WO2008153340A2

WO2008153340A2 - Apparatus for measuring straightness in addition to differences of step and angle of two objects and shaft alignment method using same

Info

Publication number: WO2008153340A2
Application number: PCT/KR2008/003310
Authority: WO
Inventors: Soon-Sik Ham
Original assignee: Soon-Sik Ham
Priority date: 2007-06-14
Filing date: 2008-06-13
Publication date: 2008-12-18
Also published as: WO2008153340A3

Abstract

The present invention provides an apparatus for measuring a step difference and an inclination angle difference between a first surface and a second surface which are to be measured, comprising: a first contacting member installed for being capable of rotating in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being capable of rotating in accordance with the inclination of a second surface to be measured on which the second contacting member contacts; a case for rotatably supporting the first contacting member and the second contacting member; a first measuring means for measuring a first rotational angle between the first contacting member and the case when the first contacting member contacts on the first surface; and a second measuring means for measuring a second rotational angle between the second contacting member and the case when the second contacting member contacts on the second surface; wherein the measuring apparatus enables to measure the step difference, the inclination angle difference, and straightness between the first surface and the second surface from the first rotational angle and the second rotational angle, without rotating or moving any one of the first surface, the second surface, and the apparatus.

Description

APPARATUS FOR MEASURING STRAIGHTNESS IN ADDITION TO DIFFERENCES OF STEP AND ANGLE OF TWO OBJECTS AND SHAFT ALIGNMENT

METHOD USING SAME Technical Field

[1] The present invention relates to an apparatus or a method for measuring a step difference and an inclination angle difference between a first surface and a second surface of the to-be-measured object(s) svch as high speed rotational shafts, high precision machineries and precisely-connected rails, and for measuring straightness or flatness of a material manufactured by rolling or drawing processes. Background Art

[2] Fig.1 and fig.2 are schematic configuration illustrating a conventional apparatus for measuring straightness. The conventional apparatus has measured straightness or flatness of a surface to be measured by means of probes 10 sliding along the surface 88. However, said method has disadvantages that movement precision of a sliding unit severely affects precision of flatness or straightness of a surface 88 so that an apparatus for measuring straightness become heavy and expensive. Furthermore, the rediced length of movement of a sliding unit for improving the movement precision can limit a size of an object to be measured. Therefore, an easily portable apparatus for measuring straightness to be used in the field of manufacturing, assembly and installation has been required.

[3] In general, three dimensional measurement which should be done in precision measurement room, even after assembling a jig with a prodct manufactured by one of pressing process, an extruding process or a rolling process make troublesome for a serially manufacturing process of the prodict, thereby causing low prodctivity. Therefore, there have been problems svch that workers keep on produdng without precisely measuring prodcts or that a flawless process cannot be realized in the field for the examination of products.

[4] Likewise, in the field of rail assembly and installation, the step difference and the inclined angle difference have been measured by means of a straight bar to check a gap between the bar and the rail, or by a naked eye check. However, an angle difference of 1/100 degrees at their connections cause lmm of step difference in case of a 5m rail for elevators, and therefore the rail cannot but be installed in zigzags. Further, the straightness of the rail is to be examined after moving car is started to move along the rail, and thus, the rail should be repeatedly adjusted after re-aligning the connections part of the rail in many times, whereby the rail assembly cannot avoid from being inferior. Also, as the assembly quality mostly depends on worker's expertness, the systematic quality control and process management cannot be achieved.

[5] On the other hand, when a connection is inferior at a coupling for connecting high speed and high torque motors or compressors, phenomena sirh as bearing or shaft damages, excessive vibration, noise and excessive energy consumption may occur. As illustrated in Fig. 4, the degree of a shaft alignment for precise rotating machineries is closely related with the life of the equipment. Therefore, a precise shaft alignment process is one of the most processes for equipment maintenance of a plant.

[6] Generally, shaft alignment method by using dial gages or a laser measuring apparatus

50 is widely used in many fields. When driving shaft 20 and driven shaft 30 are required to be aligned as shown in fig. 5, a fixing unit 40 of the dial gage 42 is installed on the driven shaft 30, and the probe 41 of the dial gage 42 which contacts with the outer surface of the driving shaft 20 is sliding along the circumstance of the rotating driving shaft 20 whereby a step difference can be measured by observing the scale change of the dial gage 42 as illustrated in fig. 6. However, considering that the misalignment of shafts 20, 30 is caused by not only step difference d'-d between shafts 20, 30 but also an inclination angle difference ΔΘ therebetween, only the scale change of the dial gage 42 cannot give enough information for correcting the misalignment. Therefore, an operator should infer the inclination angle difference from the step differences shown by the scale change of the dial gages. Therefore, it is impossible to realize the precise shaft alignment in that an operator cannot exactly recognize the inclination angle difference from step differences.

[7] As an alternative method, a laser measuring apparatus has been used. The laser measuring apparatus measures the step difference and the inclination angle difference by means of the biased distance and the reflected angle change of the laser reflected from the surfaces to be measured in condition that both driving shaft 20 and driven shaft 30 are rotating. However, the laser measuring apparatus still needs to make both of the shafts rotate for measuring the error of misalignment so that operators cannot directly obtain the step difference and the inclination angle difference immediately without rotating the shafts 20, 30. Especially, in the case of a deceleration motor which sometimes cannot rotate, the laser measuring apparatus is useless. Furthermore, the CDSt for the laser measuring apparatus is too high to use in various fields.

[8] To summarize, the conventional measuring method just measures relative errors of the step difference and the inclination angle difference furthermore with requiring both of shafts to rotate. Accordingly, the conventional method has problems that jigs should be assembled on the shaft to be measured and the extra signal lines or power lines should be connected. Also, in the case of measuring the inclination angle difference which is as important at least as the step difference, the measured value is limited only to the step difference, and thus, only professional operator can infer the inclination angle difference from the step difference whereby it is impossible to precisely align shafts for a novice, or at least, it takes mtch time to align shafts even for a professional operator.

[9]

Disclosure of Invention Technical Problem

[10] In order to overcome these disadvantages of the prior art, the present invention has an object to provide an apparatus for measuring a step difference and an inclination angle difference of two surfaces of object(s) to be measured from a first rotational angle of a first contacting member and a second rotational angle of a second contacting member. Hereinafter, the terms of the first surface and the second surface will be used as ones formed as including flat surfaces, rounded surfaces in addition to shaft surfaces to be aligned.

[11] Also, the present invention has another object of realizing a shaft alignment without requiring the two surfaces or two shafts to rotate during an alignment process by directly obtaining the step difference and the inclination angle difference between two surfaces of object(s).

[12] Further, the present invention has other object of directly measuring the step difference and the inclination angle difference of two rails and of measuring straightness of a material made by rolling or drawing processes.

[13] Yet, the present invention has an object of manufacturing a portable apparatus with simple stricture for measuring a step difference and an inclination angle difference of object(s) to be measured thereby realizing said portable apparatus to widely apply to diverse working fields.

[14] And, the present invention has other object of directly obtaining the step difference and the inclination angle difference without requiring a signal processing circuit by simply calibrating based on calibration data set having calibrated step differences and inclination angle differences in accordance with output bridge voltages which had been stored in the manufacturing process.

[15] Also, the present invention has an object of realizing to set the zero-referenced state of the apparatus before the measurement work(s) without using a separate reference plate for zero- set up. Technical Solution

[16] In order to attain the above mentioned object, the present invention provides an apparatus which comprises: a first contacting member installed for being capable of rotating in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being capable of rotating in accordance with the inclination of a second surface of the other object to be measured on which the second contacting member contacts; a case for rotatably supporting the first contacting member and the second contacting member; a first measuring means for measuring a first rotational angle between the first contacting member and the case when the first contacting member contacts on the first surface; and a second measuring means for measuring a second rotational angle between the second contacting member and the case when the second contacting member contacts on the second surface; wherein the measuring apparatus measures at least one of a step difference between the first surface and the second surface, an inclination angle difference between the first surface and the second surface, and straightness between the first surface and the second surface from the first rotational angle and the second rotational angle.

[17] That is based on a new theory in that the only measurement of inclined angles of the object(s) to be measured make it possible to obtain a step difference, an inclination angle difference therebetween in addition to straightness therebetween. Therefore, when the first contacting member and the second contacting member are contacted on the first surface and the second surface of the object(s), by measuring the rotational angles of both the first contacting member and the second member relative to the case using means sirh as strain gages or lasers or encoders, without rotating neither the first surface and/or the second surface nor the apparatus, the step difference between the first surface and the second surface and the inclination angle difference therebetween can be directly obtained from the measured inclined angles (i.e., the rotational angle of the contacting members). [18] Herein, the first surface and the second surface may belong to two separate objects, and thus the apparatus can be used for obtaining the step difference and the inclination angle difference, etc. of the separate objects sirh as for the shaft alignment. On the other hand, the first surface and the second surface may belong to one object, and thus the apparatus can be used for obtaining the straightness of two positions of the object (e.g., material manufactured by a rolling process or a drawing process) by measuring the surface inclined angles at the two positions.

[19] More concretely, the first contacting member is rotatably placed on the first surface, and thus is rotated in accordance of the inclination of the first surface, and then the first rotational angle ΘΘ1 of the first contacting member is measured. Similarly, the second contacting member is rotatably placed on the second surface and thus is rotated in accordance of the inclination of the second surface, and then the second rotational angle Θ2 of the second contacting member is measured. Then, the inclination angle difference between the first surface and the second surface is obtained by the sum (Θl + Θ2) of the rotational angles, while the step difference Δd therebetween is obtained by the following equation 1. The signs of the rotational angles follows ones shown in Fig. 15. Herein, as the rotational angles Θl, Θ2 are too small, tan(Θl) becomes Θl and tan(Θ2) becomes Θ2.

[20] Equation 1

[21] Δd = (tan(Θl)-tan(Θ2))L/2 =(Θ1- Θ2)L/2

[22]

[23] Therefore, without moving or rotating the first surface and the second surface, the only measurement of the rotational angles Θl, Θ2 of the contacting members makes possible to obtain the step difference, the inclination angle difference and the straightness between the first surface and the second surface, whereby shaft alignment process can be perfectly and completely realized without measuring related variables many times.

[24] Further, as the case rotatably supporting the first contacting member and the second contacting member are comprised by the apparatus, it is mtch easier to carry and use the apparatus in that the apparatus can be handled as one body.

[25]

[26] In order to measure the rotational angles with higher precision, it is firstly required to obtain the rotational precision of the rotational shaft of the first contacting member and the second contacting member. In the meantime, when generally used bearings are applied, large radial clearance cannot but occur. Even precise ball bearings have radial clearances between 5 /M and 10 /M, and further, the radial clearances become different whenever to measure, and thus large measurement errors may occur. Therefore, considering that precise measurement having 1/1000 degree requires the limited redial clearance about between 0.2 μm and 0.5 /M, it is impossible to realize sirh a precise measurement with the widely used ball bearings.

[27] Meanwhile, as the apparatus of the present invention does not need to rotate at high speed, the apparatus includes: a first center shaft which is penetratedly located at the rotating center of the first contacting member; a pair of first supporting shafts which are fixed in the case, wherein inner one end surface of the each first supporting shaft in the transverse direction respectively faces one of both end surfaces of the first center shaft; two of three first self-aligning small balls accommodated at either one end of the first center shaft or inner end of one of the first supporting shafts in the transverse direction, and at either the other one end of the first center shaft or inner end of the other first supporting shafts in the transverse direction; and two of one first self- aligning center ball installed at either one end of the first center shaft or inner end of one of the first supporting shafts in the transverse direction, and at either the other one end of the first center shaft or inner end of the other first supporting shafts in the transverse direction, so that each of the first self-aligning center balls pressedly contacts with the three the first self-aligning small balls simultaneously at three point.

[28] That is, as the first contacting member is rotatably supported by the first center shaft therein and the pair of the first supporting shafts arrayed both sides of the first center shaft. Herein, for example, as three of first self-aligning small balls are accommodated in retainers at both end sides of the first center shaft, and as a center ball is pressedly installed at the inner end of the first supporting shafts so as to press the three first self- aligning small balls at three points, the first contacting member is automatically self- aligned to the pair of the first support shafts. Herein, the pair of support members are desired to be fixed at their position by the headless screw.

