Thumbwheel Control Assembly With Elastic Stops for Zero-Play Sensing
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Solution Overview
Problem
Existing thumbwheel control devices suffer from residual mechanical play, limiting accuracy and precision, particularly near the rest position, due to manufacturing tolerances and static connections between the torsion spring and bearing surfaces.
Innovation Solution
A control device design incorporating elastic elements between stops and the body to constrain the torsion spring strands without gaps, ensuring firm contact and eliminating residual mechanical play, combined with a magnetic field sensor for precise angular position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a torsion spring with static connection to stops is used, then the device structure is simple and easy to manufacture, but residual mechanical play appears between the spring strands and bearing surfaces, limiting measurement precision
Solution Approach 1:
The patent introduces elastic elements that dynamically adjust the connection between the torsion spring and stops. These elastic elements allow the system to adapt to manufacturing tolerances and eliminate residual play through controlled deformation, transforming a static rigid connection into a dynamic adaptive connection that maintains precision without requiring ultra-precise manufacturing.
Solution Approach 2:
The elastic elements act as intermediary components between the torsion spring strands and the stops. These intermediaries absorb manufacturing tolerances and eliminate gaps by deforming elastically, ensuring continuous contact and eliminating residual mechanical play without requiring direct rigid contact between the spring and stops.
2Measurement precision
If manufacturing tolerances are reduced to eliminate residual play, then measurement precision improves, but manufacturing cost and complexity increase
Solution Approach 1:
The patent changes the physical state and connection parameters of the torsion spring system by introducing elastic elements. Instead of requiring tight tolerances on rigid components, the solution uses controlled elastic deformation to compensate for tolerances, allowing standard manufacturing processes to produce high-precision assemblies.
Solution Approach 2:
The system combines rigid components (torsion spring, stops) with elastic elements to create a composite structure. This composite approach leverages the advantages of both rigid and elastic materials, maintaining structural integrity while eliminating residual play through the elastic component's ability to deform and compensate for manufacturing variations.
3Measurement precision
If elastic elements are added to eliminate residual play, then measurement precision and sealing improve, but device complexity increases
Solution Approach 1:
The elastic elements serve multiple functions simultaneously: they eliminate residual mechanical play, provide sealing between components, and maintain constant contact force between the torsion spring and stops. This multi-functionality reduces the need for additional separate components, offsetting the complexity increase with functional consolidation.
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 solution optimizes precision and accuracy by eliminating residual mechanical play, particularly around the neutral position, enabling precise angular movement detection and improved sealing.
Implementation Method 1
a magnetic field sensor arranged on the printed circuit board opposite the magnet adapted to detect the angular position of the magnet
Implementation Method 2
whose movement is detected by a sensor, for example a Hall effect sensor, arranged within the body
Data Source
Figure 1A~1B
Figure 2~3A
Figure 3B
AI summary
The invention relates to a control device comprising: o a body (20) comprising a printed circuit (30), o a mobile actuator (1) able to move in pivoting relative to the body (20) about an axis 50 of rotation, o a torsion spring (7) comprising two end strands (71) resting against two respective bearing surfaces (14) of the actuator (1), said torsion spring (7) being designed to urge the actuator (1) to rotate towards a position of rest, o at least one magnet (6) rigidly secured to the actuator (1), o a magnetic-field sensor (32) arranged on the printed circuit (30) facing the magnet (6) and designed to detect the angular position of the magnet (6) and to produce an electric signal dependent on the detected angular position, characterized in that it comprises two end-stops (8) rigidly secured to the body (20), a respective elastic element (9) being arranged between each end-stop (8) and the body (20), each end-stop (8) comprising a bearing surface bearing on a respective end strand (71) of the torsion spring (7).