JPH0427012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection mold for molding a polygonal container with a synthetic resin bottom and undercuts on its inner and outer surfaces.

[Conventional technology]

Conventionally, the molding die for producing this type of molded product has a fixed mold plate, a movable mold plate, a plurality of side walls provided between them, and a movable mold plate integrated with or attached to the movable mold plate inside the side wall. It is composed of a core having an inclined surface and a slide core that is engaged with the inclined surface of the core so as to slide on the inclined surface,
In order to mold a molded product with undercuts on the inside and outside surfaces using this mold, the core must be moved inward and the sidewalls must be moved outside and removed from these undercuts. Conventionally, the following mechanism has been adopted as a mechanism for releasing the mold from these undercuts. In other words, the sidewall mold release mechanism has an inclined pin fixed to the fixed mold plate, and when the movable mold plate and sidewall move simultaneously during mold opening, the side wall is pushed outward by the inclined pin to release the mold. A cylinder that serves as the power source for moving the walls outward and a tilting pin are attached to a fixed mold plate, and the tilting pin is released from the mold by a guide. In this case, multiple side walls are released from the undercut at the same time. In a mold, the number of cylinders used is smaller than the number of sidewalls, and the sidewalls are connected by connecting pins or interlocking plates, or a mounting plate and a movable die plate attached to the movable die plate of the injection molding machine body. A spacer is installed between the molding machine and the molding machine to create a space, and an extrusion plate that is connected to the extrusion rod of the injection molding machine body and moves forward and backward is installed inside this space, and this extrusion plate and a side wall having an inclined surface are linked. There is a mechanism that connects and extrudes extrusion plates to release the sidewall outward along the slope of the reinforcing frame on the outside of the sidewall.

The core mold release mechanism is similar to the sidewall mold release mechanism described above, in which an extrusion plate is provided between the mounting plate and the movable mold plate, and this extrusion plate and slide core are connected with a link to extrude the extrusion plate. This allows the core to slide on its inclined surface and be released from the mold.

The mechanism for separating the sidewalls and core from the undercut as described above is employed, and most of its operations are carried out independently by moving the sidewalls and then moving the core. However, U.S. Patent No. 3,905,740 provides an extrusion plate between a mounting plate attached to a movable die plate of an injection molding machine and a movable die plate, and connects this extrusion plate with both a slide core and a side wall by links. The sidewall and core are moved at the same time.

[Problem that the invention seeks to solve]

Conventional injection molds have the configuration described above, so when moving the sidewalls and core individually, that is, moving the core after moving the sidewalls, the molding cycle becomes longer. Productivity drops and becomes a problem. Furthermore, when the sidewall is moved only by the tilt pins, the mold opening speed must be slowed down because an excessive force is applied to the tilt pins, which is also undesirable because the molding cycle becomes longer. In addition, a mechanism in which an extrusion plate is provided and the extrusion plate is connected to the side wall or slide core with a link requires space for the extrusion plate to move forward and backward, making the entire mold larger and heavier.The link mechanism is complicated and the number of parts increases. There are various problems such as a large number of devices, many failures, and undesirable maintenance.

The present invention was invented to eliminate these drawbacks, and compared to conventional molds, it has a smaller mold size, reduces weight, increases cycle time, reduces the number of parts, reduces failures, and facilitates maintenance. ,
Moreover, it is an injection mold that can be manufactured at low cost.

[Means for solving problems]

The injection mold of the present invention comprises a fixed mold plate, a movable mold plate, a side wall, a core, and a sliding core, and at least one drive cylinder moves the side wall along an inclined pin or an inclined guide block, and a plurality of This mold is made more compact by slidably connecting the sidewalls and between the sidewalls and the slide core using a connecting member, making it possible to simultaneously move a plurality of sidewalls and the slide core.

[Effect]

A plurality of sidewalls and a slide core are connected to each other by a connecting member, power is transmitted through the connecting member, and the plurality of sidewalls and the slide core are simultaneously moved by at least one cylinder. Therefore, it is easy to manufacture a molded product having undercuts inside and outside, shortening the cycle time, and making the mold for injection molding compact.

〔Example〕

An embodiment of the present invention will be described based on the drawings. This mold is used to produce a substantially rectangular molded product with undercuts inside and outside, and FIG. 1 is a view of the movable mold plate side with the mold closed and the fixed mold plate removed. The other drawings are cross-sectional views of FIG. 1 or other drawings.

