JP3085469U - Material small defect depth measuring instrument - Google Patents

Abstract

(57) [Abstract] [Problem] To be able to measure the depth of a small hole defect generated on the surface of a casting or the like by a simple operation and directly read the measured value. SOLUTION: A small measuring instrument having two contact legs capable of contacting not only a flat surface but also an inner surface and an outer surface of a cylinder, and one contact needle which moves linearly through an intermediate point between the two contact legs, provides a sound surface. The state where all three points are in contact is defined as the zero point, then the contact leg is moved to a sound surface near the hole, and the contact needle is applied to the bottom of the hole to measure the depth. At this time, an electronic measuring device that senses a change in position by using a combination of a core in the main body and a coil embedded in a moving slide and digitally displays the change is used.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention is a measuring instrument that measures the depth of small hole defects (dents) scattered on the surface of materials such as castings and displays the results digitally.

[0002]

[Prior art]

 When measuring the depth of a hole or groove in a workpiece, a caliper, depth gauge or dial gauge is usually used, but the reference surface for measurement must be a flat surface and the bottom must be a flat surface with some width. The surface of a casting or the like often has a cylindrical surface in addition to a flat surface, and the shape of a hole as a defect generated in the surface is irregular, and a flat portion at the bottom is often narrow. Therefore, the depth cannot be measured with a conventional measuring instrument, or the error increases. In addition, measured values are often based on scales. If the reference value is not on scale 0, the target value cannot be determined unless the difference between the measured values is calculated. Devices that can be measured are large or expensive and have a large minimum diameter, especially for the inner surface of the cylinder.

[0003]

[Problems to be solved by the invention]

 Above the hole defect, there is no sound surface without any defect, so the hole depth cannot be measured directly. The reference surface of the workpiece is generally considered to be a cylindrical curved surface. First, a healthy surface near the hole is checked at three points of the measuring instrument, and then the three points of contact are placed across the hole to create a sound surface. Is provided on the hole. In addition, hole defects, such as castings, use a movable contact with a point enough to touch only the bottom plane to be measured, which is very small.

In general, the curvature of the reference surface changes each time the measurement is performed, and the reference position of the movable contact changes. Therefore, if a fixed scale is used, the depth of the hole must be indicated by the difference between the two values. Therefore, the digital display method is adopted in which the reference plane position for the first measurement can be set to zero on the scale, and the difference from the second hole bottom position is directly displayed as a measured value.

[0005]

[Means for Solving the Problems]

 If the reference surface is a cylindrical surface, the curvature is determined by applying two contact legs, each of which has a substantially hemispherical tip at the portion protruding from the measuring device, to the reference surface, and the center of the contact leg as described above. One contact needle is provided that moves on the perpendicular bisector of the line connecting the two contact points between the tip of the contact leg and the reference plane. The curvature of the healthy part can be determined by touching the tip of this contact needle to the reference plane, and then there are two contact legs on the surface of the same curvature, and the contact needle can be in contact with the bottom of the hole at the same time. Therefore, the depth of the hole can be measured by the position difference of the tip of the contact needle. The contact needle uses a needle to contact the bottom of the narrow hole, but is mounted in a replaceable manner.

The length measuring mechanism utilizes that of an existing digital caliper or depth gauge. That is, a slide that moves linearly through the main body is combined, and the movement distance is digitally displayed by a core on the main body and a coil on the slide. One contact needle is provided on the main unit, and two contact legs are provided on the slide. Use the zero set function to determine the zero point by pressing the button with the three points in contact with the healthy part of the measurement surface. Next, place the two contacts in another healthy part and display the depth of the hole when the contact needle comes in contact with the bottom of the hole.

[0007]

[Embodiment of the invention]

 An embodiment of the invention will be described with reference to the drawings. FIG. 1 shows an overall outline of the present measuring instrument, which has a structure in which the depth of a hole defect is measured by a difference in the relative position between the main body 1 and a slide 5 which slides linearly through the main body. The main body 1 is equipped with a contact needle 4 that comes into contact with the measurement surface. In addition, since it has an electronic measuring instrument groove, there is a digital display panel 2 for displaying a measured value and a zero switch 3 for determining a reference value for measurement. On the other hand, the slide 5 has two contact legs 6 for making contact with the reference surface in the same direction as the contact needle 4 of the main body 1.

FIG. 2 illustrates the main body 1 in detail. A digital display panel 2 is provided on the front of the main body, and a zero switch 3 is provided on a side surface. A slide guide path 11 extends through the center of the main body 1 and has an arm 12 protruding from the main body 1 near the path. The contact needle 4 is fixed thereto via a needle attachment 13. Further, a core 15 for electronic measurement is built in the main body 1 so as to surround the slide guide path 11, and a power switch 14 is provided on a side surface.

