JPH0134704B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a molding sand blowing device for blowing molding sand into a mold when forming a mold such as a core used in a shell mold casting method or the like. Regarding.

(Prior Art) In general, molds for cores, etc. are made by introducing molding sand coated with a binding resin onto the surface into the cavity of the mold through a blow hole provided in a part of a set of divisible molds. In addition to blowing into the air using air pressure,
The resin coating is melted by heating this mold, and each molding sand is bonded and hardened into a shape corresponding to the cavity shape. In this method, the hardened product is Ejectopine is used to separate from the mold. In other words, when the mold is opened, the product formed by the above method is connected to the mold in which the above-mentioned injection hole is provided, so after the mold is opened, the eject pin is inserted into the above-mentioned injection hole from the outside. This forces the product to separate from the mold.

Therefore, as shown in, for example, Japanese Utility Model Application Publication No. 58-43848, a molding device for forming cores and the like by this method is used to blow molding sand stored inside the mold into a blowing hole in the mold. In addition to a sand tank having a blow hole formed at the bottom for blowing air into the cavity through the sand tank, there is also an extrusion plate on which the eject pin is disposed and driven by a cylinder or the like.

(Problems to be Solved by the Invention) However, according to the conventional molding apparatus as described above, there are two steps: a blowing process in which molding sand is blown into the mold from a sand tank, and an ejecting process in which the product is ejected from the mold using an eject pin. Since the molding is performed at different stations, the mold must be moved back and forth between the two stations each time one product is manufactured.This increases the cycle time by the amount of time required for the back and forth movement, and the overall molding equipment However, since it is necessary to provide a blow station and an eject station, the size becomes large.

In addition, the position and number of molding sand blowing holes provided in the mold vary depending on the size and shape of the product to be manufactured. Since the eject pin must be placed on the plate, in the case of the conventional molding device as described above, when replacing the mold, the blow head part at the bottom of the sand tank where the blow hole is formed, and the extrusion plate where the eject pin is arranged. Both of them had to be replaced, and this was one of the reasons for increasing the working time for mold replacement.

The present invention deals with the above-mentioned situation in conventional molding equipment, and by configuring the blowing process and ejecting process to be performed at the same station, the time required to move the mold can be omitted and the cycle time can be reduced. The purpose is to shorten the time and make it possible to downsize the molding apparatus, and to shorten the working time when replacing molds.

(Means for Solving the Problems) That is, the present invention provides molding sand stored in a sand tank through a blow hole provided at the bottom of the tank and a blow hole provided in the mold. In a foundry sand blowing device designed to blow sand into a cavity, the sand tank is divided into an upper tank and a lower tank, and an eject pin is arranged in the lower tank to face a blow hole provided at the bottom thereof. Further, the upper tank is provided with an eject pin pushing means for driving the eject pin from the upwardly retracted position to a position where the tip end projects downward through the blow hole.

(Function) Therefore, according to the foundry sand blowing device according to the present invention, pressurized air is injected into the sand tank while the blow hole of the sand tank and the blow hole provided in the mold are communicated with each other. When introduced, the foundry sand in the sand tank is blown into the cavity of the mold, and
After the mold sand has hardened and the mold is opened, the tip of the eject pin is made to protrude from the blow hole and plunge into the blow hole of the mold, and the product is separated from the mold. Thus, the blowing process and the ejecting process are performed at the same station without moving the mold.

In particular, since the blow hole and the eject pin placed opposite thereto are provided in the lower tank, when changing to a mold with a different position or number of molding sand blowing holes, only the lower tank needs to be replaced. That would be enough.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

As shown in FIG. 1, the foundry sand blowing device 1 according to this embodiment is supported by a frame 2 in a hanging manner, and a lower surface 3a is in contact with the upper surface of a mold A installed below. It has a sand tank 3 which is used as a blow head part. This sand tank 3 is attached to the lower end of a piston rod 5 that protrudes downward from a lifting cylinder 4 installed on the upper surface of the frame 2, and the piston 6 is moved by supplying and discharging hydraulic pressure (or air pressure) to and from the cylinder 4. By vertical movement, it is raised and lowered via the piston rod 5 between the illustrated position and a position a certain distance above it (see FIG. 2). Here, a plurality of guide rods 7...7 are erected on the upper surface 3b of the sand tank 3, and these rods 7...7 are connected to guide sleeves 8...8 fixedly provided on the upper surface of the frame 2, respectively. They are slidably fitted, and the sand tank 3 is raised and lowered while being guided by them.

The piston rod 5 is shaped like a hollow pipe, and its lower end is connected to the upper surface 3b of the sand tank 3.
A pipe 9 is inserted into the inside of the rod 5. The gap between the rod 5 and the pipe 9 is an air passage 10 leading into the tank 3, and the end of the rod 5 protruding from the upper end of the cylinder 4 is provided with a pressurized air source (not shown). ) is provided with an air inlet 11 into the air passage 10 or into the tank 3. Further, the inside of the pipe 9 is a sand passage 12 that also communicates with the inside of the tank 3, and a sand supply device (not shown) is connected to the upper end of the pipe 9 from the sand passage 12 to the tank 3.
A sand inlet 13 is provided to introduce the foundry sand B into the tank 3, and an opening 12a at the lower end of the sand passage 12 into the tank 3 is provided with a cylinder 14 installed at the upper end of the pipe 9 that penetrates the inside of the pipe 9. Rod 1
An on-off valve 16 is provided which can be moved up and down via 5,
When the opening/closing valve 16 opens the opening 12a, the molding sand B is supplied into the tank 3 through the sand passage 12.

