore and engaged respectively with the threaded sections of the tie bars; anda plurality of transmission mechanisms for transmitting the driving force of the first bevel gear to the second bevel gears, each of the transmission mechanisms having a third bevel gear engaged with the first bevel gear, a fourth bevel gear engaged with the second bevel gear, and a clutch interposed between the third and the fourth bevel gear.