FIG. 3 explains the slide 5 in detail. There are two contact legs 6 on one side, but in order to prevent the slide 5 from dropping off from the slide guide path of the main body 1, close the both ends after assembly. One each of the stoppers 51 and 52 is attached. Inside the slide 5, a coil 53 for sending electronic position information to the main body 1 is embedded.

FIG. 4 shows a state in which a contact point of the measuring instrument is applied to a sound portion on a cylindrical reference surface to grasp its curvature. The case where the display value of the barrel is set to zero is shown. That is, the two contact legs 6 of the slide 5 are brought into contact with the healthy part of the object to be measured, and the other end is lightly held down with a finger. The body 1 is pushed down with another two fingers as it is, and the zero switch 3 is pressed with the contact needle 4 pressed against the healthy part. At this time, the three contacts are arranged on one plane perpendicular to the central axis of the cylindrical surface to be measured.

FIG. 5 shows a state immediately after measuring the depth of the hole. That is, in a state where the reference display value of the length measurement is zero in the healthy part, the two contact legs 6 are applied to the healthy part of the measured object with the contact needle 4 facing the bottom of the hole. At this time, the two contacts and the contact needle 4 are located on one plane perpendicular to the central axis of the cylindrical surface to be measured. Next, when the main body 1 is lowered and the contact needle 4 comes into contact with the lowest surface of the hole while holding the position of the contact leg 6, the digital display panel 2 indicates the depth of the hole.

FIG. 6 is a perspective view showing a state in which a zero point serving as a reference for length measurement is determined in a healthy part of a measured object near a hole to be measured.

FIG. 7 is a perspective view showing a state where the contact needle 4 is applied to the bottom of the hole and the depth is measured.

[0014]

[Effect of the invention]

 Since the present invention is configured as described above and has the functions, the following effects are exhibited.

As described in claim 1, the measurement can be directly performed not only when the reference surface is a flat surface but also when the reference surface is a cylindrical surface. In addition, the sharp needle tip allows contact with the very narrow hole bottom without processing.

The direct reading of the measured value included in claim 1 is based on the fact that the combined state of the three contact positions in the sound part can be set as a zero point. This set of zeros does not result in measurement errors, even if the contact points, which are deemed unfavorable by the measuring instrument, occur.

The depth of a hole defect existing on the surface of a casting or the like determines whether the defect is to be compared with an allowable value as a casting surface defect and whether or not the defect remains on the processed surface after the casting surface is processed. And determine the success or failure of the product. Nevertheless, at present, it is difficult to make a comparison with a sound reference plane and it is inaccurate even if a judgment error is made by visual inspection or a ruler that can contact the hole bottom is used. If it is judged that the depth of the hole is larger than the actual one, the non-defective product will be discarded. By using this measuring instrument, the pass / fail of the product related to hole defects can be accurately judged, and the waste of the product and machining work can be prevented.

[Brief description of the drawings]

FIG. 1 shows an entire measuring instrument.

FIG. 2 is a perspective view of a main body.

FIG. 3 is a perspective view of a slide.

FIG. 4 shows a state where a zero point is set on a sound reference plane before depth measurement.

FIG. 5 shows a state in which a contact needle is applied to the bottom of the hole to measure the depth.

FIG. 6 is a perspective view showing a state where a zero point is set on the inner surface of the cylinder.

FIG. 7 is a perspective view showing a state where the hole depth is measured on the inner surface of the cylinder.

[Explanation of symbols]

 1 Body 2 Digital display board 3 Zero switch 4 Contact needle 5 Slide 6 Contact leg 11 Slide guideway 12 Arm 13 Needle mount 14 Power switch 15 Core 51 Clasp 52 Clasp 53 Coil

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[Procedure amendment]

[Submission date] December 27, 2001 (2001.12.
27)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims for utility model registration

[Correction method] Change

[Correction contents]

[Utility model registration claims]

Claims (1)

[Utility model registration claims] 1. With respect to naturally occurring small surface hole defects in a casting or the like, when the reference surface of the object to be measured is a flat surface, a cylindrical outer surface or a cylindrical inner surface, the hole defects are irregular in surface and narrow in bottom. In this case, a small defect depth measuring instrument characterized by a structure in which a measuring instrument can be directly applied to a measurement surface to measure the depth. The state where there are 3 contact points of the measuring instrument on the reference plane of the measured object is defined as the zero point of the length measurement. The digital length measurement structure is used so that the value of the depth (minimum distance from the assumed reference plane to the bottom) can be directly read.