Microswitch Plate Spring With Lateral Stress Projections
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Solution Overview
Problem
Snap-action disk switches have a limited service life due to stress cracks in the edge area and are too large for use as microswitches, limiting their stroke and size.
Innovation Solution
Designing a microswitch with a plate-shaped spring element featuring a switching dome that can move through a plane formed by the plate, with lateral projections to absorb stresses and increase service life, and incorporating a support base to prevent unintentional short circuits, along with a ball actuation element and peripheral sealing jacket for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a snap-action disk switch is designed with a separating element to increase the stroke, then the switching path is increased, but the outer contour and overall size of the switch becomes larger
Solution Approach 1:
The spring element is designed as a plate with a switching dome that moves through the plane formed by the plate, utilizing three-dimensional movement within a compact two-dimensional footprint. The lateral projections extend in the plane of the plate while the switching dome moves perpendicular to this plane, achieving long stroke in one dimension without increasing overall device volume.
Solution Approach 2:
The spring element is segmented into distinct functional regions: the plate body providing structural support, the switching dome providing the actuating surface, and lateral projections providing stress relief. This segmentation allows each component to optimize its function independently while maintaining a compact overall structure.
2Productivity
If the spring element is moved repeatedly, then the switching function is achieved, but stress cracks develop in the edge area limiting service life
Solution Approach 1:
Lateral projections are provided on the plate that project laterally from the switching dome. These projections absorb the stresses that occur when the switching dome is moved by pressing down on it, preventing stress concentration and crack initiation in the edge areas of the spring element, thereby extending service life.
3Force
If the switching dome is moved closer to the conductor track to increase sensitivity, then the actuation force is reduced, but unintentional short circuits may occur
Solution Approach 1:
The plate is designed with non-uniform thickness and lateral projections that create different structural properties in different regions. The switching dome area is optimized for low actuation force, while the lateral projections and plate body provide structural rigidity and maintain safe distances from conductor tracks, preventing short circuits.
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 microswitch achieves a longer service life, increased stroke, and minimized size while preventing unintentional short circuits and protecting against dirt and dust, ensuring reliable operation.
Implementation Method 1
the spring element is designed as a plate, the area of which around the center of mass is designed as a switching dome lifted off the conductor tracks, that the switching dome can be moved through the plane formed by the plate
Implementation Method 2
a peripheral sealing jacket is provided on the ball, through which the space between the ball and the cover is closed. Consequently, dirt and dust particles can be prevented from penetrating into the interior of the housing of the microswitch by the sealing jacket
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
A microswitch (1) comprises a housing (2) in which two conducting paths (3) and a supported spring element (11) are arranged. The spring element is formed as a plate (12). A detatchable switching dome is formed on an area of the plate around the centre of the conducting path. A switching dome (13) is movable through the levels formed on the plate. The two opposite shaped parts (19) are provided at plates which run away laterally in the levels formed by the plate.