JP2020165845A - Outer diameter measuring instrument - Google Patents

Abstract

To provide an inexpensive outer diameter measuring instrument capable of easily measuring the outer diameter of cylindrical or circular columnar objects having various outer diameters.SOLUTION: Provided is an outer diameter measuring instrument 1 constituted of first and second rod-like bodies 10 and 20 that are mutually connected in a rotatable manner, and a scale display part 30 fixed to the second rod-like body 20. In the outer diameter measuring instrument, on tip portions of the first and second rod-like bodies 10 and 20, each pair of abutting points 11a and 11b, and 21a and 21b each are disposed for abutting on an outer peripheral surface of a measuring object A when measuring an outer diameter thereof. When all the two pairs of abutting points 11a and 11b, and 21a and 21b are abutted along a circumferential direction of the outer peripheral surface of the measuring object A, an outer diameter indication part 12 attached to the first rod-like body 10 points to a portion indicating a value of the outer diameter of the measuring object A out of an outer diameter scale 31 of the scale display part 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to an outer diameter measuring instrument capable of easily measuring the outer diameter of a circular portion of a cross section in tower tanks, large pipes, and the like.

When measuring the outer diameter of a cylindrical or columnar object, an outer diameter measuring instrument such as a caliper or a ring scale is generally used, but in these outer diameter measuring instruments, a tower tank installed in a factory. It is not possible to measure large objects such as calipers and large-diameter pipes that have a radius larger than the length of the caliper or the jaw of the wheel. In this case, the outer diameter can be obtained by measuring the length of the entire circumference using a tape measure and dividing this by the pi. However, in the case of large vertical tower tanks, it is difficult to read the scale while winding the tape measure so that it does not shift in the vertical direction, and of course, the object to be measured having the entire circumference longer than the length of the tape measure is measured. Can not do it.

Therefore, Patent Document 1 proposes a device that automatically measures the outer diameter of a cylindrical object to be measured by sandwiching it between two rotatable stylus. That is, the device of Patent Document 1 is composed of two rod-shaped stylus provided rotatably, a stopper protruding from an intermediate point of the center of rotation thereof, and a calculation device. The angle formed by these two stylus when the outer peripheral surface of the object to be measured is sandwiched between these two stylus while bringing the tip of the object into contact with the outer peripheral surface of the object to be measured is measured, and the measurement result is obtained. Based on this, the outer diameter of the object to be measured is obtained by performing arithmetic processing on the arithmetic apparatus.

Further, in Patent Document 2, a gyro compass and a distance meter are installed at positions horizontally separated from the outer peripheral surface of the cylindrical measurement object, and at arbitrary three locations in the circumferential direction of the outer peripheral surface of the measurement object. A technique for obtaining the outer diameter of the object to be measured by measuring the polar coordinate distance and the azimuth with the above installation position as the origin and performing arithmetic processing on the arithmetic device based on the obtained measured values. Is disclosed.

Japanese Patent Application Laid-Open No. 06-066550 Japanese Unexamined Patent Publication No. 62-238409

However, in the above-mentioned apparatus of Patent Document 1, when the object to be measured is sandwiched between two stylus, it is necessary to bring the object to be measured into contact with the outer peripheral surface of the object to be measured not at the tip thereof but at the intermediate portion thereof. It could not be applied to large-sized tower tanks where the tips of these two stylus come into contact with each other. In addition, a complicated gear mechanism, angle sensor, etc. are required to measure the angle formed by two stylus when an object to be measured is sandwiched, and an expensive CPU, etc. is required to obtain the outer diameter from the measurement result. Since an arithmetic unit is required, it is not possible to easily obtain the outer diameter of the object to be measured at low cost.

Further, the outer diameter measuring method of Patent Document 2 requires expensive devices such as a gyrocompass, a range finder, and a control device, and requires some skill in handling these devices. Therefore, this is also outside the object to be measured. The diameter could not be easily obtained at low cost. The present invention has been made in view of the problems of the conventional outer diameter measuring instrument described above, and is an inexpensive outer diameter measurement capable of easily measuring the outer diameter of a cylindrical or columnar object having various outer diameters. The purpose is to provide a vessel.

In order to achieve the above object, the outer diameter measuring instrument according to the present invention comprises a first and second rod-shaped bodies rotatably connected to each other and a scale display unit fixed to the second rod-shaped body. The outer diameter measuring instrument is provided with a pair of contact points that come into contact with the outer peripheral surface of the outer diameter of the object to be measured at the tips of the first and second rod-shaped bodies. When all the two pairs of contact points are brought into contact with the outer peripheral surface of the measurement object along the circumferential direction, the portion of the outer diameter scale of the scale display portion that indicates the value of the outer diameter of the measurement object is displayed. It is characterized in that the indicating portion attached to the first rod-shaped body points to it.

According to the present invention, it is possible to easily measure the outer diameter of an object having a circular cross section of any size at no cost. In addition, the structure of the measuring instrument can be made simple and lightweight, which makes it convenient to carry.

