JPH0451008Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a green molding sand kneading device that adds clay such as bentonite as a binder to silica sand and further adds moisture and the like to adjust the kneading.

(Prior art) In general, in order to mix and adjust green mold sand, as shown in Fig. 1, a kneading tank 3 having a cylindrical side wall 1 and a bottom plate 2 form a cross-sectional shape, and a hole penetrates through the center of the bottom plate 2 of this kneading tank 3. A kneading device is used which includes a head 5 attached to a rotary shaft 4 and rotary rollers 7, which are arranged to be rotatable in a vertical plane and revolved in a horizontal plane via rocker arms 6, 6. 8 in the figure,
8 is a cylinder for pressurizing the rotating roller.

(Problem to be solved by the invention) It is well known that when green mold sand is kneaded by the above-mentioned kneading device, efficient kneading cannot be achieved unless the hardness of the part stepped on by the rotating rollers 7, 7 exceeds a predetermined level. be. In order to check the kneading state of the conventional kneading device, the inventors stopped the device in the middle of kneading green mold sand and removed the bottom plate 2 of the kneading tank 3.
The hardness of the green mold sand from the center to the side wall 1 was measured. The results were as shown by the solid line in Figure 2. As shown in FIG. 1, the sections B to D in FIG. 2 are as shown in FIG. is the section from the outside of the rotating roller 7 to the side wall 1. Also, section A in FIG. 1 indicates the diameter of the rotating shaft 4. Therefore, from the standpoint of kneading efficiency, it is desirable that the range of high hardness in FIG. 2 be the entire region C.
However, in reality, it can be seen that the hardness of the inner 1/3 of the part stepped on by the rotating roller 7 is rapidly reduced.

(Purpose of the invention) The present invention is based on the C
The purpose of this invention is to provide a kneading device that can efficiently knead the green mold sand in the entire section with high hardness.

(Process and means to solve the problem) The inventors conducted a detailed investigation to find out the reason why green mold sand does not have high hardness in some areas even in areas trampled by the rotating roller 7 in conventional kneading equipment. As a result, it was discovered that the dimensional relationship between section B and section D was B=1.2D. From this, it was predicted that the green mold sand in section B would escape (move) toward section A when the green mold sand in section C was stepped on by the rotating roller. Based on this prediction, a kneading device was manufactured in which the diameter of the rotating shaft 7 was increased, the dimension of section B was shortened, and the dimensions of section B and section D were made equal.

(Function) Green molding sand was kneaded using this kneading device, and the hardness of the kneaded sand from section B to section D was measured, and it was found that the high hardness region was wide as shown by the chain line in Figure 2. In other words, the green molding sand has a high hardness throughout the C section trampled by the rotating rollers 7, 7.

(Effect) As is clear from the above explanation, in the green sand kneading device equipped with rotating rollers, the section dimension from the inside of the rotating shaft to the inside of the rotating roller is made equal to the section dimension from the outside of the rotating shaft to the side wall. Over the entire area trampled by the rotating rollers,
It can make green molding sand highly hard and is useful for improving kneading efficiency.

In addition, in the above explanation, the diameter of the rotating shaft 4 is increased and the dimension of section B is shortened, so that the relationship B=D is established. Even if the relationship B=D is established, the same effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of the green mold sand kneading device, and FIG. 2 is a graph showing the hardness measurement results of the green mold sand in the kneading tank. 1... Side wall, 4... Rotating shaft, 7... Rotating roller.

Claims (1)

[Scope of utility model registration request] A kneading tank 3 having a cylindrical side wall 1 and a bottom plate 2 has a cross-sectional shape, and a rotating shaft 4 penetrating through the bottom plate 2 is arranged so as to be able to rotate in a vertical plane and revolve in a horizontal plane via rocker arms 6, 6. Rotating rollers 7, 7
In a green sand kneading device consisting of,
A green sand kneading device characterized in that a dimension B from the outside of the rotary shaft 4 to the inside of the rotary roller 7 and a dimension D from the outside of the rotary roller 7 to the side wall 1 of the kneading tank 3 are made equal.