GB2098744A - Temperature compensated force or pressure sensing apparatus - Google Patents
Temperature compensated force or pressure sensing apparatus Download PDFInfo
- Publication number
- GB2098744A GB2098744A GB8214106A GB8214106A GB2098744A GB 2098744 A GB2098744 A GB 2098744A GB 8214106 A GB8214106 A GB 8214106A GB 8214106 A GB8214106 A GB 8214106A GB 2098744 A GB2098744 A GB 2098744A
- Authority
- GB
- United Kingdom
- Prior art keywords
- generating
- representative
- temperature
- force
- signal
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G23/00—Auxiliary devices for weighing apparatus
- G01G23/01—Testing or calibrating of weighing apparatus
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
- G01G3/18—Temperature-compensating arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L27/00—Testing or calibrating of apparatus for measuring fluid pressure
- G01L27/002—Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination
- G01L27/005—Apparatus for calibrating pressure sensors
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
- Measuring Fluid Pressure (AREA)
- Measurement Of Force In General (AREA)
Abstract
Temperature compensated force sensing apparatus for sensing force on a force input member (212), comprising: A. means (250) for storing a calibration function W(F,T) where <IMAGE> where F is a function of the input force, T is representative of the temperature of said system, and where <IMAGE> where Kij are constants, B. means (244) for generating a sensor signal FW, where FW is representative of the input force at the temperature of said system, C. means (250) for generating a temperature signal FT, where FT is representative of the temperature of said system, D. means (250) for generating a force signal for said object from said stored calibration function, including means for evaluation W(F,T), where F=FW and T=FT. The same principles can be applied to a pressure sensing apparatus. <IMAGE>
Description
SPECIFICATION
Temperature compensated force sensing apparatus
The present invention is in the field of instrumentation, and more particularly, relates to force and pressure measuring systems.
Typical prior art force measuring systems in the form of scales, for example, include a plafform, or weighing pan, for receiving the weight to be measured. The weighing pan is coupled by a force transducer to a support member, or frame. In various forms of the prior art sensing systems, the transducer and weighing pan are coupled to the support member by linkages adapted to permit relatively accurate weight sensing for objects in the pan. By way of example, the force sensors might incorporate strain gauges, or a movable coil in a fixed magnetic field in a feedback arrangement.
While the prior art weighing systems do provide a relatively accurate measure of objects placed in the weighing pan, there are a number of shortcomings of the known systems. For example, many such systems are particularly sensitive to off-center loading of the object-to-be-measured in the weighing pan. Such off-center loading may give rise to errors due to frictional losses in the system. To counteract such losses, the prior art scale systems often utilize various forms of mechanical linkages for reducing such errors. For example, U.S. Patent No. 4,026,416 discloses a flexure arrangement restricting motion of the weighing pan along a single sensing axis. However, such systems are relatively limited in their range of motion and thus the range of weights permitted.
A further disadvantage of many of the prior art systems is variation of those systems with temperature, such as may be due to the temperature effects on the sensing transducer and associated circuitry, as well as temperature variation of the various mechanical assemblies.
Accordingly, it is an object of the present invention to provide a high accuracy and high precision weighing system which is compensated for variations in temperature of the system.
It is another object to provide a pressure measuring system which is compensated for variations in temperature of the system.
The present invention is temperature compensated force sensing apparatus for sensing force on a force input member comprising: A. means for storing a calibration function W(F, T) where
where F is a function of the input force, T is representative of the temperature of said system, and where
where Kij are constants, B. means for generating a sensor signal Fw, where Fw is representative of the input force at the temperature of said system C. means for generating a temperature signal FT, where FT iS representative of the temperature of said system, D. means for generating a force signal for said object from said stored calibration function, including means for evaluating W(F,T), where F=Fw and T=FT.
With this configuration, the system provides an output signal, i.e. the force signal, which is representative of the input force, i.e. the weight of the object in the pan.
