WO1996006323A1 - Device for measuring mechanical tension, extension and bending - Google Patents

Device for measuring mechanical tension, extension and bending Download PDF

Info

Publication number
WO1996006323A1
WO1996006323A1 PCT/NO1995/000138 NO9500138W WO9606323A1 WO 1996006323 A1 WO1996006323 A1 WO 1996006323A1 NO 9500138 W NO9500138 W NO 9500138W WO 9606323 A1 WO9606323 A1 WO 9606323A1
Authority
WO
WIPO (PCT)
Prior art keywords
base plate
measuring
measuring part
secured
extension
Prior art date
Application number
PCT/NO1995/000138
Other languages
French (fr)
Inventor
Bjørn BURMANN
Original Assignee
Scan-Sense A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scan-Sense A/S filed Critical Scan-Sense A/S
Priority to EP95930062A priority Critical patent/EP0783661A1/en
Priority to AU33566/95A priority patent/AU3356695A/en
Publication of WO1996006323A1 publication Critical patent/WO1996006323A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge

Definitions

  • the present invention is related to a device for measuring mechanical tension, extension and bending.
  • tension strips are time consuming and the demand large to the highest purity and accuracy, also to the surroun- dings.
  • Another disadvantage with existing methods is that tension strips only can be used once.
  • Measurements also have been made optically, especially in laboratories and partly based on polarised light and the interference occurrence. It furthermore is well known to use devices which are secured by bolts to the structure to be measured, whereby the measurement as such is provided by means of tension strips.
  • the measuring device is used as a mechanical shunt as it has a relatively large mechanical rigidity. In this way the devices as such may influence the structure on which measurements are to take part and therefore also influence the measurements.
  • the devices used today to measure tension, extension and bending in a structure all have disadvantages. Such measure ⁇ ments take a long time, the preparation of the structure as such is time consuming as material to be measured must be clean thoroughly and therefore possible painting or other surface treatment, must be removed.
  • the measuring device furthermore very commonly have an extension coefficient different from the material to be measured, a fact what makes the measuring results depending on temperature fluctuations. This is also concerned with the tension strength as the electrical conductivity likewise is dependent on the temperature.
  • the measuring device according to the present invention avoids the above mentioned disadvantages. Additionally further advantages are achieved, together with a substantially increased measuring accuracy and small dimensions.
  • the device according to the present invention is distinguished above the prior embodi ⁇ ments also in that handling is very easy and quick and the device does have no influence on the material to be measured.
  • figure 1 a ground view of the base plate of the device fully equipped
  • figure 2 discloses only the base plate in figure 1
  • figure 3 discloses one embodiment of the device according to the invention in a version built into a housing disclosing the base plate of providing figures as a house base.
  • the base plate 1 is manufactured preferably in an aluminium alloy having a known and uniform texture.
  • a pattern is cut out with small tolerances by means of laser cutting, in such way that a measuring part 13 is provided, being displaceable within the slots made by the cutting.
  • the measuring part 13 is connected with the rest of a base plate 1 by a number of bridges 14 which act like plate springs and which maintain the measuring part 13 centralized in an unloaded condition.
  • the base plate 1 is secured to the structure to be measured by means of for example magnets which can be used for measuring ferric materials.
  • magnets which can be used for measuring ferric materials.
  • other materials such as tree, concrete etc. screws, double sided tape or such are used.
  • the figures disclose one embodiment having three magnets 4.
  • One magnet 4 is secured to the measuring part 13 and two magnets 2 and 3 are secured to one end of the base plate 1.
  • a sensor 12 is secured between the measuring part 13 and the rest 3 of the base plate 1, preferably a highly sensitive magnet sensor. A change of the material length between the magnets 2, 3 and magnet 4 therefore will immediately be registrated by the sensor 12.
  • a further sensor 11, corresponding to the first mention, is secured between the base plate 1 and the opposite end in the longitudinal direction of the measuring part 13. This sensor 11 abuts a part 15 of the base plate 1 which is movable in the longitudinal direction by means of an eccentric disc 5 with the purpose of calibrating the measuring device.
  • the part 15 is, like the measuring part 13, connected with the base plate by bridges 14. With such a device, calibration can be made all along the entire range of the measuring scale.
  • the device according to the present invention may be displaced by pressure from both sides against cams 6.
  • the cams 6 thereby press against the middle of the base plate 1 and thereby displace flexible movable wedges 9 and 10 into correspon ⁇ ding recesses in the measuring part 13. With such a constant pressure the device is locked in such a way that the calibration is maintained even when moving the device to another place.
  • Figure 3 discloses one embodiment of the device accor ⁇ ding to the present invention, built into a housing having a display 8, a plug 7 for connection of a serial interface and a push bottom set for operation of different functions computed and possibly to be disclosed in the display 8.
  • the device furthermore suitably may have a securement against overloading.
  • Signals from the sensors 11 and 12 are transmitted to an electronical part for computing the signals which thereafter may be disclosed in the display and/or transmitted to a computer by means of an interface.
  • the device is suitable to measure stress as a function of a load as this is expressed as a relative change of the length, compression or extension.
  • the device also can measure bending expressed by the bending radius.
  • the change of the length may be measured and disclosed directly as a function of the load measuring length units, such as in ⁇ m.
  • the readings may be expressed directly in kN in such a way that the device according to the invention principally also can be used as a dynamometer.
  • the unit microprocessor comprises constant values for the specific material which may be stored in advance or selected when activating the device, depending of the material onto which the device is secured. In this way a device is provided, the measuring results of which are completely compensated for changes due to temperature variations.

