JP2011112608A - Depth finder for minor defect within material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a finder finding a position on a surface over a hole easily with a small tool in the measurement of hole defect depth on a material surface and the like. <P>SOLUTION: A complete cylindrical surface around a hole is utilized, an arbitrary point existing on a partial cylindrical surface is adopted as the point over a hole when a defect part has no hole, on an arc passing through the point concerned a mechanism consisting of two magnets 4 having contact with the cylindrical surface at two points of equal distance from the point concerned and a hinge 1 containing two pins 11 is utilized, and then a constant distance from the hinge 1 is defined to be the point over the hole at the apex of a scale 3 in the central underpart of the hinge 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

        The present invention is a measuring instrument that measures the depth of small hole defects (dents) scattered on the surface of a material such as a cast product.

In the case of a material such as a cast product, it is difficult to determine the measurement reference position, and since the defect is small and the shape is irregular, the depth measurement is difficult or takes time.

Since there is no sound surface (hereinafter referred to as a sound surface) when there is no defect at the top of the hole defect, normal measurement cannot be performed. Therefore, in the present invention, the position of the sound surface is easily determined using a mechanism in which a hinge, a magnet, or the like is combined.

    The shape of the object to be measured is various, but a cylindrical surface (including a plane with an infinite radius) is generally considered in the vicinity of the defect. Therefore, when considering a sound cylindrical surface near the defect, the line of intersection with the vertical surface of the central axis of the cylindrical surface is a circle (or a straight line).

As shown in FIG. 2, the constituent elements of the present plan have the following characteristics.
The center line of the magnet 4 and the scale 3 is on one plane. The distance from the nearby pin 11 to the magnet 4 or the scale 3 is the same. The scale 3 moves perpendicular to the hinge 1 plate.
Length a = length b = length c = length d

The magnet is cylindrical and both end faces are perpendicular to the center line. When this end face is placed on the object to be measured, the magnetic force makes contact with the cylindrical surface of the object to be measured with the diameter of the end face. See FIG.
Therefore, the center line of the magnet intersects the central axis of the measured object cylindrical surface.

If two magnets and a plane containing each axis of the scale are placed so as to be perpendicular to the center line of the cylindrical surface, the three points of the center of the lower end surface of the magnet and the tip of the scale are the same circle. Line up. At this time, the length of the scale below the hinge is the same as the height of the magnet. See FIG. 4 and FIG.
Here, the thickness of the hinge is assumed to be 0. Each symbol points to the next point. See FIG.
O: Center of a circle formed by a cylindrical cross section M: Center of upper end surface of magnet N: Center of lower end surface of magnet (contact point between magnet and cylindrical surface)
P: Center of the hinge pin C: Height position of the hinge of the shank axis S: Contact point between the shank and the cylinder

What is clear from the setting conditions is as follows.
Length ON = Length OS (Radius)
Angle PMN = Angle PCS (right angle)
Length PM = Length PC (0005)
Here, when the triangle PMO and the triangle PCO are compared, both are right triangles, and the length PO is common, and the length PM = the length PC, so the length MO = the length CO from the Pythagorean theorem. Since length ON = length OS, length MN = length CS.
In other words, the length of the scale below the hinge is constant regardless of the value of the radius of curvature of the surface to be measured.

The measuring device of the present invention is fixed on an iron plane, and the measuring device set with the position of the scale relative to the main body as a reference point (depth 0) is placed on the surface of a defective casting or the like as shown in FIG. Is adsorbed, the lower end of the scale corresponds to the position of the sound surface (see 0003) of the defective portion.
As for the depth of the defect, if the lower end of the scale is applied to the bottom of the defect, there is a movement of the scale according to the depth.

First, according to the present invention, the measurement operation is generally convenient as follows.
There is no need to calibrate the scale reference point each time.
There is no need to hold down the measuring instrument due to magnetic adsorption.
The operation for measurement is simple.

Since there is no quick tool for measuring the depth of defects in castings and the like, it is usually a visual measurement by humans and can be said to be inaccurate.
If a product defect exceeding the allowable value is shipped, waste is generated in the next process, and if it is less than the allowable value, this is also uneconomical. If the measurement accuracy is improved by using the present invention, waste can be prevented.

Since the object of use of the present invention is the depth of small defects such as castings and forgings, the measurement range is several millimeters. The gap between the magnet and the scale should be as small as possible. Since the object to be measured is an iron-based metal, the lower end of the scale is worn. Therefore, the needle-like portion at the tip is made of a hard material and can be exchanged.
In order to make it easier to confirm that the needle tip is in contact with the bottom of the hole, the height of the magnet should be appropriately adjusted and the hinge width (pin length direction) should be reduced.

The following numbers indicate the length, and the unit is millimeters.
Magnet: Diameter 10, height 6
Distance between magnet and pin: 8
Measurement range: 5
Measurement example Cylindrical section radius Defect depth
Casting 35 0.6
Casting 62 1.5

It is the whole figure of a measuring device Indicates the positional relationship between hinge parts and attached parts Indicates the adhesion state of the magnet It is a three-point contact state diagram of a measuring device It is a geometric illustration Shows the arrangement of contact points between the cylindrical surface and the measuring instrument

1 Hinge 2 Body 3 Scale 4 Magnet 11 Pin 12 Screw

Claims (1)

In the hinge (1) having two pins (11), the main body (2) is attached to the center upper part and the magnets (4) are attached to the lower parts on both sides. The main body (2), the two magnets (4), The two pins (11) are a combination of a scale (3) that is arranged at equal intervals on a straight line in a plane, passes through the center of the body (2), and slides vertically on the hinge (1). A material small defect depth measuring instrument with a structure more than reading the depth of hole defects on the surface of castings, etc., by the amount of movement of the scale (3)

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