According to another aspect of the invention, the system includes an apparatus for generating the calibration function W(F,T). The calibration generator includes a device for generating a succession of sensor signals in response to the application of a succesion of m predetermined weights to the weighing pan while the system is at each of n different temperatures, T1, T2 , T,, respectively. The calibration generator further includes a device for solving the calibration function W(F,T) for aj(T) and generating coefficient signals representative of ai(T) for each of then temperatures. The calibration is solved for values of i = 1, 2,...., and m, and where F equals a respective one of the sensor signals generated at the associated temperature, and where W(F,T) equals the respective weights associated with the sensor signals.
The calibration generator further includes a device for solving aj(T) for K1 and generating signals representative of K for each i value. A1(T) is solved for j=1,2,..., and n and where aj(T) equals the respective one of the coefficient signals associated with the temperatures T1,T2,...,Tn and T equals the respective temperatures associated with those coefficient signals.
In one embodiment of the invention, the devices for solving W(F,T) and aj(T) is a programmed digital computer. In a preferred form, m equals 4 and n equals 3.
In an embodiment of the invention adapted for pressure measurement, the sensor signal generator is adapted to generate a signal Fw which is representative of an input pressure. The calibration function is the same function of F and T, but F is a function of input pressure.
The apparatus of the present invention, in the force measurement form, is also useful as an accelerator transducer, i.e. where the input force is an inertial force applied to the force input member.
Embodiments of the present invention will now be described, by way of example, with reference the accompanying drawings, in which Figure 1 shows in schematic form a weighing system embodying the present invention;
Figure 2 shows in block diagram form the processor of the system of Figure 1; and
Figure 3 shows in block diagram form a pressure measuring system embodying the present invention.
Figure 1 shows a schematic representation of a weighing system 210 in accordance with the present invention. That system includes force input member in the form of a weighing pan 212 and associated support post 214 adapted for motion along a reference axis 216. The post 214 is coupled by way of a mechanical damper assembly 218 to a reference member (or housing) 220 which is fixed with respect to axis 216. The pan 212 and its support post 214 are coupled to an armature member 226 by a parallel motion linkage assembly 160. The armature member 226 is coupled by a parallel motion linkage assembly 110 to the support member 220. A force transducer 10 is coupled between the armature member 226 and the support member 220. The transducer 10 is coupled by line 10a to a position sensor 244.Position sensor 244 in turn provides an output signal on line 244a which is representative of the motion of an element of the force transducer 10 which is due to displacement of pan 212 from the weight to be measured in that pan.
A processor 250 is responsive to the signal on line 244a to provide an output signal on line 250a. The latter signal is representative of the weight of the object on the weighing pan 212.
By way of example, the elements in system 210 may be of the same form as those correspondingly numbered elements described in the incorporated reference U.S. Patent Application Serial No. (SET113).
Figure 2 shows the processor 250 of system 210 in block diagram form. The processor 250 includes a first (or weight) oscillator which provides a signal on line 244a which has a frequency representative of the detected force applied by a weight on pan 212. The height oscillator includes the force transducer 10 and position sensor 244 as described in the incorporated reference. The signal on line 244a is coupled to a counter 260 which provides a digital count signals Fw on line 260a (Fw), which are representative of the frequency of the signal on line 244a.
Atemperature sensor 264 provides an oscillatory signal on line 264a in which the frequency of the signal on that line is representative of the temperature of the system 210. The signal on line 264a is coupled to a counter 266 which provides digital count signals (FT) on line 266a which are representative of the frequency of the signal on line 264a. Lines 260a and 266a are applied to a microprocessor 270.
Microprocessor 270 includes an associated random access memory (RAM) 272 and a read only memory (ROM) 274, and an input/output keyboard 276. Microprocessor 270 also provides an output signal on line 250a suitable for driving a conventional display. A timing network 280 provides timing control signals to the blocks in processor 250.
In one form of the invention, the microprocessor may be a Mostek type 38P70/02, ROM 274 is a Hitachi type HM462532, and a RAM 272 is an NCR type 2055.
