JPS59150324A - Hardness meter for casting mold - Google Patents

Abstract

PURPOSE:To make it possible to certainly measure the hardness of a casting mold, by a method wherein an indenter projected from the lower surface of a base stand through a spring is pressed to the surface of the casting mold and the movement thereof toward the penetrating direction is converted to rotary motion which is, in turn, read by two kinds of graduations of AFS hardness and NIK hardness. CONSTITUTION:An indenter 2 having a spherical surface at the leading end thereof is projected from a base stand 1 having a flat surface 1A at the lower surface thereof by a spring 3. When the flat surface 1A is closely contacted with the surface of a casting mold, the leading end 2A of the indenter 2 is partially penetrated into the casting mold and slightly pushed in the base stand 1. The latter movement is enlarged by a rack 4, a small diameter gear 5, a large diameter gear 6, an intermediate small gear 9 and an intermediate large gear 10 and converted to the rotation amount of a pinion 7. Because the intermediate large gear 10 is lacking in the half of teeth, the pinion 7 is not rotated by the movement of the indenter in AFS hardness of 50 or less. Both AFS and NIK hardnesses can be simultaneously read from the AFS hardness graduations 11A and NIK hardness graduations 11B graduated on a dial plate 11 by the indicator 8 attached to the pinion 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a hardness meter for measuring the hardness of a mold.

One method for evaluating the quality of a mold is to measure the hardness of the mold.

As a simple on-site method, we press the mold with our fingers to intuitively judge whether it is good or bad, but this requires skill.

The American Foundry Standard Hardness (8tanda) is used to scientifically express hardness.
There are two hardnesses: hardness according to RD (hereinafter referred to as AF8 hardness) and hardness according to the green mold hardness test method established by the Japan Foundry Association (hereinafter referred to as NIK hardness).

AF8 hardness is based on the amount pushed by an indenter with a spherical tip into the mold surface with a predetermined force, and is expressed as a hardness number from 0 to 100.

Like Prinell hardness, NIK hardness is calculated by dividing the force required to press a spherical indenter against the surface of a mold to form a dent by the area of the dent formed, and the hardness number of the mold is appropriately indicated. The size of the indenter and the force to be applied are specified.

As shown in FIG. 1, the relationship between the AF8 hardness and the NIK hardness shows that the change in the AF8 hardness within the NIK hardness range of 5 to 80 is slight.

FIG. 2 shows a hardness meter for measuring AF8 hardness.

Reference numeral 1 denotes a base, which has a plane IA on its lower surface. The indenter 2, which protrudes and retracts in a direction perpendicular to the plane IA of the base 1, has a spherical surface at its tip 2A.
is pushed in the direction of protruding from the plane IA.

Reference numeral 4 denotes a rank installed above the indenter 2 in the axial direction, and meshes with the small diameter gear 5 which rotates integrally with the large diameter gear 6.

Pinion 7 meshes with large diameter gear 6.

A pointer 8 is integrally attached.

These racks4. Small diameter gear5. The number of teeth of the large-diameter gear 6 and the pinion 7 are determined so that the pinion 7 rotates once per movement of the indenter 2.

09 is a scale plate, which divides 860 degrees into 100 equal parts and performs AF.
It is marked with 8@j degrees and can be read with the 8 pointer.

Now, when the plane IA of the base l is brought into close contact with the surface of the mold,
The tip 2A of the indenter 2 partially enters the mold and is also pushed into the base 1 to some extent. In other words, if the hardness of the mold is high, the amount pushed into the base 1 will increase, so the amount of push of the indenter 2 should be determined by appropriately selecting the force of the spring 8.

In other words, the pointer 8 according to the amount of rotation of the pinion 7 moves to the scale plate 09.
AFS hardness can be read from the position where .

If you want to calculate the AF8 hardness in this way and replace it with the NIK hardness, you will use the graph in Figure 1, but if the AF8 hardness is 75 or higher, you will not be able to accurately read the NIK@ hardness. Therefore, you have to create a conversion table and search from that table, but it takes a lot of time.

In addition, it is meaningless for the mold hardness to be less than 50 on the AF8 hardness, especially for molds suitable for quantity.Although quality control standards require an AF8 hardness of 80 or more, due to the scale plate 09. It was not possible to increase the accuracy of only that part, and it was not possible to read even the smallest values.

