JPH0328294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an injection molding apparatus, and more particularly to an injection molding apparatus for injection molding a molded article formed from at least two types of resins.

(Prior Art) Molded products made of at least two types of resins having different properties such as color are conventionally injected using an injection molding apparatus shown in FIG. 8, which is equipped with two injection mechanisms such as injection cylinders. molded.

The device 10 shown in FIG. 8 will be explained using a key top used in a keyboard or the like as an example.

The apparatus 10 includes two injection mechanisms 12 and 14 provided in parallel and a mold rotation mechanism (not shown).

In this apparatus 10, first, as shown in FIG. 8a, a first molded product having protrusions that will become letters, etc. in the final molded product is formed on the upper surface, and resin is injected from the injection mechanism 12 into the cavity of the mold. Shaped by.

At this time, the tip of the slide core 16 is in contact with the bottom surface of the recess of the cavity bush 18 in which grooves such as letters are formed.

Next, as shown in FIG. 8b, the mold is rotated by the mold rotation mechanism to form a second cavity into which the first molded product is inserted, and then,
Key top colored resin is injected into the second cavity from the injection mechanism 14 so that the upper surface of the protrusion of the first molded product appears on the upper surface of the final molded product, the key top, and the letters form a symbol.

The tip of the slide core 16 shown in FIG. 8b is lowered approximately 1 mm below the upper surface of the first molded product by using the mold clamping force and the cam, forming a tunnel-shaped portion.

For example, when forming a character such as "A" or "O" on a molded product, this tunnel-shaped part is formed by closing the protrusion on the top surface of the first molded product that forms the character. It is used as a resin passageway to fill the inner part surrounded by the key top color resin.

(Problems to be Solved by the Invention) According to the above-mentioned apparatus, a key top or the like on which characters, symbols, etc. appear on the upper surface can be molded by injection molding.

However, since such conventional devices require a mold rotation mechanism, they are large and require a large volume, making them expensive.

Furthermore, in the conventional apparatus, in order to automatically take out the final molded product, it is necessary to use a take-out robot.

In this way, even when using a take-out robot,
The installation of a take-out robot makes the injection device complicated and expensive, and makes it difficult to shorten the molding cycle.

In other words, the time taken by the take-out robot to take out the molded product is approximately 4
This is because it takes about 5 seconds, and the mold needs to be kept open during this time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an injection molding apparatus for injection molding a molded product made of at least two types of resin, which does not require a mold rotation mechanism and can shorten the ejection time. There is a particular thing.

(Means for Solving the Problems) As a result of intensive studies to achieve the above object, the inventor of the present invention molded a first molded product in contact with a strip, and while attaching the first molded product to the strip, The inventors have discovered that by transporting the mold to the position where the second cavity is formed, it is possible to eliminate the need for a mold rotation mechanism, and have arrived at the present invention.

That is, the present invention involves inserting a first molded product obtained by first molding in which one of at least two resins is injected into a cavity of a mold into a second cavity of a mold in which the other resin is injected. In an injection molding device that performs injection molding, when the mold is placed on the parting surface and the mold is closed, the inner wall surface or edge of the through holes drilled at predetermined intervals will form a cavity for the first molded product. A metal strip to which the first molded product is attached after first molding, and a metal strip to which the first molded product attached to the strip is transferred to the position where the second cavity of the mold is formed. The present invention is characterized by comprising a transport means for transporting the strip, and a detachment means for detaching a molded article attached to the strip obtained by injecting the other resin into the second cavity from the strip. Injection molding equipment.

(Function) According to the present invention, the first molded product attached to the metal strip is transferred to the position where the second cavity is formed by the movement of the strip, so no mold rotation mechanism is required. can be,
The device can be downsized.

Furthermore, the final molded product can be removed by simply separating it from the metal strip, and the molded product can be removed quickly and easily without using a removal robot, reducing the molding cycle. The shortening and molded product removal work can be easily automated.

(Example) The present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a plan sectional view showing an embodiment of the injection molding apparatus of the present invention.

The injection molding apparatus shown in Fig. 1 is an apparatus for injection molding key tops, including a first molding apparatus [1a] that molds a first molded product, and a second molding machine [No. 1a] that injects key top-colored resin into a second cavity to produce a final molded product. It consists of a final molding device [FIG. 1c] for molding, and a take-out device [FIG. 1d] for taking out the final molded product from the final molding die.

In this embodiment, the first molding device [FIG. 1a] and the final molding device [FIG. 1c] are installed together in one mold.

The first molding apparatus shown in FIG.
A plurality of first cores 56 provided in 2
A plurality of first cavities 22 and 26 are formed by a plurality of first cavity bushes 62 provided on the upper die 20.

This first core 56 (hereinafter sometimes referred to as core 56) is provided with a first molded product protruding rod 60 for protruding the first molded product from the core 56, and near the core 56, a belt-like rod is provided at the same time as the first molded product is protruded. A strip protruding rod 61 that protrudes from the body 30 is provided. Furthermore, a runner protruding rod 58 is provided between the cavities 22 and 26 to protrude a runner formed during injection molding.

