JPH0227059B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for making a self-hardening mold.

Conventionally, sand mixed with binders and hardeners for self-hardening mold making is generally filled into a flask on a model plate by a blowing method using compressed air. This method had problems such as the need for a complicated blow head to blow the sand into it and a large clamping device to clamp the casting flask with great force to prevent the sand from blowing out.

The present invention was made in view of the above circumstances, and
It is an object of the present invention to provide a method for making a self-hardening mold that does not require a complicated blow head or a large clamp device when filling sand into a flask or the like.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. 1 is a model board;
A hollow chamber 2 is formed inside. and,
The upper surface of the model plate 1 is communicated with a hollow chamber 2 via a plurality of bend holes 3, 3, and the hollow chamber 2 is communicated with a vacuum pump 7 via a conduit 4, an on-off valve 5, and a vacuum receiver tank 6. ing. Reference numeral 8 denotes a casting flask positioned on the model plate 1 via pins (not shown). Reference numeral 9 denotes a hopper which is provided with a cylinder 10 and is movable up and down. has been completed. And the bottom plate 1 of the hopper 9
In 1a, there are complicated truncated conical sand discharge holes 12, 12.
The sand discharge holes 12, 12 are opened and closed by a slide gate 14 that reciprocates by the expansion and contraction operation of the cylinder 13.
The cylinder 13 is fixed to the main body member 11b via a bracket 15. Further, a hollow chamber 16 is formed inside the bottom plate 11a, and the lower surface of the bottom plate 11a is communicated with the hollow chamber 16 through a plurality of bend holes 17, 17, and the hollow chamber 16 is connected to the hollow chamber 16 through a branch pipe 18. It is connected in communication with the conduit 4. Furthermore, a seal member 19 is embedded in the lower outer periphery of the bottom plate 11a. Further, within the main body member 11b of the hopper 9, a stirring blade 22 attached to the lower end of a vertical rotation shaft 21 rotated by a downward motor 20 is arranged so as to be horizontally rotatable. A kneading tank 23 has a horizontally cylindrical shape and has both openings closed.
A horizontal rotating shaft 25 rotated by a horizontal motor 24 fixed to the side plate of the kneading tank 23 is disposed with the other end supported by the side plate of the kneading tank 23, and a plurality of kneading blades 26 are attached to the rotating shaft 25. ing. A supply port 27 is formed at the upper right end of the kneading tank 23, and a discharge port 28 is formed at the lower left end.
7 is a slide gate 3 operated by a cylinder 29.
0 and hopper 31 are attached. The cylinder 29 is fixed to the hopper 31 via a bracket 32, and the discharge port 28 faces the hopper 9. In addition, near the supply port 27 of the kneading tank 23, a pump (not shown) and a binder storage tank for self-hardening mold making are connected via conduits 33, 34 and on-off valves 35, 36, and a pump (not shown) and a binder storage tank for making self-hardening molds are connected via conduits 33, 34 and on-off valves 35, 36. The hardening agent storage tanks are connected to each other.

Next, the operation of the device configured as described above will be explained. The rotating shaft 2 is driven by driving the motors 20 and 24.
1, 25, stirring blade 22 and kneading blade 26, 2
6 is rotated, the cylinder 10 is extended and the bottom plate 11a of the hopper 9 is fitted into the flask 8 on the model plate 1 to define a hollow chamber C. Next, the cylinder 29 is extended, and after a predetermined period of time has elapsed, the cylinder 29 is retracted to reciprocate the slide gate 30 and open the hopper 31.
A predetermined amount of sand is supplied into the kneading tank 23, and further,
The on-off valves 35 and 36 are opened and closed after a predetermined period of time to supply a predetermined amount of binder and hardener into the kneading tank 23, thereby kneading the sand and the binder and hardener into the hollow chamber. The same amount of sand as the volume of C is put into the hopper 9. Next, open the on-off valve 5 to open the hollow chamber 2,
After depressurizing C and 16 by suction, when the slide gate 14 is moved by the contraction operation of the cylinder 13 and the sand discharge holes 12 and 12 are opened, the height of the kneaded sand in the hopper 9 is leveled by the rotation of the stirring blade 22. The sand is sucked into the hollow chamber C from the sand discharge holes 12, 12. In this case, the inside of the hollow chamber C is the upper and lower bend holes 3 and 1.
Since the hopper 9 receives suction and pressure reduction from the hopper 7, the mixed sand in the hopper 9 is uniformly sucked and filled throughout the hollow chamber C. After filling the sand, the on-off valve 5 is closed to stop the suction to the hollow chambers 2, C, and 16.
Subsequently, the slide gate 14 is returned to its original position by the extension operation of the cylinder 13, and the sand discharge holes 12, 12 are closed. Next, the cylinder 10 is further extended to lower the hopper 9, and the bottom plate 11a closes the hollow chamber C.
Squeeze out the sand inside. After the squeeze is completed, the cylinder 10 is contracted to raise the hopper 9, and the pattern plate 1 and the flask 8 are kept in a state of alignment until the filled sand in the flask 8 is hardened. The frame 8 is separated from the model plate 1 to obtain a desired mold.

In addition, when the shape of the model part of the model board 1 is simple, or when the viscosity of a binder is low and the fluidity|liquidity of kneading sand is good, the squeeze process may be omitted. Also,
Similar effects can be obtained even if the slide gate 14 is omitted.

As is clear from the above explanation, in the present invention, the sand in the hopper is filled into the flask on the model plate by suction while being leveled by the rotation of the stirring blade. It has such excellent effects that blow-out is eliminated, and a large clamping device for clamping flasks and the like and a complicated structure of a blow head are no longer necessary.

[Brief explanation of drawings]

FIG. 1 is a front view, partially cut away, of an apparatus used in carrying out the present invention. 1: Model board, 9: Hopper, 22: Stirring blade.

Claims (1)

[Scope of Claims] 1. Sand mixed with a binder and a hardening agent for self-hardening mold making is stored in a hopper equipped with stirring blades, while a casting flask is placed on a model plate and the sand is mixed with a binder and a hardening agent. The upper opening of the flask is sealed by the bottom plate of the hopper, and a hollow chamber is formed by the three members, the model plate, the flask, and the bottom plate, and the height of the sand in the hopper is leveled by the rotation of the stirring blades. The entire amount of sand in the hopper is sucked and filled into the hollow chamber by suctioning and depressurizing the hollow chamber, and after maintaining the pattern matching state between the model plate and the casting flask until the filling sand is hardened, the hardened sand is removed. A method for making a self-hardening mold, characterized by separating the flask from the model plate. 2. Sand mixed with a binder and a hardening agent for self-hardening mold making is stored in a hopper equipped with stirring blades, while a casting flask is placed on a model board and the upper opening of the flask is opened. It is sealed by the bottom plate of the hopper, and a hollow chamber is formed by three members: the model plate, the casting flask, and the bottom plate, and the height of the sand in the hopper is leveled by the rotation of the stirring blade, and the pressure inside the hollow chamber is reduced by suction. Then, the entire amount of sand in the hopper is sucked and filled into the hollow chamber, and the filled sand in the hollow chamber is further squeezed by the bottom plate, and then the pattern plate and the flask are maintained in a matching state until the filled sand is hardened. and then separating the mold containing hardened sand from the model plate.