It is a top view of a specific example of the outer diameter measuring instrument which concerns on this invention. It is a top view of the 2nd rod-shaped body (a) and the 1st rod-shaped body (b) constituting the outer diameter measuring instrument of FIG. 2 is a plan view (a) of the tip end portion of the first rod-shaped body of FIG. 2, and a plan view (b) of an alternative example thereof. It is a top view of the display board which comprises the outer diameter measuring instrument of FIG. It is a top view which shows the state of measuring the outer diameter of the object to be measured using the outer diameter measuring instrument of FIG.

Hereinafter, a specific example of the outer diameter measuring instrument according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the outer diameter measuring instrument 1 of a specific example of the present invention includes first and second rod-shaped bodies 10 and 20 rotatably connected to each other and a substantially semicircle sandwiched between them. It is composed of three members with a plate-shaped display unit 30. These three members are connected by a connecting means 50 such as a rivet, a bolt / nut, etc. at the center point O of the above rotation. Of the above three members, the tips of the first and second rod-shaped bodies 10 and 20 are brought into contact with the outer peripheral surfaces of the outer diameter of the object to be measured, and the contact points 11a, 11b, 21a, 21b. Are provided in pairs, and they are provided line-symmetrically with respect to the bisector L ₀ of the angle θ formed by the first and second rods 10 and 20 at the center point O of the rotation. ..

Specifically, as shown in FIG. 2 (a), (b) , the first rod-shaped body 10, a pair of contact points 11a, 11b are on a straight line _{L 1} passing through the center O of the rotating It provided the position, similarly to the second rod-like body 20, a pair of contact points 21a, 21b are provided at positions on the straight line L ₂ passing through the center point O of the pivoting. Then, the pair of contact points 11a of the first rod-like member 10, the distance _{D 1} of the from the midpoint 11c and 11b to the center point O of the pivoting, the contact point 21a of the pair of second rod-shaped member 20 is equivalent to the distance _{D 2} from the midpoint 21c and 21b to the center point O of the pivoting. The distances D ₁ and D ₂ of the first and second rod-shaped bodies 10 and 20 are not particularly limited, but in consideration of ease of carrying and handling, about 500 to 1500 mm is preferable, and 1000 mm is more preferable.

As shown in FIG. 3A, the pair of contact points 11a and 11b of the first rod-shaped body 10 have an apex angle of 90 degrees (right angle) adjacent to the first rod-shaped body 10 in the longitudinal direction. It is preferable that it is the top of each of the two chevron protrusions, and similarly, the pair of contact points 21a and 21b of the second rod-shaped body 20 are in the longitudinal direction of the second rod-shaped body 20. It is preferably the top of each of the two mountain-shaped protrusions having an apex angle of 90 degrees adjacent to the top. Alternatively, as in the first rod-shaped body 110 of the alternative example of FIG. 3 (b) (only the first rod-shaped body is displayed for simplicity), the edge extending in the longitudinal direction is cut out in a substantially V shape. May form a pair of contact points 111a and 111b.

As shown in FIG. 4, the substantially semicircular plate-shaped display portion 30 sandwiched between the first rod-shaped body 10 and the second rod-shaped body 20 is a circle centered on the center point O of the rotation. Along the arcuate edge, a scale (hereinafter, also referred to as an outer diameter scale) 31 of the outer diameter of the object to be measured measured by the outer diameter measuring instrument 1 is displayed. Although the numerical sequence corresponding to the outer diameter scale 31 is not drawn in FIG. 4, it is preferable that the numerical values are described at regular intervals like a general protractor or a ruler.

Further, the display unit 30 is suitably removably fixed to the second rod-shaped body 20 so as not to easily rotate with respect to the second rod-shaped body 20. The fixing method in this case is not particularly limited, but it is preferable to have a structure in which the display unit 30 can be easily replaced by simply removing the coupling means 50. For example, a structure of fixing with double-sided tape, a structure of providing a protrusion such as a pin on the back side of the display portion 30 and locking it to the edge of the second rod-shaped body 20 can be mentioned.

When all of the above two pairs of contact points 11a, 11b, 21a, 21b are brought into contact with the outer peripheral surface of the object to be measured along the circumferential direction, the object to be measured among the outer diameter scales 31 of the display unit 30. The outer diameter indicating portion 12 having a shape such as a triangle or an arrow is displayed on the first rod-shaped body 10 so as to indicate the portion where the value of the outer diameter of is displayed.

