JPH0438501B2 - - Google Patents

Description

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

(Prior art) Conventionally, as a method for making self-hardening molds, Japanese Patent Application Laid-open No. 1989-
As disclosed in Japanese Patent No. 213336, self-hardening foundry sand necessary for filling one mold box or flask is produced by kneading binder-coated sand and curing agent-coated sand in a kneading tank, There is a method in which the self-hardening foundry sand is once stored in a hopper and then filled into a mold box etc. using the so-called suction method to form a mold. Since the mixture hardens after a short period of time, it is necessary to immediately charge the mixture into a mold box or the like after kneading. Therefore, in the above-mentioned molding method, when a large mold is to be molded, the kneading tank and hopper must have a large capacity to accommodate the large mold, resulting in problems such as an enormous increase in equipment costs.

(Object of the invention) The present invention was made in view of the above circumstances, and
The purpose of the present invention is to provide a mold making method that can accommodate large mold boxes and flasks even with relatively small kneading tanks and hoppers.

(Means for Solving the Problems) The present invention provides a self-hardening mold manufacturing method that is manufactured by kneading binder-coated sand and curing agent-coated sand, and that hardens in a short period of time after kneading. A self-hardening mold making method in which a mold is made from foundry sand, which includes binder-coated sand obtained by adding and kneading a binder and hardener-coated sand obtained by adding and kneading a hardening agent. and are temporarily stored separately in a preliminary hopper with a gate, and then the two types of coated sand are kneaded in a kneading tank to form self-hardening foundry sand, which is then stored in the hopper, and the self-hardened foundry sand is sucked into the hopper. Between the step of charging the self-hardening foundry sand into the molding box or flask and storing the self-hardening foundry sand in the hopper and the step of charging the self-hardening foundry sand into the molding box or flask, Binder-coated sand and curing agent-coated sand are manufactured and temporarily stored in a reserve hopper, and thereafter, each of the above steps is repeated to fill the mold box or flask with the self-hardening foundry sand. That is.

(Embodiment of the Invention) Hereinafter, an embodiment of the present invention will be described in detail based on the drawings. 1 is a vertically split mold box, fixed mold 2
and a movable mold 4 moved by a horizontal cylinder 3.
It is made up of. A cavity 5 having a baseboard portion 5a which also serves as a sand suction hole is provided in the mold box 1, and on the backs of the fixed mold 2 and the movable mold 4,
Hollow chambers 6 and 7 are formed, and the cavity surfaces of the fixed mold 2 and the movable mold 4 are communicated with the hollow chambers 6 and 7 via vent holes 8 and 9, respectively. Further, the hollow chambers 6 and 7 include a flexible conduit 10, a conduit 11,
It is communicatively connected to a vacuum pump 14 via an on-off valve 12 and a vacuum receiver tank 13. 15
1 is a funnel-shaped hopper that is movably disposed directly above the closed mold box 1. A slide gate 16 and an intermediary member 17 are attached to the lower end of the hopper 15, and the slide gate 16 supports a bracket 18. The horizontal cylinder 19, which is fixed to the hopper 15 via the hopper 15, is extended and contracted to move from side to side. Reference numeral 20 denotes a vertical cylindrical kneading tank with an open bottom. Inside the kneading tank 20, a vertical rotating shaft 22 rotated by a downward motor 21 is disposed. A vane 23 is attached. A cylinder 52 is installed at the bottom of the kneading tank 20.
A slide gate 53 is provided which is operated by.

Reference numerals 46 and 47 denote preliminary hoppers, which are arranged directly above the kneading tank 20. And spare hopper 46,4
7 are provided with slide gates 50 and 51 operated by cylinders 48 and 49, respectively. The kneading tank 24 has a horizontal cylindrical shape and has both openings closed.
Inside, a horizontal rotating shaft 26 rotated by a horizontal motor 25 fixed to the side plate of the kneading tank 24 is disposed with the other end supported by the side plate of the kneading tank 24. A kneading blade 27 is attached. A supply port 28 is formed at the upper left end of the kneading tank 24, and a discharge port 29 is formed at the lower right end, and the supply port 28 is equipped with a slide gate 31 and a hopper 32 operated by a cylinder 30. The discharge port 29 faces the reserve hopper 46. Further, a pump and a self-hardening mold-making binder storage tank (not shown) are connected to the vicinity of the supply port 28 of the kneading tank 24 via a conduit 33 and an on-off valve 34 . 35 is the kneading tank 24
The kneading tank 35 has a horizontal rotating shaft 37 rotated by a motor 36, and the rotating shaft 37 also has a plurality of root blades 38.
is installed. A supply port 39 is formed at the upper right end of the kneading tank 35, and a discharge port 40 is formed at the lower left end. 43 is attached, and the discharge port 40 faces the spare hopper 47.
Further, a conduit 4 is provided near the supply port 39 of the kneading tank 35.
4 and an on-off valve 45, a pump (not shown) and a hardening agent storage tank for self-hardening mold manufacturing are connected in communication.

