Rod-Shaped Force Sensor With Thin-Film Wheatstone Bridge
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Solution Overview
Problem
Existing force-measuring technologies are not economical or effective in accurately evaluating traction and pressure forces in structures like bolts, hooks, and cranes, particularly for lifting devices, where they fail to provide reliable and temperature-stable measurements.
Innovation Solution
A force-sensing device with a helical contour and a thin-film metallic sensor integrated into a rod-shaped carrier, featuring four measuring resistors connected via a Wheatstone circuit, which is screwed into structures to detect expansions and compressions, providing a temperature-stable and zero-point-stable measurement system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional force-measuring technologies are used in structures like bolts, hooks, and cranes, then force measurement is possible, but the measurements are not temperature-stable and not reliable
Solution Approach 1:
The patent uses a Wheatstone bridge circuit with four measuring resistors arranged to detect changes in electrical resistance caused by mechanical deformation. This configuration allows the system to measure force-induced deformations while compensating for temperature effects, as the bridge circuit can distinguish between resistance changes due to strain and those due to temperature variations.
Solution Approach 2:
The force-sensing device integrates a metallic thin-film sensor element with a rod-shaped sensor carrier, creating a composite measurement system. The thin-film element is welded into the structure of the sensor carrier, forming a unified component that combines the sensing functionality with the mechanical structure, improving both reliability and temperature stability.
2Measurement precision
If existing force-measuring technologies are used, then force detection is possible, but they are not economical
Solution Approach 1:
The force-sensing device is designed as a modular component that can be independently manufactured and then integrated into the structure. The sensor element is separately produced and welded into the sensor carrier, allowing for specialized manufacturing of the sensing component while keeping the overall structure simple and economical to produce.
Solution Approach 2:
The patent replaces complex mechanical force measurement mechanisms with an electrical sensing system based on resistance changes in the thin-film element. This substitution simplifies the measurement process, reduces manufacturing complexity, and lowers costs while maintaining high measurement precision through the Wheatstone bridge evaluation circuit.
3Stability of the object's composition
If the force measuring sensor is integrated into the structure of the expansion measuring screw, then temperature stability and zero-point stability are improved, but the device complexity increases
Solution Approach 1:
The force measuring sensor is merged with the sensor carrier by welding the thin-film element directly into the rod-shaped carrier structure. This integration creates a unified component where the sensor becomes part of the mechanical structure, eliminating the need for separate mounting hardware and reducing overall device complexity while improving stability.
Solution Approach 2:
The integrated sensor component serves multiple functions: it acts as both the mechanical element (sensor carrier) and the sensing element (thin-film sensor). This multi-functionality reduces the number of separate components needed, simplifying the overall device while maintaining temperature and zero-point stability.
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 and reliable measurement of forces, allowing for the evaluation of tractive forces and load distribution, enabling early detection of excessive mechanical stress and ensuring safe operation of lifting devices by providing precise deformation data.
Implementation Method 1
The welded-in force measuring sensor becomes a component of the structure of the expansion measuring screw and is elastically shaped or deformed when the expansion measuring screw is loaded or when the load is removed from it
Implementation Method 2
The sensor measuring resistors loaded at this time generate changes in resistance that are evaluated
Implementation Method 3
The resistors are evaluated via a Wheatstone circuit and are run to the screw head via a cable lead-through to the other screw end and evaluated by an electronic component or by a display
Data Source
AI summary
A force-sensing device for measuring a traction- and/or pressure force load in a structure, for example, in a container-locking bolt is provided. The force-sensing device is constructed shaped like a rod and a sensor section detects expansions and/or compressions of the structure.