The mold hardness tester of the present invention includes a base having a flat surface on its lower surface, an indenter that protrudes and retracts from the lower surface of the base, a spring that presses the indenter in a direction to protrude from the lower surface of the base, and a base that has a flat surface on its lower surface. A rotating mechanism with a partially toothed gear or rank that converts the movement in the direction of sinking into the rotational movement of the pinion, a pointer attached to the pinion, and the AF8 hardness and NIK hardness are read from the position of the pointer. It consists of a scale plate having two types of scales.゛ □ In other words, the scale plate that should originally display AF8 hardness is
Corresponding to hardness, rNIK hardness is also displayed, so 1
23 types of hardness can be read at once from one pointer, eliminating the need to convert each time as in the past.

In addition, the conventional pinion, that is, the pointer, is
It only rotated, but in the present invention, it has the possibility of rotating more than one rotation.

However, by using a rotation mechanism with a gear or rack with some teeth missing, the pinion is rotated only in the necessary areas, so even the slightest movement of the indenter is magnified, allowing for more accurate hardness readings. becomes possible.

An embodiment of the hardness tester shown in FIGS. 8 to 4 will be described below. FIG. 1 shows only the main parts, and the other parts are the same as in FIG. 2.

Figure 8 shows a rotation mechanism that converts the movement of the indenter 2 in the direction (upward in the figure) in which it sinks into the base (not shown, number 1 in Figure 2) into rotational movement of the pinion 7. It is something that

9 is an intermediate small gear, and 10 is an intermediate large gear.

Although it rotates as a unit and the ratio of the number of teeth is 1:2 (□), half of the teeth of the intermediate large gear 10 are missing.

The intermediate small gear 9 meshes with the same large diameter gear 6 as shown in FIG.
The intermediate large gear 10 is appropriately shifted in position so as to mesh with the pinion 7.

Figure 4 shows only the scale plate 11, where 2 circles are divided into 50 equal parts and the AF8 hardness scale 11 has an AF8 hardness of 50 to 100.
It is engraved with A and also has a NIK rating corresponding to AF8 hardness.
A hardness scale 11B is engraved.

The procedure for using the hardness tester thus constructed is the same as that shown in FIG.

In other words, for molds of the same hardness, the amount that the indenter 2 is pushed into the base is the same.

However, in the hardness tester of this embodiment, the movement of the indenter 2 is controlled by the intermediate small gear 9. The intermediate large gear 10 converts the amount of rotation of the pinion 7 to twice that of the conventional one. However, since half of the teeth of the intermediate large gear 10 are missing,
There are also areas where the pinion 7 does not rotate despite the movement of the indenter 2. In other words, in this embodiment, the initial indenter 2
This is to prevent the pinion 7 from rotating with respect to the movement of the indenter 2 when measuring AF8 hardness of 50 or less. Therefore, the pinion 7 will rotate when the AF8 hardness is 50 or more, and the AF8 hardness can be read from the AF8 hardness scale 11A indicated by the pointer 8. Also, the NIK hardness can be read at the same time using the pointer 8.

In this way, according to the hardness testers of the two examples, AFS hardness and N
Because it can read IK hardness at the same time.

It is convenient and does not require much time for conversion.

In addition, the pinion 7 is stopped for the movement of the indenter 2 showing the AF8 hardness of 0 to 50, and the movement of the indenter 2 from 50 to 100 is converted into a rotation of the pinion 70360 degrees, and the scale plate 1
Since the scales 11A and IIB are arranged on the circumference of 1, the accuracy of reading 1 degree of hardness is also improved.

In this embodiment, the intermediate large gear 10 has no teeth, but the rack 4 may of course have no teeth.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between AF8 hardness and NIK hardness. Fig. 2 is a diagram of a conventional hardness tester, Fig. 8 and Fig. 4 are main part diagrams of a hardness tester showing an embodiment of the present invention, Fig. 3 is a diagram of a rotating mechanism, and Fig. 4 is a diagram of a hardness tester according to an embodiment of the present invention. It is a diagram of a scale plate. 1: Base, IA: Plane, 2: Indenter, 8: Spring. 4 Nirakku, 5: Small diameter gear, 6: Large diameter gear, 7: Pinion, 8: Pointer, 9: Intermediate small gear, 1O: Intermediate large gear, 1
1: Scale plate, IIA: AF8 hardness scale, IIB: NIK
Hardness scale. Figure 2 Figure 1

Claims (1)

[Claims] A base having a flat surface on its lower surface, an indenter that protrudes and retracts from the lower surface of the base, a spring that presses the indenter in a direction that causes it to protrude from the lower surface of the base, and a movement that moves the indenter in a direction that sinks into the base. AF8 hardness and NI from the position of the rotating mechanism that has a partially toothed gear or rank that converts the rotation into the rotational movement of the pinion, the pointer attached to the pinion, and the position of the pointer.
A mold hardness meter comprising a scale plate having two types of scales for reading K hardness.