US3692129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Load cell weighing systems
Assignee: HOWE RICHARDSON Co
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Filing: 1971-04-12
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Granted: 1972-09-19
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Expires: 1991-04-12
Abstract
Abstract An electrical load cell-type weighing system having a plurality of load cells supporting a load-receiving structure and providing electrical potentials, the sum of which is a function of the weight of a load applied to the load-receiving structure. Summing resistor networks directly connect the load cell bridges independently of each other to a summing junction of a single ended operational summing amplifier. The potentials produced by the load cells are algebraically summed at the summing junction. Another disclosed feature pertains to a defective load cell testing circuit comprising a switch for selectively providing a short circuit connection across the output terminals of each load cell bridge to determine whether the load cell is defective. Another feature pertains to a special operational amplifier summing network which selectively provides weight measurements in different units of mass such as pounds and kilograms.
Inventors
- 👤 Chapin A Pratt
- 👤 Gilbert A Godwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:46
CPC Classifications
G; G01; G01G; G01G3/00; G01G3/12; G01G3/14; G01G19/00; G01G19/02; G01G19/021; G01G3/142; Y; Y10; Y10S; Y10S177/00; Y10S177/03
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
151 words
In a weighing system, a structure for receiving a load to be weighed, a plurality of load cells supporting said structure and being operative to develop a corresponding plurality of potentials, the sum of said potentials being a function of the weight of the load applied to said platform, a single ended operational summing amplifier, signal utilization means operatively connected to the output of said amplifier, a summing junction connected to an input terminal of said amplifier, a summing resistor network independently connecting each of the load cells to said summing junction for applying the load celldeveloped potentials to said junction without amplification, and feedback means connected between said junction and the output of said amplifier and cooperating with said amplifier to provide at the output of said amplifier an electrical signal with a value that is a function of the algebraic summation of the signals applied to said summing junction.
Claim 2
Dependent Claim
151 words
In a weighing system, a structure for receiving a load to be weighed, a plurality of load cells supporting said structure and being operative to develop a corresponding plurality of potentials, the sum of said potentials being a function of the weight of the load applied to said platform, a single ended operational summing amplifier, signal utilization means operatively connected to the output of said amplifier, a summing junction connected to an input terminal of said amplifier, a summing resistor network independently connecting each of the load cells to said summing junction for applying the load celldeveloped potentials to said junction without amplification, and feedback means connected between said junction and the output of said amplifier and cooperating with said amplifier to provide at the output of said amplifier an electrical signal with a value that is a function of the algebraic summation of the signals applied to said summing junction.
Claim 3
Dependent Claim
90 words
The weighing system defined in claim 1 wherein each load cell includes a bridge circuit having a pair of input terminals and a pair of output terminals, power source means for applying a D.C. potential across the input terminals of each load cell bridge circuit, the potentials applied to the input terminals of said bridge circuits being flOating with respect to a source of reference potential, said amplifier having an inverting input terminal connected to said summing junction and a non-inverting input terminal connected to said source of reference potential.
Claim 4
Dependent Claim
52 words
The weighing system defined in claim 2 wherein each summing resistor network comprises a summing resistor connected between one output terminal of its associated load cell bridge circuit and said summing junction, and wherein the other output terminal of each load cell bridge circuit is connected to said source of reference potential.
Claim 5
Dependent Claim
28 words
The weighing system defined in claim 3 wherein means are provided for selectively providing a short circuit path across the output terminals of each load cell bridge circuit.
Claim 6
Dependent Claim
58 words
The weighing system defined in claim 3 wherein a selectively actuatable switch is provided for each of said load cell and is connected between the output terminals of its associated load cell bridge circuit, each of the switches being selectively actuatable to provide a short circuit path across the output terminals of its associated load cell bridge circuit.
Claim 7
Dependent Claim
40 words
The weighing system defined in claim 2 wherein each summing resistor network comprises a summing resistor and a load cell trimming potentiometer connected in series between one output terminal of its associated load cell bridge circuit and said summing junction.
Claim 8
Dependent Claim
93 words
The weighing system defined in claim 2 wherein each summing resistor network comprises a pair of summing resistors and selectively actuatable means for alternatively connecting said summing resistors in the active circuit between said summing junction and one output terminal of the associated one of said load cell bridge circuits to provide a current path between said one output terminal and said summing junction, said summing resistors respectively having different pre-selected values that respectively provide for the read-out of the weight of said load in terms of two different pre-selected units of mass.
Claim 9
Dependent Claim
47 words
The weighing system defined in claim 2 comprising means in each summing resistor network for selectively altering the summing resistor value between each bridge circuit and said summing junction to alternatively provide for the read-out of the weight of said load in different pre-selected units of mass.
Claim 10
Dependent Claim
89 words
In a weighing system, a structure for receiving a load to be weighed, at least one load cell having a bridge circuit, said bridge circuit having a pair of input terminals and a pair of output terminals, means for applying a potential across said input terminals, said load cell being operatively associated with said structure to develop a potential across said output terminals that is a function of the weight of a load applied to said structure, and means for selectively providing a short circuit across said output terminals.