That is, as shown in FIG. 5, the first and first contact points 11a, 11b, 21a, and 21b of the two pairs of contact points 11a, 11b, 21a, and 21b are all in contact with the outer peripheral surface of the measurement object A having the radius R along the circumferential direction. When the object A to be measured is sandwiched between the rod-shaped bodies 10 and 20 of 2, the angle formed by the first and second rod-shaped bodies 10 and 20 at the center point O of their rotation is θ ₁ , and the following equation 1 Relationship is established. Note that D ₁ is the distance between the intermediate point 11c of the pair of contact points 11a and 11b described above and the center point of the rotation.
[Equation 1]
Outer diameter _{= 2R = 2D 1 · tan (} θ 1/2)

Therefore, in these first and second rod-shaped bodies 10, 20, when the angle θ formed at the center point O of their rotation is any angle within the angle range of more than 0 degrees and less than 180 degrees, The outer diameter scale 31 is displayed so that the outer diameter indicating unit 12 indicates the value of the outer diameter obtained by the above formula 1. As a result, when the two pairs of contact points 11a, 11b, 21a, 21b of the two rod-shaped bodies 10 and 20 are brought into contact with the outer peripheral surface of the measurement object A along the circumferential direction, the outer diameter is indicated. By simply reading the portion instructed by the unit 12, the outer diameter of the object to be measured A can be immediately known without performing complicated operations such as calculation.

The outer diameter scale may be provided on a wide portion of the second rod-shaped body 20 having a substantially trapezoidal shape. As a result, the outer diameter measuring instrument can be configured by the two members, so that the structure can be further simplified. Further, when the first and second rod-shaped bodies 10 and 20 are expanded within an angle range of more than 0 degrees and less than 180 degrees about the center point O of the rotation, they are rotated. An angle scale 32 for displaying the angle formed at the center point O may be displayed on the surface of the display unit 30 along the outer diameter scale 31. In this case, it is preferable to provide an angle indicating portion 13 indicating the value of the angle scale 32 in the wide portion of the first rod-shaped body 10 having a substantially trapezoidal shape, in addition to the outer diameter indicating portion 12 indicating the outer diameter scale 31. ..

The materials of the two rod-shaped bodies 10 and 20 are not particularly limited as long as they do not bend or bend when the outer diameter is measured, but at least the first rod-shaped body 10 is made of a transparent resin. Is preferable, and it is more preferable that it is made of polycarbonate. As a result, the outer diameter scale 31 and the angle scale 32 of the display unit 30 located on the back side of the first rod-shaped body 10 can be easily read.

Further, it is preferable that the first rod-shaped body 10 is provided with a round spirit level 51 capable of confirming the horizontality of the outer diameter measuring instrument 1 by the position of air bubbles in the wide portion. As a result, the longitudinal directions of the two rod-shaped bodies 10 and 20 can be maintained horizontally at the time of measurement, so that all of the above two pairs of contact points 11a, 11b, 21a and 21b are placed on the outer peripheral surface of the measurement object A. It is possible to make the contact more reliably along the circumferential direction. Therefore, it becomes possible to measure the outer diameter of a vertical columnar object or a cylindrical object with higher accuracy.

1 Outer diameter measuring instrument 10 First rod-shaped body 11a, 11b This contact point 11c Midpoint 12 Outer diameter indicator 13 Angle indicator 20 Second rod-shaped body 21a, 21b This contact 21c Midpoint 30 Display part 31 Outer diameter scale 32 Angle scale 50 Coupling means 51 Leveling device L ₁ , L ₂ Straight line passing through the center point O D ₁ , D ₂ Distance between the midpoint of the contact point and the center point L ₀ Inner angle bisector A Measurement object R Radius O Rotation Center points θ, θ ₁ Angle formed by the rod-shaped body at the center point of rotation

Claims (7)

An outer diameter measuring instrument including first and second rod-shaped bodies rotatably connected to each other and a scale display unit fixed to the second rod-shaped body, and these first and second rod-shaped bodies. The tip of the body is provided with a pair of contact points that come into contact with the outer peripheral surface of the object to be measured when measuring the outer diameter of the object to be measured, and all of these two pairs of contact points are located on the outer peripheral surface of the object to be measured. When the contact is made along the direction, the indicator portion attached to the first rod-shaped body points to the portion of the outer diameter scale of the scale display portion that indicates the value of the outer diameter of the measurement object. Characterized outer diameter measuring instrument. The pair of contact points of each of the first and second rods is located on a straight line passing through the center point of the rotation, and is an intermediate point between the pair of contact points of the first rod. 1. The distance from the center point of the rotation to the center point of the rotation is equal to the distance from the midpoint of the pair of contact points of the second rod-shaped body to the center point of the rotation. The described outer diameter measuring instrument. The outer diameter measuring instrument according to claim 1 or 2, wherein the scale display unit is a substantially semicircular display plate sandwiched between the first and second rod-shaped bodies. When the first and second rod-shaped bodies are expanded within an angle range of more than 0 degrees and less than 180 degrees around the center point of the rotation, the angle formed by them at the center point of the rotation is displayed. The outer diameter measuring instrument according to any one of claims 1 to 3, wherein the angle scale is displayed on the scale display unit along the outer diameter scale. The outer diameter measuring instrument according to any one of claims 1 to 4, wherein a spirit level is provided on the first rod-shaped body. The outer diameter measuring instrument according to claim 5, wherein at least the first rod-shaped body is formed of a transparent resin. Each of the first and second rod-shaped bodies is characterized in that the tops of two protrusions having an apex angle of 90 degrees adjacent to each other in the longitudinal direction are the contact points of the pair. The outer diameter measuring instrument according to any one of 6.

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