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US5509293A
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Dynamic payload monitor
Assignee: Caterpillar Inc
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Filing: 1994-12-20
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Granted: 1996-04-23
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Expires: 2014-12-20
Abstract
Abstract A method for dynamically measuring and indicating payload weight for a machine having at least one lift cylinder for elevating a payload carrier is provided. The method includes the steps of lifting a load of known mass during calibrating and sensing a calibration lift cylinder velocity during calibration. To determine payload, lift cylinder hydraulic pressure and lift cylinder extension are sensed during a lifting operation of the machine. A first estimate of the payload is determined as a function of the lift cylinder hydraulic pressure and extension. The method further includes the steps of determining an operating lift cylinder velocity during the lifting operation and determining a velocity correction factor as a function of the calibration lift cylinder velocity and the operating lift cylinder velocity. A second estimate of the payload is calculated as a function of the first estimate and the velocity correction factor.
Inventors
- 👤 Arundhati Karumanchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:40
CPC Classifications
G; G01; G01G; G01G19/00; G01G19/08; G01G19/10; G01G23/00; G01G23/01
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
143 words
A method for dynamically measuring and indicating payload weight for a machine having at least one lift cylinder for elevating a payload carrier, including the steps of: lifting a load of known mass during a calibration operation; sensing a calibration lift cylinder velocity during said calibration operation; lifting a load of an unknown mass during a lifting operation; sensing a lift cylinder hydraulic pressure during said lifting operation; sensing a lift cylinder extension during said lifting operation; determining a first estimate of the payload as a function of said lift cylinder hydraulic pressure and extension; determining an operating lift cylinder velocity during said lifting operation; determining a velocity correction factor as a function of said calibration lift cylinder velocity and operating lift cylinder velocity; calculating a second estimate of the payload as a function of said first estimate and said velocity correction factor.
Claim 2
Independent Claim
143 words
A method for dynamically measuring and indicating payload weight for a machine having at least one lift cylinder for elevating a payload carrier, including the steps of: lifting a load of known mass during a calibration operation; sensing a calibration lift cylinder velocity during said calibration operation; lifting a load of an unknown mass during a lifting operation; sensing a lift cylinder hydraulic pressure during said lifting operation; sensing a lift cylinder extension during said lifting operation; determining a first estimate of the payload as a function of said lift cylinder hydraulic pressure and extension; determining an operating lift cylinder velocity during said lifting operation; determining a velocity correction factor as a function of said calibration lift cylinder velocity and operating lift cylinder velocity; calculating a second estimate of the payload as a function of said first estimate and said velocity correction factor.
Claim 3
Dependent Claim
27 words
A method, as set forth in claim 1, including the step of defining a velocity correction factor curve having an endpoint at said calibration lift cylinder velocity.
Claim 4
Dependent Claim
16 words
A method, as set forth in claim 2, wherein said velocity correction factor curve is linear.
Claim 5
Independent Claim
72 words
A method for determining a velocity correction factor to be used in determining a payload weight for a machine having at least one lift cylinder for elevating a payload carrier, including the steps of: lifting a known mass during a calibration operation; sensing a calibration lift cylinder velocity during said calibration operation; and determining the velocity correction factor as a function of said calibration lift cylinder velocity and operating lift cylinder velocity.
Claim 6
Independent Claim
72 words
A method for determining a velocity correction factor to be used in determining a payload weight for a machine having at least one lift cylinder for elevating a payload carrier, including the steps of: lifting a known mass during a calibration operation; sensing a calibration lift cylinder velocity during said calibration operation; and determining the velocity correction factor as a function of said calibration lift cylinder velocity and operating lift cylinder velocity.
Claim 7
Dependent Claim
27 words
A method, as set forth in claim 4, including the step of defining a velocity correction factor curve having an endpoint at said calibration lift cylinder velocity.
Claim 8
Dependent Claim
16 words
A method, as set forth in claim 5, wherein said velocity correction factor curve is linear.
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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) | 1999-04-23 | 1999-10-23 | 2000-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-04-23 | 2003-10-23 | 2004-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-04-23 | 2007-10-23 | 2008-04-23 | $7700.00 | Window Closed / Lapsed |