Abstract

Device for measuring mechanical tension, extension and bending based on longitudinal changes of an object, comprising a base plate (1) which at one end is adapted to be secured in two points to the object, a measuring part (13) being displaceable in relation to the rest of the base plate (1), however connected yieldingly with the base plate (1), and being adapted to be secured at a third point of the object, and that a sensor (12) being arranged between the measuring part (13) and the rest of the base plate (1), whereby a processor is adapted to compute the signals from the sensors (11, 12) to provide measuring data for respectively mechanical tension, extension and bending related to physical changes of the material.

Description

Device for measuring mechanical tension, extension and bending
The present invention is related to a device for measuring mechanical tension, extension and bending.
Measuring of extension in structures and parts thereof traditionally has been accomplished by gluing tension strips on the structure. To secure such tension strips, the material must be cleaned very thoroughly to ensure that the tension strip has good contact with the base material. Thereafter a resistant wire is secured. Resistant wires normally used have a size like a post stamp or such. The resistant wire is connected electrically with a measuring device which is registrating changes in the electri- cal resistance based on the extension or possibly the compression of the base material caused by a load, as the resistant wire likewise is exposed to the same influence.
Use of tension strips is time consuming and the demand large to the highest purity and accuracy, also to the surroun- dings. Another disadvantage with existing methods is that tension strips only can be used once.
Measurements also have been made optically, especially in laboratories and partly based on polarised light and the interference occurrence. It furthermore is well known to use devices which are secured by bolts to the structure to be measured, whereby the measurement as such is provided by means of tension strips. Here the measuring device is used as a mechanical shunt as it has a relatively large mechanical rigidity. In this way the devices as such may influence the structure on which measurements are to take part and therefore also influence the measurements.
From prior art, reference is made to DE 3 504 872 and GB 1 286 993 as examples of prior art devices.
The devices used today to measure tension, extension and bending in a structure all have disadvantages. Such measure¬ ments take a long time, the preparation of the structure as such is time consuming as material to be measured must be clean thoroughly and therefore possible painting or other surface treatment, must be removed. The measuring device furthermore very commonly have an extension coefficient different from the material to be measured, a fact what makes the measuring results depending on temperature fluctuations. This is also concerned with the tension strength as the electrical conductivity likewise is dependent on the temperature.
The measuring device according to the present invention avoids the above mentioned disadvantages. Additionally further advantages are achieved, together with a substantially increased measuring accuracy and small dimensions. The device according to the present invention is distinguished above the prior embodi¬ ments also in that handling is very easy and quick and the device does have no influence on the material to be measured.
The above mentioned advantages and special effects are achieved with the device according to the present invention as defined with the features stated in the claims. The drawing discloses in figure 1 a ground view of the base plate of the device fully equipped, figure 2 discloses only the base plate in figure 1, and figure 3 discloses one embodiment of the device according to the invention in a version built into a housing disclosing the base plate of providing figures as a house base.
The base plate 1 is manufactured preferably in an aluminium alloy having a known and uniform texture. In the base plate a pattern is cut out with small tolerances by means of laser cutting, in such way that a measuring part 13 is provided, being displaceable within the slots made by the cutting. The measuring part 13 is connected with the rest of a base plate 1 by a number of bridges 14 which act like plate springs and which maintain the measuring part 13 centralized in an unloaded condition.
The base plate 1 is secured to the structure to be measured by means of for example magnets which can be used for measuring ferric materials. For measuring other materials, such as tree, concrete etc. screws, double sided tape or such are used.
The figures disclose one embodiment having three magnets 4. One magnet 4 is secured to the measuring part 13 and two magnets 2 and 3 are secured to one end of the base plate 1. A sensor 12 is secured between the measuring part 13 and the rest 3 of the base plate 1, preferably a highly sensitive magnet sensor. A change of the material length between the magnets 2, 3 and magnet 4 therefore will immediately be registrated by the sensor 12. A further sensor 11, corresponding to the first mention, is secured between the base plate 1 and the opposite end in the longitudinal direction of the measuring part 13. This sensor 11 abuts a part 15 of the base plate 1 which is movable in the longitudinal direction by means of an eccentric disc 5 with the purpose of calibrating the measuring device. The part 15 is, like the measuring part 13, connected with the base plate by bridges 14. With such a device, calibration can be made all along the entire range of the measuring scale.
The device according to the present invention may be displaced by pressure from both sides against cams 6. The cams 6 thereby press against the middle of the base plate 1 and thereby displace flexible movable wedges 9 and 10 into correspon¬ ding recesses in the measuring part 13. With such a constant pressure the device is locked in such a way that the calibration is maintained even when moving the device to another place.
Figure 3 discloses one embodiment of the device accor¬ ding to the present invention, built into a housing having a display 8, a plug 7 for connection of a serial interface and a push bottom set for operation of different functions computed and possibly to be disclosed in the display 8. The device furthermore suitably may have a securement against overloading.
Signals from the sensors 11 and 12 are transmitted to an electronical part for computing the signals which thereafter may be disclosed in the display and/or transmitted to a computer by means of an interface.
The device is suitable to measure stress as a function of a load as this is expressed as a relative change of the length, compression or extension. The device, however, also can measure bending expressed by the bending radius. Furthermore the change of the length may be measured and disclosed directly as a function of the load measuring length units, such as in μm.
With knowledge of the material of the structure, the cross section, the module of elasticity etc., the readings may be expressed directly in kN in such a way that the device according to the invention principally also can be used as a dynamometer.
By measurement during short periods of time, the differences between the extension coefficient based on the temperature, of the material and of the measuring device will be without significance. In case of permanent installation of the device for surveillance, however, a compensation is made as the unit microprocessor comprises constant values for the specific material which may be stored in advance or selected when activating the device, depending of the material onto which the device is secured. In this way a device is provided, the measuring results of which are completely compensated for changes due to temperature variations.

