Instrumented Pin Sensor Structure for Compact Force Sensing
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Solution Overview
Problem
Existing pin-type sensors for articulating components are susceptible to environmental degradation and require complex assemblies due to their design, limiting their use in miniature assemblies that need environmental protection and compact designs.
Innovation Solution
An instrumented pin sensor with a partially circular cross-section and a strain sensing electrical circuit on a flat surface, integrated with electrical leads, allowing for compact force measurement without additional protective structures, using thin film strain gauges and strain focusing features to resist harsh environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bonded foil strain gauges are used with adhesive interfaces, then strain sensing capability is achieved, but environmental performance degrades due to humidity, heat and chemicals
Solution Approach 1:
The patent replaces bonded foil strain gauges with a monolithic piezoresistive element integrated directly into the pin structure. This substitution eliminates the adhesive interface that is susceptible to environmental degradation, while maintaining strain sensing capability through the piezoresistive effect where electrical resistance changes in response to applied mechanical stress.
Solution Approach 2:
The patent employs a composite structure combining the pin body material with the piezoresistive element, creating an integrated sensor system that leverages the mechanical properties of the pin material and the electrical sensitivity of the piezoresistive component. This composite approach eliminates the need for separate adhesive layers while achieving both structural and sensing functions.
2Reliability
If additional protective structures such as outer housings and inner conduits are incorporated, then sensing circuitry is protected from environment, but device complexity increases
Solution Approach 1:
The patent merges the protective function with the structural pin body itself. The monolithic piezoresistive element is integrated directly into the pin, eliminating the need for separate protective housings and conduits. The pin structure serves both as the mechanical component and as the protective enclosure for the sensing element.
Solution Approach 2:
The patent extracts the protective function from separate external components and integrates it directly into the pin structure itself. By making the piezoresistive element an integral part of the pin, the protection is inherent rather than additive, removing the need for additional protective structures.
3Reliability
If hollow cylinders are fabricated to provide protected tunnels for wires, then electrical connections are protected, but minimum size is limited and compact design is hindered
Solution Approach 1:
The patent extracts the electrical connection function from separate wire leadouts and integrates it directly into the pin structure through the piezoresistive element. This eliminates the need for hollow protective tunnels, allowing the pin to be solid and compact while maintaining protected electrical connections within the pin body itself.
Solution Approach 2:
The patent combines the electrical connection function with the structural pin body by integrating the piezoresistive element directly into the pin material. This merging eliminates the need for separate wire routing and protective conduits, enabling a compact solid design.
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
The sensor provides reliable force measurement in miniature assemblies by resisting environmental factors and eliminating the need for complex assemblies, enabling precise strain gauge placement and reduced size.
Implementation Method 1
a strain sensing electrical circuit having at least one strain sensing gauge, the strain sensing electrical circuit fixedly disposed on the second outer surface of the support body
Data Source
AI summary
An instrumented pin sensor includes: a support body in the form of a pin having an axial cross section that is only partially circular, forming a first outer surface with a profile that follows the partially circular axial cross section, and a second outer surface with a profile that does not follow the partially circular axial cross section; a strain sensing electrical circuit having at least one strain sensing gauge, the strain sensing electrical circuit fixedly disposed on the second outer surface; a plurality of electrical leads having a first end electrically connected to the strain sensing electrical circuit and fixedly attached to the second outer surface of the support body, and a second end extending from the support body; wherein the second outer surface runs the entire length of the support body with material of the support body only on an underside of the second outer surface.