JP3077577B2 - Ejector device for vertical injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ejector device for a vertical injection molding machine using a turntable.

[0002]

2. Description of the Related Art As a vertical injection molding machine, as shown in FIG. 4, a turntable 2 having a pair of lower dies 1, 1 is provided.
The upper die 5 attached to the movable platen 4 is horizontally rotated about the book tie bar (center shaft) 3 and positioned at a predetermined position by a positioning device (not shown). (Not shown) to lower the mold, inject the resin into the cavities of the dies 1 and 5, and move the turntable 2 from directly below the upper mold 5 to another position by rotation of the turntable 2. It is known that a molded product in the lower mold 1 is taken out by an ejector device (not shown). The movable platen 4 is supported by three tie bars 3, 6, and 6, and the turntable 2 is rotatably supported by a fixed platen (fixed member) 7.

[0003]

In the above-mentioned conventional vertical injection molding machine, a positioning device for accurately stopping the turntable 2 at a predetermined position and an ejector device for taking out a molded product from the lower mold 1 are dedicated. However, since each of them is provided separately, there is a problem that the entire structure becomes complicated.

[0004]

According to a first aspect of the present invention, a turntable provided with at least a pair of lower dies is disposed below an upper die which is moved up and down by a mold clamping device. In a vertical injection molding machine supported by a fixed member and rotatably provided about a central axis, a positioning hole is formed in the turntable so as to penetrate vertically, and a drive is provided below the turntable. The upper part is raised by the device, the upper part is inserted into the above-mentioned positioning hole, and the ejector pin is provided to position the turntable at a predetermined position and then further raised to push out the molded product from the lower mold.

It is desirable that the lower portion of the positioning hole be tapered downward and the upper end of the ejector pin be tapered.

[0006]

1 to 3 show one embodiment of an ejector device of a vertical injection molding machine according to the present invention. The same members as those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Reference numeral 10 denotes a bush. Push 10
Are provided on the turntable 2 at two 180 ° intervals symmetrically with respect to the center axis 3, and form a circular positioning hole 10 a penetrating vertically through the turntable 2. The lower portion of the positioning hole 10a is tapered downward. The bush 10 is detachably fixed to the turntable 2 by a C-shaped retaining ring 11.

A stopper 12 is fixed to the lower surface of the periphery of the turntable 2 with a bolt 13. Stopper 1
2 is symmetrical with respect to a straight line orthogonal to a straight line connecting the centers of the two bushes 10, 10.

On the turning surface of the stopper 12, two cushioning members 14, 14 are provided fixed to a fixture 15, respectively. The two cushioning members 14, 14 are configured to abut the stopper 12 to stop the turntable 2 in a cushioning manner, and are arranged symmetrically with respect to a straight line connecting the centers of the bushes 10, 10. The rotation stop angle of the turntable 2 by the stopper 12 and the cushioning members 14 is
The angle is substantially 180 degrees due to the buffer function of the buffer member 14.

Reference numeral 17 denotes a hydraulic cylinder (drive device).
It is. The hydraulic cylinder 17 is fixed to a tubular mounting member 18 and provided vertically below the bush 10 (the lower bush in FIG. 1) at a rotational position away from the upper mold 5 (FIG. 4). An ejector pin 19 having a circular cross section is inserted vertically into a hole 18 a of the attachment 18, and is screwed to a piston rod 17 a of the hydraulic cylinder 17 and fixed with a screw 20. Ejector pin 19 is piston rod 1
7a can be adjusted up and down freely.

The ejector pin 19 has a tapered upper end 19a and an outer diameter equal to (strictly, slightly smaller than) the inner diameter 10a of the positioning hole so that the ejector pin 19 can be inserted into the positioning hole 10a. It has been. The hydraulic cylinder 17 is configured to operate in two stages. The first operation inserts the upper portion of the ejector pin 19 into the positioning hole 10a, and the second operation moves the ejector pin 19 to the turntable 2.
It is designed to protrude above. The hydraulic cylinder 17 is provided with a proximity switch 22 for detecting the end of the first operation of the hydraulic cylinder 17 and a proximity switch 23 for detecting the end of the next operation. A bush 24 is fitted into the upper end of the hole 18 a of the fixture 18 and is fixed with a screw 25.

