JPS6233020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing foundry sand and a testing machine therefor.

Generally, in order to regenerate the recovered sand obtained from demolding into foundry sand that can be used to make molds, the recovered sand is charged into a kneader and mixed with a specified binder and water. The properties of molding sand vary greatly depending on the length of kneading time, often causing the operation of a molding plant to be temporarily halted, and moreover, resulting in a large number of defective casting products. By the way, the quality of kneading of foundry sand is determined by its stickiness.
Currently, there are 3 tests: tensile test, bending test, and surface stability.
Judgments are made based on the results of different types of tests. Judging the quality of kneading of foundry sand using these three types of tests is extremely troublesome, and at the same time, it requires specialized knowledge and skill to handle as it is a special device, resulting in problems such as poor work efficiency. It was hot.

The present invention was made in order to solve the above problems, and its purpose is to provide a testing method for molding sand that can accurately determine the quality of kneading of molding sand with one type of test, and The purpose of the present invention is to provide a testing machine that is easy to carry and does not require skill. Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. Reference numeral 1 denotes a C-shaped testing machine main body which is provided with two boss parts facing each other at a required interval vertically, and a through hole 3 oriented in the vertical direction is provided in the lower boss part 2 of the main body 1. and a vertically elongated opening 4 extending from the outer periphery to the through hole 3. The lower part of an elevating table 5, which has a flat surface at the upper end on which a test piece of about 50 mmφ x 50 mm can be placed, is fitted into the through hole 3 so as to be able to slide vertically. A base of a handle 6 for lifting the lifting table 5 by hand passes through the opening 4 and is fixed thereto. In addition, the upper boss portion 7 of the main body 1
A stepped through hole 8 oriented in the vertical direction is connected to the through hole 3.
The stepped through hole 8 is formed so that its center line coincides with the stepped through hole 8.
As shown in FIG. 2, the press head 9 has a disk-shaped press head 9 with a diameter of about 40 mmφ, a wedge-shaped projection 10 extending back and forth through the center of the bottom surface of the press head 9 at the lower end, and a threaded portion 11 at the upper end. A pressing shaft 12 having a diameter is inserted through the shaft so as to be able to rise and fall freely, and the pressing shaft 12 is connected to a stopper 13 and a nut 1 screwed into the threaded portion 11.
4 is suspended from the upper boss portion 7, and is pushed downward by a wound compression coil spring 15. Further, a scale plate 16 is fixed to the upper end of the main body 1 to indicate the height at which the pressing shaft 12 has risen.
17 is a magnetic pointer placed on the stopper 13.

With this structure, a test piece of 50 mmφ x 50 mm manufactured by compacting the foundry sand to be evaluated for the quality of mixing by a predetermined method is placed on the lifting table 5, and the operator operates the handle 6. When the lifting table 5 is raised to raise the test piece, the wedge-shaped protrusion 10 of the pressing shaft 12 first comes into contact with the upper surface of the test piece, and the lift table 5 and the wedge-shaped protrusion 10 move up with the test piece held between them. As the lifting table 5 rises, the repulsive force of the coil spring 15 increases, and the wedge-shaped protrusion 10 sticks into the test piece and then penetrates deeply into the test piece. The magnetic pointer 13 is pushed up against the repulsive force of the stopper 15, and the magnetic pointer 13 is slid upward through the stopper 13 while contacting the scale plate 16. When these rise to some extent and the repulsive force of the compression coil spring 15 further increases, and the wedge-shaped protrusion 10 penetrates deeply into the test piece, the test piece is split vertically from the center by the wedge-shaped protrusion 10, and the pressing shaft 12 descends. , the maximum height at which the test piece pushes up the pressing shaft 12 when the magnetic pointer 17 adheres to the scale plate 16 is shown. In this way, the adhesion of the foundry sand can be perceived from the results shown on the scale plate 16, and the quality of the kneading can be judged.Moreover, since the test piece is always split vertically near the center, the adhesion of the foundry sand can be removed. As it is subjected to a dividing action, the area of the divided surface becomes constant, allowing accurate and stable measurement of adhesive force. after that,
The elevating table 5 and the like are lowered and the test piece is removed from the elevating table 5.

In the above embodiment, the lifting table 5 is raised manually, but it may also be raised mechanically using a motor or the like.

As is clear from the above description, in the present invention, a pressing head having a wedge-shaped protrusion of a certain length on the lower surface is pressed against a test piece to divide the test piece, and the pressing force at that time is measured. Therefore, since there is a close relationship between the adhesion and the pressing force, which determines the quality of the mixing of foundry sand, it is possible to accurately determine the quality of the mixing of foundry sand with one type of test. Since the piece is split near the center, it receives the action of splitting the sticky foundry sand, and the area of the split surface is always constant, making it possible to obtain accurate and stable measurement values. Furthermore, the testing machine only needs to be equipped with an elevating table on which the test piece can be placed and a pressure head that presses the test piece, making it compact, lightweight, and easy to carry, making on-site measurements extremely simple. This results in excellent effects such as improved work efficiency.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially cutaway front view, and FIG. 2 is a view taken along arrows A to A in FIG. 1. 5: Elevating table, 9: Pressing head, 10: Protrusion, 16: Scale plate, 17: Magnetic pointer.

Claims (1)

[Claims] 1. A pressing head having a wedge-shaped protrusion of a certain length on the lower surface is pressed against a test piece manufactured by compacting foundry sand to divide the test piece into two, and the pressing force at that time is calculated. A testing method for foundry sand characterized by measuring. 2. A wedge-shaped protrusion 10 of a certain length is installed directly above the lifting table 5 for placing the test piece, which is arranged to be able to rise and fall.
A pressure head 9 having a pressure spring 1 on the lower surface is provided so as to be movable up and down at a required interval, and the pressure head 9 is attached to a compression spring 1.
5. A testing machine for foundry sand, characterized in that the molding sand is pressed downward with a pressing head 9, and height display means 16, 17 are attached to the pressing head 9 to display the rising height.