JPH10202712A - Fall preventing device of mold clamping device in injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a mold by preventing the fall of an end housing by the reaction force of the opening and closing operation of the mold clamping device of an injection molding machine, ant to uniformize the opening of the parting surface of the mold at the time of molding. SOLUTION: This mold clamping device is constituted so that the tie bar nut 26 provided on the back surface of an end housing 3 in an axially immovable manner is threaded with the screw part of the tie bar formed at the end part of the tie bar 4 to move the end housing 3 before and behind to adjust mold thickness. In this case, a tie bar screw part is set to a trapezoidal screw 24 and the end part of the tie bar 4 is supported at two places of a support part 22 provided at the front end part of a through-hole 21 of the end housing 3 into which the tie bar 4 is inserted and a spacer 23 provided at the rear end part thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing a mold clamping device from falling down in an injection molding machine, and more particularly, to a device for preventing a mold clamping device from falling down.

[0002]

2. Description of the Related Art A toggle-type mold clamping device of a commonly used injection molding machine will be described with reference to the drawings. FIG.
FIG. 3 is an overall configuration diagram of a double toggle type mold clamping device, and FIG. 3 is an enlarged cross-sectional view of a main part of FIG.

In FIG. 2, a fixed board 1 and an end housing 3 are connected by four tie bars 4 at a predetermined interval. The movable platen 2 is slidably provided on these tie bars 4. A fixed mold 15 is attached to the fixed board 1, and a movable mold 16 is attached to the movable board 2.

The double toggle mechanism comprises a first link 7 having one end pivotally connected to the movable plate 2 via a first toggle pin 10, and a second toggle pin 11 and a third toggle pin 12 on both sides thereof.
Through the other end of the first link 7 and the end housing 3
And a third link 9 pivotally connected to the middle of the second link 8 and the crosshead 6 via a fourth toggle pin 13 and a fifth toggle pin 14, respectively. ing.

[0005] The end-handling 3 includes a mold clamping cylinder 5.
The piston rod 5 a is attached to the crosshead 6 through the end housing 3. As shown in FIG. 3, the end housing 3 is provided with a through hole 31 into which the tie bar 4 is inserted.
The front end of the tie bar 4 has a small diameter.
It is 2. Except for the support portion 32, the through hole 31 has a diameter slightly larger than the tie bar diameter.

At the end of the tie bar 4 penetrating the end housing 3, a triangular screw 3
4 is formed, and a tie bar nut 36 provided on the back surface of the end housing 3 so as to be rotatable by the adjusting body 35 but immovable in the axial direction is screwed to the triangular screw 34. A gear is formed on the outer peripheral portion of each tie bar nut 36, and is simultaneously driven to rotate by a mold thickness adjusting motor (not shown) provided on the end housing 3. Note that the end housing 3 can be moved back and forth by wheels provided at a lower portion thereof.

In the above-described configuration, when pressure oil is supplied to the rear chamber of the mold clamping cylinder 5, the piston rod 5a advances rightward in the drawing, and the advance force of the piston rod 5a is transmitted from the crosshead 6 to the double toggle mechanism. , The movable platen 2 is similarly advanced rightward, and the fixed mold 15 and the movable mold 16 are clamped as shown in FIG.
When pressure oil is supplied to the front chamber of the mold clamping cylinder 5,
The mold is opened by the operation opposite to the above operation.

When the mold thickness is adjusted by replacing the mold, the tie burner nut 36 is rotated by the mold thickness adjusting motor with the toggle mechanism extended. Thereby, the movable platen 2 moves along the tie bar 4 together with the end housing 3, and the distance between the movable platen 2 and the fixed platen 1 is adjusted.

[0009]

Since the end housing of the conventional mold clamping device is connected to the tie bar only through its support, when the toggle mechanism is operated to open and close the mold, the reaction force is increased. Accordingly, the end housing may be inclined around the support portion as a fulcrum. When the end housing is tilted, the movable plate that is integrated with the end housing via the toggle mechanism is also tilted, and the tie bar is also bent, so that the mold guide pins for centering the two dies reduce galling. May occur. In addition, when mold clamping and molding are performed using a mold having a poor cavity balance, the biased injection pressure acting on the cavity causes the end housing integral with the movable plate to be inclined and the movable plate to be inclined. Then, the mold attached to the movable plate is inclined, and the opening of the parting surface of the mold differs depending on the direction, so that a molded product with low accuracy may be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is intended to prevent the end housing from falling down due to the reaction force of the opening and closing operation of a mold clamping device of an injection molding machine, thereby reducing the mold. It is an object of the present invention to protect and make the opening of a parting surface of a mold uniform during molding.