Claim 11
Dependent Claim
89 words
In a weighing system, a structure for receiving a load to be weighed, at least one load cell having a bridge circuit, said bridge circuit having a pair of input terminals and a pair of output terminals, means for applying a potential across said input terminals, said load cell being operatively associated with said structure to develop a potential across said output terminals that is a function of the weight of a load applied to said structure, and means for selectively providing a short circuit across said output terminals.
Claim 12
Dependent Claim
40 words
The weighing system defined in claim 9 including amplifier means and signal utilization means connected to the output of said amplifier means, and means for applying the potential at said output terminals to the input circuit of said amplifier means.
Claim 13
Dependent Claim
57 words
The weighing system defined in claim 9 including an operational amplifier, a summing junction connected to the input of said amplifier, signal utilization means connected to the output of said amplifier, one of said output terminals being connected to said summing junction and the other of said output terminals being connected to a source of reference potential.
Claim 14
Dependent Claim
24 words
The weighing system defined in claim 11 wherein said means for providing a short circuit across said output terminals comprises a selectively actuatable switch.
Claim 15
Dependent Claim
183 words
In a weighing system, a structure for receiving a load to be weighed, a plurality of load cells supporting said structure and each having a bridge circuit, each bridge circuit having a pair of input terminals and a pair of output terminals, means for applying a potential across the input terminals of each bridge circuit, and said load cells being operative to respectively develop potentIals across their output terminals, the sum of said potentials being a function of the weight of the load applied to said structure, an operational amplifier, signal utilization means connected to the output of said amplifier, a summing junction connected to the input of said amplifier, means for connecting said bridge circuits to said summing junction independently of each other and including summing resistor means connected between one output terminal of each bridge circuit and said summing junction, and means for selectively providing a short circuit across the output terminals of each bridge circuit to remove the potential applied by each bridge circuit to said summing junction independently of the potentials applied by each of the other bridge circuits.
Claim 16
Dependent Claim
183 words
In a weighing system, a structure for receiving a load to be weighed, a plurality of load cells supporting said structure and each having a bridge circuit, each bridge circuit having a pair of input terminals and a pair of output terminals, means for applying a potential across the input terminals of each bridge circuit, and said load cells being operative to respectively develop potentIals across their output terminals, the sum of said potentials being a function of the weight of the load applied to said structure, an operational amplifier, signal utilization means connected to the output of said amplifier, a summing junction connected to the input of said amplifier, means for connecting said bridge circuits to said summing junction independently of each other and including summing resistor means connected between one output terminal of each bridge circuit and said summing junction, and means for selectively providing a short circuit across the output terminals of each bridge circuit to remove the potential applied by each bridge circuit to said summing junction independently of the potentials applied by each of the other bridge circuits.
Claim 17
Dependent Claim
48 words
The weighing system defined in claim 13 wherein said short circuit providing means comprises a switch connected across the output terminals of each bridge circuits, said switches being selectively actuatable independently of each other to establish the short circuits across the associated pairs of bridge circuit output terminals.
Claim 18
Dependent Claim
28 words
The weighing system defined in claim 13 wherein the other of said output terminals of each pair of output terminals is connected to a source of reference potential.
Claim 19
Dependent Claim
154 words
In a weighing system, a structure for receiving a load to be weighed, at least one load cell operatively connected to said structure for developing a D.C. output potential that is a function of the weight of a load applied to said structure, an operational amplifier, a summing junction connected to the input of said amplifier, a summing resistor network electrically connecting said load cell to said summing junction, signal read-out means, means electrically connecting the output of said amplifier to said read-out means to provide for the read-out of the weight of the applied load under the control of the potential at the output of said amplifier, and means in said network for selectively altering the summing resistor value between said load cell and said summing junction to alternately provide for the read-out of the weight of the applied load at said read-out means in a plurality of different pre-selected units of mass.
Claim 20
Dependent Claim
154 words
In a weighing system, a structure for receiving a load to be weighed, at least one load cell operatively connected to said structure for developing a D.C. output potential that is a function of the weight of a load applied to said structure, an operational amplifier, a summing junction connected to the input of said amplifier, a summing resistor network electrically connecting said load cell to said summing junction, signal read-out means, means electrically connecting the output of said amplifier to said read-out means to provide for the read-out of the weight of the applied load under the control of the potential at the output of said amplifier, and means in said network for selectively altering the summing resistor value between said load cell and said summing junction to alternately provide for the read-out of the weight of the applied load at said read-out means in a plurality of different pre-selected units of mass.
Claim 21
Dependent Claim
75 words
The weighing system defined in claim 16 wherein said network comprises a pair of summing resistors respectively having different pre-selected values to respectively provide for the read-out of the weight of said load in two different preselected units of mass at said read-out means, and wherein said selectively actuatable means is actuatable to alternatively connect said resistors in the active circuit between said load cell and said summing junction to provide a current path therebetween.
Claim 22
Dependent Claim
111 words
The weighing system defined in claim 16 wherein said network comprises a pair of separate circuit branches respectively having first and second summing resistors, said summing resistors respectively having different pre-selected values that respectively provide for the read-out of the weight of said load in two different pre-selected units of mass, and wherein said selectively actuatable means comprises switching means in each of said branches for alternatively connecting said summing resistors in an active circuit between said load cell and said summing junction to provide a current path through the one of the summing resistor in the active circuit for thereby applying the load cell output potential to said summing junction.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |