Snap-Action Electrical Switch for Power Tools
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Solution Overview
Problem
Existing electrical switches for power tools, particularly those with control or regulation electronics, face premature contact system failure due to 'teasing' under heavy-duty conditions, especially in low-voltage applications and during vibrations.
Innovation Solution
The electrical switch incorporates a snap-action contact system for the bridging contact, which switches over with a snapping movement, providing effective protection against premature failure by ensuring reliable operation even under high loads and vibrations, and includes a signaling device interacting with a control device to manage motor speed and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional contact system is used in the electrical switch, then the device complexity is reduced, but the reliability deteriorates due to premature contact system failure under heavy-duty conditions and vibrations
Solution Approach 1:
The contact system is designed as a snap-action mechanism that dynamically switches between states. The contact carrier can rapidly transition between engaged and disengaged positions, creating a dynamic switching action that eliminates creeping contact movements and prevents teasing under vibration and heavy loads.
Solution Approach 2:
The contact system is segmented into distinct functional components: a fixed contact, a movable contact carrier with spring bias, and a snap-action switching mechanism. This segmentation allows each component to perform its specific function optimally while contributing to overall system reliability.
2Ease of operation
If the actuating element directly controls the contact system, then the ease of operation is improved, but the reliability deteriorates due to teasing of the contact system under vibrations and heavy loads
Solution Approach 1:
The snap-action contact carrier acts as an intermediary between the actuating element and the fixed contact. It absorbs and isolates the harmful vibrations and load variations, preventing them from being transmitted to the contact surfaces. The spring-loaded mechanism provides mechanical isolation that protects the contact system from teasing.
3Power
If the contact system operates under high loads and vibrations, then the power tool performance is improved, but the reliability deteriorates due to premature contact system failure
Solution Approach 1:
The spring-loaded contact carrier provides beforehand cushioning by maintaining constant spring pressure on the contact surfaces. This pre-compression absorbs shock loads and vibration energy before they can damage the contact system, extending its lifespan under high-power operating conditions.
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 significantly enhances the operational reliability of the switch by protecting the bridging contact against failure, maintaining metered starting and run-up characteristics while preventing premature destruction, thus ensuring reliable operation under demanding conditions.
Implementation Method 1
the bridging contact system for the control device is designed as a snap-action contact system, with which the contact system switches over with a snapping movement
Implementation Method 2
The carriage and thus also the switching contact are operatively connected to the actuating member by means of an elastic element, which can, for example, be a compression spring acting on the carriage
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an electrical switch (1), in particular for an electrical tool having an electric motor, such as for an electric drill, a hammer drill, an electric screwdriver, or the like, having an actuating element (3) adjustable between a starting and an end position. The switch (1) comprises a signal device (4) having an operative connection to the actuating element (3) for generating a signal associated with the adjustment travel of the actuating element (3). The switch (1) further comprises a contact system (6), wherein the actuating element (3) acts in a switching manner on the contact system (6) in one position. The contact system (6) is designed as a snap-action contact system.