Patent US4574899A successfully refreshed from Google Patents.
US4574899A
Expired / Lapsed
US
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Compensated multi-load cell scale
Assignee: Mettler Toledo International Inc
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Filing: 1984-10-10
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Granted: 1986-03-11
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Expires: 2004-10-10
Abstract
Abstract The present invention relates to an improved scale arrangement comprising three or more load cells which are compensated for both lateral and longitudinal displacement of the load on the scale platter or platform and to a method of accurately compensating the scale so that the output of the scale is independent of the position of the weight on the scale. Only two strain gages are provided for each load cell which gages are connected in a single bridge circuit. Compensating resistor networks are connected to at least certain of the strain gages.
Inventors
- 👤 Neil C. Griffin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:58
CPC Classifications
G; G01; G01G; G01G3/00; G01G3/12; G01G3/14; G01G3/1402; G01G3/1404; G01G3/142
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
96 words
Weighing apparatus comprising a load receiving platform, N load cells supporting said platform, where N is at least four, each of said load cells having only two strain gages mounted thereon, said strain gages being connected in at least one electrical bridge circuit to provide a signal indicative of the magnitude of a load on the platform and compensating resistors connected in circuit with at least one strain gage of at least N-1 of the load cells to make the output of the bridge circuit substantially independent of the location of a load on the platform.
Claim 2
Dependent Claim
96 words
Weighing apparatus comprising a load receiving platform, N load cells supporting said platform, where N is at least four, each of said load cells having only two strain gages mounted thereon, said strain gages being connected in at least one electrical bridge circuit to provide a signal indicative of the magnitude of a load on the platform and compensating resistors connected in circuit with at least one strain gage of at least N-1 of the load cells to make the output of the bridge circuit substantially independent of the location of a load on the platform.
Claim 3
Dependent Claim
57 words
Weighing apparatus as claimed in claim 1 and wherein the gages of each arm of the bridge circuit are in series, the respective gages of each load cell are positioned adjacent each other in different arms of the bridge, and a compensating resistor is connected across the combination of adjacent gages of three of the load cells.
Claim 4
Dependent Claim
18 words
Weighing apparatus as claimed in claim 1 wherein the compensating resistors are connected in series with the gages.
Claim 5
Dependent Claim
18 words
Weighing apparatus as claimed in claim 1 wherein the compensating resistors are connected in parallel with the gages.
Claim 6
Dependent Claim
34 words
Weighing apparatus as claimed in claim 1 wherein said load cells are beams constructed as integral parts of said platform, each beam having a free end and a fixed end merging into said platform.
Claim 7
Dependent Claim
63 words
Weighing apparatus as claimed in claim 1 wherein each load cell has a strain gage subject to tension and a strain gage subject to compression, corresponding gages from each of N/2 load cells connected in one arm of the bridge circuit and the other gage from each of the same N/2 load cells connected in the same adjacent arm of the bridge circuit.
Claim 8
Dependent Claim
13 words
Weighing apparatus as claimed in claim 1 wherein N is equal to four.
Claim 9
Independent Claim
145 words
A method of compensating a scale having at least three load cells and no more than two strain gages per load cell, comprising the steps of arranging the strain gages of the load cells in a bridge circuit to provide an output signal representative of a load on the scale, placing a load on the scale sequentially in a number of locations and obtaining a load indication for each of said locations, utilizing said load indications to calculate the values of compensating resistors required to be connected in circuit with certain of the strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale, and connecting said compensating resistors in circuit with the appropriate strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale.
Claim 10
Independent Claim
145 words
A method of compensating a scale having at least three load cells and no more than two strain gages per load cell, comprising the steps of arranging the strain gages of the load cells in a bridge circuit to provide an output signal representative of a load on the scale, placing a load on the scale sequentially in a number of locations and obtaining a load indication for each of said locations, utilizing said load indications to calculate the values of compensating resistors required to be connected in circuit with certain of the strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale, and connecting said compensating resistors in circuit with the appropriate strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale.
Claim 11
Dependent Claim
68 words
A method as claimed in claim 8 for compensating a scale having no more than four load cells, including the steps of arranging the gages of each arm of the bridge circuit in series, arranging the respective gages of each load cell adjacent each other in different arms of the bridge, and connecting a compensating resistor across the combination of adjacent gages of some of the load cells.
Claim 12
Dependent Claim
20 words
A method as claimed in claim 8 including the step of connecting compensating resistors in series with the appropriate gages.
Claim 13
Dependent Claim
20 words
A method as claimed in claim 8 including the step of connecting compensating resistors in parallel with the appropriate gages.
Claim 14
Dependent Claim
69 words
A method as claimed in claim 8 for compensating N load cells each having a strain gage subject to tension and a strain gage subject to compression, including the steps of connecting corresponding gages from each of N/2 load cells in one arm of the bridge circuit and connecting the other gage from each of the same N/2 load cells in the same adjacent arm of the bridge circuit.
Claim 15
Dependent Claim
70 words
A method as claimed in claim 8 wherein said scale has four load cells and said load indications are utilized to calculate the values of compensating resistors required to be connected in circuit with at least one of the strain gages of each of at least three of the load cells to render the output of said bridge circuit substantially independent of the location of a load on the scale.
Claim 16
Independent Claim
157 words
A method of compensating a scale having N load cells, where N is at least 4, and no more than two strain gages per load cell, comprising the steps of arranging the strain gages of the load cells in a bridge circuit to provide an output signal representative of a load on the scale, placing a load on the scale sequentially in a number of locations and obtaining a load indication for each of said locations, utilizing said load indications to determine the values of compensating resistors required to be connected in circuit with at least one strain gage of at least N-1 of the load cells to render the output of said bridge circuit substantially independent of the location of a load on the scale, and connecting said compensating resistors in circuit with the appropriate strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale.
Claim 17
Independent Claim
157 words
A method of compensating a scale having N load cells, where N is at least 4, and no more than two strain gages per load cell, comprising the steps of arranging the strain gages of the load cells in a bridge circuit to provide an output signal representative of a load on the scale, placing a load on the scale sequentially in a number of locations and obtaining a load indication for each of said locations, utilizing said load indications to determine the values of compensating resistors required to be connected in circuit with at least one strain gage of at least N-1 of the load cells to render the output of said bridge circuit substantially independent of the location of a load on the scale, and connecting said compensating resistors in circuit with the appropriate strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale.
Claim 18
Dependent Claim
18 words
A method as claimed in claim 14 wherein the values of the compensating resistors are determined by calculation.
Claim 19
Independent Claim
106 words
The method of compensating scales having a platform supported by at least three load cells connected in an electrical bridge circuit, which method comprises the steps of (1) determining the response of each load cell by placing a test weight over each load cell, (2) calculating attenuated responses for the respective load cells in small decrements until the responses of the respective load cells are all substantially equal, and (3) calculating from said responses the magnitudes of compensating resistors to be connected to the respective load cells so that the response of the scale is substantially independent of the position of the load on the platform.
Claim 20
Independent Claim
106 words
The method of compensating scales having a platform supported by at least three load cells connected in an electrical bridge circuit, which method comprises the steps of (1) determining the response of each load cell by placing a test weight over each load cell, (2) calculating attenuated responses for the respective load cells in small decrements until the responses of the respective load cells are all substantially equal, and (3) calculating from said responses the magnitudes of compensating resistors to be connected to the respective load cells so that the response of the scale is substantially independent of the position of the load on the platform.
Claim 21
Dependent Claim
20 words
The method of compensating scales in accordance with claim 16 including repeating the steps of the method of claim 16.
Claim 22
Dependent Claim
98 words
A scale arrangement comprising in combination a scale platform, a plurality of at least four load cells supporting the platform, each load cell having a single strain gage responsive to tension and a single strain gage responsive to compression, an electrical bridge circuit comprising the strain gages of each load cell connected in adjacent arms of the bridge circuit, and a single resistor connected to both of the strain gages of at least three of the load cells so that the output of the bridge circuit is substantially independent of the position of a load on the platform.
Claim 23
Dependent Claim
98 words
A scale arrangement comprising in combination a scale platform, a plurality of at least four load cells supporting the platform, each load cell having a single strain gage responsive to tension and a single strain gage responsive to compression, an electrical bridge circuit comprising the strain gages of each load cell connected in adjacent arms of the bridge circuit, and a single resistor connected to both of the strain gages of at least three of the load cells so that the output of the bridge circuit is substantially independent of the position of a load on the platform.
Claim 24
Dependent Claim
99 words
A scale arrangement comprising in combination a scale platform, a plurality of at least four load cells supporting the platform, each load cell having a single strain gage responsive to tension and a single strain gage responsive to compression, an electrical bridge circuit comprising the strain gages of each load cell connected in adjacent arms of the bridge circuit, and a resistor connected between intermediate points of at least three pairs of adjacent arms of the bridge circuit so that the output of the bridge circuit is substantially independent of the position of a weight on the scale platform.
Claim 25
Dependent Claim
99 words
A scale arrangement comprising in combination a scale platform, a plurality of at least four load cells supporting the platform, each load cell having a single strain gage responsive to tension and a single strain gage responsive to compression, an electrical bridge circuit comprising the strain gages of each load cell connected in adjacent arms of the bridge circuit, and a resistor connected between intermediate points of at least three pairs of adjacent arms of the bridge circuit so that the output of the bridge circuit is substantially independent of the position of a weight on the scale platform.
Claim 26
Dependent Claim
29 words
Weighing apparatus as claimed in claim 28 wherein said compensating resistors are connected in circuit with individual strain gages to modify the response of the respective individual strain gage.
Claim 27
Dependent Claim
52 words
A method as claimed in claim 8 including the step of utilizing the load indications in calculating the values of compensating resistors required to be connected in circuit with certain individual strain gages to render the output of the bridge circuit substantially independent of the location of a load on the scale.
Claim 28
Independent Claim
126 words
A method of compensating a scale having a platform supported by at least three load cells connected in an electrical bridge circuit, comprising the steps of determining the responses of at least some of the load cells by placing a test weight over each of those load cells in sequence and reading the outputs of the bridge circuit, calculating attenuated responses for those load cells in small decrements until the differences in the responses of the load cells are minimized within desired limits, and calculating from said responses the magnitudes of compensating resistors to be connected to at least some of those load cells so that changes in the response of the scale with changes in the position of the load on the platform are reduced.
Claim 29
Independent Claim
126 words
A method of compensating a scale having a platform supported by at least three load cells connected in an electrical bridge circuit, comprising the steps of determining the responses of at least some of the load cells by placing a test weight over each of those load cells in sequence and reading the outputs of the bridge circuit, calculating attenuated responses for those load cells in small decrements until the differences in the responses of the load cells are minimized within desired limits, and calculating from said responses the magnitudes of compensating resistors to be connected to at least some of those load cells so that changes in the response of the scale with changes in the position of the load on the platform are reduced.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |