JPS635848A - Blowing device for molding sand - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 whose surface is coated with caking resin into the cavity of the mold through a blow hole provided in a part of a set of divisible molds. The resin coating is melted by blowing air into the mold using air pressure and heating the mold, thereby bonding and hardening each molding sand into a shape corresponding to the cavity shape. , in this method, an ejector pin is used to separate the cured product 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, a molding apparatus for forming cores and the like by this method is equipped with a tank in which foundry sand is stored, as shown in, for example, Japanese Utility Model Application Publication No. 58-43848. One station is equipped with an eject pin and its drive device, and the other station is equipped with an eject pin and its drive device, and where the process of separating the product from one mold after opening the mold (eject process) is carried out. It will be done.

(Problems to be Solved by the Invention) However, according to the above-described molding apparatus, the blowing process and the ejecting process are performed at different stations;
The mold must be moved back and forth between both stations each time a product is manufactured, which increases the cycle time by the amount of time required for the back and forth movement. Due to the necessity of providing it, the size will be increased.

The present invention addresses the above-mentioned situation in conventional molding equipment, and by making it possible to perform the blowing process and ejecting process at the same station, the time required to move the mold is omitted, thereby reducing the cycle time. The purpose of this is to shorten the time and downsize the molding device.

(Means for Solving the Problems) That is, the present invention provides for blowing molding sand stored in a sand tank into a cavity of the mold through a blow hole provided in the tank and a blow hole provided in the mold. In the foundry sand blowing device, an eject pin is disposed in the sand tank so as to face the blow hole, and the tip of the eject pin passes through the blow hole from a position where the eject pin is retracted into the sand tank. The present invention is characterized in that an eject pin driving means is provided at a position protruding outside the tank. In other words, the sand tank itself for storing and blowing foundry sand is provided with an eject function. It is something to do.

(Function) Therefore, according to the foundry sand blowing device according to the present invention, pressurized air is introduced into the sand tank with the blow hole of the sand tank communicating with the blow hole provided in the mold. Then, the molding sand in the sand tank is blown into the cavity of the mold, and after the molding sand has hardened and the mold is opened, the tip of the eject pin is projected from the blow hole to open the mold cavity. The product is separated from the forming mold by plunging into the mold, and in this way, the blowing process and the ejecting process can be performed at the same station without moving the mold.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a foundry sand blowing device 1 according to this embodiment is suspended from a frame 2, and has a lower surface 3.
A has a sand tank 3 which is a blow head part that comes into contact with the upper surface of a mold A installed below. This sand tank 3 is attached to the lower end of a piston rod 5 that protrudes downward from an elevating cylinder 4 installed on the upper surface of the frame 2, and a piston 6 is connected by supplying and discharging hydraulic pressure (or air pressure) to and from the cylinder 4. By the vertical movement of the piston rod 5, the piston rod 5 is raised and lowered between the illustrated position and a position a certain distance above the piston rod (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 a guide sleeve 8 fixed to the upper surface of the frame 2. . . 8 so as to be vertically movable, and the sand tank 3 is raised and lowered while being guided by these.

The piston rod 5 has a hollow pipe shape, and its lower end extends from the upper surface 3b of the sand tank 3 to the tank 3.
A pipe 9 is inserted into the inside of the rod 5. Then, the rod 5 and the pipe 9
The space between the rod 5 and the tank 3 is an air passage 10 communicating with the inside of the tank 3, and the end of the rod 5 protruding from the upper end of the cylinder 4 is connected to the air passage 10 or the tank from a pressurized air source (not shown). Air population 11 into 3 is provided. The inside of the pipe 9 is also a sand passage 12 that communicates with the inside of the tank 3, and a sand supply device (not shown) is provided at the upper end of the pipe 9 to supply molding sand B from the sand passage 12 to the tank 3. Sand entrance 1 to introduce
3 is provided, and the opening 12a to the tank 3 at the lower end of the sand passage 12 is provided with an opening/closing switch which is moved up and down via a rod 15 passing through the inside of the pipe 9 by a cylinder 14 installed at the upper end of the pipe 9. A valve 16 is provided, and when the opening/closing valve 16 opens the opening 12a, the foundry 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.
Flange portions 17a, 1 provided on the outer peripheral edge of the upper end, respectively.
8a are fastened by the fastening members 19...19, so that both tanks 17, 18 are combined to form a hollow sand tank 3.

Inside the upper tank 17, there is a pressing plate having an outer circumferential wall 20a and an inner circumferential wall 20b fitted to the inner circumferential surface of the upper tank 17 and the outer circumferential surface of the piston rod 5 protruding into the tank 17 so as to be vertically slidable, respectively. 20 is installed inside the upper tank 17 (sand tank 3), and the upper surface 3b of the upper tank 17 (sand tank 3) is provided with a pressing plate 20 via piston rods 21 . eject cylinder 22 that moves up and down between the
・22 is installed.