(Operation of the invention) Next, the operation of the device configured as described above will be explained. The motors 21, 25, 36 are driven to rotate the rotating shafts 22, 26, 37 and the kneading blades 23, 2.
7 and 38 are rotated, cylinder 3
0 and 41 are operated to extend, and after a predetermined time elapses, they are contracted to reciprocate the slide gates 31 and 42, supplying a predetermined amount of sand in the hoppers 32 and 43 into the kneading tanks 24 and 35, respectively, and furthermore, the on-off valve 34 and 45 are opened and closed after a predetermined period of time to supply a predetermined amount of binder and curing agent into the kneading tanks 24 and 35. As a result, in the kneading tank 24, the sand to which the binder has been added is mixed again. In the tank 35, sand to which a curing agent has been added is kneaded and manufactured. The binder-coated sand produced in the kneading tank 24 is temporarily stored in a preliminary hopper 46, and the effect agent-coated sand produced in the kneading tank 35 is temporarily stored in a preliminary hopper 47. Next, slide gates 50, 51
The coated sand in the preliminary hoppers 46 and 47 is thrown into the mixing tank 20 and kneaded by the kneading blades 23 and 23 to make self-hardening foundry sand.Then, the slide gate 53 is opened to make the self-hardened foundry sand. Pour into hopper 15.

Next, the on-off valve 12 is opened to reduce the pressure inside the hollow chambers 6 and 7 and the cavity 5, and then the cylinder 1 is opened.
When the slide gate 16 is moved by the extension operation of 9 and the lower end opening of the hopper 15 is opened, the hopper 15
The sand inside is sucked into the cavity 5 and charged. After sand charging is completed, the cylinder 19 is contracted to return the slide gate 16 to the hopper 15.
Close the bottom opening of.

By the way, when the capacity of the molding sand used in the cavity 5 or the flask (not shown) is large, the cavity 5 etc. cannot be sufficiently filled with molding sand in one sand charging process. Therefore, between the process of storing self-hardening molding sand in the hopper 15 and the process of charging the molding sand into the cavity 5 etc., each of the above-mentioned coated sand manufacturing processes is performed again, and the manufactured coated sand is transferred to the preliminary hopper 46, 47. Store it temporarily. Immediately after the foundry sand from the above process in the hopper 15 is charged into the cavity 5 etc., the two types of coated sand produced in the subsequent process are kneaded in the kneading tank 20. Insert it inside. By repeating each of the above steps, molding sand with a short pot life can be filled into the cavity 5 and the like within the pot life. After filling the molding sand into the cavity 5, etc., the cylinder 19 is contracted to return the slide gate 16 to close the lower end opening of the hopper 15, and then close the on-off valve 12 to open the hollow chamber 6,
The suction action to 7 is stopped and this state is maintained until the filling sand is hardened. After the filling sand in the cavity 5 hardens, the cylinder 3 is contracted to move the movable mold 4 to the left to obtain a desired mold. Next, the cylinder 3 is extended to move the movable mold 4 to the right, and thereafter, by repeating the above operation, the mold can be intermittently molded.

Incidentally, a plurality of preliminary hoppers 46 and 47 may be provided to feed the coated sand into the kneading tank 20, and thereby the kneading tanks 24 and 35, the motor 25,
36 can be made smaller.

(Effects of the Invention) As is clear from the above description, according to the present invention, the manufactured binder-coated sand and curing agent-coated sand are temporarily stored in separate preliminary hoppers with gates. After charging the hard molding sand into the molding box, etc., the two types of coated sand in the preliminary hopper are immediately kneaded and charged into the molding box, etc., so the molding sand can be charged several times in a short period of time. As a result, even a small device can sufficiently handle large and large-capacity mold boxes and flasks, resulting in excellent effects.

[Brief explanation of drawings]

FIG. 1 is a front view, partially cut away, of an apparatus used in carrying out the present invention.

Claims (1)

[Claims] 1. A method for making a self-hardening mold in which a mold is made from self-hardening foundry sand that is produced by kneading binder-coated sand and hardening agent-coated sand and hardens in a short period of time after kneading, the method comprising: The binder-coated sand obtained by adding and kneading the caking agent and the curing agent-coated sand obtained by adding and kneading the curing agent are temporarily stored separately in a preliminary hopper with a gate, and then the two types of coated sand are is kneaded in a kneading tank to form self-hardening foundry sand, which is then stored in a hopper, and the self-hardened foundry sand is charged into a mold box or flask by a suction method, and the self-hardened foundry sand is stored in the hopper. Between the process of placing self-hardening molding sand into the mold box or flask, binder-coated sand and curing agent-coated sand are separately manufactured and temporarily stored in a reserve hopper. A method for making a self-hardening mold, comprising repeating each of the steps and filling the mold box or flask with the self-hardening molding sand.