A brake control method for an injection molding machine includes the steps of obtaining mold clamping force information indicating the mold clamping force of a mold opening/closing mechanism and determining whether or not the mold clamping force of the mold opening/closing mechanism exceeds a predetermined value, based on the mold clamping force information. When the mold clamping force of the mold opening/closing mechanism does not exceed the predetermined value and when a servo amplifier cuts off the supply of power to a servomotor that drives the mold opening/closing mechanism, a brake mechanism for applying braking force to the mold opening/closing mechanism is actuated. On the other hand, when the mold clamping force of the mold opening/closing mechanism exceeds the predetermined value, the brake mechanism will not be actuated.

A clamping apparatus of an injection molding machine is provided. A first driving device operates a movable platen to perform mold opening/closing. A second driving device applies a clamping force to the movable platen. A screw mechanism converts rotational power of the driving devices into linear power. By contact/separation between a first rotation plate coupled to a screw shaft and a second rotation plate, a power transmission device switches transmission of power from the second driving device to the screw mechanism. At the normal time, an urging mechanism integrally moves the screw shaft and the first rotation plate in a mold closing direction and releases the connection of the second driving device. When the mold closing is completed, the urging mechanism allows the screw shaft and the first rotation plate to integrally move in a mold opening direction, and brings the second driving device into a connected state.

An injection molding apparatus including a stack mold tool and a ball screw centering device. The stack mold tool including a stationary mold block, a center mold block movable relative to the stationary mold block, and a distal mold block movable relative to the center mold block. The ball screw centering device includes a center bearing housing connected to the center mold block, a rotatable shaft having a first side ball track and a second side ball track, a first nut coupled to the stationary mold block, the first nut including a track portion cooperating with the first side ball track to define a passage for a first set of ball bearings, and a second nut coupled to the distal mold block, the first nut including a track portion cooperating with the second side ball track to define a passage for a second set of ball bearings.

A brake control method for an injection molding machine includes the steps of obtaining mold clamping force information indicating the mold clamping force of a mold opening/closing mechanism and determining whether or not the mold clamping force of the mold opening/closing mechanism exceeds a predetermined value, based on the mold clamping force information. When the mold clamping force of the mold opening/closing mechanism does not exceed the predetermined value and when a servo amplifier cuts off the supply of power to a servomotor that drives the mold opening/closing mechanism, a brake mechanism for applying braking force to the mold opening/closing mechanism is actuated. On the other hand, when the mold clamping force of the mold opening/closing mechanism exceeds the predetermined value, the brake mechanism will not be actuated.

An injection molding machine capable of opening/closing a movable mold relative to a stationary mold by moving a crosshead backward and forward to move a movable platen backward and forward relative to a stationary platen through a toggle link. The injection molding machine includes a reciprocating mechanism that receives a counterforce exerted on the crosshead in the back-and-forth direction when the movable mold and the stationary mold are closed, and a load acquisition unit that acquires a load exerted on the reciprocating mechanism in a direction perpendicular to the back-and-forth direction of the crosshead.

Provided is a mold opening/closing device that can prevent a ball screw shaft from reaching a risky speed while using a ball screw having a cantilever supporting structure. A mold clamping device according to the present invention is provided with: a ball screw having a ball screw shaft and a ball screw nut that meshes with the ball screw shaft; and a motor that drives the ball screw. One end of the ball screw shaft is supported by a fixation plate or a movable plate so as to be rotatable or non-rotatable, while being restricted in movement in an axial direction and thereby serving as a fixed end, and the other end thereof serves as a free end. Further, the mold clamping device is characterized in that a distance between the ball screw nut and the fixed end is shorter than a distance between the fixed plate and the movable plate.

The present invention aims to stably maintain the posture of a crosshead by means of guide bars without an increase in the size of a link housing or tie bars. An opening/closing apparatus according to the present invention includes: a pressure-receiving plate (14); a fixed platen (12) to which a fixed mold (18) is to be mounted; a frame (11) on which the pressure-receiving plate (14) and the fixed platen (12) are installed; and a movable platen (16) which is movable on the frame (11) and to which a movable mold (19) is to be mounted. The opening/closing apparatus also includes: a crosshead movement mechanism including guide members (50) extending from the pressure-receiving plate (14), and a crosshead (25) whose movement is guided by the guide members (50); an opening/closing mechanism for opening/closing a mold, including a toggle link mechanism (22) connecting the pressure-receiving plate (14), the crosshead (25) and the movable platen (16), and a drive mechanism for driving the toggle link mechanism (22); and a guide member support mechanism for supporting the guide members (50). The guide member support mechanism has support portions (56) which are slidable on the upper surface of the frame (11).

The present invention aims to stably maintain the posture of a crosshead by means of guide bars without an increase in the size of a link housing or tie bars. An opening/closing apparatus according to the present invention includes: a pressure-receiving plate (14); a fixed platen (12) to which a fixed mold (18) is to be mounted; a frame (11) on which the pressure-receiving plate (14) and the fixed platen (12) are installed; and a movable platen (16) which is movable on the frame (11) and to which a movable mold (19) is to be mounted. The opening/closing apparatus also includes: a crosshead movement mechanism including guide members (50) extending from the pressure-receiving plate (14), and a crosshead (25) whose movement is guided by the guide members (50); an opening/closing mechanism for opening/closing a mold, including a toggle link mechanism (22) connecting the pressure-receiving plate (14), the crosshead (25) and the movable platen (16), and a drive mechanism for driving the toggle link mechanism (22); and a guide member support mechanism for supporting the guide members (50). The guide member support mechanism has support portions (56) which are slidable on the upper surface of the frame (11).

A molding machine includes; a fixed platen capable of having a fixed mold attached thereto; a moving platen capable of having a moving mold attached thereto; a mold clamping mechanism clamping the moving mold and the fixed mold with each other by moving the moving mold; a driving unit operating the mold clamping mechanism; and a control unit controlling the driving unit, wherein the control unit compensates an operation loss of the driving unit occurring from an operation start of the driving unit to an operation start of the moving mold to set the moving mold at a desired position.

A tandem mold for creating injection-molded parts from synthetic material includes a first part (2), a second part (4), a third part (6), and a guide (20, 22, 26, 28). A first parting surface is defined between the first part (2) and the third part (6), and a second parting surface is defined between the second part (4) and the third part (6). The mold also includes, for each parting surface, at least one mechanical stop (44) that is movable between a first position, where said stop prevents a drive mechanism from reaching the closed position of the mold, and a second position, or retracted position, where the mold can reach its closed position.