Figure 2 shows the state in which the mold is closed and the resin is injected.A fixed mold plate 2 is fixed to the mounting plate 1, a movable mold plate 4 is fixed to the mounting plate 3 with bolts 5, and the mounting plate 1 is attached to the injection molding machine. The mounting plate 3 is fixed to a fixed die plate (not shown) and to a movable die plate. Therefore, as the movable die plate of the injection molding machine moves, the mounting plate 3, the movable die plate 4, etc. move from side to side (in FIG. 2).
The inside of the mounting plate 1 has a runner block 6 having a passage for introducing molten resin into the cavity (space for molding a molded product).
A part of it extends into the fixed mold plate 2, and its tip is connected to a gate 7 provided inside the fixed mold plate 2. The inside of the fixed mold plate 2 is a mold for molding the outer surface of the side wall of the molded product 8 near the bottom surface. Reference numeral 9 denotes a hydraulic cylinder that penetrates the movable mold plate 4 from the mounting plate 3 side and moves the two movable mold plates 4 diagonally so that they open mutually on the fixed mold plate 2 side.
installed on. Each hydraulic cylinder 9
A nut 12 having a cylindrical shape and a headband-shaped groove 11 in the center is screwed onto the tip of the rod 10, and the groove 11 forms the surface of the side wall of the molded product 8 (upper and lower surfaces in FIG. 2). Sidewalls for 13, 14
A U-shaped notch 15 (see FIG. 9) is fitted in the rod 10 of the hydraulic cylinder 9 so that when the rod 10 of the hydraulic cylinder 9 moves forward or backward, the side walls 13 and 14 simultaneously move along an inclined pin to be described later. Further, two sidewalls 24 and 25 are provided separately, which are combined with the sidewalls 13 and 14 to form the other two outer surfaces of the molded product 8, and these four sidewalls 13, 14, 24, 25, most of the outer surface of the molded product 8 is molded.

Reference numerals 33 denote guide pins for positioning the fixed mold plate 2 and the movable mold plate 4. Four guide pins 33 protrude from the mounting plate 3 side through the movable mold plate 4 to the fixed mold plate 2 side, and the tips of these guide pins 33 are It is adapted to fit into a hole 16 at a corresponding position in the fixed mold plate 2 when the mold is closed. A core 17 with a trapezoidal cross section is located approximately in the center of the movable mold plate 4.
is fixed to the movable template 4 with bolts 34. In addition, a slide core 1 is placed on the outside of this core 17.
The slide cores 18 and 19 are fixed to the core 17 with bolts 20 and are connected by a T-shaped guide piece 21, and the slide cores 18 and 19 are movable along the slope of the trapezoidal cross section of the core 17 to open the mold. At this time, the slide cores 18 and 19 slide on the inclined surface of the core 17 and contract inward. Core 17 and slide cores 18, 19 together form the inner surface of molded article 8. When the mold is opened, the side walls 13, 14, 24, 2 move in the direction of constricting inside the slide cores 18, 19 (up and down in FIG. 2).
5 are adapted to move in directions that spread outward from each other (up and down in FIGS. 2 and 3).

As shown in FIGS. 3 and 4, the movable mold plate 4 has eight inclined pins 22 and 23 extending toward the fixed mold plate 2 at the same angle as the hydraulic cylinder 9.
through the side walls 13, 14, 2
4, 25, these inclined pins 22, 23 are sandwiched and fixed between the mounting plate 3 and the movable mold plate 4, and the side walls 13, 14, 24, 25 are provided through these inclined pins 22, 23. The guide moves diagonally. Two of these tilt pins 22 and 23 are inserted into each side wall to hold each side wall during movement.

As shown in Fig. 5, the side walls 24, 25
One ends of interlocking plates 26 and 27 for connecting to other sidewalls 13 and 14 are attached approximately at the center of the movable mold plate 4 in the moving direction above and below. The other ends of these interlocking plates 26 and 27 are connected to the sidewall 1
When the sidewalls 13 and 14 are inserted into the grooves 28 cut in the grooves 3 and 14 and moved by the hydraulic cylinder 9 using the inclined pins 23 as guides, the sidewalls 1
Power is transmitted while sliding in the grooves 28 of No. 3 and 14.

In addition, as shown in FIG. 4 and FIG.
Connecting plates 29 and 30 for connecting the side walls 24 and 25 and moving the movable mold plate 4 in the mold opening/closing direction are fixed at one end with bolts 31, and these connecting plates 29, The other end of the connecting plate 30 is inserted into a groove 32 cut into the slide cores 18, 19, and when the side walls 24, 25 move, the connecting plates 29, 30 slide in the groove 32 and are connected to the slide cores 18, 19. Moving. In addition, in this embodiment, the side walls 13 and 14 and the side walls 24 and 25 are directly connected and moved by the hydraulic cylinder 9.
The side walls 24, 25 and the slide cores 18, 19 are connected by connecting plates 29, 30, but the side walls 13, 14 and the slide cores 18, 19 are Connecting plates 29, 30 connect slide cores 18, 19 and side walls 24, 25.
It is also possible to connect with In this embodiment, the core 17 is fixed to the movable mold plate 4, and the cylinder 9 and the inclined pins 22, 23 are also fixed to the movable mold plate 4. However, no gate marks are left on the outer surface of the molded product 8. In such a mold structure, the core may be fixed to the fixed mold plate, and the cylinder and the inclined pin may also be fixed to the fixed mold plate. In this case, the runner block has a structure in which it penetrates through the interior of the core attached to the fixed mold plate.