[29] Therefore, as there is not any clearance between the first self-aligning small balls and the first self-aligning center balls, the positions of the first self-aligning small balls and the first self-aligning center balls are perfectly determined. Thus, although the spherical surfaces of the first self-aligning small balls and the first self-aligning center balls are not highly precisely machined or formed, the rotational shaft of the first contacting member can be highly precisely rotatable with low cost.

[30] Herein, the balls and the retainers are formed of ceramics, when the first supporting shafts are installed to press the first center shaft, the rolling motion of the balls in the retainers can be realized. Further, in case that an external impact is applied, the rotation of the first contacting member is not influenced by the external impact.

[31] That is, as the first supporting shafts and the first center shafts are pressedly fixed in the transverse direction with a predetermined elastic preload between balls, in case that an external load or impact is applied to the shafts, the shafts can be restored to their original positions thereby buffering the external impact or load.

[32] Meanwhile, the two of three first self-aligning small balls may be installed at the inner end of the first supporting shaft instead of the end of the center shaft, from which similar effects can be obtained. Similar to the rotational shaft of the first contacting member, with regard to the rotational shaft of the second contacting member, the apparatus farther comprises: a second center shaft which is penetratedly located at the rotating center of the second contacting member; a pair of second supporting shafts which are fixed in the case, wherein inner one end surface of the each first supporting shaft in the transverse direction respectively faces one of both end surfaces of the second center shaft; two of three second self-aligning small balls accommodated at either one end of the second center shaft or inner end of one of the second supporting shafts in the transverse direction, and at either the other one end of the second center shaft or inner end of the other second supporting shafts in the transverse direction; and two of one second self-aligning center ball installed at either one end of the second center shaft or inner end of one of the second supporting shafts in the transverse direction, and at either the other one end of the second center shaft or inner end of the other second supporting shafts in the transverse direction, so that each of the second self-aligning center balls pressedly contacts with the three of the second self-aligning small balls simultaneously at three point, whereby the second contacting member can be precisely rotatable without radial clearance.

[33]

[34] In case that the first surface is formed of a flat surface having a step difference from the second surface and/or is formed of an inclined surface in the longitudinal indirection to the second surface, the first contacting member includes two contact balls which are longitudinally apart distributed at the first contacting member in order to get in contact with the first surface, and the second contacting member includes three contact balls which are triangularly distributed at the second contacting member in order to get in contact with the second surface. From this constriction, although the flatness of the second surface is not perfectly flat, the first contacting member can precisely rotate in accordance with the inclination of the first surface with condition that the second contacting member can stably contact with the second surface at triangularly distributed three positions, whereby the contacting members can be adhered closely and stably to the first surface and the second surface regardless of the direction of the inclination or the degree of the surface inclination.

[35] Meanwhile, in case that the first surface and the second surface are formed of transversely rounded surfaces sirh as shafts to be aligned, the first contacting member includes four contact balls which are rectangularly distributed at the first contacting member in order to get in contact with the first surface, and the second contacting member includes two contact rollers arrayed in the transverse direction and distributed longitudinally apart at the second contacting member to be contacted with the second surface. Therefore, the first contacting member can be maintained to stably adhere to the transversely rounded first surface, and thus the second contacting member can reliably contact with the second surface, for example, which may be applied to shaft alignment process.

[36] However, in accordance with the transverse curvature of the first surface, the contacted height of the first contacting member which contacts with the first surface at four positions by the four contact balls may differ. Therefore, in order to accurately apply the apparatus in the wide range of the curvature, it is effective to calibrate the curvature of the surfaces to have been measured based on the conversion table or on the conversion equation predetermined in advance.

[37] Also, it is an alternative that an adapter having a conformed surface to the surfaces of the object(s) is attached to the contacting members thereby assisting the contacting members are closely adhered on the surfaces of the object(s).

[38]

[39] The first measuring means and the second measuring means can measure the rotational angles of the contacting members by diverse methods. For example, with the installation of a laser radiation part and a laser receiving part in the case, the laser radiation part discharges laser to the contacting members and then the laser receiving part respectively receives the laser which is reflected from the contacting members, the rotational angles of the contacting members can be measured in accordance with the receiving angle or the receiving location at the laser receiving part. In addition, a static electricity sensor for sensing the gap between specific points of the contacting members and the case is installed in the case, and then, the rotational angles of the contacting members can be measured by the signal from the static electricity sensor. Also, by installing encoders with high precision at each of the rotational shafts of the contacting members, the rotational angles of the contacting members can be measured by the signal from the encoders. As described hereinafter, it is most effective to measure the rotational angles of the contacting members using strain gages in that signal processing is actually omitted or very simple and precise and accurate measurement can be simply realized at a low cost.

[40]

[41] Specifically, the first measuring means includes at least one first leaf spring of which one part is fixed to the case and of which one end is fixed to the first contacting member, and at least one first strain gage having all the same resistance attached on the first leaf spring for constituting a first wheatston bridge. Similarly, the second measuring means includes at least one second leaf spring of which one part is fixed to the case and of which one end is fixed to the second contacting member, and at least one second strain gage having all the same resistance attached on the second leaf spring for constituting a second wheatston bridge. Herein, the first leaf spring and the second leaf spring are installed to be deformed by the rotation of the first contacting member and the second contacting member. Therefore, the first rotational angle can be measured by the output signal of the bride voltage of the first wheatston bridge, and also the second rotational angle can be measured by the output signal of the bride voltage of the second wheatston bridge. From this constriction, the rotational angles (i.e., the relative angle displacement from the case) of the contacting members can be measured by using stain gages more precisely and accurately at a low cost compared with by using a laser or encoders.

[42] Herein, the first leaf springs may be formed as a pair of first leaf springs, each of which one end is fixed to the first contacting member and the other end is fixed to the case respectively. Also, the second leaf springs may be formed as a pair of second leaf springs, each of which one end is fixed to the second contacting member and the other end is fixed to the case respectively. In order that the pair of leaf springs are equally deformed each other, the pair of first leaf springs and the pair of the second leaf spring are arrayed bisymmetrically to their rotational center each other.

[43]

[44] Also, the first strain gages are formed as plural. That is, two first strain gages are attached respectively at the same position but on both faces of the one of the first leaf springs. Therefore, the deformations of the first strain gages are all the same, however, the first strain gage attached on the inner face of the first leaf spring may be elongated, and the first strain gage attached on the outer face of the first leaf spring may be contracted, whereby the strain signs of the first strain gages differ from each other. Similarly, the other two first strain gages are attached respectively at the same position but on both faces of the other one of the first leaf springs. All the first strain gages are located at positions apart by the same distance from the rotational center of the first contacting member, and thus the resistance absolute variations of the first strain gages are all the same. Also, the initial resistances of the first strain gages are set to be all the same.

[45] Herein, the first wheatston bridge is constricted so that two first strain gages on the elongated surface of the first leaf springs in accordance with the rotation of the first contacting member in one direction face each other, and that the other two first strain gages on the contracted surface of the first leaf springs in accordance with the rotation of the first contacting member in the one direction face each other.

[46] Similarly, the second strain gages are formed as plural. That is, two of second strain gages are attached respectively at the same position but on both faces of the one of the second leaf springs. Therefore, the deformation of the second strain gages are all the same, however, the second strain gage attached inner face of the first leaf spring may be elongated, and the second strain gage attached outer face of the first leaf spring may be contracted, whereby the strain signs of the second strain gages differ with each other. Similarly, the other two second strain gages are attached respectively at the same position but on both faces of the other one of the second leaf springs. All the second strain gages are located at positions apart by the same distance from the rotational center of the second contacting member, and thus the resistance absolute variation of the second strain gages are all the same. Also, the initial resistances of the second strain gages are set to be all the same.

[47] Herein, the second wheatston bridge is constricted so that two second strain gages on the elongated surface of the second leaf springs in accordance with the rotation of the second contacting member in one direction face each other, and that the other two second strain gages on the contracted surface of the second leaf springs in accordance with the rotation of the second contacting member in the one direction face each other.

[48] From the constriction that the strain gages are distributed bisymmetrically to the rotational center of the contacting members, although the contacting members and the case which may be formed from different material are deformed differently by thermal expansion in accordance with the temperature change, all the strain gages arrayed bisymmetrically to the rotational center of the contacting members are also deformed theoretically by the same amount, an error due to the thermal deformation differences of the strain gages is automatically compensated. Also, although impacts may be applied to the vertical direction to the surface to be measured during the measurement, all the strain gages arrayed bisymmetrically to the rotational center of the contacting members are also deformed or twisted by the same amount, an error due to a possible impact during the measurement is also automatically minimized.

[49] From the constriction above, the bridge voltages of the wheatston bridges are obtained as output signals which are proportional to the rotational angles Θl, Θ2 of the contacting members. Therefore, without including a complex signal processing control circuit, the rotational angles Θl, Θ2 can be obtained just by calibrating the bridge voltages as output signals, from which the step difference between the first surface and the second surface and the inclination angle difference therebetween can be obtained by the sum of the rotational angles and by the equation 1. That is, the step difference and the inclination angle difference therebetween can be obtained by measuring the bridge voltages of the wheatston bridges, and then by calibrating the bridge voltage using a calibration data set stored in the manufacturing process in advance to get the rotational angels Θl, Θ2, and then by simple calculation of the rotational angels Θl, Θ2.

[50] In this regard, the calibration of the step difference and the inclination angle difference is easily and automatically set in the manufacturing process using a standard measurement tool. Concretely, the calibration gains are obtained in accordance with the bridge voltage variations by the variation slope of the value measured using the standard measurement tool in condition that the leaf spring's linearity is realized. Therefore, by storing the gains in a ROM of hardware as a calibration data set in advance in the manufacturing process of the apparatus, of which calibration is now being widely applied to a field of electric balance or thermometer or hygrometer as having a merit of an easy mass production, the rotational angles Θl, Θ2 are easily obtained from the measured bridge voltages of wheatston bridges.

[51] In order to redtce the error of the attached positions of the strain gages and to enhance the signal stability, it is desirable for the strain gages to deform uniformly for all the length of the strain gages. For this reason, constant moment should be applied to the positions where the strain gages are attached.

[52] Referring to Fig. 16, the moment by horizontal force Fh applying to the first leaf spring linearly increases from a position shown as the drawing number 2, the moment by vertical force Fv applying to the first leaf spring decreases from a position shown as the drawing number 1 to the position shown as the drawing number 3. Therefore, it is possible to realize the constant moment area B by forming the area from the position shown as the drawing number 2 to the position shown as the drawing number 3 into the inclined area B. Thus, when the strain gages are attached on the inclined area B, high sensitivity and stable signals from the strain gages can be obtained.

[53] For this reason, the first leaf springs are partitioned to a plurality of first partitioned areas including a 1-1 area having the one end fixed to the first contacting member, a 1-4 area having the one part fixed to the case and parallel with the 1-1 area, and a first inclined area on which the first strain gages are attached between the 1-1 area and the 1-4 area, the partitioned area being partitioned by a plurality of bending portions, whereby the signals from the strain gages become stable and have high sensitivity.

[54] The above principle is also applied to the second leaf spring. Therefore, the second leaf springs are partitioned to a plurality of second partitioned areas including a 2- 1 area having the one end fixed to the second contacting member, a 2-4 area having the one part fixed to the case and parallel with the 2- 1 area, and a second inclined area therebetween on which the second strain gages are attached between the 2- 1 area and the 2-4 area, the second partitioned area being partitioned by a plurality of bending portions.

[55] In the meantime, the horizontal force Fh and the vertical force Fv applying to the first leaf spring relates with the ratio of the length of the 1-1 area A and the length of the 1-4 area B. That is, the moment by the horizontal force Fh is determined by the vertical length between the 1-1 area A and the 1-4 area D, while the moment by the vertical force Fv is determined by the horizontal length between the end of the 1-1 area A and the end of the 1-4 area D. Therefore, in order that the moment is consistent in the inclined area B, the increased moment by the horizontal force Fh should be the same to the decreased moment by the vertical force Fv. To this end, the inclination of the inclined area B should be similar to the imaginary line connecting the end of the 1-1 area A and the end of the 1-4 area D. Thus, the inclination of the inclined area B of the first leaf springs is formed as having an inclination of the imaginary line connecting both ends of the each first leaf spring, while the inclination of the inclined area of the second leaf springs is formed as having an inclination of the imaginary line connecting both ends of the each second leaf spring. Herein, the end of the 1-1 area A and the end of the 1-4 area mean the positions where the first leaf springs are fixed instead of physical end thereof.

