Measuring and testing – Specimen stress or strain – or testing by stress or strain... – Specified electrical sensor or system
Patent
1982-02-18
1984-04-17
Myracle, Jerry W.
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
Specified electrical sensor or system
G01L 122
Patent
active
044427182
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to means for measuring nonelectric parameters and, more particularly, to strain gauges.
BACKGROUND ART
There are known strain gauges of the type that comprises a sensitive element, such as a tensoresistor element, which interacts with a movable support through which a signal, indicative of the value of strain, is applied to the strain gauge. The sensitive element converts the signal to an electric signal to be subsequently processed by an automatic system for processing and recording strain values (cf., e.g., FRG Application No. 2,647,780 cl. G. 01 B 7/16, published Apr. 27, 1978).
One of the crucial problems in connection with strain gauges of this type is the temperature compensation due to changes of the values of deformation depending on the ambient temperature. There are different solutions to the problem (cf., e.g., USSR Inventor's Certificate No. 301,514, cl. G 01B5/30, published in "Discoveries, Inventions, Industrial Designs and Trade Marks" Gazette No. 14, 1971).
In some cases use is made of thermoresistor compensation elements placed in series with the sensitive elements.
It is also common to use mechanical thermocompensation elements of a material possessing a linear thermal expansion coefficient roughly equal to that of the article subjected to strain measurements. There are cases when the mechanical thermocompensation elements and the article subjected to strain measurements are of the same material.
In such strain gauges the mechanical termocompensation element is rigidly attached to a second support and coupled through a tensoresistor sensitive element to a first support which is movable (cf., e.g., British Patents No. 1,469,644, cl. G 01B 5/30 and No. 1,443,771, cl. G 01 B5/30).
All the above gauges are checked and graduated prior to installation on an article to be tested. After a gauge is installed in place, its graduation and checking are either totally impossible or require much time. For example, a strain gauge may be checked by connecting it into one of the arms of a bridge measuring circuit and by comparing the signal appearing across the diagonally opposite pair of junctions of the bridge to the original and supplemented signal of the same gauge.
In fact, the method boils down to checking the electric circuit alone; no provision is made for checking the entire signal circuit, including the mechanical parts of the strain gauge.
DISCLOSURE OF THE INVENTION
The invention is aimed at providing strain gauge and an electric circuit for adjustment and calibration of same that would make it possible to graduate and calibrate the gauge after installation on an article to be tested.
The foregoing aim is attained by providing a strain gauge which comprises a tensoresistor sensitive element interacting with a movable support through which a signal corresponding to the actual strain value is applied to the strain gauge, a thermoresistor compensation element and a mechanical thermocompensation element made of a material whose linear thermal expansion coefficient is about equal to the thermal expansion coefficient of the material of which are article subjected to strain measurements is made and rigidly coupled to a second support and also coupled, through the tensoresistor sensitive element, to the movable support, the strain gauge being characterized, according to the invention, in that it includes a spacer element which separates the tensoresistor sensitive element from the mechanical thermocompensation element and is of a material whose linear thermal expansion coefficient is substantially lower than the thermal expansion coefficient the material of the mechanical thermocompensation element, and in that the latter carries a heater element and a thermoresistor element which are intended to strain the mechanical thermocompensation element according to a program in the course of adjusting and calibrating the strain gauge after it is placed on the article subjected to strain measurements and after it is brought into operation.
The spacer element
REFERENCES:
patent: 2547926 (1951-04-01), Cook
patent: 3853000 (1974-12-01), Barnett et al.
Klokova Nadezhda P.
Komarova Galina N.
Piskov Georgy M.
Podboronov Boris P.
LandOfFree
Strain gauge and electric circuit for adjustment and calibration does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Strain gauge and electric circuit for adjustment and calibration, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Strain gauge and electric circuit for adjustment and calibration will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-89664