Power Tool Switch Locking Mechanism Design
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Solution Overview
Problem
Existing electrical switches for power tools, particularly 'overhanging trigger switches', face challenges in implementing a simple and user-friendly lock-on and lock-off mechanism that is versatile and safe, as previous designs are complex and not suitable for all actuators, leading to potential accidents due to snagging or jamming.
Innovation Solution
The design features a locking element that works in conjunction with a plunger, with an extension on the plunger and a rib on the actuating member, allowing ergonomic operation and easy switching between lock-on and lock-off functions, utilizing a spring for reset and enabling movement in both directions, thus preventing snagging and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking element is designed to work with the actuating member, then the lock-on and lock-off functions can be implemented, but the design becomes complex and not suitable for all actuators
Solution Approach 1:
The patent introduces a plunger as an intermediary component that mediates between the actuating member and the locking element. The plunger has an extension that protrudes beyond the actuating member, allowing the locking element to engage with this extension rather than directly with the actuating member. This intermediary approach simplifies the locking element design while maintaining reliable lock-on and lock-off functions across different actuator types.
2Reliability
If the locking element is manually movable transversely to the actuating member, then lock-on and lock-off can be achieved, but the operation may be difficult and prone to snagging
Solution Approach 1:
The patent changes the dimensional approach by having the locking element move in a direction substantially perpendicular to the longitudinal axis of the actuating member. Instead of moving transversely across the actuating member's length, the locking element engages with the plunger extension from the side, moving in a direction that avoids snagging on the actuating member while achieving reliable locking.
3Reliability
If the locking element engages directly with the actuating member, then the locking function can be implemented, but it may cause snagging and jamming leading to accidents
Solution Approach 1:
The plunger extension serves as a mediator that separates the locking element from direct engagement with the actuating member. This intermediary structure eliminates the harmful snagging and jamming effects by providing a dedicated engagement surface on the plunger extension that is optimized for smooth interaction with the locking element, preventing the locking element from catching on the actuating member during operation.
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 provides a safe, ergonomic, and versatile locking mechanism that reduces the risk of accidents by ensuring smooth operation and easy conversion between lock-on and lock-off functions, increasing operational safety and reducing costs through compatibility with existing switch designs.
Implementation Method 1
The locking element can expediently be reset from the operating position to the starting position by means of an elastic force, which can be generated, for example, by a spring.
Data Source
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AI summary
The invention relates to an electric switch (4), in particular for electric tools, such as drilling machines, grinders, saws, planes, right-angle grinders, circular saws or similar, with a contact system that can be switched between an off position and on position. The switch (4) comprises a displaceable actuating element (5) for switching the contact system. A tappet (7) is actively connected to the actuating element (5) and to the contact system for switching the contact systems. The actuating element (5) can be maintained and/or blocked in the off position for lock-OFF and/or in the on position for lock-ON of the contact switch by means of a locking element (8) that can be displaced approximately transversal to the actuating element (5) between an initial position and an actuation position. Said locking element (8) interacts with the tappet (7) in order to maintain and/or block the contact system.