[56]

[57] Meanwhile, the zero-reference set of the apparatus is realized by that the posture of the contacting members are restricted at one predetermined position respectively by being contacted with the predetermined at least two locations, thereby setting each zero-reference set position of the contacting members, whereby the zero-reference set can be realized without separate reference block or plate which users should have carried for the zero-reference set.

[58] For example, the apparatus further comprises: a first zero-set member rotatably installed in the case for contacting its at least one surface with the first contacting member at said two locations thereby letting the first contacting member be arrayed at the zero-reference set posture; a first pressing spring oompressively installed to be contacted with the first zero-set member for pressing the first zero-set member to rotate and to contact with the first contacting member at predetermined zero-reference set posture; a second zero-set member rotatably installed in the case for contacting its at least one surface with the second contacting member at said two locations thereby letting the second contacting member be arrayed at the zero-reference set posture; and a second pressing spring oompressively installed to be contacted with the second zero- set member for pressing the second zero-set member to rotate and to contact with the second contacting member at predetermined zero-reference set posture.

[59] In other words, in condition that the electric power of the apparatus is OFF, when the first zero-set member contacts at two locations with the first contacting member which is pushed and rotated by the pressing of the first pressing spring, the movement and the rotation of the first contacting member and the first zero-set member are simultaneously restricted. By letting this state as the zero-reference set posture, zero- reference set procedure is automatically done together with turning on the electric power of the apparatus. Herein, as the first pressing spring exerts the constant force to the first zero-set member rather than inconsistent force in accordance with users, when the pressing force by the first pressing spring reaches one to overcome the friction between the unbalance force of the first contacting member and the rotation part of the first contacting member, the first contacting member always becomes positioned at the predetermined constant posture where the zero-reference set is realized. After completing the zero-reference set procedure, the restriction between the first contacting member and the first zero-set member is released whereby the first contacting member becomes freely rotatable again. Then, the step difference and the inclination angle difference or the straightness between the first surface and the second surface is measured by contacting the contacting members on the surfaces to be measured. [60] The zero-reference set procedure of the second contacting member is realized by the similar way to the first contacting member.

[61]

[62] Meanwhile, in spite of the wide range of temperature or aging of the components or wear of the contact balls or rollers in order to maintain the constant zero-reference set for the high accuracy of the measurement, it is effective for the contacting members to contact with the zero-set members at two points formed by spherical surface sirh as a ball. Therefore, the first zero-set member or the first contacting member includes a pair of first zero-contact balls protrudedly formed on the contact surface of the first zero-set member with the first contacting member as being apart from the rotational center of the first contacting member in the different direction each other, and the second zero- set member or the second contacting member includes a pair of second zero-contact balls protrudedly formed on the contact surface of the second zero-set member with the second contacting member as being apart from the rotational center of the second contacting member in the different direction each other. From the zero-contact balls, the contacting members are reliably restricted by the zero-set members at constant postures. In the specification and claims, although the term of "zero-contact ball" is used as including 'ball', the term of "zero-contact ball" means a member having a spherical surface to be contacted with the contacting members.

[63] Meanwhile, all of the thermal expansion coefficients of the case, the zero-set members, the contacting members and the zero-contact balls may differ with one another in corresponding with temperature variations. Therefore, the case generally made of aluminum having higher thermal expansion characteristics is more deformed than other components. Accordingly, as temperature rises, the rotational shaft of the zero-set member moves away from the contacting member, the positions where the zero-set members and zero-contact balls contact each other are also raised, and accordingly, the contact positions between the contacting member and the zero-set members cannot contact at the predetermined zero-reference set position. As shown in Fig. 36, when the zero-set members move upward away from the contacting members by thermal expansion, compared with the positions where zero-set members contact with the contacting members when any thermal expansion does not occur, the gap at the zero-contact ball 66a which is located at the nearer to the center of the apparatus in the longitudinal direction occurs as shown by dot line 66 larger than the gap at the other zero-contact ball 66b which is located at the farther to the center of the apparatus. Therefore, it is desirable that the zero-contact ball 66a moves more than the other zero- contact ball 66b in accordance with the movement of the rotational shaft of the zero-set members.

[64] To this end, in the example case that the zero-contact balls are installed on a surface of the contacting members, first thermal expansion members are insertedly held in the first contacting member respectively below each of the pair of the first zero-contact balls, the one of the first thermal expansion members sirh as aluminum located below one of the pair of the first zero-contact balls which are located at the nearer to the center of the apparatus in the longitudinal direction being more deformed in accordance of the temperature change than the other of the first thermal expansion member sirh as stainless steel below the other of the pair of the first zero-contact balls; and, second thermal expansion members are insertedly held in the second contacting member respectively below each of the pair of the second zero-contact balls, the one of the second thermal expansion members located below one of the pair of the second zero-contact balls which is located at the nearer to the center of the apparatus in the longitudinal direction being more deformed in accordance of the temperature change than the other of the second thermal expansion member below the other of the pair of the second zero-contact balls. Herein, although the length or the thickness of the thermal expansion members may be variable, the length and the thickness thereof should be restricted so that the zero-contact ball at nearer to the center of the apparatus moves more than the other zero-contact ball farther to the center of the apparatus in correspondence with temperature change.

[65] From above, in case that the case is made of material having high thermal expansion characteristics, although the rotational shaft of the zero-set member moves upward by temperature change (herein, the horizontal movement of the rotational shaft of the zero-set member does little effect on the zero-reference set procedure), the zero- contact balls at the nearer to the center on the contacting members become protruded more than the other zero-contact balls at the farther to the center in accordance with the temperature change, whereby a possible zero-reference set error due to temperature change can be minimized.

[66]

[67] And, as the object(s) to be measured is generally formed of steel, each of the contacting members includes magnetic respectively thereby enhancing the adherence of the contacting members to the surfaces of the object(s).

[68] Concretely, the apparatus further comprises an adherence assistance unit including a handle shaft extended from a knob, at least one cam integrally combined with the handle shaft, a moving body for being contacted with the outer surface of the cam so as to move reciprocally within the case by the distance of the eccentricity of the cam in accordance with the rotation of the cam, and a magnetic fixed to the moving body. Therefore, in case that the apparatus is to be contacted on the surfaces of the object(s), the magnetic approaches to the surfaces of the object(s) by rotating the handle shaft together with the cam in one direction, and by making the moving body move towards the surfaces. Also, in case that the apparatus is to be separated from the surfaces of the object(s), the magnetic moves away from the surfaces of the object(s) by rotating the handle shaft together with the cam in the other direction, and by making the moving body move away from the surfaces. From this constriction, it is easier to adheredly install the apparatus on the surfaces of the object(s) to be measured.

[©]

[70] Meanwhile, the present invention provides with an apparatus which comprises: a case; a first contacting member rotatably installed in the case in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being rotatably installed in the case in accordance with the inclination of a second surface of the other object to be measured on which the second contacting member contacts; at least one first leaf spring of which one part is fixed to the case and of which at least one end is fixed to the first contacting member, the first leaf spring being deformed by the rotation of the first contacting member; at least one second leaf spring of which one part is fixed to the case and of which at least one end is fixed to the second contacting member, the second leaf spring being deformed by the rotation of the second contacting member; at least one first strain gage attached on the first leaf spring; and at least one second strain gage attached on the second leaf spring; wherein the rotational angle of the first contacting member and the rotation angel of the second contacting member are obtained from a bridge voltage of at least one wheatston bridge which includes at least one first strain gage and at least one second strain gage, whereby at least one of a step difference between the first surface and the second surface, an inclination angle difference between the first surface and the second surface, and straightness between the first surface and the second surface is measured.

[71] That is, by constricting the wheatston bridge including both the first strain gage and the second strain gage in one wheatston bridge circuit for measuring the rotational angles of the contacting members, instead of measuring each of the rotational angles of the contacting members respectively, the step difference and the inclination angle difference between the first surface and the second surface can be obtained.

[72] More concretely, the first strain gages are formed as at least one pair which are attached respectively on an inner face and an outer face of the first leaf spring, the first strain gages being located between the one part of the first leaf spring and the end fixed to the first contacting member; and the second strain gages are formed as at least one pair which are attached respectively on the inner face and the outer face of the second leaf spring, the second strain gages being located between the one part of the second leaf spring and the end fixed to the second contacting member; and further, a third wheatston bridge is constricted so that at least one strain gage attached on the contracted surface of the first leaf springs face the other at least one second strain gage on the elongated surface of the second leaf spring and/or that at least one strain gage attached on the elongated surface of the first leaf springs face the other at least one second strain gage on the contracted surface of the second leaf spring, whereby the inclination angle difference between the first surface and the second surface is obtained from the bridge voltage of the third wheatston bridge. Therefore, without requiring a complex signal processing control circuit, and without measuring the rotational angles of the contacting members, the inclination angle difference therebetween can be directly obtained only by calibrating the bridge voltages of the third wheatston bridge using gains stored in ROM.

[73] That is, only changing the connection method of wheatston bridge makes it possible to obtain the inclination angle difference between the surfaces to be measured without any operational complex circuit and without measuring each of the rotational angles of the contacting members, as the first strain gages and the second strain gages simultaneously constitute the cross-type third wheatston bridge, whereby an analog type apparatus or a cheap measurement apparatus for measuring the inclination angle difference therebetween can be easily achieved.

[74] Herein, the first strain gages and the second strain gages are attached on the leaf springs at positions where the deformations of the first strain gages are all the same to those of the second strain gages. For example, the first leaf springs and the second leaf springs is formed as having their constant thickness over all their lengths, and also the relative positions of the first strain gages from the rotational center of the first contacting member are all the same to those of the second strain gages from the rotational center of the second contacting member.

[75] Also, the first strain gages are formed as plural. That is, two first strain gages are attached respectively at the same position but on both faces of the one of the first leaf springs. Therefore, the deformation of the first strain gages are all the same, however, the first strain gage attached inner face of the first leaf spring may be elongated, and the first strain gage attached outer face of the first leaf spring may be contracted, whereby the strain signs of the first strain gages differ with each other. Similarly, the other two first strain gages are attached respectively at the same position but on both faces of the other one of the first leaf springs. All the first strain gages are located at positions apart by the same distance from the rotational center of the first contacting member, and thus the resistance absolute variation of the first strain gages are all the same. Also, the initial resistances of the first strain gages are set to be all the same. From this constriction that the resistances are arrayed bisymmetrically, the calibration of the bridge voltage becomes mtch easier.

[76] Meanwhile, the first strain gages are formed as at least one pair which are attached respectively on an inner face and an outer face of the first leaf spring, the first strain gages being located between the one part of the first leaf spring and the end fixed to the first contacting member; and the second strain gages are formed as at least one pair which are attached respectively on the inner face and the outer face of the second leaf spring, the second strain gages being located between the one part of the second leaf spring and the end fixed to the second contacting member. Further, the apparatus further comprises a fourth wheatston bridge constricted so that at least one strain gage attached on the contracted surface of the first leaf springs face the other at least one second strain gage on the contracted surface of the second leaf spring and/or that at least one strain gage attached on the elongated surface of the first leaf springs face the other at least one second strain gage on the elongated surface of the second leaf spring, whereby the step difference between the first surface and the second surface is obtained from the bridge voltage of the fourth wheatston bridge. Therefore, without requiring a complex signal processing control circuit, and without measuring the rotational angles of the contacting members, the step difference Δd therebetween can be directly obtained only by calibrating the bridge voltages of the third wheatston bridge using gains stored in ROM.

[77]

[78] In the meantime, the present invention also provides with a method of aligning a first shaft and a second shaft, which comprises: a step of placing the first contacting member on the longitudinal outer surface of the first shaft and so that the first contacting member rotates in accordance of the longitudinal outer surface inclination of the first shaft; a step of placing the second contacting member on the longitudinal outer surface of the second shaft and so that the second contacting member rotates in accordance of the longitudinal outer surface inclination of the second shaft; a step of measuring a first rotational angle of the first contacting member in accordance with the first surface of the first shaft; a step of measuring a second rotational angle of the second contacting member in accordance with the second surface of the second shaft; a step of indicating the obtained angel difference and the obtained step difference between the first surface and the second surface which are obtained from the measured first rotational angle and the measured second rotational angle; and a step of aligning the first shaft and the second shaft while checking the indicated step difference and the inclination angle difference therebetween.

