JPS59199229A - Two-stage injection apparatus of injection mold - Google Patents

Abstract

PURPOSE:To obtain the inexpensive two-stage ejection apparatus of an injection mold, by projecting an ejection pin and a stripper plate by an ejection rod while, at the same time, further projecting the ejection pin by pushing the first piston in a first air cylinder. CONSTITUTION:When a synthetic resin is allowed to fill a mold cavity 20 and cooled, a movable side mold die set, to which a first and a second air cylinders 8, 10 are attached, is retracted to perform mold opening but an ejection plate 17 and a second piston 11 are pushed by an ejection rod 19 slightly prior to completing mold opening and a stripper plate 3 and an ejection pin 6 are simultaneously projected. At this time, air in the gap 12 of an air cylinder 10 is compressed while pressed by the piston 11 and flowed into the air sump 9 of the air cylinder 8 from an air passing hole 13. In this case, a first piston 17 is pushed against the elasticity of a spring 14 and, therefore, the ejection pin 6 further advances to project a molded article.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The invention relates to a two-stage ejection device for an injection mold.

[Prior Art] Conventionally, a two-stage ejection device used to remove a molded product from an injection mold includes a first ejector plate 2 to which an ejector bin 1 is attached, and a second ejector plate from which a stripper plate 3 is ejected, as shown in FIG.
The first protruding plate 2 and the second protruding plate 4, which were detachably connected in the first stage, move to simultaneously move the protruding pin 1 and the stripper plate 3, At the second stage, when the second protrusion plate 2.4 moves slightly, the mechanism that connects the first protrusion plate 2 and the second protrusion plate 4 is released, and only the first protrusion &2 moves and the protrusion pin 1 was protruding from the molded product 5.

The above-mentioned two-stage ejecting device includes a first ejecting plate 2, a second ejecting plate 4, and a first ejecting plate 2. In order to incorporate the mechanism for connecting or detaching the second ejector plate 2.4, the structure of the mold die set with the single-stage ejector device has to be significantly modified, which increases the thickness of the mold die set. A large injection molding machine had to be used.

[Object of the Invention] An object of the present invention is to obtain an inexpensive two-stage ejection device for an injection mold without changing the thickness of the mold die set.

[Summary of the invention]

Two injection molds according to the present invention to achieve the above object.
The stage ejecting device has a return spring installed in a first air cylinder in which the base of the ejecting pin serves as a first piston, and an empty cartridge reservoir is provided between the first piston and the second piston. is fixed to a first air cylinder, a return spring is provided for the first air cylinder and the second piston, and the second air cylinder on which the second piston slides is fixed to the template, The air reservoir and the gap in the second air cylinder are connected through a ventilation hole, and the protruding rod for the stripper plate is protruded together with the second piston, and at the same time, the gap in the second air cylinder is compressed. The air flows into the air reservoir and pushes the first piston,
The ejection pin is further ejected to perform two-step ejection.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a sectional view showing an embodiment of a two-stage ejecting device for an injection mold according to the present invention, and FIG. 3 is an enlarged sectional view showing an air cylinder portion of the device. As shown in FIGS. 2 and 3, this embodiment includes a first air cylinder 8 in which the base of a protruding pin 60 slides as a first piston 7, and an air reservoir at the tip of the first air cylinder 8. 9 and sliding on the inner wall of the second air cylinder 10 is provided, and the air cylinder 8 of the anchor 1 is disposed between the air gap 12 in the second air cylinder 10 and the air reservoir 9. Penetrating ventilation hole 1
3 is provided between the end inner wall of the first air cylinder 8 and the first piston 7 to increase the spring 1A for returning the first piston. The second air cylinder 10 configured as described above is fixed to a template 15, and a spring 16 is installed within the template 15 to restore movement of the first air cylinder 8 and the second piston 11. . stripper plate 6
A protrusion plate 17 that protrudes from the air cylinder 17 is provided with a hole 18 through which the second air cylinder 10 is inserted, and a protrusion rod 19 is provided for moving the second piston 11 provided on the protrusion plate 17 and the second air cylinder 10, respectively. ing.

During molding, when the synthetic resin is filled into the mold cavity 2o and cooled, the movable mold die set to which the first and second air cylinders 8 and 10 are attached moves back and opens the mold, but it takes a little while to complete the mold opening. The ejector plate 17 and the second piston 11 are pushed forward by the ejector rod 19, and the stripper plate 3 and ejector pin 6 are ejected by the same amount at the same time. At this time, the second air cylinder 1 is pushed by the fourth piston 11.
The air in the gap 12 is compressed and flows into the air reservoir 9 of the first air cylinder 8 through the ventilation hole 13, and the protruding pin 6 is pressed against the elastic force of the spring 14 to push the first piston 7.
moves further forward to eject the molded product. Spring 1 when closing the mold
4 pushes the first piston 7, the spring 16 pushes the first air cylinder 8, and the ejecting pin 6 and the second piston 11 return to their original positions.

[Effects of the Invention] As described above, the two-stage ejecting device according to the present invention uses the base of the ejecting pin as the first piston and the first piston with the spring provided inside.
fixing the second air cylinder, in which the air cylinder slides inside together with the second piston, to the mold plate, and moving the second piston and the ejector plate by the ejector rod to eject the ejector pin and the stripper plate; 2nd above
The air in the gap in the air cylinder is compressed and guided to the air reservoir in the first air cylinder, and this pressure pushes the first piston in the first air cylinder and further protrudes the protruding pin. Unlike the conventional two-stage ejector, there is no need to incorporate two sets of production plates and a mechanism for connecting and separating them, and modification of the mold die set with the single-stage ejector requires only a small part, making it inexpensive. In addition, since the thickness of the mold die set does not increase, a normal size injection molding machine can be used for molding.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional two-stage ejector for an injection mold, FIG. 2 is a cross-sectional view of a two-stage ejector for an injection mold according to the present invention, and FIG. 3 shows an air cylinder portion of the above device. FIG. 6...Strapper plate, 6...Ejecting pin,
7... First piston, 8... First air cylinder, 9... Air reservoir, 10... Second air cylinder,
11...Second piston, 12...Gap, 13...
・Vent hole, 1! 1.16... Spring, 15... Template plate, 17... Protruding plate, 19... Protruding rondo lift 2 Figure

Claims (1)

[Claims] a first air cylinder in which a base of an ejection bottle that protrudes a molded product slides as a first piston; a second air cylinder in which a second piston fixed to the first air cylinder slides; a return spring for the first piston provided in the air cylinder; a return spring for the first air cylinder and the second piston provided in the mold plate; and a stripper that moves outside the second air cylinder. an air reservoir and a second air cylinder provided with a protruding plate for a plate, a second air cylinder fixed to the template, and provided between the first piston and the second piston within the first air cylinder; 2 of the injection molding mold, in which the second piston and the protrusion plate are connected to each other by a ventilation hole, and the second piston and the protrusion plate are simultaneously protruded by a protrusion rod.
Step arrow pulling device.