JPS5943301A - Stretched steel wire rule - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly accurate tensioned steel wire ruler that is not affected by inclination and is mainly used as a standard for straightness and flatness in measuring machines and machine tools.

East German Patent Specification No. 139 295 describes a precision tensioned steel wire ruler consisting of a number of single steel wires and having one steel wire system stretched in a frame.
In this case, the sag of the steel wire system is determined by measuring its natural frequency. For this purpose, the steel wire system is vibrated mechanically or electrically by means of an exciter and the natural frequencies are investigated for evidence of resonance. With this method, the sag in the direction of gravity (ie the maximum sag) can be determined very precisely and can therefore be taken into account when measuring straightness and flatness.

However, the maximum sag correction is only valid for the vertical position of the steel wire system with respect to the direction of gravity. For other positions of the steel wire system relative to the direction of gravity, for measurements on a test surface that is not oriented horizontally, e.g. due to tilting of the equipment, i.e. if the perpendicular to the steel wire system is 0<δ≦ relative to the direction of gravity. In the case of forming an angle of 90°, the maximum slack must be multiplied by cos δ to be corrected and defined. For this purpose, the angle δ must be measured in each case, for example using an angle level.

Application information 2182 Engineering precision instrument "Straightness instrument GM1200" on which the said patent specification No. 139295 is based
In order to investigate the inclination of a steel wire system, for example, the longitudinal axis of the steel wire system is utilized as an instrument-specific component in a spirit level. The spirit level is first set and fixed on the measuring object and then pressed against a reference plane on the instrument in order to measure the required angle of rotation of the steel wire system. In order to take the inclination into account in the sag correction, the evaluation device must measure the adjustment amount for the inclination angle.

These setting procedures, which have to be carried out before the actual measurement process, require expensive handling of the instrument, can lead to incorrect settings due to operator inadvertence, and reduce measurement accuracy and measurement economy. Become something.

The aim of the invention is to eliminate deficiencies in the current state of the art, increase measurement accuracy and avoid sources of error when carrying out measurements.

The problem underlying the present invention is to create a tensioned steel wire ruler that is independent of temperature and gravity and that automatically compensates for the slack in the steel wire even when the steel wire system is tilted. be.

The problem of a tension-independent steel wire ruler having a steel wire system consisting of a large number of thin tension wires and a scanning system for scanning the wire system is solved according to the invention, namely: , - a second steel wire system consisting of a large number of parallel thin steel wires is stretched in the frame parallel to the above-mentioned first steel wire system, and the second steel wire system satisfies the condition k>1. - having a sag k times the sag of the first steel wire system due to gravity, - a scanning system for scanning the second and second steel wire systems is arranged on a carrier mounted on the guide of the cradle; The carrier is then combined with a sensor that scans the surface of the measuring object, and in particular the air gap between the scanning systems for scanning the steel wire system with k times the sag causes the scanning for the other steel wire system to be being able to be adjusted in relation to the size of the door gap of the system and the evaluation device used; - viewed in the longitudinal direction of the steel wire system, on each side of the carrier containing the scanning system, a first and a second steel wire system; A common or separate support element for the steel wire system, also primarily a support element that can be commonly or individually adjustable in perpendicularity and parallelism to the steel wire system, is provided for supporting the steel wire system against the surface of the object to be measured. - The scanning systems for the first and second steel wire systems are connected to a common evaluation device.

If the coils of the scanning system are interconnected in a carrier frequency bridge circuit and a carrier frequency measuring amplifier is arranged in the indicator branch of the circuit, which amplifier is connected to the register unit or the indicating unit, the scanning system A particularly advantageous evaluation of the measured signal is achieved.

It is particularly advantageous if the second steel wire system has twice the sag of the first steel wire system due to gravity.

Furthermore, the second steel wire system has twice the slack of the first steel wire system, and the air gap between the scanning systems of the second steel wire system is twice the air gap between the scanning systems of the first steel wire system. With double the value, an advantageous situation is achieved.

To define the steel wire sag, the coils of the scanning system are interconnected in a carrier frequency bridge circuit with multiple indicator branches, and each of the indicator branches is equipped with one single channel amplifier. Alternatively, each channel of a multi-channel amplifier is advantageously arranged.

By setting the slack of the second wire system to be k times that of the first wire system and by arranging the first wire system in the frame parallel to the first wire system, the measurement signal of the scanning system is Of these, the signal component corresponding to the steel wire sag can be determined by any inclination state of the tensioned steel wire ruler if a corresponding adjustment of the air gap between the scanning systems or a multiplication of the measurement signal of the first scanning system by k is carried out in the evaluation device. It will also be deleted.

Therefore, the following relation holds true for the measurement signal of the scanning system.

M2 = yp + yD M3 = yp + kyD By multiplying M2 by K and forming the difference between the two measurement signals M2 and M3, which are composed of the sag component yp and the component yp due to the measurement object, the measurement object that is not affected by the sag is determined. A measured value M is obtained.

M=kM2-M3=(k-1)yp where k>1. Therefore, when using the tensioned steel wire ruler, an automatic separation of the components yp and yD takes place, even if the inclination angle δ of the tensioned steel wire ruler is not clearly known.

The measured value M can be investigated with a simple carrier frequency bridge circuit. The circuit is a component of the evaluation device, in which all the coils of the scanning system are interconnected, and a single carrier frequency amplifier is arranged in the indicator branch of the bridge circuit.

It is also particularly advantageous for the user that the slack in the steel wire can be checked in a simple manner. It is therefore also possible to check the adjustment state of the steel wire system after a considerable period of use.

Other important advantages of this are: - the flatness and straightness of the measuring object can be checked in any angular state without having to check the steel wire ruler or the inclination angle of the measuring object beforehand; - e.g. It does not require wear-sensitive components such as potentiometers, the steel wire ruler has low technical outlay and is versatile, - the steel wire ruler is easy to handle and The measurement economy is quite high.

Next, the present invention will be explained in detail based on the embodiments shown in the drawings.

The closed tension steel wire ruler shown in FIG. 1 has a pedestal 1,
A holding device and a tensioning device (not shown) are used in the frame, and a first steel wire system 2 consisting of a large number of parallel thin steel wires is used.
and a second steel wire system 3 are arranged, which steel wire systems are supported opposite the measuring object 6 by means of indicator elements 4 and 5. The support elements 4 and 5 can be adjusted in the direction along the steel wire system or also in the direction perpendicular to it. In the case of the support elements 4 and 5 shown in FIG. 1, the support arms 7 and 8 and 9 and 10 are each adjusted in height simultaneously.

A guide step 12 is provided on the guide 11 arranged on the pedestal 1.
is arranged to be movable parallel to the direction of extension of the steel wire systems 2, 3, said guide step displacing a carrier 13 with a scanning system 14, 15, 16, 17. A first steel wire system 2 is located between the scanning systems 14 and 15, and a second steel wire system 3 is located between the scanning systems 16 and 17. The carrier 13 has a sensor 18 at its tip, and the surface of the measurement object G is scanned using the sensor. The scanning systems 14, 15, 16, 17 follow the movement of the sensor 18 in accordance with irregularities in the shape of the object to be measured.

The steel wire systems 2 and 3 are stretched in the frame 1 such that the second steel wire system 3 has k times as much slack as the first steel wire system 2, with k>1. In practice, it is advantageous to take k=2, since in that case a particularly advantageous relation is obtained for the evaluation of the measurement signals produced by the scanning system 14, 15, 16, 17 in the evaluation circuit. This is because it will be done.

The scanning systems 14, 15, 16, 17 are primarily coiled inductive transmitters.

In FIG. 2 the sagging of the steel wire systems 2 and 3 is shown. In this case, by way of example, the sag of the steel wire system 3 is shown to be twice as large as the sag of the steel wire system. The maximum values of slack are represented by y1 and y2. The inclination of the steel wire ruler with the inclination angle δ affects the sag in the individual steel wire system with a cosine function. (y2-y1) cos δ holds true.

FIG. 3 shows a tensioned steel wire ruler very schematically, which ruler is constructed similarly to FIG. Frame 1
A steel wire system 2, 3 is strung through the steel wire system and is scanned by a scanning system 14, 15, 16, 17. The scanning system 14, 15, 16, 17 comprises:
carrier 13 with a sensor 18 for scanning the measuring object 6;
It is located in Separate support elements 19, 20, 21, 22 are provided for the steel wire systems 2 and 3, which support elements extend both parallel and perpendicular to the surface of the measuring object and to the steel wire systems 2, 3. can also be adjusted. Two of these support elements 19, 21 and 20, 22 are arranged on each side of the carrier 13.

The implementation of electronic measurement data processing to realize the measurement equation kM2-M3=(k-1)yP=M is performed using the carrier frequency bridge circuit of FIG.

In the circuit a guided scanning system 14, 15, 16, 1
7 coils 23 and 26 of scanning systems 15 and 16 and coils 24 and 2 of scanning systems 15 and 16.
4 are each connected in series with one bridge branch circuit. A carrier frequency measuring amplifier 27 is arranged in the indicator branch of the bridge circuit, which amplifier is connected to a register unit or indicating unit 28 for outputting the measured value of the measuring object 6.

In order to realize the measurement equation yp=2M2-M3 with k=2, in particular a scanning system 14 with intervening steel wire system 2;
The ratio of the air gap B2 between the scanning systems 15 and the air gap B3 between the scanning systems 16 and 17, in which the steel wire system 3 is interposed, is 1:2, ie B3=2B2. As a result, the inductance during scanning is reduced to steel wire systems 2 and 3.
When displaces inside air gaps B2 and B3, it changes at a rate of 1 part and 2 parts. This measure allows the measuring amplifier 27 to have a unified amplifier for both measuring signals M2M3, making it possible to use a single-channel carrier frequency amplifier.