[79] That is, when the first contacting member and the second contacting member are closely placed on the first surface and the second surface respectively, the step difference and the inclination angle difference therebetween are rightly indicated from the measured first rotational angle and the measured second rotational angle. Thus, without rotating the first shaft and the second shaft during the shaft alignment process, by adjusting the first shaft and the second shaft so that both the step difference and the inclination angle difference become zero, the alignment of the first shaft to the second shaft can be easily done.

[80] In order to measure more precisely, at least three sets of which each includes the first contacting member and the second contacting member are installed in the vertical direction, in the horizontal direction and in the diagonal direction respectively for aligning the first shaft and the second shaft. That is, as the diameter of the first shaft is not exactly same to that of the second shaft, although the step difference obtained by the sets installed in the vertical direction and the horizontal direction may be zero, the shaft alignment may not be completely done. For this reason, the information of another set is required to align shafts completely. Therefore, when the step differences obtained by the three sets of apparatus become the same, although the diameter of the first shaft is not the same to that of the second shaft, the shafts can be perfectly and completely aligned.

[81]

[82] Meanwhile, the present invention also provides with a method of aligning a first shaft and a second shaft by measuring a step difference between the first shaft and the second shaft and an inclination angle difference between the first shaft and the second shaft, which comprises: a step of setting a zero-reference set posture of a first contacting member and a second contacting member; a step of placing the first contacting member on the first shaft and so that the first contacting member rotates in accordance of the surface inclination of the first shaft, and of placing the second contacting member on the second shaft and so that the second contacting member rotates in accordance of the surface inclination of the second shaft; a step of measuring a first angle of the first contacting member on the first shaft from the zero-reference set posture of the first contacting member; a step of measuring a second angle of the second contacting member on the second shaft from the zero-reference set posture of the second contacting member; a step of indicating the step difference between the first shaft and the second shaft and the inclination angle difference between the first shaft and the second shaft, which are obtained by the first angle and the second angle; and a step of aligning the first shaft and the second shaft while checking the indicated step difference and the inclination angle difference therebetween.

[83] In this regard, as the apparatus is frequently and repeatedly used and as the drift characteristic is changed, in order to measure precisely, the zero-reference set procedure is desired to be done right before the measurement.

[84]

Advantageous Effects

[85] As explained above, the present invention provides an apparatus for measuring a step difference and an inclination angle difference between a first surface and a second surface which are to be measured, comprising: a first contacting member installed for being capable of rotating in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being capable of rotating in accordance with the inclination of a second surface of the other object to be measured on which the second contacting member contacts; a case for rotatably supporting the first contacting member and the second contacting member; a first measuring means for measuring a first rotational angle between the first contacting member and the case when the first contacting member contacts on the first surface; and a second measuring means for measuring a second rotational angle between the second contacting member and the case when the second contacting member contacts on the second surface; wherein the measuring apparatus enables to measure the step difference, the inclination angle difference, and straightness between the first surface and the second surface from the first rotational angle and the second rotational angle, without rotating or moving any one of the first surface, the second surface, and the apparatus.

[86] Also, the present invention provides an apparatus and a method for directly measuring the step difference and the inclination angle difference between two surfaces of shafts to be aligned thereby enabling to align shafts without the rotation of the shafts.

[87] Further, the present invention provides an apparatus as a portable with simple stricture for measuring a step difference and an inclination angle difference of object(s) to be measured thereby enabling to widely apply to diverse working fields.

[88] Further, the present invention provides an apparatus of directly measuring the step difference and the inclination angle difference of two rails and of measuring straightness of a material made by rolling process or drawing process, etc.

[89] And, the present invention also provides an apparatus of directly obtaining the step difference and the inclination angle difference using al least one wheatston bridge including strain gages attached on the leaf spring which is deformed in accordance with the inclination of the surfaces to be measured, whereby the step difference and the inclination angle difference can be obtained only by simple calibration using calibration data set having calibrated step differences and inclination angle differences corresponding to output bridge voltages stored in the manufacturing process without requiring a complex signal processing.

[90] Also, the present invention provides an apparatus which enables to simply set the zero-referenced state of the apparatus without using a separate reference plate for zero- set up.

[91]

Brief Description of the Drawings

[92] Accordingly, the present invention will be understood best through consideration of, and reference to, the following Figures, viewed in conjunction with the Detailed Description of the Preferred Embodiment referring thereto, in which like reference numbers throughout the various Figures designate like stricture and in which:

[93] Figs. 1 and 2 are schematic views illustrating a conventional apparatus for measuring straightness.

[94] Fig. 3 is a graph for tolerance guide of shaft alignment

[95] Fig. 4 is a graph for life of rotating machineries owing to the shaft-misalignment

[96] Figs. 5 to 8 are conventional configurations for the shaft alignment

[97] Figs. 9 and 10 are a measurement principle of an apparatus in accordance with the first embodiment of the present invention. [98] Fig. 11 is a configuration of the arrangement of first strain gages of the apparatus

[99] Fig. 12 is a first wheatston bridge circuit comprised of the first strain gages

[100] Fig. 13 is a configuration of the arrangement of second strain gages of the apparatus [101] Fig. 14 is a second wheatston bridge circuit comprised of the second strain gages [102] Fig. 15 is a schematic side view of the apparatus in Fig. 9 which the apparatus contacts with a first surface and a second surface. [103] Fig. 16 is a schematic view of configuration of a first leaf spring deformed in accordance with the inclination of the first surface when the apparatus contacts with a first surface and a second surface as shown in Fig. 15. [104] Fig. 17 is a schematic view of configuration of a second leaf spring deformed in accordance with the inclination of the second surface when the apparatus contacts with a first surface and a second surface as shown in Fig. 15.

[105] Fig. 18 is a dissembled perspective view of the apparatus in Fig. 15. [106] Fig. 19 is an assembled perspective view of the apparatus in Fig. 15. [107] Fig. 20 is a plane view of Fig. 19. [108] Fig. 21 is a side view of Fig. 19.

[109] Fig. 22 is a cross-sectional view from cut line A-A in Fig. 20. [110] Fig. 23 is a cross-sectional view from cut line B-B in Fig. 20. [I l l] Fig. 24 is a cross-sectional view from cut line C-C in Fig. 21. [112] Fig. 25 is a cross-sectional view from cut line D-D in Fig. 21. [113] Fig. 26 is a cross-sectional view from cut line E-E in Fig. 21. [114] Fig. 27 is a perspective view of the first contacting member and the first measuring means in Fig. 18.

[115] Fig. 28 is a front view of Fig. 27. [116] Fig. 29 is a perspective configuration of rotational shaft installed at the rotational center of the first contacting member in Fig. 27. [117] Fig. 30 is a side view of the first center shaft of Fig. 29. [118] Fig. 31 is a longitudinal cross-sectional view of Fig. 29. [119] Fig. 32 is a perspective view of the first contacting member of Fig. 18 which is turned over.

[120] Fig. 33 is a dissembled perspective view of Fig. 32 [121] Fig. 34 is a cross-sectional view from cut line F-F in Fig. 32. [122] Fig. 35 is a dissembled perspective view of zero- set member of Fig. 18. [123] Fig. 36 is a back view of the first contacting member and the zero-set member between which an inconstant gap occurs due to the thermal expansion. [124] Fig. 37 is a perspective view of an adherence assistance unit of Fig. 18.

[125] Fig. 38 is a dissembled perspective view of Fig. 37.

[126] Fig. 39 is a perspective view of an apparatus which has different type of contact mechanism compared with the apparatus of Fig. 9 [127] Fig. 40 is a configuration of measurement between a transversely rounded first surface and a transversely rounded second shaft using the apparatus of Fig. 39. [128] Fig. 41 is a configuration of measurement using an adapter using the apparatus of

Fig. 39.

[129] Fig. 42 is a configuration of the adapter of Fig. 41. [130] Fig. 43 is a perspective view of installation of the apparatus of Fig 41 in three positions around the shafts. [131] Fig. 44 is a side view of Fig. 43. [132] Fig. 45 is a front view of Fig. 41. [133] Fig. 46 is a front view of indication unit of Fig. 41. [134] Fig. 47 is a schematic diagram of measuring the flatness degree using the apparatus of Fig. 18. [135] Fig. 48 is a third wheatston bridge for obtaining the inclination angle difference between the first surface and the second surface. [136] Fig. 49 is a third wheatston bridge for obtaining the step difference between the first surface and the second surface. [137] Fig. 50 is a configuration of the zero-set member in accordance with other embodiment of the present invention. [138] Fig. 51 is a configuration of the zero-set member in accordance with another embodiment of the present invention. [139]

Best Mode for Carrying Out the Invention [140] Hereinafter, the apparatus for measuring a step difference and an inclination angle difference, or straightness or flatness between a first surface and a second surface to be measured in accordance with a first embodiment of the present invention will be explained in detail in conjunction with the accompanying drawings. In describing the present invention, detailed description of laid-out function or stricture is omitted in order to clarify the gist of the present invention. [141] Figs 9 to 40 are the configuration and the operational principle of the apparatus in accordance with a first embodiment of the present invention. As shown in the figures, the apparatus 100 in accordance with a first embodiment of the present invention obtains a step difference Δd and a inclination angle difference Θ1+Θ2 (the direction of the angle is referred to Fig. 15), or straightness or flatness between a first surface and a second surface to be measured by letting two contacting members 110, 110' on the first surface 20 and the second surface 30 at two locations so that the contacting members 110, 110' rotates centering around their rotational shafts 115, 115' in accordance with the inclination of the surfaces 20, 30, and by measuring the rotational angles Θl, Θ2 of the contacting members 110, 110'.

[142] More concretely, as shown in Figs 18 to 40, the apparatus 110 comprises a pair of contacting members 110, 110' which rotate respectively in accordance with the inclination angles, a case for rotatably supporting the contacting members 110, 110' and form the exterior of the apparatus 100, a pair of leaf springs 130, 130' which are deformed by the rotation of the contacting members 110, 110' so as to measure the rotational angles Θl, Θ2 of the contacting members 110, 110', a pair of zero-set members 140, 140' which are rotatably fixed to the case 120 and let the contacting members 110, 110' be arrayed to the predetermined posture by the contact therewith, an adherence assisting unit 150 installed in the case 120 for assisting the apparatus 100 to be closely adhered towards the surfaces 20, 30 or to be separated from the surfaces 20, 30, strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e attached on both the inner surface and the outer surface of the pair of leaf springs 130,130' where are apart from the center part of the leaf springs 130, 130' and are also apart from the end of the leaf springs 130, 130', and a indication unit 160 for indicating the step difference Δd and the inclination angle difference Θ1+Θ2 between the surfaces 20, 30 which are obtained from the resistance changes of the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e.

[143] The contacting members 110, 110' includes a first contacting member 110 which contacts on the first surface 20 and a second contacting member 110' which contacts on the second surface 30. Therefore, the leaf springs 130, 130' also include a first leaf spring 130 used for measuring the first rotational angle Θl of the first contacting member 110 and a second leaf spring 130' used for measuring the second rotational angle Θ2 of the second contacting member 110. Further, the zero-set members 140, 140' also include a first zero-set member 140 used for letting the first contacting member 110 be the predetermined posture for zero-reference set and a second zero-set member 140' used for letting the second contacting member 110' be the predetermined posture for zero-reference set.

[144] Herein, the components 110, 130, 140 for measuring the first rotational angle Θl are the same or similar to those 110', 130', 140' for measuring the second rotational angle Θ2, except the arrangement and the number of contact balls 117, 117' of the first contacting member 110 and the second contacting member 110'. Therefore, the components relating to measurement of the second rotational angle Θ2 sirh as the second leaf springs 130' are endowed as their drawing numbers as having I 'J compared with the drawing numbers of those relating to measurement of the first rotational angle Θ2, and hereinafter, in order to clarify the gist of the present invention, the detailed explanation of the components relating to measurement of the second rotational angle Θ2 is omitted.

[145] Referring to Fig. 27, the first contacting member 110 includes a first contacting body 111 having a pair of concaved parts I l ia for fixing the first leaf springs 130' , two zero-contact balls 112, 113 on the top surface of the first contacting body 111 so as to be contacted at two consistent points with one surface of the first zero-set member 140, a pair of fixing bolts 114 for fixing one end of the first leaf springs 130 to the concaved parts I l ia respectively so that the first leaf springs 130 are deformed in proportion to the rotational angle Θl of the first contacting body 111, a first rotational shaft 115 for being a rotational center of the first contacting body 111, a center shaft bolt 116 formed of a headless bolt for fixing a first center shaft 115b in the first contacting body 111 by pressing the outer surface of the first center shaft 115b, and three of first contact balls 117 distributed triangularly apart from one another beneath the first contacting body 111 so that the first contacting member contacts with the first surface 20 at three points. Herein, both of the first zero-contact balls 112, 113 are arrayed at one side from rotational center 140a of the zero-set member 140, and the first zero- contact balls 112, 113 are arrayed apart from the rotational center 115 of the first contacting member 110 in the different direction each other.

[146]

[147] Herein, the first zero-contact balls 112, 113 assist that the first contacting body 111 can contact with first zero-set member 140 at the predetermined two points so as to set the first contacting member to the consistent predetermined zero-reference posture. Herein, as the thermal expansion characteristics of the first contacting member 110, case 120 and the first zero-set member 140 made of different material are different with one another, when the case 120 is expanded or contracted by the temperature change, the zero-reference posture of the first contacting member 110 where the first zero-set contact balls 112, 113 contact with the first zero-set member 140 moves from the predetermined zero-reference posture, thereby causing a problem that the first contacting member 110 is set at wrong posture rotated from the predetermined zero- reference posture.

[148] Therefore, it is necessary to correct the movement of the first zero-set member 140 due to the thermal expansion or contract by making the first zero-contact balls 112, 113 vertically move in accordance with the expansion or contract of the case 120. In case that the temperature rises, as the first zero-set member 140 moves away from the first contacting member 110 due to the thermal expansion of the case 120 which generally made of aluminum having a high thermal expansion characteristics, as shown in Fig. 36 the gap between the zero-contact ball 112 located in an inner side 66a of the apparatus 100 in the longitudinal direction and the first zero-set member 140 becomes wider that the gap between the zero-contact ball 113 located outer side 66b thereof and the first zero-set member 140. Therefore, in order to compensate the thermal displacement of the case 120 by the protruded length of the first zero-contact balls 112, 113, first thermal expansion members 112a, 113a are insertedly held in the first contacting member 110 respectively below each of the pair of the first zero- contact balls 112, 113. Specifically, the one 112a of the first thermal expansion members is formed as having high thermal expansion characteristics (e.g., made of aluminum and formed as long), and is located below the first inner zero-contact ball 112 at the nearer to the center of the apparatus in the longitudinal direction. Also, the other one 113a of the first thermal expansion members is formed as having low thermal expansion characteristics (e.g., made of stainless and formed as short), and is located below the first outer zero-contact ball 113 at the farther from the center of the apparatus.

[149] From this constriction, in proportion to the upward movement of the rotational center 140a of the zero-set member 140 due to the thermal expansion of the case 120, the one first zero-contact ball 112 at the inner side 66a of the first zero-contact balls becomes more protruded by the thermal expansion of the one first thermal expansion member 112a, and the other first zero-contact ball 113 at the outer side 66b of the first zero-contact balls becomes less protruded by the thermal expansion of the other first thermal expansion member 113a, whereby the first contacting member 110 can be positioned at the predetermined constant zero-reference set posture for the zero- reference set procedure by the protrudable zero-contact balls in spite of the movement of the rotational center 140a of the first zero-set member 140.

[150] Herein, as described above, the zero-contact balls 112, 113 and the thermal expansion members 112a, 113a may be on a top surface of the first contacting member 110, as shown in Fig. 50, zero-contact balls 242, 243 and the thermal expansion members may be on the bottom surface of the zero-set member 240 whereby the same or similar operational effect can be achieved. When the first contacting member 110 is restricted at the predetermined zero-reference set posture by two point contacts with the zero-contact balls 112, 113, 242, 243, it is desirable to array the zero-contact balls 112, 113, 242, 243 on the same surface to be the opposite side each other with respect to the rotational center 115, 315' so that any rotational moment cannot be exerted on the first contacting member 110.

[151]

[152] As shown in Figs. 29 to 31, the rotational shaft 115 includes a first center shaft 115b which is inserted in the transverse direction at the rotating center of the first contacting member 110, a pair of first supporting shafts 115a, 115c screwed and fixed with parallel to the first center shaft 115a in the case 120 so that each one end of the first supporting shafts 115a, 115c faces and presses the both ends of the first center shaft 115a by adjusting the screw fastening between the female screw hole of the case 120 and male screws on their outer surfaces, two of three first self-aligning small balls 115d accommodated in the retainer at both ends of the first center shaft 115a respectively, and two of one first self- aligning center ball 115e installed at each one end of the first supporting shafts 115b, 115c. Herein, each of the first self-aligning center balls 115e pressedly contacts with three of the first self- aligning small balls 115d simultaneously at three point by adjusting the screw fastening of the first supporting shafts 115b, 115c with respect to the case 120.

[153] Therefore, although there becomes a clearance between the female screw of the case 120 and the male screw on the outer surface of the first supporting shaft 115b, 115c, as the one first self- aligning center ball 115e is maintained to be contacted with the three self-aligning small balls 115d at three points and to be simultaneously pressed to the three self- aligning small balls 115d, the rotational center of the rotational shaft 115 is always automatically self- aligned. Thus, any clearance during the minute rotation of the first contacting member 110 is fundamentally removed, and the friction resistance thereof is also minimized thereby enabling the precise and minute measurement. To this end, it is desirable that the first center shaft 115a is inserted into the first contacting member 110 by a clearance fit instead of an interference fit. Further, the first self- aligning small balls 115d and the first self- aligning center ball 115e are made of ceramics whereby the relative motions thereof are induced to do rolling motion with one another and thus the friction therebetween is minimized.

[154] [155] As shown in Fig. 18, three contact balls 117 on the bottom surface of the first contacting member 110 are distributed triangularly apart from one another in order to get in contact with the first surface 20, and two contact balls 117' on the bottom surface of the second contacting member 110' are distributed longitudinally apart from each other in order to get in contact with the second surface 30. From this constriction, in case that the transverse roundness of the first surface 20 is negligible with respect to the second surface 30, for example in the case that the first surface 20 and the second surface 30 are flat surfaces with a step difference with each other or that at least one of the first surface 20 or the second surface 30 is only longitudinally inclined, although the second surface 20 is not perfectly flat, the first contacting member 110 and the second contacting member 110' can stably and steadily adhere to the surfaces 20, 30 by that the first contacting member 110 stably contacts with the first surface 20 at three points.

[156] On the other hand, as shown in Fig. 40, in case that the first surface 20 and the second surface 30 are rounded surfaces in the transverse direction sich as a shaft alignment, as shown in Fig. 39, the first contacting member 110 includes four contact balls 217 which are rectangularly distributed on the bottom surface of the first contacting member 110 in order to get in contact with the first surface 110 at four positions, and the second contacting member 110' includes two contact rollers 217' which are longitudinally apart distributed are arrayed in the transverse direction on the bottom surface of the second contacting member 110' to be contacted with the second surface 30 at two positions. From this constriction, the first contacting member 110 is maintained to be stably and steadily contacted with the first surface 20 having a round in transverse direction at four points, and thus the contact rollers 217' can also stably and reliably contact with the second surface 30.

[157]

[158] The case 120 rotatably supporting the contacting members 110, 110' which center around the rotational shafts 115, 115' includes a fixing block 121 integrally fixed to the case 120 by fixing screw 12 Ix for playing a role of stopper for limiting the rotational angle of the contacting members 110, 110' so that the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e and the leaf springs 130, 130' may not be deformed over their elastic range, and a fixing plate 123 for fixing each one end of the leaf springs 130, 130' at the upper part of the fixing block 121 by fixing screw 123a. That is, as each one end of the leaf springs 130, 130' is fixed to the contacting member 110, 110' and the other each end of the leaf springs 130, 130' is fixed to the case 120 via the fixing block 121, the leaf springs 130, 131 are deformed by the rotational displacement of the contacting members 110, 110'.

[159]

[160] The first leaf springs 130 are formed of a pair for each contacting members 110, 110' and are used for measuring the rotational angles Θl, Θ2 of the contacting members 110, 110'. The first leaf springs 130 is configured as same and operated as same to the second leaf springs 130', and thus, hereinafter, explanations will be done only for the first leaf springs 130'.

[161] As shown in Fig. 27 and Fig. 28, the first leaf springs 130 are formed of a pair including a 1-1 leaf spring 131 and a 1-2 leaf spring 132, each of which one end is fixed to the fixing block 121 by the fixing plate 123 and each of which the other end is fixed to the longitudinal both sides of the first contacting body 111 by fixing bolts 114. The 1-1 leaf spring 131 and the 1-2 leaf spring 132 are formed and arrayed bisym- metrically to the rotational shaft 115 of the first contacting member 110.

[162] Referring to Fig. 16 for explaining the 1-1 leaf spring in detail as one of the first leaf springs 130, the 1-1 leaf spring 131 is partitioned to four partitioned areas A, B, C, D partitioned by a plurality of three bending portions which includes a 1-1 area A from the drawing number 1 to the drawing number 2 having the one end fixed to the first contacting member 110, a 1-4 area D from the drawing number 4 to the drawing number 5 having the one part fixed to the case 120 and parallel with the 1-1 area A, a first inclined area B from the drawing number 2 to the drawing number 3 where the part RIi, RIe of the first strain gages RIi, RIe, R2i, R2e are attached, a 1-3 area C from the drawing number 3 to the drawing number 4 which vertically connects the first inclined area B with the 1-4 area D. The inclined area B is the area where the moment by a horizontal force Fh and the moment by a vertical force Fv applying to the 1-1 leaf spring 131 are offset each other, and thus the moment by external forces becomes constant, thereby obtaining high sensitivity and stable signal from the strain gages RIi, RIe attached on the inclined area B.

[163] Herein, the inclination of the inclined area B is determined by one the inclination of an imaginary line 77 between the one 1 end and the other end 5 of the 1-1 leaf spring 131.

[164]

[165] The strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e having all the same resistances are attached on the inner surface and the outer surface of the inclined area B of each leaf spring 131, 132, 131', 132', and the terminals T for fixing signal wires of the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e are fixed on the 1-1 area A or other place.

[166] As shown in Fig. 12, the first strain gage RIe attached on the outer surface of the 1-1 leaf spring 131 faces the first strain gage R2i attached on the inner surface of the 1-2 leaf spring 132, and the first strain gage RIi attached on the inner surface of the 1-1 leaf spring 131 faces the first strain gage R2e attached on the outer surface of the 1-2 leaf spring 132 thereby constituting a first wheats ton bridge. Similarly, As shown in Fig. 14, the second strain gage R3e attached on the outer surface of the 2-1 leaf spring 131' faces the second strain gage R4i attached on the inner surface of the 2-2 leaf spring 132', and the second strain gage R3i attached on the inner surface of the 2-1 leaf spring 132 faces the second strain gage R4e attached on the outer surface of the 2-2 leaf spring 132' thereby constituting a second wheatston bridge.

[167] As shown in Fig. 16 and Fig. 17, the leaf springs 130, 130' and the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e facing each other in the wheatston bridges are elongated together or contracted together in accordance with the rotation of the contacting members 110, 110'. That is, the resistances of the strain gages facing each other in the wheatston bridges vary as having the same sign. Also, as all the strain gages are apart by the same distance from the rotational center of the contacting member 110, 110', and as the leaf springs 130, 130' are formed and arrayed as bisymmetric with respect to the rotational center of the contacting member 110, 110', the absolute variation of the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e become all the same. Further, although the components formed of different material of the apparatus 100 are thermally expanded, and/or although external impacts are applied to the apparatus 100 in the vertical direction from the to-be-measured surfaces 20, 30, as the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e are arrayed bisym- metrically with respect to the rotational center 115, 115' of the contacting members 110, 110', and thus the deformation due to the thermal expansion or vertical impact thereon becomes theoretically the same to the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e and the leaf springs 130, 130', the errors therefrom are offset with one another. Most of all, although a minute distortion may occur at a rotational center of the contacting members 110, 110', as the minute distortion may influence on the pair of leaf springs by the same degree, this kind of distortion is also automatically compensated.

