JPH02231501A - Accurate length measuring instrument for long-sized moving magnetic body - Google Patents

Abstract

PURPOSE:To reduce the cost and labor for length measurement and to rationalize the length measurement by equalizing the measurement unit intervals of respective length measuring units and arranging magnetizing heads and detection heads on along a length measurement line at the same interval. CONSTITUTION:The two length measuring units 2 and 2' are arranged along the length measurement line where the long-sized moving magnetic body 1 to be measured moves and the magnetizing heads 3 gives the body 1 to be measured magnetic marks corresponding to the length measuring units 2 and 2' and the detection heads 4 and 4' detect them; and said operation is repeated at intervals and counting means 7 and 7' performs counting operation to find length measured values respectively. The measurement unit intervals L and L' of the length measuring units 2 and 2' are equal to each other, the magnetizing heads 3 and 3' and detection heads 4 and 4' are arranged along the length measurement line at the same interval l0, which is set except to integral multiples of the measurement unit intervals L and L'. The counting means 7 and 7' perform the counting operation to find the length measured values individually and the length measured values are sent to a counting difference arithmetic means 8 to find the difference between the length measured values.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention involves attaching a magnetic mark to a long moving magnetic object such as a steel plate or wire rod, and repeating the operation of detecting the magnetic mark in a lengthwise manner. This invention relates to a precision measuring device for measuring long moving magnetic objects.

(Prior art) A magnetic mark is attached to a long moving magnetic object (hereinafter referred to as the object to be measured) moving on a measurement line using a magnetizing head, and the mark is placed at a position spaced apart from the magnetizing head by the measurement unit interval. A technique for measuring the length of an object by sequentially repeating the operation of detecting a magnetic mark with a detection head and counting the detection signals of the detection head is disclosed in JP-A-52-114348 and other publications. This has been known for a long time.

(Problems to be Solved by the Invention) Various measures have been taken to improve measurement accuracy in this type of length measuring device. interval)
It has not been possible to completely eliminate the possibility of errors occurring due to changes in temperature, malfunctions, and temperature differences between the object to be measured and the length-measuring object, such as the distance-maintaining hardware between the heads, due to rapid temperature changes. It has been extremely difficult to completely eliminate such error factors even if measures such as electromagnetic shielding, shielding from the outside world, and air conditioning are taken.

Therefore, in the past, when measuring the length of gauge wire for prefabricated strands for long suspension bridge main cables, etc., especially in cases where measurement errors are absolutely unacceptable, in order to confirm the measurement results,
The object that has been passed through the measurement line once is passed through the measurement line again and measured again, and it is passed only if the difference is within a predetermined value, reducing measurement costs, saving labor, and streamlining. There were limits to what could be achieved. In view of these conventional problems, the present invention was provided for the purpose of reducing length measurement costs, saving labor, and streamlining the measurement process.

(Means for Solving the Problem) The present invention provides, as a specific means for solving the problem, a magnetizing head 3, 3° that attaches a magnetic mark to a long moving magnetic object 1 that moves on a length measurement inner; The magnetic mark is magnetized by the magnetizing head 3,
A detection head 4.4'' detects at a position spaced apart from 3゛ by the measurement unit interval L, L', and a magnetizing head so that when the detection head 4.4' detects a magnetic mark, it attaches the next magnetic mark. A plurality of sets of length measuring units each having a magnetization control means 5.5' for driving a 3.3° angle, and a counting means 7, 7' for calculating a length measurement value by counting the detection signals of the detection heads 4, 4'. 2.2°, the measuring unit intervals L and L' of these length measuring units 2.2' are made the same, and the magnetizing heads 3.3 of these length measuring units 2 and 2' are made the same. and the detection heads 4 and 4 are placed at the same interval 1.
o, and the measurement unit spacing L,
Among L' and the interval 20, the large interval is set to a value that greatly avoids an integer multiple of the small interval, and counting difference calculation means 8 is provided for calculating the relative difference between the measured length values of each length measuring unit 2, 2°. It is something that

(Function) When measuring the length, a magnetic mark is attached to the long moving magnetic object 1 using the magnetizing head 3.3'' for each lengthening unit 2.2'.
The operation of detecting it with the detection head 4.4'' is repeated lengthwise, and the counting means 7 and 7'' count it to obtain the measured length values separately.Then, the measured length values are calculated by the counting difference calculating means 8. The error in the measured length value is calculated and a pass/fail judgment is made.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a first embodiment of the present invention, in which two sets of first and second length measuring units 2, This is the case when 2゛ is placed.