As can be proven by calculation, the result of the measurement signal processing in the bridge circuit of FIG.
And 3, any arbitrary position or interval is not affected by the slack of the steel wire.

Scanning systems 14, 15, 16, shown in FIG.
17, the air gap B2 between the coils 23 and 24 and the air gap B3 between the coils 25 and 26 are not equal, so an adjustment must be made during assembly of the tensioned steel wire ruler.

FIG. 6 shows an evaluation circuit for determining the sag yD of the steel wire systems 2 and 3, which circuit includes a bridge circuit in which the scanning system 1
The coils 23 and 26 and 24 and 25 of 4, 15, 16, 17 are connected in parallel, and a single channel carrier frequency amplifier 29 is arranged in the indicator branch.

This determination of the sag is based on the following equation yD=M2-M3, using the same air gap size as in the measurement on the measuring object 6.

FIG. 7 shows a carrier frequency bridge circuit for defining slack, which circuit includes a plurality of indicator branches, each of which has one single channel amplifier or multiple A respective one channel 30, 31 of channel amplifiers is arranged. In this case, the signals M2 and M3 can be detected separately and subtracted later. 32 and 33 represent the resistances required in the individual bridge circuits.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a tensioned steel wire ruler. Figure 2 shows the slack state of the steel wire ruler used. FIG. 3: Tensioned steel wire ruler with separate indicating element. Figure 4. Scanning system with different air gaps. Figure 5, evaluation circuit for examining measured values. Figure 6: Evaluation circuit for defining slack. FIG. 7: Another evaluation circuit for determining sag in steel wire systems. 1... Frame, 2... First steel wire system 3... Second steel wire system 4, 5... Support element, 6... ...Measurement object 7, 8, 9, 10...Support arm 11...Guide, 12...Guide step 13...Carrier 14, 15, 16 , 17... scanning system 18
...Sensors 19, 20, 21, 22...Support elements 23, 2
4, 25, 26... Coil 27... Carrier frequency measuring amplifier 28... Register unit or indication unit 29... Single channel carrier frequency amplifier 30 , 31... Channel, 32
, 33...Resistors B2, B3...Air gap, patent applicant

Claims (5)

[Claims] (1) A tension steel wire ruler that is not affected by inclination, that is: - a frame on which a steel wire system consisting of a large number of parallel thin steel wires is stretched by a holding device and a tension device, and - a steel wire system in its extension direction; - an inclination-independent tensioned steel wire ruler having a scanning system for scanning the wire, a supporting element supporting the line system, - an evaluation device connected to the scanning system, - consisting of a large number of parallel thin steel wires; A second steel wire system 3 is stretched in parallel to the first steel wire system 2 in the frame 1, and the second steel wire system 3 is connected to the first steel wire by gravity under the condition of k>1. having a slack k times the slack of the wire system 2; - the carrier 13 attached to the guide 11 of the pedestal 1;
A scanning system 14, 15, 16, 17 is arranged which scans the first and second steel wire systems 2, 3, the carrier 13 being coupled with a sensor 18 which scans the surface of the measuring object 6. , and in particular, the air gap B3 between the scanning systems 16, 17 scanning the steel wire system 3 with k times the slack is the same as the air gap B22 of the scanning systems 14, 15 for the other steel wire system 2. , can be adjusted in relation to the evaluation device used;
Looking in the longitudinal direction of the steel wire system shims 2, 3, the scanning system 14
, 15, 16, 17 on both sides of the carrier 13 receiving
A common or separate support element for the first and second steel wire systems 2, 3, also primarily steel wire systems 2, 3;
supporting elements which can be commonly adjusted or individually adjusted perpendicularly and parallel to the surface of the measuring object 6 are provided for supporting the steel wire systems 2, 3 against the surface of the measuring object 6; - the first and second steel wire systems; Tensioned steel wire ruler, characterized in that the scanning systems 14, 15, 16, 17 for 2, 3 are connected to a common evaluation device. (2) Coil 2 of scanning system 14, 15, 16, 17
2, 23, 24, 25 are interconnected in a carrier frequency bridge circuit, in which a carrier frequency measuring amplifier 27, 29 is arranged in the inductor branch circuit of the circuit, which amplifier is connected to a register unit or an indicator. The tensioned steel wire ruler according to claim 1, characterized in that it is connected to the unit 28. (3) The tensioned steel wire ruler according to claim 1, wherein the second steel wire system 3 has twice the slack of the first steel wire system due to heavy force. (4) The second steel wire system 3 has twice the slack of the first steel wire system, and the scanning system 16 of the second steel wire system 3
, 17 has twice the value of the air gap B2 between the scanning systems 14, 15 of the first steel wire system 2. Line ruler. (5) In order to define the slack of the steel wire, the scanning system 1
4, 15, 16, 17 coils 22, 23, 24, 25
are interconnected in a bridge circuit and are characterized in that in each of their indicator branch circuits one single-channel amplifier 29 or in each case one channel 30, 31 of a multi-channel amplifier is arranged. The tensioned steel wire ruler according to claim 1.