On the other hand, inside the lower tank 18, a plurality of cylindrical bodies 23 . . . 23 are arranged upright from the bottom surface thereof.

Holes 23a...23a that open to the lower surface 3a of the tank 3 are formed in the lower end surfaces of these cylindrical bodies 23...23, and these holes 23a...23a are connected to the mold A from inside the sand tank 3. 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. ing. Eject pins 24...24 are inserted into these cylindrical bodies 23...23 so as to be able to move up and down, and each eject pin 24 is pushed upwardly by a spring 25 mounted within the cylindrical body 23. The eject pins 24 are normally held at the upper end position shown in the figure, and at this time, the upper end 24a of each eject pin 24 is located directly below the pressing plate 2o in the upper position, and the lower end 24b is located in the blow hole. 23a from above.

Here, each of the cylindrical bodies 23...23 or eject pins 24...24 is connected to a molding sand blowing hole A provided in the earthen wall of the mold A (upper mold A1) and communicating with the inside of the cavity A'.
11...A'', and 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 of the above-mentioned blow holes 23a...23a and each blow hole A"...A" are communicated with each other.In that case, both holes 23
In order to seal the communication portions a and A", ring-shaped elastic bodies 26 are respectively attached to the portions of the cylinders 23 that protrude downward from the tank bottom surface 3a, and these elastic bodies 26...2
The lower surface 3a of the tank and the upper surface of the mold A are brought into contact with each other through a hole 6. In addition, the introduction hole 23b communicating with the blow hole 23a in each cylinder 23 is inclined at a predetermined angle in order to smoothly blow out the molding sand B. The angle is set so that the molding sand B does not fall from the blow hole 23a when air is not introduced.

Next, the operation of this embodiment will be explained.

First, as shown in Fig. 1, a sand passage 1 is installed in the sand tank 3.
The required amount of molding sand B is supplied from 2, and the tank 3 is moved to the lower position by the lifting cylinder 4, and its lower surface 3a is placed on the upper surface of the mold A (upper mold A1) set downward. make them face each other. At this time, each blow hole 23a...23a opened in the lower surface 3a of the sand tank 3 is connected to the blow hole A"...A" opened in the upper wall of the upper mold A1, and the inside of the sand tank 3 and The cavity A' formed between the upper mold A1 and the lower mold A2 of the mold A is the introduction hole 2 in the cylinder body 23.
3b, the blow hole 23a and the blow hole in the upper die A1.

Next, in this state, if 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 1o, the foundry sand stored in the tank 3 The above 8 holes 23b are closed due to air pressure.
, 23a, A'' and is filled into the cavity A' of the mold A. Then, this molding sand B is heated through the mold A, so that the resin coating is melted, bonded and hardened, and the above-mentioned The core has a shape corresponding to the shape of cavity A'.

When the core is formed in the mold A in this way, 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. Furthermore, after the sand tank 3 is raised, the upper mold A1 of the mold A is raised by a separately provided lifting means C1C to open the mold A. At this time, the inside of the cavity A' is lifted. The core formed in the upper mold A1 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 die A1 again in contact with the lower surface 3a of the sand tank 3 in the upper position, the ejecting cylinders 22, 22 are operated, and the pressing plate 2o is It is moved from the upper position shown by the chain line in the figure to the upper direction l shown by the solid line. Therefore, the cylinder body 23...2
The eject pins 2 were inserted into the respective eject pins 3 and had upper end portions 24a...24a located directly below the press plate 20.
4...24 are pressed downward all at once against the springs 25...25, and the lower ends 24b...24b of each eject pin 24...24 are the lower end surfaces of the cylinders 23...23. The blow holes A'1...A in the upper mold A1 pass through the blow holes 23a...23a formed in the upper die A1.
' will be thrust into the interior. As a result, the core that has been coupled to the lower part of the upper mold A1 is forcibly separated from the upper mold A1 and taken out onto the receiving member E that has been carried downward.

In this way, the core is formed, and according to this device 1, the molding sand B is placed in the cavity A' of the mold A.
The blowing step for blowing in the mold A1 and the ejecting step for taking out the core from the upper mold A1 are performed at the same location, so there is no need to move the mold A laterally between the two steps.

Here, according to this embodiment, the sand tank 3 is divided into an upper tank 17 and a lower tank 18, and the blow hole 23a, eject pin 24, etc. are arranged on the lower tank 18 side. Depending on the size and shape of the core, molding sand injection holes A″...A″ in the upper mold A1
When the installation position of the tank changes, it can be handled by simply replacing the lower tank 18.