Next, the operation will be explained. The mold is clamped by a mold clamping device of an injection molding machine (not shown), and molten resin is injected under pressure from the runner block 6 in the state shown in FIG. The injected resin is press-fitted from the gate 7 into the cavity in which the molded product 8 is to be molded, and is cooled to harden except for the runner block 6 portion. Next, the mold opens. First, the fixed mold plate 2 is placed, and as shown in FIGS. 7 and 8, the core 17 and hydraulic cylinder 9 are attached directly to the movable mold plate 4.
and sidewalls 13, 14, 24, 25 connected by interlocking plates 26, 27, and a connecting plate 29,
Slide cores 18 and 19 connected by 30 move to the left together with molded product 8. The state shown in FIG. 7 is that after the movable mold plate 4 has retreated to the retraction limit (moved to the left), the hydraulic cylinder 9 is actuated to move the rod 10 forward (moved to the right) to move the side walls 13, 14, 24, 25.
While moving the slide cores 18 and 19 to the right side, move the sidewalls 13, 14, 24, and 25 away from the molded product 8 (in the vertical direction), and at the same time move the slide cores 18 and 19 inward to remove the undercut of the molded product 8. It is shown removed from the In this state, the molded product 8 is removed manually or by a removal device.

The side walls 13, 14, 24, 25 move using the inclined pins 22, 23 as guides, and the slide cores 18, 19 move using the guide pieces 21 as guides. The side walls 13, 14 are moved directly by the hydraulic cylinder 9, and the side walls 24, 25 are moved via interlocking plates 26, 27. Furthermore, the slide cores 18 and 19 are connected to the connecting plate 2.
9,30. The state shown in Fig. 7 is that after the movable mold plate 4 has retreated to its retreat limit, the hydraulic cylinder 9
Although the explanation has been made assuming that the movable template 4 is activated,
It is also possible to operate the hydraulic cylinder 9 while the vehicle is retracting, and it is advantageous to adopt this method in order to shorten the operating cycle during work. The mold closing operation after removing the molded product 8 is performed in the reverse order of the mold opening.

〔Effect of the invention〕

The present invention connects the sidewalls and the sidewalls and the slide core with a simple connecting member without providing members such as extrusion plates and links, so it is compared to conventional molds for molded products that have undercuts on the inside and outside. This makes the mold smaller and reduces weight, and the sidewall and slide core move at the same time, which increases cycle up. In addition, it has remarkable effects such as reducing the number of parts, reducing failures, facilitating maintenance, and being able to manufacture at low cost.

[Brief explanation of drawings]

Figures 1 to 9 are drawings showing an embodiment of the present invention. Figure 1 is a plan view of the movable mold plate after removing the fixed mold plate during molding, and Figure 2 is a plan view of the movable mold plate during molding. 3 is a sectional view taken along line B-B in FIG. 1, FIG. 4 is a sectional view taken along line D-D in FIG. 7, and FIG. 5 is a sectional view taken along line C in FIG.
6 is a sectional view taken along the line E--E in FIG. 4, and FIG. 7 is a sectional view taken along the line A--A in FIG. 1 when the mold is opened. FIG. 8 is a sectional view taken along the line B--B in FIG. 1 and shows the mold opening. FIG. 9 is a sectional view taken along the line FF in FIG. 2. 2... Fixed mold plate, 4... Movable mold plate, 9... Hydraulic cylinder, 13, 14, 24, 25... Side wall, 17... Core, 18, 19... Slide core, 22, 23... Inclined pins, 26, 27...
Interlocking plate, 29, 30...connecting plate.

Claims (1)

[Scope of Claims] 1. A fixed mold plate, a movable mold plate, a plurality of side walls that are disposed between the fixed mold plate and the movable mold plate and are moved by cylinders using tilt pins or tilt guide blocks as guides, and the side walls. A mold comprising a core fixed to the movable mold plate or the fixed mold plate and having an inclined surface, and a slide core that moves by engaging with the core, between the plurality of side walls and the side An injection molding mold, characterized in that the wall and the slide core are slidably connected by a connecting member, and the side wall and the slide core are simultaneously moved by at least one drive cylinder. . 2. The injection mold according to claim 1, wherein the drive cylinder and the tilting pin are attached to a movable mold plate. 3. The injection mold according to claim 1, wherein the drive cylinder and the tilting pin are attached to a fixed mold plate.