In operation, the signals on line 244a and 264a are characterized by frequencies representative of the weight of an object on a pan and the temperature of system 210, respectively. The counters 260 and 266 are controlled by the timing network 280 in order to act as window counters providing digital counts representative of the frequencies of the signals on line 244a and 264a (Fw and FT).
Generally, the memory 272 stores data representative of a calibration function W(F,T).
The calibration function W(F,T) is defined as
where F is representative of the weight of an object and T is representative of the temperature of the weighing system 210. In this definition,
where K1 are constants. In the present embodiment, m=4 and n=3. Generally, the values Fw and FT may be used to evaluate the calibration function to provide a value representative of the weight of an object on the pan 212.
The present embodiment may also be used in a calibration mode to generate the calibration function and store data representative of that function in memory 272. To perform this calibration procedure with the present embodiment, a succession of four known weights are deposited on the pan 212 at each of three temperatures. In other embodiments, different numbers of weights and temperatures may be used.
The processor 250 then in effect generates a set of four simultaneous equations where based on W(F,T) where that function is set equal to each of the weights and the detected value for Fw for each weight is plugged in for F. Processor 250 solves these four simultaneous equations to provide signals representative of a1 evaluated at temperatures Ta, T2 and T3, a2 evaluated at temperatures T1, T2, and T3, a3 evaluated atT1,
T2, and T3, and a4 evaluated at Ta, T2, and T3.
Processor 250 then uses these resultant values for a1 to solve the function a1(T) for Kjj. Generally, the three values for a1 (i.e. at the temperature T1, T2, and T3) is set equal to the three values of a1, (i.e. at the three different temperatures T1, T2, and T3.) is solved for the values of K", K12, and K13.
Similarly, the values of a2 at the three temperatures is used to determine K2r, K22, and K23, and the values for a3 are used to determine K3a, K32, and K33 and the values of a4 are used to determine K4a, K42, K43.
Following the determination of these values for Ki1, the calibration function W(F,T) is fully specified. Data representative of these values is stored in RAM 272.
In a general calibration mode, Processor 250 determines a "calibration surface" for the weighing system 210, where a weight value (W) is a function of the frequency of the oscillator of sensor 244 (F) for applied weights and the temperature of system 210 (T). This functional relationship W(F,T) which describes the calibration surface for a system 210 is referred to as the calibration function. A succession of reference weights are placed on the weighing pan 212 at each of a number of temperatures. In response to the placement of the weights on the pan 212, the force on the pan from the weight are transferred to the force transducer 10, with the linkages 160 and 110 minimizing the effect of moments applied about axis 216 (such as might arise from off-center loading of the weight).The forces applied to the transducer 10 causes a relative movements of the conductive surfaces of that transducer, resulting in a capacitance changes. Those capacitance changes cause a corresponding changes in the output frequency of the oscillator on line 244a.
The processor then utilizes those valves in the manner described above to fully define W(F,T) and then stores data representative of this function in RAM 272.
In the weight measuring mode, in response to the placement of the weight-to-be-measured on the pan 212, the Processor 250 utilizes those signals (on line 244a) in conjunction with the signal from the temperature oscillator 264 (on line 264a) to identify the value of the calibration function W(F,T) at the corresponding values for F and T. That value of W(F,T) is converted to a signal representative of the weight on the pan 212 at the current temperature of the system 210.
Figure 3 shows in block diagram form, a pressure measuring system 278 which includes a pressure sensor 280 and processor 250. In the preferred form, pressure sensor 280 is an oscillator which includes a capacitive pressure transducer (such as the model 270, manufactured by Setra Systems, Inc., having a deformable diaphragm) as the sensing element. In general the system 280 operates in a manner substantially the same as the configuration of Figure 1, except that sensor 280 provides an oscillatory signal characterized by a frequency which is a function of the input pressure.
