Load-Sensing Bolt With Laminated Strain Gauge for Weight Machines
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Solution Overview
Problem
Resistance training equipment, such as weight machines, lacks efficient sensor systems for accurately measuring and digitizing the resistance force exerted during exercises, hindering the development of engaging digital user experiences.
Innovation Solution
A load sensing bolt with integrated strain gauges is used to support the pulley of a weight machine, capturing force data through a strain gauge laminated onto its exterior surface, and a controller determines the weight setting by combining data from the load sensing bolt and an optional incremental weight sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional weight machines are used without integrated sensors, then mechanical simplicity and ease of manufacture are maintained, but measurement capability and digital data collection are lacking
Solution Approach 1:
The strain gauge is laminated directly onto the exterior surface of the bolt, merging the sensing function with the structural component. This integration eliminates separate sensor housings and reduces the number of parts, thereby improving measurement capability without proportionally increasing device complexity
Solution Approach 2:
The bolt serves dual functions: it mechanically supports the pulley and simultaneously acts as a sensing element through the integrated strain gauge. This multi-functionality reduces the need for separate measurement devices, addressing the contradiction between measurement precision and device complexity
2Measurement precision
If strain gauges are laminated onto the bolt surface, then accurate force measurement is achieved, but manufacturing complexity and installation difficulty increase
Solution Approach 1:
The strain gauge is laminated onto the bolt during the manufacturing process rather than as a separate installation step. This preliminary action ensures proper alignment and bonding while the bolt is being produced, reducing the complexity of field installation and maintenance
Solution Approach 2:
The traditional mechanical connection method is replaced by lamination, which uses adhesive bonding instead of mechanical fastening. This substitution simplifies the integration process and allows for more precise positioning of the sensing element on the bolt surface
3Adaptability or versatility
If existing weight machines are retrofitted with sensor systems, then digital user experiences are enabled, but mechanical integrity and structural stability may be compromised
Solution Approach 1:
The bolt is designed to simultaneously fulfill mechanical support and sensing functions without requiring separate components. This approach maintains the original mechanical structure's integrity while adding digital capabilities, as the same component serves both purposes rather than adding extraneous parts that could compromise structural stability
Solution Approach 2:
By merging the structural and sensing functions into a single integrated component, the retrofit process avoids adding separate sensor assemblies that would require additional mounting hardware, drilling, or structural modifications. This preserves the original mechanical integrity while enabling digital functionality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate measurement of resistance force, allowing for enhanced digital user experiences by retrofitting existing weight machines, preserving their mechanical integrity and facilitating data-driven coaching and community sharing.
Implementation Method 1
a strain gauge for sensing force transferred from the weight plates and the incremental weights by the pulley to the load sensing bolt
Data Source
AI summary
A load sensor includes a bolt configured to support a pulley of a weight machine, and a strain gauge laminated onto an exterior surface of a shoulder section of the bolt.