[168] As shown in Fig. 16, when the first contacting member 110 rotates by the angle Θl, each of the first strain gages having initial resistance of R which is attached on the elongated surface gains k*Θl and thus comes to have its resistance of R+k*Θl, while each of the first strain gages having initial resistance of R which is attached on the contracted surface loses k*Θl, and thus comes to have its resistance of R-k*Θl. Similarly, as shown in Fig. 17, when the second contacting member 110' rotates by the angle Θ2, each of the second strain gages having initial resistance of R which is attached on the elongated surface gains k*Θ2 and thus comes to have its resistance of R+k*Θ2, while each of the second strain gages having initial resistance of R which is attached on the contracted surface loses k*Θ2 and thus

[1Φ] comes to have its resistance of R-k*Θ2. Herein, the k is a constant which varies in accordance with the gage factor and the elastic coefficient of the leaf springs 130, 130' due to their material and configurations.

[170] Therefore, when the contacting members 110, 110' rotate by rotational angles Θl, Θ2 respectively, the strain gages attached on the leaf springs 130, 130' have their resistance as shown in the following table

[171] Table 1 [Table 1] [Table ]

[172] Therefore, the bridge voltage ΔV1 of the first wheatston bridge of Fig. 12 is obtained as following equation.

[173] ΔV1 = (Rle*E)/(Rle+Rli)-(R2e*E)/(R2i+R2e) [174] If the resistances of the strain gages in Table 1 are substituted to the above equation, the bridge voltage ΔV1 of the first wheatston bridge of Fig. 12 is obtained as following equation 2. [175] Equation 2

[176] ΔVl=(E*k* Θl)/R

[177] Namely, the bridge voltage ΔV1 is proportional to the rotational angle Θl (i.e., the inclination of the first surface 20) of the first contacting member 110. Herein, E is the input voltage to the first wheatston bridge of Fig. 12, R is the initial resistance of the strain gages RIi, RIe, R2i, R2e, and k is a constant which varies in accordance with the gage factor and the elastic coefficient of the leaf springs 130 due to their material and configurations. Thus, only measuring the bridge voltage ΔV1 of the first wheatston bridge and then calibrating the bridge voltage ΔV1 with a calibration data set stored in the manufacturing step can make it obtain the first rotational angle Θl without requiring a complex signal processing control unit or an operational control circuit.

[178]

[179] Similarly, the bridge voltage ΔV2 of the second wheatston bridge of Fig. 14 is obtained as following equation.

[ 180] ΔV2 = (R4e*E)/(R4e+R4i)-(R3e*E)/(R3i+R3e)

[181] If the resistance of the strain gages in Table 1 is substituted to the above equation, the bridge voltage ΔV2 of the second wheatston bridge of Fig. 14 is obtained as following equation 3.

[182] Equation 3

[183] ΔV2=(E*k* Θ2)/R

[184] Also, the bridge voltage ΔV2 is proportional to the rotational angle Θ2 (i.e., the inclination of the second surface 30) of the second contacting member 110'. Herein, E is the input voltage to the second wheatston bridge of Fig. 14, R is the initial resistance of the strain gages R3i, R3e, R4i, R4e, and k is a constant which varies in accordance with the gage factor and the elastic coefficient of the leaf springs 130' due to their material and configurations. Thus, only measuring the bridge voltage ΔV2 of the second wheatston bridge and then calibrating the bridge voltage ΔV2 with a calibration data set stored in the manufacturing step can make obtain the second rotational angle Θ2 without requiring a complex signal processing control unit or an operational control circuit.

[185] Also, the inclination angle difference ΔΘ between the first surface 20 and the third surface 30 can be easily obtained by the equation ΔΘ = Θ1+ Θ2 from the measured each rotational angles Θl, Θ2, while the step difference Δd therebetween also can be obtained by the equation 1. [186]

[187] As illustrated by Fig. 35, the first zero-set member 140 is rotatably supported by a rotational shaft 145. When one surface 140b, 140c of the first zero-set member 140 contacts with the zero-oontact balls 112, 113, the rotations of both the first contacting member 110 and the first zero-set member 140 are simultaneously restricted each other where the first contacting member is positioned at the predetermined zero-reference set posture. In the zero-reference set posture, by turning on the power of the apparatus 100, the zero-reference set procedure can be completed without any separate flat plate.

[188] Herein, as the first zero-set member 140 is pushed to rotate with consistent force by the first pressing spring 142 and to contact with the first contacting member 110, the more precise zero-reference set procedure is achieved than the case that users directly handle for the zero-reference set procedure. Thereafter, by releasing the restricted state of the contacting members 110, 110' from the zero-set members 140, 140', and by contacting the contacting members 110, 110' on the surfaces 20, 30 and then by measuring the inclination angles Θl, Θ2, the step difference Δd, the inclination angle difference ΔΘ, and straightness or flatness between the surfaces 20, 30 can be obtained.

[189] Also, the rotational shaft 145 is constituted by the same to the rotational shaft 115 of the contacting members 110, and thus, the first zero-set member 140 is also precisely and softly rotated to enable the precise zero-set reference set procedure.

[190] Moreover, contact plates 140b, 140c made of ceramics or reinforced glass having a precisely finishing surface are attached on the bottom surface of the first zero-set member 140. Accordingly, it is possible to manufacture the first- zero set member 140 with an enough margin in its dimensions, and also to precisely set zero-reference of the apparatus 100.

[191] Herein, the contact surfaces of the first zero-set member 140 and the first contacting member 110 meet at two points, and as shown in Fig. 22 are apart away from the rotational shaft 115 in the opposite direction, thereby effectively restricting the rotation of the first contacting member 110.

[192] As illustrated in Fig. 51, a V-groove may be formed on the bottom surface of zero-set members 340' for accommodating a zero-contact ball 312 on the top surface of the contacting members 310', whereby the contacting members 310' meets the zero- set me mbers 340' at two points and thus the posture of the contacting members 310' can be restricted. In this case, in that the V-groove is located right up to the rotational center 315', the posture of the contacting members 310' becomes also restricted by contacting with the zero-set member 340a at two points which are apart from the rotational center 315' in the opposite direction and by pressing the zero-set member 340' by a pressing spring 342'. Although it is not shown in figures, it would be possible to assist the zero-reference set procedure by installing another zero-contact ball having a hemi-sphere surface at a third position.

[193]

[194] As shown in Figs 18, 37 and 38, the adherence assisting unit 150 includes a moving body 151 formed of a permanent magnet or formed as having a permanent magnet so that the apparatus 100 can be closely adhered to the surfaces 20, 30 usually made of steel, a handle shaft 152 rotatably supported by the case 120 with penetrating the moving body 151 and having a knob 152a at one end extended to the outside, a pair of cams 153 integrally combined with the handle shaft 152, a plate 164 combined to the top surface of the moving body 151 with being located above the cams 153.

[195] From this constriction, as the handle shaft 152 rotates, the cams 153 integrally rotating with the handle shaft 152 pushes the moving body 151 upwards or pulls the moving body 151 downwards whereby the magnetic of the moving body 151 moves away from the surfaces 20, 30 or approaches to the surfaces 20, 30, and thus, the apparatus 100 can be stably and closely adhere to the surfaces 20, 30 or can be separated from the surfaces 20, 30. Further, in order to easily adhere to or separate from the surfaces 20, 30, the distance between the magnetic and the surfaces 20, 30 of the object(s) may be controlled by adjusting the knob 152a.

[196] Meanwhile, the plate 164 of the adherence assisting unit 150 moves upwards or downwards in accordance with the rotation of the handle shaft 152. Herein, when the plate 164 moves upwards, the zero-set members 140, 140' come to freely rotate and thus the zero-set members 140, 140' contact with the contacting members 110, 110' by the pressing spring 142 to make the contacting members 110, 110' positioned at the predetermined zero-reference set posture. To the contrary, when the plate 164 moves downwards, the plate 164 pushes the part of the zero-set members 140, 140' and thus to make the contacting members 110, 110' released from the predetermined zero- reference set posture.

[197] As illustrated by Fig. 46, the indication unit 160 includes a casing 161 for accommodating circuits having wheatston bridges, an angle indication part 162 for indicating a measured inclination angle difference, an step indication part 163 for indicating a measured step difference, and a power supply cable or battery 164 for supplying input voltage E, E' to the wheatston bridges. [198]

[199] As shown in Fig. 20, the arrangement of the first zero-set member 140 and the first contacting member 110 is reversed in the transverse direction to that of the second zero-set member 140' and the second contacting member 110', whereby the configurations of the zero-set members 140, 140' and the contacting members 110, 110' are exactly same instead of being formed bisymmetrically. Thus, it can be possible to manufacture and manage the first components and the second components as same ones. Further, as the plate 164 of the adherence assisting unit 150 diagonally contacts with each of the zero-set members 140, 140', it can be prevented for the plate 164 to be biasedly lifted.

[200] On the other hand, only with the apparatus 100, the step difference and the inclination angle difference of rails or precise assemblies can be measured. However, in measuring the objects having rounded surface sirh as shafts, it is convenient to use an adaptor 190 shown in Fig. 42 for assisting the adherence to the surfaces 20, 30. The adaptor 190 is precisely corrected to combine a contact member 192 to be adhered to the surfaces 20, 30 with a combining plate 191 to be fixed to the contacting members 110, 110'.

[201]

[202] Hereinafter, a process of aligning shafts using the apparatus 100 in accordance with the first embodiment of the present invention is explained.

[203] Fig. 41 shows a configuration that the apparatus 100 is installed on the surfaces 20a, 30a of shafts 20, 30 to measure the step difference Δd and the inclination angle difference ΔΘ therebetween. Like this way, as shown in Figs. 43 and 44, three apparatuses 100 are installed on the surfaces 20a, 30a in the vertical direction, in the horizontal direction and in the diagonal direction. This installation, in case that the diameter of shafts 20, 30 are different each other, can remove the problem that shaft misalignment may occur when the step differences Δd in the horizontal direction and in the vertical direction becomes all zero. That is, from this installation, a complete shaft alignment can be achieved in case that the diameter of shafts 20, 30 may differ each other.

[204] Also, as the indication unit 160 shows the step difference and the inclination angle difference therebetween, an operator can easily catch errors of shaft alignment by intuition and more promptly finish the alignment. Further, different from the conventional shaft alignment, as an operator recognizes from the indication unit 160 the errors of shaft alignment right after adjustment without rotating the shafts 20, 30, it becomes mtch easier to align shafts.

[205]

[206] Another method of the shaft alignment may be used by means of the apparatus 100. That is, in condition that the only first contacting member 110 is contacted with the first surface 20a and that the first shaft 20 is combined with the second shaft 30 with a coupling, the changes of the step differences and the inclination angle differences can be obtained by rotating the shafts 20, 30. Compared with the conventional method using dial gages, which show only step differences and the inclination angle differences should be inferred from at least two dial gages, the method of the present invention uses the separate information of the step differences in addition to the inclination angle difference by the apparatus 100 whereby a layman can do the shaft alignment successfully.

[207]

[208] Meanwhile, as shown in Fig. 34, when the contacting members 110, 110' are installed to be contacted on the rounded surface 97, the straightness or the roundness of the surface 97 can be obtained by the following equation 4.

[209] Equation 4

[210] Curvature = pitch of apparatus / sinβ

[211]

[212] From the equation 4, the straightness or the roundness or the flatness may be measured using the apparatus 100.

[213]

Mode for the Invention

[214] Hereinafter, the apparatus in accordance with a second embodiment of the present invention is explained.

[215] The apparatus of the second embodiment of the present invention has the same configurations except the wheats ton bridges (i.e., the connection method of strain gages) and measuring principle therefrom. In order that the apparatus is to be manufactured cheaper or constricted by analog sensors, the step differences and the inclination angle difference therebetween can be obtained by crossing the connection of the stain gages to constitute wheatston bridges. Herein, like the predescribed first embodiment, all the strain gages attached on the leaf springs 130, 130' are as shown in Fig. 9.