Claims (9)
1. Temperature compensated force sensing apparatus for sensing force on a force input member, comprising:
A. means for storing a calibration function W(F,T) where
where F is a function of the input force, T is representative of the temperature of said system, and where
where Kij are constants,
B. means for generating a sensor signal Fw, where Fw is representative of the input force at the temperature of said system,
C. means for generating a temperature signal FT, where FT iS representative of the temperature of said system,
D. means for generating a force signal for said object from said stored calibration function, including means for evaluating W(F,T), where F=Fw and T=FT.
2. Apparatus as claimed in claim 1, further comprising calibration means for generating said calibration function W(F,T), said calibration means including:
A. means for generating a succession of sensor signals in response to the application of a succession of m predetermined forces to said pan with said system being at each of n temperatures T1, T2 Tn, B. means for solving said calibration function for aj(T) and generating coefficient signals representative of aj(T) for each of said n temperatures, where i=1,2,...,m and where F equals a respective one of the sensor signals generated at the associated temperature, and where W(F,T) equals the respective forces associated with said sensor signals,
C. means for solving aj(T) for Kij and generating signals representative of Kij for each i value,
where j=1,2,...,n and aj(T) equals a respective one of said coefficient signals associated with said temperatures T1,T2,...Tn and T equals the respective temperatures associated with said coefficient signals.
3. Apparatus as claimed in claim 1 or claim 2, in which m=4 and n=3.
4. Apparatus as claimed in claim 1 or claim 2, wherein said sensor signal generating means includes a first oscillator and wherein Fw is representative of the frequency of said first oscillator, and wherein said temperature signal generating means includes a second oscillator and wherein FT iS representative of the frequency of said second oscillator.
5. Temperature compensated pressure measuring apparatus for measuring an input pressure, comprising:
A. means for storing a calibration function W(F,T) where
where F is a function of the input pressure, T is representative of the temperature of said system, and where
where Kij are constants,
B. means for generating a sensor signal Fw, where Fw is representative of the input pressure at the temperature of said system,
C. means for generating a temperature signal FT, where FT iS representative of the temperature of said system,
D. means for generating a pressure signal for said object from said stored calibration function, including means for evaluating W(F,T), where F=Fw and T=FT.
6. Apparatus as claimed in claim 5, further comprising calibration means for generating said calibration function W(F,T), said calibration means including:
A. means for generating a succession of sensor signals in response to the application of a succession of m predetermined pressures to said pan with said system being at each of n temperatures Ta,T2,...,Tn, B. means for solving said calibration function for aj(T) and generating coefficient signals representative of aj(T) for each of said n temperatures, where i=1,2,...,m and where F equals a respective one of the sensor signals generated at the associated temperature, and where W(F,T) equals the respective pressures associated with said sensor signals,
C. means for solving aj(T) for Kij and generating signals representative of K1 for each i value,
where j=1,2,...,n and aj(T) equals a respective one of said coefficient signals associated with said temperatures T"T2,...Tn and T equals the respective temperatures associated with said coefficient signals.
7. Apparatus as claimed in claim 5 or claim 6, where m=4 and n=3.
8. Apparatus as claimed in claim 5 or claim 6, wherein said sensor signal generating means includes a first oscillator and wherein Fw is representative of the frequency of said first oscillator, and wherein said temperature signal generating means includes a second oscillator and wherein FT iS representative of the frequency of said second oscillator.
