CN101738153A

CN101738153A - Apparatus for measuring radius of circular arc

Info

Publication number: CN101738153A
Application number: CN200810236310A
Authority: CN
Inventors: 刘龙兵
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-07
Filing date: 2008-11-07
Publication date: 2010-06-16

Abstract

The invention discloses an apparatus for rapidly measuring the radius of a circle or a circular arc. By making use of the relation between the chord height and the chord length of the circle or the circular arc, a special scale is manufactured through a conversion of geometrical curves. During the measurement, the movement of a slider drives a pointer to point the number on the scale so that the radius of the measured circle or circular arc can be read directly; and thus, the defects of inaccurate and inconvenient measurement on the radius, even radius measurement failure in engineering can be overcome.

Description

Apparatus for measuring radius of circular arc

Technical field

The present invention relates to a kind of measurer of measuring circle or arc radius, can widespread use in various engineering surveys.

Background technology

In real work, the measurement of circle or arc radius is very inconvenient, and our common way is to look for 2 points on circular arc, measures chord length and action, calculates radius value then.Because the action position is bad fixed, the result that this method draws is often inaccurate, and sometimes action can not be measured at all, can only estimate individual numerical value roughly, brings very big inconvenience to surveying work.

Summary of the invention

In order to measure the radius of circle or circular arc easily, the invention provides a kind of apparatus for measuring radius of circular arc, need not the radius that directly measures circle or circular arc by calculating.

The technical solution adopted for the present invention to solve the technical problems is: seek the geometric relationship formula between chord length and the action, utilization AutoCAD software is with geometric relationship formula curveization, reflect concrete size and produce scale by curve again, design organization then, the concrete grammar division is as follows:

One, the relation of radius R and action X

As shown in Figure 1, draw one section any radius arc, fixed two some B and C, setting BC length is 2 units, is known that by Pythagorean theorem R and X have following relation:

R ²＝(R-X) ²+1

The expansion abbreviation gets:

2R＝X+1/X(｜X｜≤1，｜2R｜≥2) (1)

Negative value is represented external arc.In other words, under the certain situation of BC length, as long as measure action X, just can draw radius R, by geometry as can be known, formula (1) available functions image represents that it is the function of functions that is formed by stacking by a direct proportion function and an inverse proportion function.

Two, the functional image (is example with X 〉=0) of drawing

Open AutoCAD software on computers, drawing a length equals 1.1 horizontal linear OX and length and equals 41 vertical curve OR and constitute a rectangular coordinate system, horizontal linear is (or littler every 0.05 five equilibrium, distance is more little accurate more), through type (1) is found out corresponding 2R value and is marked point, on OX, look for 1: 0.025 again, through type (1) is found out corresponding 2R value and is also done a gauge point, it is exactly functional image such as Fig. 2 of formula (1) that these gauge points are linked up with smooth curve, what note is, 2 of head and the tail do not connect, and they are as directed usefulness.Along with the variation of X, we just can find the value of 2R like this.

Three, make scale (is example with BC length 200mm)

If a unit=100mm, i.e. BC=200mm, the delete flag point amplifies 100 times with image.On vertical axes, look for a bit (arc diameter is such as 300), make horizontal line and curve is given the G point by this point, make vertical curve and transverse axis is given the G1 point by the G point, as shown in Figure 3, the G1 point is labeled as 150 (arc radius), thus and thus makes the scale that a series of point has just been made X 〉=0, as shown in Figure 4 on the OX axle, is the scale that a mirror image obtains X≤0 with this scale with vertical axes, is labeled as infinity with 0 at last, and scale is made and finished as Fig. 5.Print by 1: 1 with a high-resolution printers, scale can be printed.

Four, mechanism design, as shown in Figure 6:

Two fixed claws are tip spacing 200mm 8., and slide bar is 9. at center position, and 10. the slide bar top has pointer, and the scale bottom is provided with guide groove, and slide bar slides in guide groove.

The invention has the beneficial effects as follows: direct reading when measuring circle or arc radius, need not to calculate, particularly suitable in the inconvenient occasion of measurement action; By the conversion of geometric relationship and curve, its volume-diminished is simple in structure, low cost of manufacture.

Description of drawings

The invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is the graph of a relation of radius R and action X;

Fig. 2 is the function curve diagram of 2R=X+1/X (| X|≤1, | 2R| 〉=2);

Fig. 3 is scale method for making figure, by this figure radius is reacted on the scale, reduces the design size of instrument;

Fig. 4 is the scale map of X 〉=0;

Fig. 5 is a scale map;

Fig. 6 is the mechanism map of arc measuring instrument.1. and 2. among Fig. 6,3. set nut regulates screw mandrel, 4. setting nut, 5. set nut, 6. adjuster bar, 7. handle, 8. fixed claw, 9. slide bar, 10. pointer.

Embodiment

Before the use, by slide bar pointer is transferred infinite general goal (be pointer centre position), screw set nut 1., 4. finely tuning slide bar by setting nut makes pointer overlap fully with infinite general goal mark (can to make a flat plate that is used to return to zero, length is longer slightly than two fixed claw spacings), screw set nut slide bar is fixed, 6. mobile adjuster bar makes its end and two fixed claws 8. be located along the same line the end, screw set nut 5., the zeroing operation is finished.1. and 2. now just can measure arc radius, unclamp set nut, 6. 8. two fixed claws all touched the surface of circle or circular arc with adjuster bar, the numeral that 10. pointer points to is exactly measured radius distance value.

Claims

1. apparatus for measuring radius of circular arc is justified or arc radius by three point measurements, it is characterized in that: utilize the relation of chord length and action to produce scale by geometrical curve, when measuring radius, the mobile drive pen travel of middle slide bar is read numerical value.

2. apparatus for measuring radius of circular arc according to claim 1, it is characterized in that: 4. finely tune slide bar by setting nut during zeroing and pointer and infinite general goal mark are overlapped fully and fixed slip bar, 6. mobile again adjuster bar makes its end and two fixed claws 8. be located along the same line the end.

3. apparatus for measuring radius of circular arc according to claim 1 is characterized in that: when making instrument two fixed claws 8. tip spacing can change length, to adapt to the measurement of different stage radius.