Axial load cell
Inventors
Pearlman, Jonathan L. • DUVALL, JONATHAN A. • BUCIOR, SAMUEL T.
Assignees
University of Pittsburgh • US Department of Veterans Affairs
Publication Number
US-11944426-B2
Publication Date
2024-04-02
Expiration Date
2039-01-11
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Abstract
A load cell apparatus includes a base member, a cap member, a number of first members provided between the base member and the cap member and forming at least a portion of a support wall of the load cell apparatus, and a plurality of strain gauges directly coupled to the number of first members, the plurality of strain gauges being positioned to measure an axial load applied to the load cell in a direction extending from the cap member to the base member.
Core Innovation
The invention provides a load cell apparatus comprising a base member, a cap member, a number of first members positioned between the base and cap members forming at least part of a support wall, and multiple strain gauges directly coupled to these first members. These strain gauges are arranged to measure axial loads applied in a direction from the cap member to the base member.
This invention addresses the limitations in conventional weight measurement tools, especially for wheelchair users and those with impaired lower extremity function who currently require specialized or assistance-dependent scales to track their weight. Existing load cell assemblies using single cantilever beam load cells suffer from accuracy problems when loads are off-center, and configurations with multiple cantilever beams increase cost.
The load cell provided utilizes a ring or multiple first members made of a material with a substantially linear stress-strain curve, allowing direct strain gauge attachment to accurately measure axial loads. This design offers a potentially more cost-effective and accurate solution suitable for integrations in everyday furniture or weight measurement systems for wheelchair users and similar populations.
Claims Coverage
The patent contains two independent claims covering load cell apparatus configurations and systems that include such apparatuses. These claims highlight inventive features relating to the structure, materials, strain gauge arrangements, and component configurations of the load cell.
Load cell apparatus with first members forming support wall and directly coupled strain gauges
The load cell includes a base member, a cap member, and a number of first members positioned between them forming part of a support wall. The first members are made of a material having a substantially linear stress-strain curve, and a plurality of strain gauges are directly coupled to these first members positioned to measure axial loads applied from the cap to the base.
Load cell apparatus featuring a lid member with spokes positioned above strain gauges
The load cell further comprises a lid member located between the cap member and the first members. This lid member includes multiple spokes, each having an end portion positioned directly above a corresponding strain gauge, enhancing the structural configuration around the strain gauges.
The inventive features focus on the load cell's structural components made of materials with substantially linear stress-strain behavior, the direct coupling of strain gauges to these members for axial load measurement, and a specialized lid member design that interfaces with the strain gauges to potentially improve performance.
Stated Advantages
Provides improved accuracy for measuring axial loads by directly coupling multiple strain gauges to first members forming a support wall made of materials with a substantially linear stress-strain curve.
Offers a cost-effective and practical design suitable for regular weight monitoring, particularly for wheelchair users who face challenges with existing weight measurement tools.
Enables integration into environments such as beds for in-home monitoring systems, facilitating independent weight tracking without requiring specialized assistance.
Documented Applications
The load cell apparatus is used in bed-integrated monitoring systems to measure and monitor the weight of individuals, including wheelchair users, in a home environment.
Load cells are positioned beneath the legs of beds to measure forces applied axially, and the resulting data is used to determine and display the weight of one or more users.
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