Each length measuring unit 2.2' is a length measuring method that attaches a magnetic mark to the object to be measured, such as a steel plate or wire rod, and repeats the operation of detecting it in a length measuring method to measure the length. Each of these length measuring units 2, 2° basically consists of magnetizing heads 3, 2, which are arranged along the length measuring line at predetermined measuring unit intervals L, L'. 3゛ and detection head 4
．． 4'', magnetization control means 5, 5° and detection signal processing means 6, 6°, which control these operations or perform signal processing;
Furthermore, it comprises counting means 7, 7'' for calculating the length measurement value by counting the number of repetitions of magnetization and detection from the detection signal.The counting means 7.7' of each length measuring unit 2.2'' The output side of is connected to the count difference calculation means 8, and
2.2' is configured to find the difference in length measurement values.

Measurement unit interval L, L" for each length measurement unit 2, 2°
are the same (L=L'), and the magnetizing head 3.
The detection head 4.3 and the detection head 4.4 are respectively arranged at the same distance io along the length measurement line. This interval j2o is set to a value that largely avoids an integral multiple of the measurement unit interval L, L'', and is designed to prevent errors due to proximity and overlap of magnetic marks.
'<<ffio.

The detection signal processing means 6'' of the second length measuring unit 2° is equipped with a circuit for identifying the magnetic mark produced by the magnetizing head 3 of the first length measuring unit 2, and distinguishes between the first magnetic mark and the second magnetic mark. is configured to prevent misidentification.

The following methods can be used for this identification.

(2) Giving a difference, for example, strength or weakness or a different waveform to the magnetic marks produced by each magnetizing head 3, 3'.

■ After determining the values of the measurement unit intervals L, L' and the interval j2o, the magnetic mark passing through the detection head 4'' is identified from the traveling speed of the object 1 and the elapsed time.For example, the magnetic mark passing by the magnetizing head 3 This is done by measuring the time 1 until the magnetic mark is detected by the detection head 4, and then calculating and predicting the time t until the magnetic mark reaches the detection head 4' using the following equation.

Traveling speed ν, = L/t, distance of detection head 4.4' (/! o-L) + L' = i!
．． o('.' L = L') + l o W
v; t; J = io/vl = i! ．． o・
t4/L= <l o/L) Time for the magnetic mark by the tl magnetizing head 3'' to reach the detection head 4' tk tk=L''/ν8-L' ・ti/L= t, Checking the length measurement error , is performed by the counting difference calculation means 8, but L,
L'. The value of I2o is fixed, and the time when the magnetic mark by the magnetizing head 3 of the first length measuring unit 20 reaches the detection head 4 of the second length measuring unit 2 can be calculated and set by measuring t. By measuring the difference time ΔL between the time and the time actually detected by the detection driver 4'',
You can also check below.

L ΔL = Vi・Δt -・ΔLt. In the above configuration, when measuring the length of the object 1 to be measured, each magnetization control means 5, 5° is activated by a start signal, and a magnetic mark is attached to the object 1 by each magnetizing head 3.3°. . Then, this magnetic mark is detected by each detection head 4, 4°, signal processing is performed by each detection signal processing means 6, 6°, and the signal is transmitted to each magnetizing head 3 via each magnetization control means 5, 5°.
, 3' is driven to attach the next magnetic mark, and this process is repeated thereafter. On the other hand, each detection signal is counted by each counting means 7.7" via each detection signal processing means 6.6", and the length measurement value of the object 1 is determined for each length measurement unit 2.2'. . Then, each of the measured length values is sent to the counting difference calculation means 8, and the difference between the two measured length values is calculated and compared. In other words, the relative difference between two length measurements taken separately at any measurement point (generally the final point where the total length can be determined) is determined, and if the value is less than a predetermined value, the test is passed; if it exceeds the predetermined value, the test is rejected. It is determined that the length is measured again. This is theoretically the same as the conventional method of re-measuring the length of the object l whose length has been measured once by running the length measurement line once again, and determining whether the object is acceptable or not based on the difference.