[216] The first strain gages RIe, RIi, R2e, R2i attached on the first leaf springs 130 contain the information of the rotational angle Θl of the first contacting member 110, while the second strain gages R3e, R3i, R4e, R4i attached on the second leaf springs 130' contain the information of the rotational angle Θ2 of the second contacting member 110. [217] When the contacting members 110, 110' contact on the surfaces 20, 30, the resistance of the strain gages varies as a following table 2. [218] Table 2

[Table 2]

[Table ]

[219] Herein, ΔR12 is the resistance variation of the first strain gages RIe, RIi, R2e, R2i attached on the first leaf spring 130, and ΔR34 is the resistance variation of the second strain gages R3e, R3i, R4e, R4i attached on the second leaf spring 130'. Also, the absolute value of ΔR12 is proportional to the rotational angle Θl of the first contacting member 110, and the absolute value of ΔR34 is proportional to the rotational angle Θ2 of the second contacting member 110'. Accordingly, Table 2 can be rewritten as following table 3.

[220] Table 3

[Table 3] [Table ]

[221] Herein, R is the initial resistance of the strain gages RIi, RIe, R2i, R2e, R3i, R3e, R4i, R4e, and k is a constant which varies in accordance with the gage factor and the elastic coefficient of the leaf springs 130, 130' due to their material and configurations.

[222] The electric current i2 from R2e to R2i in the third wheatston bridge of Fig. 48 and the electric current i3 from R3i to R3e are obtained as the following equation 5.

[223] [224] Equation 5 [225] 12 =E/(R2i+R2e) [226] 13 =E/(R3e+R3i) [227] Herein, E is the input voltage to the second wheatston bridge. Therefore, the bridge voltage ΔV3 of the third wheatston bridge is induced as following equation 6.

[228] [229] Equation 6 [230] ΔV3 = [ R2i/(R2i+R2e) - R3e/(R3e+R3i) ] *E [231] thus, ΔV3 = [(ΔR12+ΔR34) /2R] *E [232] If ΔR12 of the equation 6 is substituted by k'* Θl and if ΔR34 of the equation 6 is substituted by k' * Θ2, then the following equation 7 is established.

[233] [234] Equation 7 [235] ΔV3 = k'*( Θl + Θ2)/R [236] [237] That is, the bridge voltage ΔV3 of the third wheatston bridge of Fig. 48 outputs the signal proportion to the inclination angle difference ΔΘ.

[238]

[239] In the similar way, the fourth wheatston bridge is constituted by that the first strain gage RIe attached on the outer surface of the first leaf spring 131 faces the second strain gage R4i attached on the inner surface of the second leaf spring 132', while the first strain gage RIi attached on the inner surface of the first leaf spring 131 faces the second strain gage R4e attached on the outer surface of the second leaf spring 132'. The bridge voltage ΔV4 of the fourth wheatston bridge of Fig. 49 is expressed as following equation 8.

[240]

[241] Equation 8

[242] ΔV4 = [ Rli/(Rli+Rle) - R4i/(R4e+R4i) ] *E

[243] If the resistance of the strain gages in Table 3 is substituted to the above equation 8, the bridge voltage ΔV4 of the fourth wheatston bridge of Fig. 49 is obtained as following equation 9.

[244]

[245] Equation 9

[246] ΔV4 = k'*(Θ2-Θl)/R

[247] Namely, the bridge voltage ΔV4 of the fourth wheatston bridge is proportional to the step difference Δd between the first surface 20 and the second surface 30.

[248]

[249] The above wheatston bridge constrictions in accordance with the first embodiment of the present invention can directly output the signals on the step difference or the inclination angle difference between the surfaces 20, 30 only by simple amplification of the bridge voltages without any processing unit sirh as a CPU, and thus, it is very useful to apply to a cheap measurement apparatus or an analog sensor or to apply the case which needs only one of the step difference or the inclination angle difference therebetween.

[250] Further, the reversion of connection between +V and -V (i.e., bridge voltage) may change the signs of the output of step difference, etc.

[251]

Industrial Applicability

[252] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of sirh metes and bounds are therefore intended to be embraced by the appended claims.

Claims

[1] A measuring apparatus which comprises: a first contacting member installed for being capable of rotating in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being capable of rotating in accordance with the inclination of a second surface of the other object to be measured on which the second contacting member contacts; a case for rotatably supporting the first contacting member and the second contacting member; a first measuring means for measuring a first rotational angle between the first contacting member and the case when the first contacting member contacts on the first surface; and a second measuring means for measuring a second rotational angle between the second contacting member and the case when the second contacting member contacts on the second surface; wherein the measuring apparatus measures at least one of a step difference between the first surface and the second surface, an inclination angle difference between the first surface and the second surface, and straightness between the first surface and the second surface from the first rotational angle and the second rotational angle.

[2] The apparatus as claimed in claim 1, further comprises: a first center shaft which is penetratedly located at the rotating center of the first contacting member; a pair of first supporting shafts which are fixed in the case, wherein inner one end surface of the each first supporting shaft in the transverse direction respectively faces one of both end surfaces of the first center shaft; two of three first self-aligning small balls accommodated at either one end of the first center shaft or inner end of one of the first supporting shafts in the transverse direction, and at either the other one end of the first center shaft or inner end of the other first supporting shafts in the transverse direction; and two of one first self-aligning center ball installed at either one end of the first center shaft or inner end of one of the first supporting shafts in the transverse direction, and at either the other one end of the first center shaft or inner end of the other first supporting shafts in the transverse direction, so that each of the first self-aligning center balls contacts with the three of the first self-aligning small balls simultaneously at three point.

[3] The apparatus as claimed in claim 2, further comprises: a second center shaft which is penetratedly located at the rotating center of the second contacting member; a pair of second supporting shafts which are fixed in the case, wherein inner one end surface of the each first supporting shaft in the transverse direction respectively faces one of both end surfaces of the second center shaft; two of three second self-aligning small balls accommodated at either one end of the second center shaft or inner end of one of the second supporting shafts in the transverse direction, and at either the other one end of the second center shaft or inner end of the other second supporting shafts in the transverse direction; and two of one second self-aligning center ball installed at either one end of the second center shaft or inner end of one of the second supporting shafts in the transverse direction, and at either the other one end of the second center shaft or inner end of the other second supporting shafts in the transverse direction, so that each of the second self-aligning center balls contacts with three of the second self-aligning small balls simultaneously at three point.

[4] The apparatus as claimed in claim 3, wherein the second self-aligning small balls, the second self-aligning center ball and the second self-aligning small balls, the second self-aligning center ball are made of ceramics.

[5] The apparatus as claimed in claim 1, wherein the first contacting member includes two contact balls which are longitudinally apart distributed at the first contacting member in order to get in contact with the first surface, and wherein the second contacting member includes three contact balls which are triangularly distributed at the second contacting member in order to get in contact with the second surface.

[6] The apparatus as claimed in claim 1, wherein the first contacting member includes four contact balls which are rectangularly distributed at the first contacting member in order to get in contact with the first surface at four positions, and wherein the second contacting member includes two contact rollers which are longitudinally apart distributed are arrayed in the transverse direction at the second contacting member and in order to get in contact with the second surface.

[7] The apparatus as claimed in one of claims 1 to 6, wherein the first measuring means measures the first rotational angle by discharging a laser to the first contacting member and by receiving the laser reflected from the first contacting member; and wherein the second measuring means measures the second rotational angle by discharging a laser to the second contacting member and by receiving the laser reflected from the second contacting member;

[8] The apparatus as claimed in one of claims 1 to 6, wherein the first measuring means measures the first rotational angle by an encoder; and the second measuring means measures the second rotational angle by an enoorder;

[9] The apparatus as claimed in one of claims 1 to 6, wherein the first measuring means includes at least one first leaf spring of which one part is fixed to the case and of which one end is fixed to the first contacting member, the first leaf spring being deformed by the rotation of the first contacting member; and at least one first strain gage attached on the first leaf spring, the first strain gage having all the same resistance constituting a first wheatston bridge; and wherein the second measuring means includes at least one second leaf spring of which one part is fixed to the case and of which one end is fixed to the second contacting member, the second leaf spring being deformed by the rotation of the second contacting member; and at least one second strain gage attached on the second leaf spring, the second strain gage having all the same resistance constituting a second wheatston bridge; whereby the first rotational angle is obtained by the bride voltage of the first wheatston bridge, and the second rotational angle is obtained by the bride voltage of the second wheatston bridge.

[10] The apparatus as claimed of claim 9, wherein the first leaf springs are formed as a pair of first leaf springs, each of which one end is fixed to the first contacting member and the other end is fixed to the case respectively, the pair of first leaf springs being arrayed bisymmetrically to the rotational center with each other; wherein the first strain gages are formed as plural, of which two first strain gages are attached respectively on both faces of the one of the first leaf springs and of which the other two first strain gages are attached respectively on both faces of the other one of the first leaf spring, and wherein all the first strain gages are located at positions apart by the same distance from the rotational center of the first contacting member; wherein the first wheatston bridge is constricted so that two first strain gages on the elongated surface of the first leaf springs in accordance with the rotation of the first contacting member in one direction face each other, and that the other two first strain gages on the contracted surface of the first leaf springs in accordance with the rotation of the first contacting member in the one direction face each other; wherein the second leaf springs are formed as a pair of second leaf springs, each of which one end is fixed to the second contacting member and the other end is fixed to the case respectively, the pair of second leaf spring beings arrayed bisymmetrically to the rotational center with each other; wherein the second strain gages are formed as plural, of which two second strain gages are attached respectively on both faces of the one of the second leaf springs and of which the other two second strain gages are attached respectively on both faces of the other one of the second leaf spring, and wherein all the second strain gages are located at positions apart by the same distance from the rotational center of the second contacting member; and wherein the second wheatston bridge is constricted so that two second strain gages on the elongated surface of the second leaf springs in accordance with the rotation of the second contacting member in one direction face each other, and that the other two second strain gages on the contracted surface of the second leaf springs in accordance with the rotation of the second contacting member in the one direction face each other.

[11] The apparatus as claimed in claim 10, wherein the first leaf springs are partitioned to a plurality of first partitioned areas including a 1-1 area having the one end fixed to the first contacting member, a 1-4 area having the one part fixed to the case and parallel with the 1-1 area, and a first inclined area on which the first strain gages are attached between the 1-1 area and the 1-4 area, the partitioned area being partitioned by a plurality of bending portions; and wherein the second leaf springs are partitioned to a plurality of second partitioned areas including a 2-1 area having the one end fixed to the second contacting member, a 2-4 area having the one part fixed to the case and parallel with the 2-1 area, and a second inclined area therebetween on which the second strain gages are attached between the 2- 1 area and the 2-4 area, the second partitioned area being partitioned by a plurality of bending portions.

[12] The apparatus as claimed in claim 11, wherein the inclination of the first inclined area is formed to be an inclination of a imaginary line between the one end and the other end of the first leaf spring, and wherein the inclination of the second inclined area is formed to be an inclination of a imaginary line between the one end and the other end of the second leaf spring.

[13] The apparatus as claimed in one of claims 1 to 5, wherein the posture of the first contacting member is restricted at one predetermined position by being contacted with the predetermined at least two locations, thereby setting a zero-reference set position of the first contacting member; and wherein the posture of the second contacting member is restricted at one predetermined position by being contacted with the predetermined at least two locations, thereby setting a zero-reference set position of the second contacting member.

[14] The apparatus as claimed in claim 12, wherein one of the two locations with which the first contacting member contacts is biased to one side from the rotational center of the first contacting member, and the other of the two locations is biased to the other side from the rotational center of the first contacting member; and wherein one of the two locations with which the second contacting member contacts is biased to one side from the rotational center of the second contacting member, and the other of the two locations is biased to the other side from the rotational center of the second contacting member.

