An injection molding includes: a clamping mechanism (conversion mechanism and toggle mechanism) for moving a fixed platen that retains a fixed die toward a fixed platen that retains a fixed die to bring the fixed die and the movable die into contract, and generating a clamping force therebetween; a drive source (mold opening/closing motor) for driving the clamping mechanism; a clamping force detection unit for detecting the clamping force; an elongation value detection unit for detecting an elongation value indicating the amount of elongation of a tie bar that extends as the clamping force is generated; and an abnormality determination unit for determining an abnormality in the injection molding machine on the basis of the ratio of the elongation value and the clamping force.

A clamping device (14) comprises a pressure receiving platen (24), a stationary platen (20), a movable platen (22), a toggle mechanism (28), and a drive device (37). A first position detector (38a) detects the operation amount of the movable platen (22) based on the position of a crosshead (26); a pressure detector (35) detects the actual clamping force of a mold (19); and a second position detector (43) detects the actual position of the movable platen (22). A control portion (50) has first correction means correcting the operation amount of the movable platen (22) at the time of a minute mold opening operation based on the actual clamping force and on the set clamping force, and second correction means correcting the operation amount of the movable platen (22) at the time of the minute mold opening operation based on the operation amount of the movable platen (22) and on the position of the movable platen (22).

A drive unit for driving at least one component of a molding machine, includes a first support, a spindle, a drive for rotating the spindle, a second support, a nut, at least one rod arranged on the second support, and an oil-tight seal. The spindle, the second support, and the nut are arranged along the spindle inside the oil-tight space in each movement position of the second support and the nut.

When an injection molding machine performs molding, the mold clamping force on the mold is adjusted on the basis of a mold displacement of the mold or the injection peak pressure and injection foremost position so that the molding is performed without causing flash and by an appropriate mold clamping force with which energy can be reduced. The amount of mold displacement and also the injection peak pressure and the injection foremost position are monitored during automatic operation. If there occurs no mold displacement change exceeding a threshold or if there occurs no injection peak pressure anomaly or injection foremost position anomaly exceeding thresholds, the automatic operation is continued. If the mold displacement change occurs or if the injection peak pressure anomaly and the injection foremost position anomaly occur, the operation of the injection molding machine is stopped.

There is provided an opening/closing apparatus which can eliminate the influence of a slight gap formed between a bush and a pin in a link connecting portion of a toggle link mechanism and, in addition, can enhance workability e.g mold replacement,

An opening/closing apparatus according to an embodiment includes: a fixed platen 20 to which one mold 21 of a pair of molds is to be mounted; a movable platen 22 to which the other mold 23 is to be mounted; a pressure-receiving platen 24 connected to the fixed platen 20 via tie bars 36; an opening/closing mechanism for opening/closing the molds by moving the movable platen 22 back and forth, including a toggle link mechanism 28 connecting the pressure-receiving platen 24 and the movable platen 22; a first drive mechanism for driving the opening/closing mechanism; and a second drive mechanism 50 for applying a load to the movable platen 22 in a given direction in conjunction with the first drive mechanism.

An opening/closing device (14) includes: a stationary platen (20), a movable platen (22) capable of moving toward or away from the stationary platen (20), an opening/closing mechanism (28) having a plurality of toggle links (30, 31, 32) at least one (32) of which is connected to the movable platen (22); a driving device (37) including a cross head (26) connected to at least one (30) of the toggle links and capable of moving the movable platen (22), and a control portion (50). The control portion (50) is configured to control the cross head (26) such that the movable platen (22) moves at fixed speed during fine die-opening operation.

The present invention provides a movable platen support apparatus which, with a linear guide having a minimum necessary load rating, can secure a sufficient traveling life of the linear guide and, in addition, can secure the rigidity of the linear guide which is necessary and sufficient taking into consideration a moment that acts on a movable platen. A movable platen support apparatus 40 according to the present invention includes a guide mechanism which movably engages a rail 41 extending on a frame 11 in the direction of movement of a movable platen 16, to which a movable mold 19 is to be mounted, and which movably supports the movable platen 16. The guide mechanism includes a linear guide 42 composed of blocks 42a to 42d arranged in a line, in which at least one of the blocks 42a to 42d, e.g. the blocks 42b, 42c, has a load rating which differs from the load rating(s) of the other block(s), e.g. the blocks 42a, 42d.

A movable platen according to the present invention includes: a mold clamping platen 42 having a projecting portion 62 in a mold closing direction-side surface; a mold mounting platen 44 mounted to the projecting portion 62 of the mold clamping paten 42; and a guide mechanism 50 fixed to the mold clamping paten 42 and supporting the mold mounting platen 44. Only the mold clamping paten 42 is fixed to the guide mechanism 50, while the mold mounting platen 44 is not fixed but placed on platen surface support portions 52.

An injection molding apparatus comprises a support base and a mold carrier removably mounted to the support base. The mold carrier includes a mounting plate with attachment features for engaging the support base. A mold with two mold plates is slidably mounted to the mounting 5 plate. A clamp is operable to move the plates between open and closed positions. In the closed position, the plates abut one another. In the open position, the plates are spaced apart for removing molded articles.

A toggle link clamping mechanism with a negative rear angle comprises a tail plate, a movable mold plate, and a toggle link mechanism. The toggle link mechanism comprises a thrust seat and a pair of link assemblies symmetrically distributed with one above the other. Each link assembly is composed of two independent front links, three independent rear links, and a small link, wherein front ends of the two front links are hinged to a rear face of the movable mold plate, rear ends of the two front links are hinged to front ends of the three rear links, rear ends of the three rear links are hinged to a front face of the tail plate, one end of the small link penetrates through a middle portion of the rear link in the middle and is hinged to the middle portion of the rear link in the middle.