9. Temperature compensated force sensing apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US26508681A | 1981-05-19 | 1981-05-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2098744A true GB2098744A (en) | 1982-11-24 |
| GB2098744B GB2098744B (en) | 1985-01-23 |
Family
ID=23008914
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8214106A Expired GB2098744B (en) | 1981-05-19 | 1982-05-14 | Temperature compensated force or pressure sensing apparatus |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS57196123A (en) |
| CA (1) | CA1171178A (en) |
| CH (1) | CH662656A5 (en) |
| DE (1) | DE3218511C2 (en) |
| GB (1) | GB2098744B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2597598A1 (en) * | 1986-04-21 | 1987-10-23 | Yamato Scale Co Ltd | FORCE MEASURING DEVICE |
| DE3719532A1 (en) * | 1986-06-13 | 1987-12-17 | Yamato Scale Co Ltd | FORCE MEASURING DEVICE |
| WO1995023956A1 (en) * | 1994-03-04 | 1995-09-08 | Precision Transducers Limited | Improvements in measuring apparatus |
| ES2136573A1 (en) * | 1996-12-16 | 1999-11-16 | Bosch Gmbh Robert | Indicating physical measuring value on measuring unit with analogue indicator |
| WO1999064827A1 (en) * | 1998-06-12 | 1999-12-16 | Rupprecht & Patashnick Company, Inc. | Mass determination device having counterbalanced normalized temperature coefficients |
| CN103946672A (en) * | 2011-12-28 | 2014-07-23 | 富士电机株式会社 | Method for correcting output value of physical quantity sensor apparatus, method for correcting output value of physical quantity sensor, physical quantity sensor apparatus, and apparatus for correcting output value of physical quantity sensor |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59212723A (en) * | 1983-05-18 | 1984-12-01 | Mitsubishi Heavy Ind Ltd | Weighing system |
| DE3318977A1 (en) * | 1983-05-25 | 1984-11-29 | Siemens AG, 1000 Berlin und 8000 München | Measurement value pick-up with an information carrier containing operating data |
| DE3340207A1 (en) * | 1983-11-07 | 1985-05-15 | WTW Wissenschaftlich-technische Werkstätten GmbH, 8120 Weilheim | Method for automatically detecting the temperature dependency of measuring signals |
| DE3340512A1 (en) * | 1983-11-09 | 1985-05-15 | Sartorius GmbH, 3400 Göttingen | ELECTRIC SCALE |
| DE3440378A1 (en) * | 1984-11-05 | 1986-05-22 | Voest-Alpine Friedmann GmbH, Linz | Compensatable measured pressure value generator |
| DE3628178A1 (en) * | 1986-08-20 | 1988-02-25 | Kernforschungsz Karlsruhe | Method for linearising the characteristic of a measurement quantity and arrangement for carrying out the method |
| FR2615618B1 (en) * | 1987-05-22 | 1990-11-30 | Crouzet Sa | DIGITAL COMPENSATION PRESSURE SENSOR |
| DE4324513A1 (en) * | 1993-07-21 | 1995-01-26 | Zwosta Helge Dipl Ing Fh | Method, circuit and measurement pickup for detecting physical quantities by selective measurement of electrical quantities of the response signal |
| JPH086529A (en) * | 1994-06-20 | 1996-01-12 | Chugoku Electric Power Co Inc:The | Liquid crystal panel display device for overhead projector |
| DE19533505A1 (en) * | 1995-09-04 | 1997-03-06 | Siemens Ag | Method for compensating for the incorrect behavior of measuring devices caused by an external influencing variable |
| DE19703359A1 (en) * | 1997-01-30 | 1998-08-06 | Telefunken Microelectron | Process for temperature compensation in measuring systems |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2519727B2 (en) * | 1975-05-02 | 1980-02-21 | Maatschappij Van Berkel's, Patent N.V., Rotterdam (Niederlande) | Method of operating a weighing device |
| GB1495278A (en) * | 1975-06-13 | 1977-12-14 | Avery Ltd W & T | Compensation for weight-independent parameters in weighin |
| US4026416A (en) * | 1975-10-14 | 1977-05-31 | The Raymond Lee Organization, Inc. | Light bulb storage bank |
| DE2604437C3 (en) * | 1976-02-05 | 1981-01-15 | Sartorius Gmbh, 3400 Goettingen | Electromagnetic compensating force measuring or weighing device |
| JPS5542078A (en) * | 1978-09-21 | 1980-03-25 | Tokyo Keiso Kk | Device for measuring flow rate |
-
1982