The sand tank 3 is composed of an upper tank 17 with an open bottom and a lower tank 18 with an open top. The flange portions 17a and 18a are connected to the fastening member 19.
...By tightening by 19, both tanks 1
7 and 18 are combined and integrated to form a hollow sand tank 3.

In the upper tank 17, the inner circumferential surface and the piston rod 5 that protrudes into the tank 17 are provided.
An extruded plate 2 having an outer circumferential wall 20a and an inner circumferential wall 20b vertically slidably fitted to the outer circumferential surface of the extruded plate 2.
0 is installed inside the upper tank 17 (sand tank 3), and the extrusion plate 20 is inserted into the upper surface 3b of the upper tank 17 (sand tank 3) via piston rods 21... Eject cylinders 22...22 are installed to move up and down between the two.

On the other hand, inside the lower tank 18, a plurality of cylindrical bodies 23...23 are arranged upright from the bottom surface thereof. These cylindrical bodies 23...23 are formed with holes 23a...23a that open to the lower surface 3a of the tank 3 on the lower end surface, and these holes 23a...23a are connected from inside the sand tank 3 to the cavity A' of the mold A. Each cylindrical body 23 is provided with an introduction hole 23b on the lower side surface thereof to introduce molding sand from the bottom of the tank 3 into the blow hole 23a. And these cylindrical bodies 23...2
Eject pins 24...24 are inserted into each of the cylinders 3 so as to be movable up and down, and each eject pin 24 is urged upward by a spring 25 installed in the cylinder body 23 and is normally held at the upper end position shown in the figure. At this time, the upper end 24a of each eject pin 24 is located directly below the extrusion plate 20 in the upper position, and the lower end 24b is located so as to face the blow hole 23a from above.

Here, each of the cylindrical bodies 23...23 or eject pins 24...24 are provided in the upper wall of the mold A (upper mold _A1 ) and have injection holes A''...A'' for molding sand that communicate with the inside of the cavity A'. When the lower surface (blow head portion) 3a of the sand tank 3 is brought into contact with the upper surface of the mold A as shown in the figure, each blow hole 23a...23a and each blow The insertion holes A''...A'' are arranged to communicate with each other.
In that case, in order to seal the communication portion between both holes 23a and A'', a ring-shaped elastic body 26 is attached to the portion of each cylinder 23 that protrudes downward from the tank bottom surface 3a, and these elastic bodies 26 The lower surface 3a of the tank and the upper surface of the mold A are brought into contact with each other via the ... 26.In addition, the introduction holes 23b communicating with the blow holes 23a in each cylinder 23 allow the molding sand B to be blown out smoothly. In order to do this, the molding sand B is inclined at a predetermined angle, and this angle is set to an angle that prevents the foundry sand B from falling from the blow hole 23a when pressurized air is not introduced into the sand tank 3.

Next, the operation of this embodiment will be explained.

First, as shown in FIG. 1, a required amount of foundry sand B is supplied into the sand tank 3 from the sand passage 12, and the tank 3 is moved to a lower position by the lifting cylinder 4, so that the lower surface 3a of the tank 3 is moved downward. The mold A (upper mold A 1 ) is placed in contact with the upper surface of the mold A (upper mold A ₁ ). At this time, each blow hole 23a...23a opened on the lower surface 3a of the sand tank 3 is connected to the blow hole A''...A'' opened on the upper wall of the upper mold _A1 , and the sand tank 3
The cavity A′ formed between the upper die A ₁ and the lower die A ₂ of the mold A is connected to the introduction hole 23 in the cylinder body 23.
b, are communicated through the blow hole 23a and the blow hole A'' in the upper die _A1 .

Next, in this state, pressurized air is introduced into the sand tank 3 from the inlet 11 provided at the upper end of the piston rod 5 through the air passage 10.
The molding sand B stored in the tank 3 is filled into the cavity A' of the mold A through the holes 23b, 23a, A'' by air pressure. The resin coating is melted and bonded by heating through mold A;
It is hardened to form a core having a shape corresponding to the shape of the cavity A'.

When the core is formed in the mold A in this manner, the lifting cylinder 4 is activated, and the sand tank 3 is raised to an upper position via the piston rod 5, as shown in FIG. In addition, after the sand tank 3 is raised, separately provided elevating means C, C
The upper mold _A1 of the mold A is raised, and the mold A
The mold is opened, and at this time, the core D formed in the cavity A' is raised together with the upper mold _A1 while being connected to the lower part of the upper mold _A1 .