Claims

P a t e n t C l a i m s
1. Device for measuring mechanical tension, extension 5 and bending based on longitudinal changes of an object, CHARAC¬ TERIZED IN comprising a base plate ( 1 ) which at one end is adapted to be secured in two points to the object, a measuring part (13) being displaceable in relation to the rest of the base plate (1 ), however connected yieldingly with the base plate ( 1 ), o and being adapted to be secured at a third point of the object, and that a sensor (12) being arranged between the measuring part (13) and the rest of the base plate (1), whereby a processor is adapted to compute the signals from the sensors (11, 12) to provide measuring data for respectively mechanical tension, s extension and bending related to physical changes of the material.
2. Device according to preceding claims, CHARACTERIZED IN the measuring part (13) being connected with the rest of the base plate with at least two blade spring like connections ( 14) . o 3. Device according to preceding claims, CHARACTERIZED
IN a sensor (11, 12) being arranged on two opposite sides of the measuring part (13) and that a calibrating device ( 5 ) being adapted to allow changing the pressure against the measuring part ( 13 ) from the rest of the base plate ( 1 ) thereby to make a 5 calibration of the device possible.
4. Device according to preceding claims, CHARACTERIZED IN that outer cams (6) being adapted to, by pressure towards each other, to press wedges (9, 10) towards recesses in the measuring parts ( 13 ) thereby to secure the measuring part and thereby o maintaining the calibration of the device, when the device is removed locally, the device thereby being lifted and removed with the pressure against the cams (6) maintained.
5. Device according to preceding claims, CHARACTERIZED IN the base plate ( 1 ) being manufactured in a aluminium alloy 5 having uniformally and known texture.
6. Device according to preceding claims, CHARACTERIZED IN two magnets (2, 3) being secured to one end of the base plate ( 1 ) and that a third magnet (4 ) being secured to the measuring part (13), to secure the measuring device to the object.
PCT/NO1995/000138 1994-08-22 1995-08-21 Device for measuring mechanical tension, extension and bending WO1996006323A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP95930062A EP0783661A1 (en) 1994-08-22 1995-08-21 Device for measuring mechanical tension, extension and bending
AU33566/95A AU3356695A (en) 1994-08-22 1995-08-21 Device for measuring mechanical tension, extension and bending

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO943086A NO943086L (en) 1994-08-22 1994-08-22 Measuring device
NO943086 1994-08-22

Publications (1)