Among these protruding rods, the lower ends of the protruding rods 60 and 61 are in contact with the molded product protruding plate 63, and the lower ends of the protruding rod 58 are in contact with the runner protruding plate 59, respectively. For this reason, the first
As shown in FIG.
The protruding rods 53 and 55 that protrude through the molded product protruding plate 63 and the runner protruding plate 52 push up the protruding rods 58, 60, and 61 of each core 56 at the same time.

Further, a mesh-like groove 54 is formed on the end surface of the core 56, and a character groove 64 for forming characters, etc. is formed on the bottom surface of the cavity bush 62 of the upper mold 20.

In such a first molding device, the upper mold 2
0 and the parting line 42 between the lower mold 32,
A metal strip 30 is placed.

As shown in FIG. 2, this band-like body 30 is a horizontally long metal plate, and has a rectangular through hole 40 near its central axis.
are drilled in sets of two in the longitudinal direction,
Furthermore, a semicircular hole is formed at one side end of the strip 30 as a positioning hole 92 of the strip 30.

As shown in FIG. 1a, a core 56 is inserted into the through hole 40 formed in the band-shaped body 30, and
The inner wall surface of the through hole 40 is the first cavity 22,
It forms part of the wall surface of 26.

The first molded product 34 molded by the first molded product device shown in FIG. 1a is attached to the strip 30 (hereinafter referred to as mount ) is separated from the core 56 while being
Move to the final molding device shown in FIG. 1c.

The final molding device is composed of an upper mold 21 and a lower mold 44, and by placing the strip 30 on the parting surface of the lower mold 44, the final molding device is formed to be smaller than the core 56 of the first molding device. Lower mold 4
The first molded product 34 is placed on the upper surface of the second core 70 (hereinafter sometimes referred to as the core 70) of No. 4.

The reason why the core 70 is formed smaller than the core 56 is to cope with shrinkage of the first molded product 34 after molding.

The second cavities 24 and 28 are formed by the core 70 of the upper mold and the second cavity bush 74 of the upper mold 21, and the first molded product 34 placed on the upper surface of the core 70 is It is stored in the bitty 74.

The lower mold of such a final molding device includes a first molded product support rod 72 that adjusts the distance of the first molded product 34 from the core 70 and protrudes the final product, and a first molded product support rod 72 that adjusts the distance from the parting surface of the lower mold 44 of the strip 30. At the same time as adjusting and ejecting the final product, the strip 30
A strip supporting rod 82 for protruding the runner and a runner protruding rod 83 for protruding the runner are provided.
Furthermore, the lower ends of these rods 72, 82, 83 are connected to protruding plates 59, which are protruded by protruding rods 53, 55,
It is in contact with 63.

The final molded product 48 that has been molded in this final molding device is placed between the rods 72 and 8, as in FIG. 1b.
2 and 83, the final molded product 48 is mounted on the strip 30 and separated from the core 70, as shown in FIG.
Move to the detachment device 50 shown in FIG.

The separating device 50 is a device that separates the strip 30 and the final product 48.

This detachment device 50 is provided with an upper plate 88 and a lower plate 89 that sandwich the strip 30, and the lower plate 89 is urged upward by a spring 85.

A product protrusion plate 47 is provided below the upper plate 89 so as to be movable in the vertical direction by a drive device 51 such as a cylinder.
The lower end of the product protruding rod 84 is in contact with 7.

Therefore, when the product protruding plate 47 rises upward against the biasing force of the spring 85, the protruding rod 84
moves upward together with the product protruding plate 47, and releases the final product 48 from the strip 30 in the direction of the arrow shown in FIG.
It can be taken out during 6.

In the injection molding apparatus of this embodiment, as shown in FIG. 30 while moving a predetermined distance and moving to the next device.

The transfer device 46 may be any device that can move the strip 30 a predetermined distance, and any device that has been commonly used in the past can be used.

In this example, since the first molding device and the final molding device are installed in one mold, the fourth molding device
As shown in the figure, the strip 30 is attached to the core 5 together with the molded product.
When detaching from 6, 70, use the protruding rods 61, 82.
With the protrusion, the gripping devices 17, 17, on which the strip 30 is gripped, are ejected upward by the cylinders 19, 19.

In addition, when moving the strip 30, use the rod 6.
1, 58, 83, and 82 are lowered below the strip 30, and the grip of the strip 30 by the gripping devices 17, 17 is released.

Further, when placing the strip 30 on the parting surface of the lower die 32, the gripping devices 17, 17 for gripping the strip 30 are lowered by the cylinders 19, 19.

A rectangular through hole 4 is drilled in the strip 30 placed on the parting surface of the lower die 32 in this manner.
0 position, as shown in FIG.
matches the position of

Note that the core 56 of the first molding device has a mesh-like groove 54 formed on its upper surface.

The strip 30 may be an elongated continuous body made of metal, and may be an endless belt-like strip or a strip that can be wound like a film.

Next, the operation of the apparatus of this embodiment will be explained.

First, in the first forming apparatus shown in FIG. 1A, the transfer device 64 shown in FIG. Yotsute belt-shaped body 30
is moved a predetermined distance and placed on the parting surface of the lower mold 32, and the upper mold 20 is closed.

Part of the wall surface of the cavities 22 and 26 formed by closing the upper mold 20 and the lower mold 32,
It is formed by the inner wall surface of the through hole 40 of the band-shaped body 30.

Resin that will form the characters, etc. of the final molded product is injected into the cavities 22 and 26, and the first molded product 3
Mold 4.

The obtained first molded product 34 serves as the basis of the key top 48 shown in FIG. 2, and has a projection 76 for forming characters, etc. on the upper surface of a mesh-like groove 78.

First molded product 34 obtained in this way
After the mold is opened, the inner wall surface of the through hole 40 of the strip 30 and the first molded product 3
The protruding rod 60, with the first molded product 34 mounted on the strip 30, is in contact with the side surface 36 of the
61 and the cylinder 19 shown in FIG. 4 lifts it upward and separates it from the core 56.

At this time, the runner 68 also separates from the parting surface of the lower die 32 by the protruding rod 58 and falls.

Next, after the protruding rods 60 and 61 descend downward and the gripping device 17 releases the belt-shaped body 30, the belt-shaped body 30 on which the first molded product 34 is mounted is moved by the belt-shaped body 30 transfer device 46. is moved so that the core 70 of the final molding device shown in FIG. 1c is aligned with the inside of the recess of the first molded product 34.

Thereafter, the strip 30 is placed into the lower mold 44 of the final molding device.
The first molded product 34 and a part of the strip 30 are inserted into the cavities 24 and 28 to be formed by placing the first molded product 34 on the parting surface of the mold and closing the upper mold 21 to close the mold.

In this embodiment, the support rod 72 is adjusted to form a space between the upper surface of the core 70 and the inner bottom surface of the first molded product 34, and at the same time
The distance of the lower die 44 from the parting surface is also adjusted by the support rod 82.

Further, the inner bottom surface of the recessed portion of the cavity bush 74 of the upper mold 21 that forms the wall surfaces of the cavities 24 and 28 is in contact with the upper surface of the protrusion 76 of the first molded product 34.

When resin, which mainly forms the outer wall surface 77 of the key top 48 shown in FIG.
It fills the space between the core 70 and the first molded product 34 through a mesh groove 78 formed on the upper surface of the core 70 . Furthermore, the resin filling the space is
The island area 80 surrounded by the protrusions 76 forming characters etc. is connected to the groove part 7 located below the island area 80.
8 can be filled to form a key top 48 on which characters or the like appear on the upper surface.

This key top 48 is connected to the upper mold 2 of the final molding device.
After the molds 1 and the lower mold 44 are opened, they are removed from the core 70 while being mounted on the strip 30 by the rods 82 and 83 as in FIG. 1b, and the detachment device 50 shown in FIG. will be transferred to.

In the detaching device 50, the key top 48 is detached from the strip 30 by the product ejecting rod 84 and taken out into the product transfer hole 86.

The key top 48 taken out in this way is
As shown in FIG. 6, a circumferential recess 38 that contacts the edge of the through hole 40 of the strip 30 remains.

Moreover, the belt-shaped body 30 from which the key top 48 has been removed
is reused.

The grooves 78 formed on the upper surface of the first molded product 34 may be two grooves, as shown in FIG. 7, or may be concentric circles.

(Effects of the Invention) According to the apparatus of the present invention, molded products made of resins with different colors and properties can be easily molded.
It is also easy to automate and shorten the molding cycle.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a plan view of the band-shaped body, Figure 3 is a plan view of the detachment device,
FIG. 4 is a partial cross-sectional plan view of the injection molding apparatus, FIG. 5 is an explanatory diagram illustrating the state in which the strip is attached, FIG. 6 is a perspective view of a key top, FIG. 7 is a perspective view of another key top, and FIG. 8 is a perspective view of another key top. 1 and 2 respectively show cross-sectional views of conventional injection molding equipment. In the figure, 22, 26... first cavity, 24, 28... second cavity, 30
...Band-shaped body, 34...First molded product, 40...
...Through holes in the strip 30, 48...Final molded product.

Claims (1)

[Claims] 1. A first molded product obtained by first molding in which one of at least two resins is injected into a cavity of a mold is inserted into a second cavity of a mold in which the other resin is injected. In an injection molding device that performs injection molding, when the mold is placed on the parting surface of the mold and the mold is closed, the inner wall surface or edge of the through holes drilled at predetermined intervals will A metal strip that forms part of the cavity and to which the first molded product is attached after first molding, and the first molded product that is attached to the strip is transferred to a position in the mold where the second cavity is formed. As shown in FIG. Characteristic injection molding equipment.