Dynamic load weighing system
First Claim
1. A method for determining a weight of a load using a lift assembly comprising a weight bearing portion, at least one loadcell sensor located on or adjacent to the weight bearing portion, wherein each loadcell sensor comprises at least one weigh post, and a plurality of strain gauges operatively connected to each weigh post to take measurements of forces acting on the weigh posts, the method comprising:
- pro-calibrating the loadcell sensors of the lift assembly and generating a calibration table;
lifting the load with the lift assembly;
continuously taking strain gauge measurements of the forces acting on the weigh posts in at least two different axes while the load is being lifted;
taking multi-axis force measurements at at least one pre-determined position while the load is being lifted; and
calculating the weight of the load using the multi-axis force measurements and the calibration table,wherein accurate weights of loads can be repeatedly determined without precalibrating the loadcell sensors and generating a new calibration table before each subsequent weight determination.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and device for determining the weight of a load while the load is being lifted by a lift or fork, typically in a lift-return cycle. Loadcell sensors are located close to the lift assembly with each loadcell sensor containing strain gauges attached to weigh posts to take measurements of forces acting in a multiple number of axes. The weight of the load can be calculated using these multi-axis measurements. The ratio of the forces acting in the different axes is used to correlate the measurements taken while the load is lifted and while the load is returned. The analog signals from the strain gauges are converted to digital signals by a analog-digital converter located in the loadcell sensor and transmitted to a computer which calculates the weight of the load with the use of a calibration table.
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Citations
39 Claims
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1. A method for determining a weight of a load using a lift assembly comprising a weight bearing portion, at least one loadcell sensor located on or adjacent to the weight bearing portion, wherein each loadcell sensor comprises at least one weigh post, and a plurality of strain gauges operatively connected to each weigh post to take measurements of forces acting on the weigh posts, the method comprising:
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pro-calibrating the loadcell sensors of the lift assembly and generating a calibration table; lifting the load with the lift assembly; continuously taking strain gauge measurements of the forces acting on the weigh posts in at least two different axes while the load is being lifted; taking multi-axis force measurements at at least one pre-determined position while the load is being lifted; and calculating the weight of the load using the multi-axis force measurements and the calibration table, wherein accurate weights of loads can be repeatedly determined without precalibrating the loadcell sensors and generating a new calibration table before each subsequent weight determination. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for determining a weight of a container engaged by a lift assembly that travels through a lift-return cycle, wherein the lift assembly comprises a weight bearing portion, at least one loadcell sensor located on or adjacent to the weight bearing portion and comprising at least one weigh post, and a plurality of strain gauges operatively connected to each weigh post to take measurements of forces acting on the weigh posts, the method comprising:
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pre-calibrating the loadcell sensors of the lift assembly and generating a calibration table; causing the lift assembly to travel through the lift-return cycle which comprises lifting the container and returning the container; continuously taking strain gauge measurements of the forces acting on the weigh posts in at least two different axes throughout the lift-return cycle; taking multi-axis force measurements at at least one predetermined position while the container is lifted; and calculating the weight of the material using the multi-axis force measurements and the calibration table, wherein accurate weights of containers can be repeatedly determined without precalibrating the loadcell sensors and generating a new calibration table before each subsequent weight determination. - View Dependent Claims (10, 11, 12, 13, 16, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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14. A method for determining a weight of a container engaged by a lift assembly that travels through a lift-return cycle and of material in the container, wherein the lift assembly comprises a load bearing portion, at least one loadcell sensor located on or adjacent to the weight bearing portion, each loadcell sensor having at least one weigh post, and a plurality of strain gauges operatively connected to each weigh post to take measurements of forces acting on the weigh posts, the method comprising:
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pre-calibrating the loadcell sensors of the lift assembly and generating a calibration table; causing the lift assembly to travel through the lift-return cycle which comprises lifting the container, emptying the material from the container and returning the container; continuously taking strain gauge measurements of the forces acting on the weigh posts in at least two different axes throughout the lift-return cycle; taking first multi-axis force measurements of at least one predetermined first position while the container and material are lifted; taking second multi-axis force measurements at at least one predetermined second position while returning the container, wherein the second position correlates to the first position; and calculating the weight of the material and of the container using the first and second multi-axis force measurements and the calibration table, wherein accurate weights of material and containers can be repeatedly determined without pre-calibrating the loadcell sensors and generating a new calibration table before each subsequent weight determination. - View Dependent Claims (15, 17, 18, 19, 20, 21, 22)
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33. An apparatus for weighing a load being lifted by a lifting assembly having a weight bearing portion comprising:
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at least one loadcell sensor positioned on or adjacent to the weight bearing portion of the lifting assembly wherein each loadcell sensor comprises at least one weigh post; a plurality of strain gauges operatively connected to each weigh post to take measurements of forces acting on the weigh post in at least two different axes; and calculating means for calculating the weight of the load using the strain gauge measurements of the forces and for pre-calibrating the loadcell sensors to generate a calibration table, wherein accurate weights of loads can be repeatedly determined without precalibrating the loadcell sensors and generating a new calibration table before each subsequent weight determination. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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Specification