[0011]

The present invention has solved the above-mentioned problems as follows. In a mold clamping device for adjusting a mold thickness by screwing a tie bar nut provided on the rear surface of the end housing so as not to be movable in the axial direction to a screw portion of the tie bar formed at the end of the tie bar, and moving the end housing back and forth. The screw portion of the tie bar is a trapezoidal screw, and the end of the tie bar is divided into two portions, a support portion provided at a front end of a through hole of an end housing into which the tie bar is inserted, and a spacer provided at a rear end. To support.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fall prevention device for a mold clamping device in an injection molding machine according to the present invention has a small diameter at a front end of a through hole of an end housing into which an end of a tie bar is inserted. And at the rear end of the through hole,
A spacer for supporting a screw portion of the tie bar is provided, and the screw portion of the tie bar is a trapezoidal screw. A tie bar nut which is screwed with a trapezoidal screw of the tie bar and is immovable in the axial direction is provided on a back surface of the end housing.

[0013]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a main part of a device for preventing a mold clamping device from falling down in an injection molding machine according to the present invention. The configuration and operation of the mold clamping device of the injection molding machine according to the present invention are the same as those described with reference to FIG.

As shown in FIG. 1, the end housing 3 is provided with a through hole 21 into which the tie bar 4 is inserted, and the front end of the through hole 21 has a small diameter.
Support portion 22. A spacer 23 is fitted into the rear end of the through hole 21, and serves as a support for the tie bar 4.

At the end of the tie bar 4 penetrating the end housing 3, a trapezoidal screw 24 is formed as a threaded portion of the tie bar 4. The trapezoidal screw 24 is rotatable by the adjusting body 25 on the back surface of the end housing 3. In addition, a tie bar nut 26 that is immovably provided in the axial direction is screwed. The trapezoidal screw 24 of the tie bar 4 is fitted to the spacer 23 so as to be able to move back and forth.

Gears are formed on the outer peripheral portion of each tie bar nut 26, and are simultaneously driven to rotate by a mold thickness adjusting motor (not shown) provided on the end housing 3. In addition,
The end housing 3 can be moved back and forth by wheels provided at its lower part.

As described above, the end of the tie bar 4 on the end housing side is composed of the support portion 22 provided on the front end of the end housing 3 and the spacer 23 provided on the rear end.
Since the end housing 3 is supported at the position, the end housing 3 does not fall down due to the reaction force at the time of opening and closing operation of the mold clamping device and the uneven injection pressure acting on the cavity surface.

Further, the screw portion of the tie bar 4 is
As a result, the tie bar 4 can be securely held by the end housing 3 via the spacer 23. Furthermore, since the area in contact with the spacer 23 is larger than that of the triangular screw, the mutual contact surface pressure can be reduced, and the fatigue of the spacer 23 and the trapezoidal screw 24 can be suppressed, and the durability can be increased. Further, the thickness of the spacer 23 can be reduced.

Further, since the spacer 23 is formed as a separate piece, it is possible to employ parts made of different materials and to easily replace the spacer. In the above-described embodiment, the screw portion of the tie bar 4 is a trapezoidal screw 24, but may be a square screw.

[0020]

Since the present invention is constructed as described above, the end housing collapses due to the reaction force at the time of opening and closing operation of the mold clamping device of the injection molding machine and the uneven injection pressure acting on the cavity surface. In addition, the bending of the tie bar can be prevented to protect the mold, and the opening of the parting surface of the mold during molding can be made uniform.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a fall prevention device for a mold clamping device according to the present invention.

FIG. 2 is an overall configuration diagram of a double toggle type mold clamping device.

FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2;

[Explanation of symbols]

 3 End Housing 4 Tie Bar 21 Through Hole 22 Support 23 Spacer 24 Trapezoidal Screw 25 Adjuster 26 Tie Bar Nut

Claims (2)

[Claims] 1. A front end of a through hole (21) of an end housing (3) into which an end of a tie bar (4) is inserted has a small diameter and serves as a support portion (22) for the tie bar (4). A spacer (23) for supporting a screw portion of the tie bar (4) is provided at a rear end portion of the through hole (21), and the screw portion of the tie bar (4) is a trapezoidal screw (24). A device for preventing a mold clamping device from falling down in an injection molding machine. 2. A tie bar nut (26) screwed to a trapezoidal screw (24) of the tie bar (4) and immovable in the axial direction is provided on a back surface of the end housing (3). 2. A device for preventing a mold clamping device from falling down in an injection molding machine according to claim 1.