[15] The apparatus as claimed in claim 13, further comprising: a first zero-set member rotatably installed in the case for contacting its at least one surface with the first contacting member at said two locations thereby letting the first contacting member be arrayed at the zero-reference set posture; a first pressing spring oompressively installed to be contacted with the first zero- set member for pressing the first zero-set member to rotate and to contact with the first contacting member at predetermined zero-reference set posture; a second zero-set member rotatably installed in the case for contacting its at least one surface with the second contacting member at said two locations thereby letting the second contacting member be arrayed at the zero-reference set post ure; and a second pressing spring compressively installed to be contacted with the second zero-set member for pressing the second zero-set member to rotate and to contact with the second contacting member at predetermined zero-reference set posture.

[16] The apparatus as claimed in claim 15, further comprising: a pair of first zero-contact balls protrudedly formed on one surface of the first contacting member or the first zero- set member so as to contact the other surface of the first zero-set member or the first contacting member, as being apart from the rotational center of the first contacting member in the different direction each other; and a pair of second zero-contact balls protrudedly formed on one surface of the second contacting member or the first zero-set member so as to contact the other surface of the second zero- set member or the second contacting member, as being apart from the rotational center of the second contacting member in the different direction each other; and

[17] The apparatus as claimed in claim 16, wherein first thermal expansion members are insertedly held to be contacted with each of the pair of the first zero-contact balls, the one of the first thermal expansion members located at one of the pair of the first zero-contact balls which is located at the nearer to the center of the apparatus in the longitudinal direction being more deformed in accordance of the temperature change than the other of the first thermal expansion member at the other of the pair of the first zero-contact balls; and, wherein second thermal expansion members are insertedly held to be contacted with each of the pair of the second zero-contact balls, the one of the second thermal expansion members located at one of the pair of the second zero-contact balls which is located at the nearer to the center of the apparatus in the longitudinal direction being more deformed in accordance of the temperature change than the other of the second thermal expansion member at the other of the pair of the second zero-contact balls; whereby the zero-contact ball at nearer to the center of the apparatus is protruded more than the other zero-contact ball farther to the center of the apparatus.

[18] A measuring apparatus which comprises: a case; a first contacting member rotatably installed in the case in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being rotatably installed in the case in accordance with the inclination of a second surface to be measured on which the second contacting member contacts; a pair of first leaf springs of which one part is fixed to the case and of which one end is fixed to the first contacting member, the first leaf spring being deformed by the rotation of the first contacting member; at least one first strain gage attached on the first leaf spring for measuring a first rotational angle between the first contacting member and the case by the deformation of the first leaf spring when the first contacting member contacts on the first surface; at least second first leaf spring of which one part is fixed to the case and of which one end is fixed to the second contacting member, the second leaf spring being deformed by the rotation of the second contacting member; and at least one second strain gage attached on the second leaf spring for measuring a second rotational angle between the second contacting member and the case by the deformation of the second leaf spring when the second contacting member contacts on the second surface; wherein at least one of a step difference between the first surface and the second surface, an inclination angle difference between the first surface and the second surface, and straightness between the first surface and the second surface is measured from the first rotational angle obtained by the deformation of the first strain gage and from the second rotational angle obtained by the deformation of the second strain gage.

[19] The apparatus as claimed in claim 18, wherein the first strain gages are formed as plural, of which two first strain gages are attached respectively on inner face and outer face of the one of the first leaf springs and of which the other two first strain gages are attached respectively on inner face and outer face of the other one of the first leaf spring, and wherein all the first strain gages are located at positions apart by the same distance from the rotational center of the first contacting member; and wherein the second strain gages are formed as plural, of which two second strain gages are attached respectively on inner face and outer face of the one of the second leaf springs and of which the other two second strain gages are attached respectively on inner face and outer face of the other one of the second leaf spring, and wherein all the second strain gages are located at positions apart by the same distance from the rotational center of the second contacting member; and further comprising: a first wheatston bridge constricted so that two first strain gages attached on the elongated surface of the first leaf springs in accordance with the rotation of the first contacting member face each other, and that the other two first strain gages on the contracted surface of the first leaf springs in accordance with the rotation of the first contacting member face each other, whereby the first rotational angle is obtained from the bridge voltage of the first wheatston bridge; and a second wheatston bridge constricted so that two second strain gages attached on the elongated surface of the second leaf springs in accordance with the rotation of the second contacting member in face each other, and that the other two second strain gages on the contracted surface of the second leaf springs in accordance with the rotation of the second contacting member face each other, whereby the second rotational angle is obtained from the bridge voltage of the second wheatston bridge.

[20] The apparatus as claimed of claim 18, wherein the first leaf springs are formed as a pair of first leaf springs, each of which one end is fixed to the first contacting member and the other end is fixed to the case respectively, the pair of first leaf springs being arrayed bisymmetrically with each other; wherein the second leaf springs are formed as a pair of second leaf springs, each of which one end is fixed to the first contacting member and the other end is fixed to the case respectively, the pair of second leaf springs being arrayed bisymmetrically with each other; wherein the first strain gages are formed as plural, of which two first strain gages are attached respectively on the inner face and the outer face of the pair of the first leaf springs, all the first strain gages being located at positions apart by the same distance from the rotational center of the first contacting member and constricting a first wheatston bridge; wherein the second strain gages are formed as plural, of which two second strain gages are attached respectively on the inner face and the outer face of the pair of the second leaf springs, all the second strain gages being located at positions apart by the same distance from the rotational center of the second contacting member and constricting a second wheatston bridge; and wherein the first rotational angle is obtained from the bridge voltage of the first wheats ton bridge, and the second rotational angle is obtained from the bridge voltage of the second wheatston bridge.

[21] A method of aligning a first shaft and a second shaft by measuring a step difference between the first shaft and the second shaft and an inclination angle difference between the first shaft and the second shaft, which comprises: a step of setting a zero-reference set posture of a first contacting member and a second contacting member; a step of placing the first contacting member on the first shaft and so that the first contacting member rotates in accordance of the surface inclination of the first shaft, and of placing the second contacting member on the second shaft and so that the second contacting member rotates in accordance of the surface inclination of the second shaft; a step of measuring a first angle of the first contacting member on the first shaft from the zero-reference set posture of the first contacting member; a step of measuring a second angle of the second contacting member on the second shaft from the zero-reference set posture of the second contacting member; a step of indicating the step difference between the first shaft and the second shaft and the inclination angle difference between the first shaft and the second shaft, which are obtained by the first angle and the second angle; and a step of aligning the first shaft and the second shaft while checking the indicated step difference and the inclination angle difference therebetween.

[22] A measuring apparatus which comprises: a case; a first contacting member rotatably installed in the case in accordance with the inclination of a first surface of an object to be measured on which the first contacting member contacts; a second contacting member apart from the first contacting member in the longitudinal direction installed for being rotatably installed in the case in accordance with the inclination of a second surface to be measured on which the second contacting member contacts; at least one first leaf spring of which one part is fixed to the case and of which at least one end is fixed to the first contacting member, the first leaf spring being deformed by the rotation of the first contacting member; at least one second leaf spring of which one part is fixed to the case and of which at least one end is fixed to the second contacting member, the second leaf spring being deformed by the rotation of the second contacting member; at least one first strain gage attached on the first leaf spring; and at least one second strain gage attached on the second leaf spring; wherein the rotational angle of the first contacting member and the rotation angel of the second contacting member are obtained from a bridge voltage of wheatston bridge of which resistances includes at least one first strain gage and at least one second strain gage, whereby at least one of a step difference between the first surface and the second surface, an inclination angle difference between the first surface and the second surface, and straightness between the first surface and the second surface is measured.

[23] The apparatus as claimed in claim 22, wherein the first strain gages are formed as at least one pair which are attached respectively on inner face and outer face of the first leaf spring, the first strain gages being located between the one part of the first leaf spring and the end fixed to the first contacting member; and wherein the second strain gages are formed as at least one pair which are attached respectively on inner face and outer face of the second leaf spring, the second strain gages being located between the one part of the second leaf spring and the end fixed to the second contacting member; and further comprising: a third wheatston bridge constricted so that at least one first strain gage attached on the contracted surface of the first leaf springs face the other at least one second strain gage on the elongated surface of the second leaf spring and/or that at least one first strain gage attached on the elongated surface of the first leaf springs face the other at least one second strain gage on the contracted surface of the second leaf spring, whereby the inclination angle difference between the first surface and the second surface is obtained from the bridge voltage of the third wheatston bridge.

[24] The apparatus as claimed in claim 22, wherein the first strain gages are formed as at least one pair which are attached respectively on inner face and outer face of the first leaf spring, the first strain gages being located between the one part of the first leaf spring and the end fixed to the first contacting member; and wherein the second strain gages are formed as at least one pair which are attached respectively on inner face and outer face of the second leaf spring, the second strain gages being located between the one part of the second leaf spring and the end fixed to the second contacting member; and further comprising: a fourth wheatston bridge constricted so that at least one first strain gage attached on the contracted surface of the first leaf springs face the other at least one second strain gage on the contracted surface of the second leaf spring and/or that at least one first strain gage attached on the elongated surface of the first leaf springs face the other at least one second strain gage on the elongated surface of the second leaf spring, whereby the step difference between the first surface and the second surface is obtained from the bridge voltage of the fourth wheatston bridge.

[25] The apparatus as claimed of claim 23 or claim 24, wherein the first strain gages and second strain gages are attached on the first leaf spring and on the second leaf spring at each position where the deformation of all the first strain gages is the same to the deformation of all the second strain gages.

[26] The apparatus as claimed of claim 23 or claim 24, wherein the first contacting member contacts with the first surface at two positions, and the second contacting member contacts with the second surface at two positions.

[27] The apparatus as claimed of claim 26, wherein the first contacting member includes one traversely arrayed contact roller and one contact ball thereby contacting with the first surface at one point and at one line, and the second contacting member includes two contact balls thereby contacting with the second surface at two points.

[28] A method of aligning a first shaft and a second shaft, which comprises: a step of placing the first contacting member on the longitudinal outer surface of the first shaft and so that the first contacting member rotates in accordance of the longitudinal outer surface inclination of the first shaft; a step of placing the second contacting member on the longitudinal outer surface of the second shaft and so that the second contacting member rotates in accordance of the longitudinal outer surface inclination of the second shaft; a step of obtaining an inclination angle difference between the first surface and the second surface which is proportional to the bridge voltage of a third wheatston bridge, wherein at least one pair of first strain gages R2i, R2e are attached respectively on inner face and outer face of a first leaf spring of which one part is fixed to a case and of which one end is fixed to the first contacting member, the first strain gages being attached between the one part and the one end at which the first leaf spring is fixed, wherein at least one pair of second strain gages R3i, R3e are attached respectively on inner face and outer face of a second leaf spring of which one part is fixed to the case and of which one end is fixed to the second contacting member, the second strain gages being attached between the one fixed part and the one fixed end at which the second leaf spring is fixed, and wherein the third wheatston bridge is constricted so that the first strain gage attached on the contracted surface of the first leaf springs face the second strain gage attached on the elongated surface of the second leaf spring and/or that the first strain gage attached on the elongated surface of the first leaf springs face the second strain gage attached on the contracted surface of the second leaf spring; a step of obtaining an step difference between the first surface and the second surface which is proportional to the bridge voltage of a fourth wheatston bridge, wherein at least one pair of first strain gages RIi, RIe are attached respectively on inner face and outer face of a first leaf spring of which one part is fixed to a case and of which one end is fixed to the first contacting member, the first strain gages being attached between the one part and the one end at which the first leaf spring is fixed, wherein at least one pair of second strain gages R4i, R4e are attached respectively on inner face and outer face of a second leaf spring of which one part is fixed to the case and of which one end is fixed to the second contacting member, the second strain gages being attached between the one fixed part and the one fixed end at which the second leaf spring is fixed, and wherein the fourth wheatston bridge is constricted so that the first strain gage attached on the contracted surface of the first leaf springs face the second strain gage attached on the contracted surface of the second leaf spring and/or that the first strain gage attached on the elongated surface of the first leaf springs face the second strain gage attached on the elongated surface of the second leaf spring; a step of indicating the obtained angel difference and the obtained step difference; a step of aligning the first shaft and the second shaft while checking the indicated step difference and the inclination angle difference therebetween. [29] The apparatus as claimed of claim 28, wherein at least three sets including the first contacting member and the second contacting member are installed in the vertical direction, in the horizontal direction and in the diagonal direction respectively for aligning the first shaft and the second shaft.