JPS6154574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold clamping device for an injection molding machine, and in particular to a so-called two-cylinder type mold clamping device in which the opening and closing of a mold and the mold clamping are performed using separate cylinders. It is an object of the present invention to provide a mold clamping device whose structure can be simplified by using a tie rod that receives force as a guide for a movable platen.

A feature of the present invention is that a tie rod is provided protruding from the fixed platen to guide the movement of the movable platen, and the tie rod has a tie rod attached to the outer peripheral surface of the portion that protrudes from the movable platen to the side opposite to the fixed platen when the mold is closed. In addition to providing an engagement groove for a screw or the like, a split-shaped lock member that can be engaged with and detached from the tie rod through the engagement groove when the mold is closed is provided so as to be slidable in the axial direction of the tie rod, and move with the lock member. The present invention relates to a mold clamping device for an injection molding machine, which includes a mold clamping cylinder interposed between the plate and the mold clamping cylinder.

Embodiments of the present invention will be described below with reference to the drawings.

Although the following embodiments will be explained using a vertical injection molding machine as an example, the present invention can be similarly implemented in a horizontal injection molding machine.

1 is a fixed plate, 2 is a fixed mold attached to the fixed plate 1, 3 is a movable plate, and 4 is a movable die attached to the movable plate 3. A plurality of tie rods 5 (usually four, only two are shown in the figure) are vertically provided on the fixed platen 1 so as to pass through the movable platen 3, and the movable platen 3 is raised and lowered by the tie rods 5. That is, it is configured to guide the movement in the direction toward and away from the stationary plate 1. 6 is a bush provided in the tie rod penetrating portion of the movable platen 3, and 7 is a holder for the bush. Further, 8 is a support plate that supports the upper end of the tie rod 5, and 9 is an opening/closing cylinder for opening and closing the molds 2 and 4 by moving the movable plate 3 up and down along the tie rod 5 as described above. is installed between the fixed platen 1 and the movable platen 3.

Reference numeral 10 denotes a single-acting mold clamping cylinder, which is fitted onto the tie rod 5 on the upper surface of the movable platen 3 so that it can move together with the movable platen 3. 11 is a compression coil spring for returning the mold clamping cylinder 10. Reference numeral 12 designates a lock nut as a locking member, which is formed into a split mold shape consisting of a pair of nut pieces 13 and 14 that can be connected and separated, each having internal threads 13a and 14a on the inner surface, and which is connected to the piston 10a of the mold clamping cylinder 10. The tie rod 5 is fitted onto a bracket 15 fixed to the top surface. On the other hand, Tyrod 5 has
A male screw 5a is provided on the outer circumferential surface of the intermediate portion that projects upwardly from the movable platen 3 in the closed state of the mold shown in FIG. However, with the mold closed, the lock nut 12 is
When the nut pieces 13 and 14 are in the closed state, the lock nut 12 and tie rod 5 are engaged with each other through the screws 13a, 14a, and 5a, and become integral in the axial direction. Also, both nut pieces 13, 14
When the lock nut 12 is separated and placed in an open state, the lock nut 12 moves up and down along the tie rod 5 together with the mold clamping cylinder 10 and the movable plate 3. Numeral 16 is a cylinder for opening and closing the lock nut 12, and its cylinder tube 16a is fixed to one nut piece 13 via a plate 17 and bolt 18, and the piston rod 16b is fixed to the other nut piece 14. In this way, when the cylinder 16 is extended, both nut pieces 13,1
4 move toward each other at the same time, the lock nut 12 closes, and the cylinder 16 is contracted.
On the contrary, both nut pieces 13 and 14 move in the direction of separating from each other, and the lock nut 12 is opened.

In the above configuration, the movable platen 3 is lowered by the opening/closing cylinder 9 from the mold open position shown by the imaginary line in FIG. 1, and the molds 2 and 4 are closed as shown by the solid line. supply. At this time, at the same time or prior to the mold clamping cylinder 10, pressure oil is also supplied to the lock nut operating cylinder 16 on the extension side. In this way, mold clamping cylinder 1
As the piston 10a of No. 0 rises, the lock nut 12 closes, and the nut 12 and tie rod 5
When the screws 13a, 14a, and 5a match, they engage and become axially integrated. Therefore, the mold clamping reaction force due to the extension of the mold clamping cylinder 10 is received by the tie rod 5 via the lock nut 12, and the molds 2 and 4 are clamped with great force.

In this state, when molding is performed by raising the pressure inside the mold, and then opening the molds 2 and 4 after the pressure is reduced, the pressure oil is discharged from the mold clamping cylinder 10, and at the same time, the lock nut operating cylinder 16 is operated to the contraction side. As a result, the piston 10a of the mold clamping cylinder 10 descends and the mold clamping force is released, and at the same time the lock nut 12 opens and separates from the tie rod 5. Therefore, in this state, the movable platen 3 is moved by the opening/closing cylinder 9.
When the movable platen 3 is raised, the mold clamping cylinder 10 and the lock nut 12 are guided by the tie rod 5 and raised, and returned to the position shown by the imaginary line in FIG.

In the above embodiment, the male thread 5a is provided as the engagement groove of the tie rod 5, and the lock nut 12 as a locking member is engaged with and disengaged from the rod 5 via this male thread 5a. A plurality of circumferential grooves in the axial direction are provided as engagement grooves,
A split-shaped locking member having a protrusion corresponding to the circumferential groove may be configured to engage and disengage from the tie rod 5. Furthermore, the locking member is not limited to being divided into two pieces, but may be composed of more pieces. Furthermore, the operating mechanism for opening and closing the lock member is
Various modifications other than those described above are possible.

As described above, in the present invention, the tie rod that receives the mold clamping reaction force is configured so that it can also be used as the movement guide member of the movable platen, so the mold clamping reaction force receiving member and the movement guide member are provided separately. The structure can be made simpler and more compact than the previous one, and it is also advantageous in terms of maintenance.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional side view of the mold in a closed state showing an embodiment of the present invention, Fig. 2 is an enlarged sectional view taken along the line in Fig. 1, and Fig. 3 is an enlarged sectional view taken along the line in Fig. 2. FIG. 4 is a view corresponding to FIG. 3 in a mold clamped state. 1...Fixed plate, 2...Fixed mold, 3...Moveable plate, 4...Moveable mold, 5...Tie rod, 5a...
...Male thread as engagement groove of tie rod, 9...Mold opening/closing cylinder, 10...Mold clamping cylinder, 12...
...Lock nut as a lock member, 13, 14
... Natsuto Piece.

Claims (1)

[Claims] 1 The movable plate supporting the movable mold is moved toward and away from the fixed plate supporting the fixed mold using an opening/closing cylinder to open and close the mold, and when the mold is closed, the mold is closed using the mold clamping cylinder. In the mold clamping device of an injection molding machine configured to clamp the mold, a tie rod is provided protruding from the fixed plate to guide the movement of the movable plate, and the tie rod is provided with a tie rod that extends from the movable plate to the opposite side of the fixed plate when the mold is closed. An engagement groove for a screw or the like is provided on the outer circumferential surface of the protruding part, and a split-shaped lock member that can be engaged with and disengaged from the tie rod through the engagement groove when the mold is closed is slidable in the axial direction of the tie rod. A mold clamping device for an injection molding machine, characterized in that the mold clamping cylinder is interposed between the locking member and the movable plate.