JP3011910U - Magnetic core for film thickness meter - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a magnetic core of a film thickness meter that is not worn even by continuous measurement. [Structure] In a film thickness meter that measures the thickness of a coating film such as a coating film or a resin film on a metal surface, a cemented carbide material is embedded at the tip of a metal magnetic rod.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic core used for a probe of a film thickness meter that measures the thickness of a coating film, a resin film, or the like formed on the surface of a metal structure.

[0002]

[Prior art]

 Public steel structures such as road bridges, railway bridges, pedestrian bridges, and consumer equipment such as washing machines and refrigerators are used to prevent corrosion of the metal that is the base material, and to maintain the scenery with the surrounding environment and to improve the appearance. Is coated with paint of various colors. In addition, the surface of some metal products is coated with resin to protect the metal surface.

The coating film, the resin film or the like needs to have a certain thickness to protect the metal material. There is a film thickness meter to measure the thickness of this film. There are various types of film thickness meters, but normally a one-pole type two-point adjustment type electromagnetic film thickness meter is used. As shown in Fig. 2, the basic principle of the film thickness meter is to move the tip of a metal magnetic body (magnetic core) a around which the coil is wound toward or away from the metal surface b so that the coil The fact that the self-inductance of is changed is used. When the indicator c is connected to the magnetic body a by a cord, the change of the inductance is read as an indication value and the value is displayed. If the circuit and coil constants are set in advance so that the measurement conditions are constant, the film thickness on the metal surface can be measured.

The “unipolar” film thickness meter uses a single probe. The “two-point adjustment type” film thickness meter uses a metal plate that has a thickness of 6 mm or more and a surface roughness of 6 μmRz or less and is the same as the object to be measured to adjust the scale of the film thickness meter to “0 point”. To do. Next, a standard plank made of a non-magnetic material is placed on the same metal plate, and the thickness value of this standard plank is adjusted. For example, when the standard plate thickness is 2 mm, the value of the film thickness meter may be adjusted to 2 mm. In the thickness gauge probe adjusted in this way, the magnetic core at the tip is pressed at a right angle against the surface of the coating film, resin film, or other film to determine the film thickness between the metal surface and the magnetic core as a numerical value. Can be displayed.

FIG. 3 shows an example of a probe used in a conventional film thickness meter. This probe A has a cylindrical holder B capable of winding a coil (not shown) as shown in FIG. A metal rod-shaped magnetic core (metal magnetic body) C is inserted therein so that the tip projects. Further, as shown in FIG. 5, the magnetic core C is attached, and the holder B around which the coil E is wound is put in the inner cylinder D, and the coil E is connected to the cord F via the terminal plate behind the magnetic core C. .

The whole of these is housed in an outer cylinder G as shown in FIG. 3, and the connecting portion of the cord F is covered with a cap H, a cap cover I, or the like. The inner cylinder D and the cap H are screwed and connected, and the cap H and the cap cover I are fixed with screws J. Further, since the spring K is interposed between the inner cylinder D and the outer cylinder F, the inner cylinder D is provided with a directionality in which it projects from the tip of the outer cylinder G, and therefore the tip of the magnetic core C is provided at the outer cylinder. It projects from G.

In such a probe A, when the tip end surface of the magnetic core C is pressed against the coating surface of the coating film or the resin film at a right angle, the magnetic lines of force generated from the tip end of the magnetic core C travel behind the magnetic core C and Measure the thickness of the film. Although the tip end surface of the magnetic core C is a flat surface in the drawing, it is actually a convex surface so as to be in surface contact with the non-measurement body.

[0008]

[Problems to be solved by the device]

 Usually, the tip of the magnetic core C is made of a hard metal material, for example, a coating surface is formed by coating, and the magnetic core is contacted with the metal plate during the "zero point adjustment" or with the coating surface. The tip of C is protected against abrasion. However, in reality, the tip wears out in a few months due to careless handling and continuous frequent measurements, and as a result, measurement errors occur. Therefore, the magnetic core C needs to be repaired or the magnetic core C itself needs to be replaced, resulting in a high maintenance cost. In view of the above-mentioned conventional probe, the present invention has a magnetic core that does not wear even if continuous measurement is performed by embedding a cemented carbide material in a magnetic metal rod on the contact surface with a non-measurement body such as a coating film or a resin film. It is intended to provide.

[0009]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is a film thickness meter for measuring the thickness of a coating film such as a coating film or a resin film on a metal surface, and a superhard material 2 is embedded in the center of the tip of a magnetic metal rod 1. Is.

[0010]

【Example】

 An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a magnetic core used in the probe of the film thickness meter of the present invention, which is composed of a magnetic metal rod as in the conventional case. The magnetic core of the present invention is located at the center of the tip of the metal rod 1, for example, a ruby. It is characterized in that a cemented carbide material 2 made of steel balls, diamond, etc. is embedded and fixed. In the drawing, the cemented carbide material 2 is shown embedded in the axial direction of the metal rod 1, but this cemented carbide material is expensive, so if it is provided only at the tip of the metal rod 1. Good.

The magnetic core having the above-described structure is connected to a holder around which a coil is wound by projecting its tip and being attached to an inner cylinder or an outer cylinder in the same manner as the probe of the conventional film thickness meter described above. It is attached, and the usage condition is exactly the same as the conventional probe. Since the tip end surface of the metal rod 1 has a convex shape, the cemented carbide material 2 embedded in the center of the metal rod 1 comes into direct contact with the coating surface of the coating film, resin film, etc. It does not sound.

[0012]

As described above, the present invention embeds the cemented carbide 2 at the contact surface with the coating surface such as the coating film or the resin film at the tip of the magnetic metal rod 1 having magnetism. If the tip of the probe is rubbed against a 0-point metal plate or handled inadvertently, and there is no damage or wear even when performing frequent continuous measurements, the measurement results There is no error. As a result, the probe can be used for a long time and the maintenance cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic core of the present invention used in a film thickness meter.

FIG. 2 is an explanatory diagram showing the principle of an electromagnetic film thickness meter.

FIG. 3 is a cross-sectional view of a conventional probe.

FIG. 4 is an exploded perspective view of a holder and a magnetic core used in a conventional probe.

FIG. 5 is an exploded perspective view of an inner cylinder used for a conventional probe and a holder to which a magnetic core is attached.

[Explanation of symbols] 1 magnetic metal rod 2 super hard material A probe B holder C magnetic core D inner cylinder E coil F code G outer cylinder H cap I cap cover J screw K spring

Claims (1)

[Scope of utility model registration request] 1. A film thickness meter for measuring the thickness of a coating film such as a coating film or a resin film on a metal surface, characterized in that a superhard material 2 is embedded at the center of the tip of a magnetic metal rod 1. Magnetic core for film thickness meter.