Annular Spring PCB Contacting Unit for Vibration-Stable Limit Switches
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Solution Overview
Problem
Existing electrical contacts in impedance limit switches are prone to reliability issues, particularly under conditions of vibration, leading to potential circuit breaks.
Innovation Solution
A contacting unit comprising a printed circuit board with a radially arranged annular spring and a non-conductive housing element, which provides secure electrical contact and tolerance compensation, enhancing reliability through multiple contact points and axial-radial stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrical contacts are used in impedance limit switches, then the device can be manufactured with simple structure, but the electrical contact reliability deteriorates under vibration conditions
Solution Approach 1:
The patent employs a dynamic spring contact mechanism that can elastically deform and adapt to vibrations. The spring contact is designed to maintain constant contact pressure on the contact surface even when subjected to vibrational movements, thereby ensuring reliable electrical contact under dynamic conditions. This dynamic adaptation resolves the contradiction by making the contact system resilient to vibration rather than rigid and vulnerable.
Solution Approach 2:
The spring contact acts as a pre-designed cushioning element that absorbs and dampens vibrational shocks before they can cause contact loss. By incorporating the spring mechanism in advance, the system is prepared to withstand vibration forces, preventing circuit breaks before they occur. This beforehand cushioning approach directly addresses the vibration sensitivity issue while maintaining contact reliability.
2Reliability
If a single point contact is used between the printed circuit board and electrode, then the device complexity is reduced, but the electrical contact reliability deteriorates
Solution Approach 1:
The patent transitions from a single-point contact to a distributed areal contact by designing the spring contact to engage with an extended contact surface on the printed circuit board. This dimensional expansion from point to surface contact increases the number of contact points and distributes the electrical current across multiple paths, thereby improving reliability without requiring complex multi-component assemblies. The spring's geometry naturally creates this distributed contact pattern.
Solution Approach 2:
The spring contact structure is segmented into multiple contact zones that independently engage with different regions of the contact surface. This segmentation allows each zone to maintain its own contact pressure and electrical path, so that if one contact point fails, others remain functional. The segmented approach improves reliability while keeping the overall structure simple and integrated.
3Adaptability or versatility
If rigid electrical contacts are used, then the manufacturing precision requirements are reduced, but the tolerance compensation capability deteriorates
Solution Approach 1:
The patent utilizes the elastic properties of the spring contact to change the mechanical parameters of the contact system. The spring can deform within its elastic range to accommodate variations in contact surface position, orientation, and flatness. This parameter change capability allows the system to compensate for manufacturing tolerances without requiring ultra-precise manufacturing, as the spring adapts its shape and contact pressure to match the actual contact surface geometry.
Solution Approach 2:
The spring contact acts as a flexible element that can bend and deform to conform to the contact surface. This flexibility allows the spring to maintain reliable electrical contact even when there are minor deviations in the position or orientation of the printed circuit board contact surface. The flexible nature of the spring compensates for tolerance variations, reducing the stringency of manufacturing precision requirements.
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 ensures high electrical contact reliability and resistance to vibrations, maintaining stable circuit connections despite environmental disturbances.
Implementation Method 1
a radially arranged annular spring for establishing an electrical contact between the contact surface of the printed circuit board and the electrode of the impedance limit switch
Data Source
AI summary
A contacting device is provided for an impedance limit switch, the contacting device including: a printed circuit board having an electrically conductive contact surface; a radially disposed annular spring configured to establish electrical contact between the electrically conductive contact surface of the printed circuit board and at least one electrode of the impedance limit switch; and a non-conductive housing element. An impedance limit switch is also provided, including the contacting device; an electronic cup; and a measuring head configured to carry out a conductive and/or capacitive measurement and to record measurement data, the contacting device being configured to transmit the measurement data from the measuring head to the electronic cup via the contacting unit.