- 1982-03-31 CA CA000400030A patent/CA1171178A/en not_active Expired
- 1982-05-14 GB GB8214106A patent/GB2098744B/en not_active Expired
- 1982-05-17 DE DE19823218511 patent/DE3218511C2/en not_active Revoked
- 1982-05-18 CH CH310382A patent/CH662656A5/en not_active IP Right Cessation
- 1982-05-19 JP JP8335282A patent/JPS57196123A/en active Granted
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2597598A1 (en) * | 1986-04-21 | 1987-10-23 | Yamato Scale Co Ltd | FORCE MEASURING DEVICE |
| DE3719532A1 (en) * | 1986-06-13 | 1987-12-17 | Yamato Scale Co Ltd | FORCE MEASURING DEVICE |
| WO1995023956A1 (en) * | 1994-03-04 | 1995-09-08 | Precision Transducers Limited | Improvements in measuring apparatus |
| ES2136573A1 (en) * | 1996-12-16 | 1999-11-16 | Bosch Gmbh Robert | Indicating physical measuring value on measuring unit with analogue indicator |
| WO1999064827A1 (en) * | 1998-06-12 | 1999-12-16 | Rupprecht & Patashnick Company, Inc. | Mass determination device having counterbalanced normalized temperature coefficients |
| US6080939A (en) * | 1998-06-12 | 2000-06-27 | Rupprecht & Pataschnick Company, Inc. | Mass determination device having counterbalanced normalized temperature coefficients |
| CN103946672A (en) * | 2011-12-28 | 2014-07-23 | 富士电机株式会社 | Method for correcting output value of physical quantity sensor apparatus, method for correcting output value of physical quantity sensor, physical quantity sensor apparatus, and apparatus for correcting output value of physical quantity sensor |
| US9857782B2 (en) | 2011-12-28 | 2018-01-02 | Fuji Electric Co., Ltd. | Output value correction method for physical quantity sensor apparatus, output correction method for physical quantity sensor, physical quantity sensor apparatus and output value correction apparatus for physical quantity sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| CH662656A5 (en) | 1987-10-15 |
| JPH0247690B2 (en) | 1990-10-22 |
| GB2098744B (en) | 1985-01-23 |
| DE3218511C2 (en) | 1994-02-10 |
| JPS57196123A (en) | 1982-12-02 |
| DE3218511A1 (en) | 1983-03-03 |
| CA1171178A (en) | 1984-07-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4464725A (en) | Temperature compensated measuring system | |
| GB2098744A (en) | Temperature compensated force or pressure sensing apparatus | |
| US4799558A (en) | Digital load shift compensation | |
| US5750937A (en) | Multi-load cell force sensing apparatus | |
| EP0171237B2 (en) | Creep-compensated weighing apparatus | |
| US5336854A (en) | Electronic force sensing load cell | |
| JPH0697169B2 (en) | Sensor signal temperature compensation method | |
| US5056050A (en) | Method for determining the necessity of adjusting a high-resolution electronic balance | |
| US4382479A (en) | Weighing system | |
| WO1996017236A1 (en) | A temperature compensation method in pressure sensors | |
| Lin et al. | Force model identification for magnetic suspension systems via magnetic field measurement | |
| CN207197654U (en) | A kind of micrometer assay balance | |
| JPH03504157A (en) | Pressure or force measuring device | |
| GB2219096A (en) | Weighing machine | |
| US4440251A (en) | Scale with simplified guidance-damper construction | |
| US4750574A (en) | Accurate weight determination at sea | |
| WO2005006397A2 (en) | System and method for load sensing using piezoelectric effect | |
| US3270565A (en) | Omnidirectional acceleration device | |
| KR940022071A (en) | Force meter | |
| GB2087082A (en) | Electrically testing for straightness and evenness | |
| US3791467A (en) | Scale having a restrained movable balancing member | |
| US5183124A (en) | Compact self-adjusting weighing system having stable measurement resolution | |
| Pontius et al. | Inherent problems in force measurement: Some results in the study of force sensor-machine interaction, hysteresis, thermoelastic effect and creep are discussed | |
| US3293920A (en) | Omnidirectional acceleration device | |
| SU1645848A1 (en) | Method of detecting weigher sensing member resilient mounting stiffness |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20020513 |