According to the above configuration, when the sand tank 3 is raised after the molding sand blowing process, each blow hole 23a...
Since the molding sand B remaining in the mold 23a falls onto the upper surface of the upper mold A1, it is necessary to remove it1.This can be dealt with as follows.

That is, as shown in FIG.
If a small-diameter portion 34b is provided that protrudes into the blow hole 33a and provides a gap for blowing out the foundry sand, the molding sand may remain in the blow hole 33a or pass through the eye hole 33a and be ejected from the tank. This reduces the amount of molding sand that falls and eliminates the need for the above operations. In addition, for the same purpose, as shown in FIG. 4, the tip of the eject pin 44 is
The pin 44 may be extended so as to fit into the blow hole 43a in an upward position, and a spiral groove 44b for blowing out the molding sand may be provided on the circumferential surface of this extended portion.

Here, in the embodiment shown in FIG. 3.4, the cylindrical body 33
．． 43 are fixed to the bottom surface of the sand tank 3, and the blow holes 33a, 43a are formed on the lower end surface, and the introduction holes 33b, 43b are formed on the lower side surface, respectively.
+, and an inner cylinder 332, 432 which is screwed into the inner cylinder and fixed by a nut 37, 47, and in which the eject pin 34, 44 and a spring 35, 45 that urges the eject pin upward are housed. ing. According to such a configuration, by changing the vertical positions of the inner cylinders 332, 432, the lower end surfaces of the inner cylinders 332, 432 and the outer cylinder 3
31. The gap between the inner bottom surface of 431, that is, the above-mentioned introduction hole 3
The widths of the molding sand introduction passages 33c, 43c from 3b, 43b to the blow holes 33a, 43a are adjusted, making it possible to set the molding sand blowing state to the optimum state during the blowing process. Become.

Next, other embodiments of the present invention will be described with reference to FIGS. 5 to 7.

The foundry sand blowing device 51 according to this embodiment has a rail 52
．． It has a truck 54 equipped with wheels 53...53 that move on 52. Guide rods 56 . . . 56 erected on both sides of the upper surface of the sand tank 55 penetrate the cart 54 and protrude upward, and the upper ends of these rods 56 . Springs 57 . . . 57 are interposed between the sand tank 54 and the upper surface of the sand tank 54, so that the sand tank 55 is supported by the cart 54 in a suspended manner and can be raised and lowered.

In addition, a columnar part 60 having a double structure consisting of an outer wall 58 and an inner wall 59 is erected at the center of the upper surface of the sand tank 55, and a gap between both walls 58 and 59 extends into the sand tank 55. An air passage 61 for introducing pressurized air,
Further, the inside of the inner wall 59 is a sand passage 62 for supplying molding sand into the tank 55. In addition, a mold A (upper mold A1) is provided on the lower surface 55a of the sand tank 55, which becomes the blow head.
Blow holes 55b...55b are provided corresponding to the molding sand introduction holes A#...A71, and
Ring-shaped elastic bodies 63 for sealing are attached to downwardly protruding portions provided around the eye holes 55b...55b.

Further, each blow hole 5 is provided on the upper surface of the sand tank 55.
A plurality of cylindrical bodies 64...64 are fixedly installed at positions corresponding to the cylindrical bodies 5b...55b and their lower portions protrude into the tank 55, and inside these cylindrical bodies 64...64, Eject pins 65...65 are inserted therethrough, and springs 66...66 are housed therein to bias the eject pins downward. At the lower end of each of the eject pins 65...65, small diameter portions 65a...65 are inserted into the respective blow holes 55b...55b with required gaps.
a is provided, and each eject pin 65...
- The upper end of 65 is fixed to one connecting plate 67.

On the other hand, a frame 68 installed above the cart 54 or the sand tank 55 has a lifting cylinder 6 positioned directly above the columnar part 60 of the sand tank 55.
A pressing member 72 is attached to the lower end of a piston rod 71 that is integral with a piston 70 in the cylinder 69 . When the piston 70 moves downward as shown in the figure, the pressing member 72 presses down the sand tank 55 via the columnar part 60 and against the springs 57...57.
The lower surface 55a of is brought into contact with the upper surface of the mold A (upper mold A1) via the elastic bodies 63...63.

Also, at this time, the air passage 71a provided in the piston rod 71 is replaced by the air passage 71a provided in the pressing member 72.
It is connected to an air passage 61 in the columnar part 60 via a.

Furthermore, L-shaped hook members 73...73 are swingably suspended from the lower surface of the frame 68.