FIG. 2 shows another embodiment of the present invention, in which two sets of length measuring units I-2. 2' are intertwined and arranged in series in the traveling direction of the object 1. The measurement unit length is L - L', and as a result, the distance lo between the magnetizing heads 3 and 3 degrees is the same as the distance io between the detection heads 4 and 4 degrees, but in this case L (=L') The dimensions are determined so that the value of Ao (=fo') is largely avoided from being an integer multiple of the value of io (=fo'), and errors due to proximity and overlap of magnetic marks are prevented.
<<L. Also, regarding the method of identifying the magnetic marks produced by the magnetizing heads 3 and 3° and the method of confirming the difference between the length measurement value obtained by the first length measurement unit 2 and the length measurement value obtained by the second length measurement unit 2'', please refer to Fig. 1. Same as in case.

With this configuration, the total length of the length measuring equipment is significantly shorter than in the case shown in FIG. 1, leading to a reduction in equipment costs.

The reliability is improved as the number of length measuring units increases, so it is not necessarily limited to two sets as in the embodiment, but since equipment costs increase, about two sets is realistic.

(Effects of the Invention) According to the present invention, the magnetizing head 3, 3" attaches a magnetic mark to the elongated moving magnetic object 1 moving on a length measurement line, and the magnetizing head 3, 3" to measurement unit interval L
, detection head 4.4 detecting at a position separated by L'
゛, magnetization control means 5, 5'' that drives the magnetizing heads 3, 3'' so that the next magnetic mark is attached when the detection heads 4, 4'' detect a magnetic mark, and the detection heads 4, 4''. A plurality of sets of length measuring units 2, 2 each having a counting means 7.7 for calculating a length measurement value by counting detection signals of L' are made the same, and the magnetizing heads 3, 3' and detection heads 4, 4° of these length measuring units 2, 2' are spaced apart from each other by the same distance io along the length measuring line. , and among the measurement unit intervals L, L' and the interval fo, the larger interval is set to a value that greatly avoids an integer multiple of the smaller interval, and the relative difference between the length measurement values of each length measurement unit 2, 2° is calculated. Since 8 stages of count difference calculation are provided, the following remarkable effects can be obtained, and its practical value is extremely great.

■ The number of times the object is passed through the length measurement line can be halved (from two times to once), resulting in significant labor savings and shortening measurement time, leading to a reduction in length measurement costs. - Even if one of the plurality of length measuring units breaks down, the remaining length measuring units can measure the length, and the fault can be repaired while avoiding a complete stoppage of the line.

■ By halving the work of attaching and removing the object to the length measurement line, the work of horizontally carrying and transporting heavy objects (which can be quite heavy if the object is long) is also halved, and dangerous work is halved. Leads to improved work safety.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the invention, and FIG. 2 is a block diagram showing a second embodiment of the invention. 1... Long moving magnetic object (object to be measured), 2,2°...
・Length measuring unit, 3,3"...magnetizing head, 4,4゛...detection head, 5.5゜...magnetizing control means, 7,
7”...Counting means, 8...Counting difference calculation means.

Claims (1)

[Claims] (1) Long moving magnetic object moving on the measurement line (1)
A magnetizing head (3) (3') that attaches a magnetic mark to the magnetizing head (3) (3') and detecting the magnetic mark at a position separated by a measurement unit interval (L) (L') from the magnetizing head (3) (3'). Detection head (4) (4') and magnetization head (3) (3') that drives the magnetization head (3) (3') so that when the detection head (4) (4') detects a magnetic mark, it attaches the next magnetic mark. magnetic control means 5,
5', and counting means (7) (7') for calculating the length measurement value by counting the detection signals of the detection heads (4) (4'). and the measurement unit intervals (L) (L) of these length measurement units (2) (2')
') are the same, and these length measuring units (2
) (2'), the magnetizing head (3) (3') and the detection head (4) (4') are placed at the same interval (l) along the measurement line.
o), and the measurement unit spacing (L
) (L') and the above-mentioned interval (lo), the large interval is set to a value that is an integral multiple of the small interval, and each length measuring unit (
2) A precision length measuring device for a long moving magnetic object, characterized in that it is provided with count difference calculation means (8) for determining the relative difference between the measured length values of (2').