Reference numeral 27 denotes a hydraulic motor (actuator) for alternately rotating the turntable 2 in the opposite direction.
Reference numeral 28 denotes a guide member for guiding the turntable 2.

Next, the operation of the ejector device of the vertical injection molding machine according to the present invention having the above-described structure will be described. The turntable 2 is rotated clockwise from the state shown in FIG. 1 by the hydraulic motor 27, and the stopper 12 is brought into contact with the buffer member 14 on the left side in FIG. By this rotation of the turntable 2, the two lower dies 1, 1 are interchanged.

As soon as the turntable 2 stops, the hydraulic cylinder 17 operates to insert the upper portion of the ejector pin 19 into the positioning hole 10a. As a result, the turntable 2 is accurately positioned at a predetermined position. In this case, the lower portion 10b of the positioning hole 10a is tapered downward and the upper end 19a of the ejector pin 19 is tapered so that the positioning hole 10a is buffered by the buffering member 14. Can be accurately inserted into the positioning hole 10a even if the center of the ejector pin 19 is slightly deviated from the center axis of the ejector pin 19.

In the above state, the upper mold 5 is clamped to the lower mold 1 on the upper side in FIG. 1, and the resin is injected into their cavities. When the molded product in the lower lower mold 1 in FIG. 1 is appropriately solidified, the hydraulic cylinder 17 is actuated again to push up the ejector pin 19 into the lower mold 1 on the turntable 2 and remove the molded product. Extrude.

When the injection of the resin and the extrusion of the molded product are completed, the hydraulic cylinder 17 contracts and pulls the ejector pin 19 downward from the positioning hole 10a.
The hydraulic motor 27 operates in the reverse direction to rotate the turntable 2 counterclockwise. Thereafter, the ejector pins 19 are raised by the operation of the hydraulic cylinder 17 to position the turntable 2, and the molded product is pushed out in the same manner as described above.
The present invention can also be applied to an injection molding machine in which the turntable 2 rotates at a predetermined angle in one direction.

[0017]

As described above, the ejector device of the vertical injection molding machine according to the present invention comprises a turntable provided with at least a pair of lower dies, which is disposed below an upper die which is moved up and down by a mold clamping device. In a vertical injection molding machine supported on a fixed member and rotatably provided about a central axis, a positioning hole is formed vertically through the turntable, and below the turntable, The upper part is lifted by the driving device and inserted into the positioning hole,
After the turntable is positioned at a predetermined position, an ejector pin is provided which is further raised and pushes out the molded product from the lower mold, in addition to the extrusion function of the molded product,
Since it also has a turntable positioning function, a dedicated positioning device can be omitted, and therefore, the overall structure can be simplified and the cost can be reduced.

If the lower portion of the positioning hole is tapered downward and the upper end of the ejector pin is tapered, the variation in the stop position of the turntable becomes large due to the action of the buffer member. However, there is an advantage that it is hard to cause trouble.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an ejector device of a vertical injection molding machine according to the present invention, in which a part of a turntable is cut away.

FIG. 2 is a sectional view taken along the line (II-II) of FIG.

FIG. 3 is a sectional view taken along the line (III-III) of FIG. 1;

FIG. 4 is a schematic sectional view of a vertical injection molding machine.

[Explanation of symbols]

 Reference Signs List 1 lower die 2 turntable moon table 3 tie bar (center shaft) 5 upper die 7 fixing plate (fixing member) 10 bush 10a positioning hole 10b lower portion 17 hydraulic cylinder (drive device) 19 ejector pin 19a upper end

Claims (3)

(57) [Claims] 1. A turntable provided with at least a pair of lower dies is provided below a upper die moved up and down by a mold clamping device and supported by a fixing member to be rotatable about a central axis. In a vertical injection molding machine, a positioning hole is formed vertically through the turntable, and a lower portion of the turntable is raised by a driving device, and an upper portion thereof is inserted into the positioning hole, and the turntable is fixed to a predetermined position. An ejector device for a vertical injection molding machine, comprising an ejector pin that is further raised after being positioned at a position and extrudes a molded product from a lower mold. 2. The ejector device for a vertical injection molding machine according to claim 1, wherein a lower portion of the positioning hole is tapered so as to have a downward width. 3. The ejector device for a vertical injection molding machine according to claim 1, wherein an upper end of the ejector pin is tapered.