These hook members 73...73 are adapted to be engaged with and disengaged from the peripheral edge of the connection plate 67, and are provided with cylinders 74...74 for engaging and disengaging the hook members. Stoppers 75 . . . 75 are provided on the upper surface of the cart 54 to restrict immobility of the connecting plate 67 at a predetermined position when the engagement with the hook members 73 . . . 73 is released.

Next, the operation of this embodiment will be explained.

First, as shown in FIG. 5, with the sand tank 55 filled with a required amount of foundry sand B, the sand tank 55 is pressed downward via the columnar part 60 by the lifting cylinder 69, and the tank is opened. 55, the lower surface 55a of the mold A (upper mold A1
). At this time, the bottom surface of the sand tank 55
Each blow hole 55b...55b in a is communicated with the blow hole A"...A" in the upper die A1, and
The peripheral edge of the connecting plate 67 to which the upper end of each eject pin 65...65 is fixed is the hook member 73...73.
The plate 67 or each eject pin 6
The downward movement of the eject pins 65...65 is restricted at a predetermined position, and the eject pins 65...65 are moved by the springs 66...
66 and is located relatively above the sand tank 55. In this state, air passage 7
1a, 72a, and 61 into the sand tank 55, the blow holes 55b...5
5b and the blowing holes A''...A'' into the cavity A' of the mold A.

Next, when the molding sand B in the cavity A' is combined and hardened to form a core, the mold A is opened as shown in FIG. (The upper mold A1 is held in the same position as during blowing), and the hook members 73...73 are opened by moving the cylinders 74...
74 to swing outward to release the engagement with the peripheral edge of the connecting plate 67. At this time, each of the eject pins 65...65 is pressed against the stopper 75...7 by the spring 66...66.
5, and the small diameter portion 65a at the tip
...65a passes through each of the blow holes 55b...55b and enters the blow holes A#...A" in the upper mold A1. As a result, the blow holes A#...A" are connected below the upper mold A1. The core will be taken out, but in this embodiment as well, the blowing process for blowing the molding sand B into the cavity A' of the mold A and the ejecting process for taking out the core from the upper mold A1 are at the same location. There is no need to move the mold A laterally between the two steps.

In this embodiment, the casting sand B is replenished into the sand tank 55 at another station. In other words, as shown in FIG.
When the downward pressing force on the sand tank 55 is released by moving the piston 70 or the pressing member 72 of 9 upward, the tank 55 is moved by the spring 57 to the carriage 54.
The lower surface 55a is moved upward against the mold A (upper mold A1).
At the same time, the pressing member 72 and the columnar part 60 are also separated from each other, so that the cart 54 and the sand tank 55 can be moved along the rails 52 and 52. After moving to a predetermined sand replenishment station, the sand passage 6 inside the inner wall 59 of the columnar part 60
By connecting the supply tube 76 of the sand supply device provided at the replenishment station to the upper end of the replenishment station 2, the foundry sand B is supplied into the sand tank 55 through the passage 62.

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 gas curing type molding apparatus.

(Effects of the Invention) As described above, according to the present invention, in the molding sand blowing device that blows molding sand stored in a sand tank into a mold through a blow hole provided in the tank, An eject pin is disposed in the sand tank so as to face the blow hole, and an eject pin driving means is provided for driving the eject pin from a position where it is retracted into the tank to a position where the tip thereof projects to the outside through the blow hole. Therefore, it is possible to perform the blowing step of blowing the foundry sand into the mold through the blow hole and the ejecting step of ejecting the product from the mold using the eject pin at the same station. This eliminates the need to move the mold between the blowing process and the ejecting process, as was the case in the past.
The cycle time of this type of molding work is shortened, and the molding apparatus can be downsized.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing the state during the blowing process in the first embodiment of the foundry sand blowing device according to the present invention, FIG. 2 is a vertical cross-sectional view similarly showing the state during the ejecting process, and FIG.
The figures are enlarged longitudinal sectional views of essential parts showing other embodiments of the eject pin in this device. In addition, Fig. 5 is a longitudinal cross-sectional view during the blowing process in another embodiment of the foundry sand blowing device, Fig. 6 is the same longitudinal cross-sectional view during the ejection process, and Fig. 7 is a longitudinal cross-sectional view during sand replenishment. It is a diagram. 3.55...Sand tank, 23a, 55b...Blow hole, 24.65...Eject pin, 22.66
...Eject pin drive means (22... cylinder,
66...spring), 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 provided in the tank, wherein an eject pin is disposed in the sand tank facing the blow hole. and an eject pin drive means for driving the pin from a position where it is retracted into the sand tank to a position where the tip thereof projects out of the sand tank through the blow hole. Sand blowing equipment.