Publication Number Publication Date
WO1996006323A1 true WO1996006323A1 (en) 1996-02-29

Family

ID=19897324

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO1995/000138 WO1996006323A1 (en) 1994-08-22 1995-08-21 Device for measuring mechanical tension, extension and bending

Country Status (4)

Country Link
EP (1) EP0783661A1 (en)
AU (1) AU3356695A (en)
NO (1) NO943086L (en)
WO (1) WO1996006323A1 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3853000A (en) * 1971-02-23 1974-12-10 Peak Components Ltd Strain measuring transducer
US4114429A (en) * 1975-10-28 1978-09-19 Coal Industry (Patents) Limited Method of and apparatus for sensing strain in strained members
DE2901995A1 (en) * 1979-01-19 1980-07-31 Erich Brosa Machine component expansion monitor - using welded measuring plate incorporating measuring elements and perpendicular slits
US4522066A (en) * 1982-05-13 1985-06-11 Kistler-Morse Corporation Temperature-compensated extensometer
GB2187294A (en) * 1985-12-16 1987-09-03 Norsk Hydro As Sensor unit for attachment to a structure
GB2195770A (en) * 1985-08-28 1988-04-13 Agip Norsk Inductive deformation transducer
GB2263775A (en) * 1992-01-23 1993-08-04 James Edward Oakley Strain measuring device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3853000A (en) * 1971-02-23 1974-12-10 Peak Components Ltd Strain measuring transducer
US4114429A (en) * 1975-10-28 1978-09-19 Coal Industry (Patents) Limited Method of and apparatus for sensing strain in strained members
DE2901995A1 (en) * 1979-01-19 1980-07-31 Erich Brosa Machine component expansion monitor - using welded measuring plate incorporating measuring elements and perpendicular slits
US4522066A (en) * 1982-05-13 1985-06-11 Kistler-Morse Corporation Temperature-compensated extensometer
GB2195770A (en) * 1985-08-28 1988-04-13 Agip Norsk Inductive deformation transducer
GB2187294A (en) * 1985-12-16 1987-09-03 Norsk Hydro As Sensor unit for attachment to a structure
GB2263775A (en) * 1992-01-23 1993-08-04 James Edward Oakley Strain measuring device

Also Published As

Publication number Publication date
NO943086D0 (en) 1994-08-22
NO943086L (en) 1996-02-23
EP0783661A1 (en) 1997-07-16
AU3356695A (en) 1996-03-14

Similar Documents

Publication Publication Date Title
US4512431A (en) Weight sensing apparatus employing polymeric piezoelectric film
DE69931470D1 (en) FINGERPRINT SENSOR
US4167869A (en) Apparatus for measuring hair grooming force
CA2307502C (en) A strain gauge strip and applications thereof
EP0502658B1 (en) Dimension measuring device
GB2205411A (en) Load cell
US4380171A (en) Method and apparatus for measuring normal contact forces in electrical connector
GB2193812A (en) Roller shoe with load measurement means
US3444499A (en) Strain gauge
NL8700750A (en) ANGLE METER.
WO1996006323A1 (en) Device for measuring mechanical tension, extension and bending
JPS6441803A (en) Apparatus for measuring angle and displacement quantity using electric resistor piece
EP0320299A2 (en) Pressure transducers and a method of measuring pressure
CN112213010A (en) Temperature compensation type optical fiber pressure sensor and stress calculation method thereof
JPS5851604B2 (en) How to adjust a load cell type load cell
US3982219A (en) Digital pressure/range transducer
US4890084A (en) Inductance strain gauge
DE19954300A1 (en) Sensor to detect extension variation of component; has resistance strain gauge as primary measuring elements, which is applied to film of same material as component
RU2028583C1 (en) Pressure transducer
CN211178305U (en) Thin film strain gauge for elastomer strain measurement
US11668889B2 (en) System for applying pre-strain to an optical sensor
SU1726980A1 (en) Semiconductor strain gauge
GB2080542A (en) Measurement of shaft angle displacement
SU1364858A1 (en) Arrangement for measuring longitudinal and angular deformations of specimen
JPH03210404A (en) Shape sensor

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AM AT AU BB BG BR BY CA CH CN CZ DE DK EE ES FI GB GE HU IS JP KE KG KP KR KZ LK LR LT LU LV MD MG MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TT UA UG US UZ VN

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): KE MW SD SZ UG AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 1995930062

Country of ref document: EP

ENP Entry into the national phase

Ref country code: US

Ref document number: 1997 793854

Date of ref document: 19970422

Kind code of ref document: A

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWP Wipo information: published in national office

Ref document number: 1995930062

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1995930062

Country of ref document: EP