Then, as shown in FIG. 2, with the upper surface of the upper mold A ₁ again in contact with the lower surface 3a of the sand tank 3 in the upper position, the ejecting cylinder 2
2 and 22 are actuated, and the extrusion plate 20 is moved from an upper position shown by a chain line in the figure to a lower position shown by a solid line. Therefore, the upper end portions 24a are inserted through the cylinder bodies 23...23 and directly below the extrusion plate 20.
...each eject pin 24 where 24a was located...
24 are pressed downward all at once against the springs 25...25, and the lower ends 24b...24b of each eject pin 24...24 pass through the blow holes 23a...23a formed in the lower end surfaces of the cylinders 23...23. It will be inserted into the blow holes A''...A'' in the upper mold _A1 . As a result, the core D that has been connected to the lower part of the upper mold A ₁ is forcibly separated from the upper mold A ₁ and taken out onto the receiving member E that has been carried downward.

In this way, the core D is formed, and according to this device 1, the cavity of the mold A is
A blowing process in which molding sand B is blown into A′, and upper mold A ₁
The ejecting process for removing the core D from the mold is performed at the same location, and there is no need to move the mold A laterally between the two processes.

On the other hand, when replacing the mold A in order to manufacture a different type of core, the blow holes 23a...23a on the lower surface 3a of the sand tank 3 and the eject pins 24...24 arranged opposite to these should be changed to new locations. Each molding sand injection hole on the top surface of the mold A used
Must correspond to the installation position of A″…A″.
In this case, in this device 1, the blow holes 23a...23a and the eject pins 24...24 are both provided in the lower tank 18 of the divided sand tank 3, and a The extrusion plate 20 and its driving cylinders 22...22 are connected to the pins 24.
... 24 and is provided on the upper tank 17 side, as shown in FIG. 3, the fastening member 1
9...19 is released and the previous lower tank 18 is removed, and in its place, the cylindrical body 23'
...23', that is, the blow holes 23a'...23a', eject pins 24'...24', etc., are arranged in accordance with the newly used mold.It is sufficient to install the lower tank 18'. There is no need to replace the extrusion plate 20 and cylinders 22...22. And this lower tank 18'
Even when using the ejecting process, the ejecting pins 24'...
24' can be extruded all at once.

In the above embodiment, the extrusion plate 20 is guided by its outer circumferential wall 20a and inner circumferential wall 20b to the inner circumferential surface of the upper tank 17 and the outer circumferential surface of the piston rod 5. If the extrusion plate 20' moves up and down favorably without being guided, as shown in FIG. 4, the extrusion plate 20' may be a simple flat plate without the inner and outer circumferential walls. Further, in the above embodiments, the present invention was applied to a molding apparatus using a heat curing method, but it goes without saying that the present invention can also be applied to a molding apparatus using a gas curing method.

(Effects of the Invention) As described above, according to the present invention, in a molding sand blowing device that blows molding sand stored in a sand tank into a mold through a blow hole provided at the bottom of the tank. , the sand tank is divided into an upper tank and a lower tank, and an eject pin is disposed in the lower tank so as to face a blow hole provided at the bottom of the tank, and the tip of the eject pin is disposed in a position where the eject pin is retracted upward. Since the upper tank is provided with an eject pin extrusion means that is driven to a position where the sand protrudes downward through the blow hole, the blowing step of blowing molding sand into the mold through the blow hole and the eject pin pushing out the mold are performed. The ejecting process for removing the product from the mold can be performed at the same station. This eliminates the need to move the mold between the blowing process and the ejecting process as in the past, making this type of molding work easier. The cycle time is shortened and the molding device can be downsized. In addition, especially when replacing the mold to manufacture a different type of product, it is sufficient to replace only the lower tank where the eject pin is placed opposite the blow hole.
Compared to the conventional case in which both the blow head portion of the sand tank and the extrusion plate on which the eject pin is disposed had to be replaced, the working time when replacing the mold is reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the foundry sand blowing device according to the present invention. FIG. 1 is a longitudinal sectional view showing the state during the blowing process, FIG. 2 is a longitudinal sectional view showing the state during the ejecting process, and FIG. FIG. 3 is a vertical cross-sectional view of the main part showing the state when the lower tank is replaced, and FIG. 4 is a vertical cross-sectional view of the main part showing another embodiment of the extrusion plate. 3... Sand tank, 17... Upper tank, 1
8, 18'... lower tank, 23a, 23a'...
Blow hole, 20, 20', 22... Eject pin extrusion means, 24, 24'... Eject pin,
A...Mold.

Claims (1)

[Claims] 1. A molding sand blowing device for blowing molding sand stored in a sand tank into a mold from a blow hole at the bottom of the tank, wherein the sand tank is divided into an upper tank and a lower tank, and the sand tank is divided into an upper tank and a lower tank. An eject pin extruder in which an eject pin is disposed in the tank so as to face a blow hole provided at the bottom of the tank, and the eject pin is driven from an upwardly retracted position to a position where the tip part projects downward through the blow hole. A foundry sand blowing device characterized in that means is provided in the upper tank.