Capacitive Contact Sensor With Self-Clamping Conductive Plastic Body
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Solution Overview
Problem
Existing capacitive proximity and contact sensors face challenges in maintaining a stable and secure fastening of the electrically conductive plastic body between the insulating cover plate and the conductive contact surface, often requiring additional procedural steps like adhesives or fastening pins, which are undesirable.
Innovation Solution
The capacitive proximity and contact sensor employs an electrically conductive plastic body configured as a plug-in or clamp part, which is form lockingly and force lockingly connected to the carrier plate, eliminating the need for separate fastening steps by using clamping slots or peg-shaped mandrels for secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional fastening steps like adhesives or fastening pins are used, then the fastening stability of the plastic body is improved, but the manufacturing complexity and procedural steps increase
Solution Approach 1:
The plastic body is designed with self-fixing features (clamping slots, peg-shaped mandrels, or spring fingers) that enable it to secure itself to the carrier plate without external fastening operations. The plastic body's own structure provides the locking mechanism, eliminating the need for separate adhesive application or pin insertion steps.
Solution Approach 2:
The fastening features are integrated directly into the plastic body structure. Clamping slots and peg-shaped mandrels are formed as inherent parts of the plastic body during molding, nesting the fastening function within the body itself rather than requiring separate fastening components.
2Ease of manufacture
If the plastic body is designed with integrated fastening features, then the manufacturing process is simplified, but the design complexity of the plastic body increases
Solution Approach 1:
The fastening features (clamping slots, peg-shaped mandrels, spring fingers) are merged with the plastic body structure and formed in a single molding operation. This combines the structural function and fastening function into one integrated component, simplifying manufacturing despite the increased design complexity of the molded part.
3Reliability
If foam layers are used for electrical insulation and contact, then the electrical function is achieved, but the long-term positional stability deteriorates due to compression and shifting
Solution Approach 1:
The patent uses a flexible plastic body that can deform elastically to maintain continuous electrical contact while accommodating minor positional variations. The plastic body's flexibility allows it to adapt to surface irregularities and maintain stable electrical connection without the compression and shifting problems of foam layers.
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
This configuration ensures a stable and secure fastening of the plastic body without additional work steps, facilitating easy manufacturing and reliable sensor operation, with the plastic body being easily producible and suitable for various environments, including high-temperature applications.
Implementation Method 1
a change in a capacitance of a condenser formed by the cover plate, the plastic body and the aforementioned contact surface can be ascertained and evaluated
Data Source
AI summary
A capacitive proximity and/or contact sensor has an electrically conductive plastic body, which is disposed between an electrically insulating cover plate and an electrically conductive contact surface of a carrier plate disposed at a distance therefrom. The contact surface can be connected to a gating circuit, through which a change in a capacitance of a condenser formed by the cover plate, the plastic body and the contact surface as a result of proximity and/or contact of a contact region of the cover plate by an element, having a potential different to the potential of the contact surface, can be ascertained and evaluated. The plastic body is configured as a plug-in and/or clamp part and by plugging-in or clipping on the or by clamping on the carrier plate is connected form lockingly and/or force lockingly to the latter and thus to the contact surface.