Trigger Lock-On Mechanism for Power Tool Safety
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Solution Overview
Problem
Power tools pose safety risks due to accidental activation and require a trigger mechanism that can be easily switched between ON and OFF positions to manage operator fatigue, especially during extended use.
Innovation Solution
A trigger mechanism with a locking mechanism that allows the trigger to be locked in the ON position, featuring a movable locking mechanism that can be unlocked from the OFF position and locked into the ON position using a specific aperture and biasing system, enabling easy switching between ON and OFF states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a trigger mechanism is designed to stay in the ON position for extended periods, then operator fatigue is reduced, but the risk of accidental activation increases
Solution Approach 1:
The trigger mechanism is segmented into two independent functional components: a trigger assembly for activating the power tool and a separate locking mechanism for maintaining the ON state. This segmentation allows the trigger to be pulled briefly to activate, then released while the locking mechanism independently maintains the powered state, reducing operator fatigue without compromising safety against accidental activation.
Solution Approach 2:
The locking mechanism acts as an intermediary between the trigger and the power tool activation system. When engaged, it maintains the trigger in the pulled position without requiring continuous operator input. The locking mechanism includes a locking member that interfaces with a cam surface on the trigger, providing a mechanical intermediary that safely maintains the ON state while allowing easy disengagement when needed.
2Ease of operation
If a locking mechanism is added to lock the trigger in the ON position, then operator fatigue is reduced during extended use, but the device complexity increases
Solution Approach 1:
The locking mechanism is merged with the existing trigger assembly as an integrated unit. The locking member, cam surface, and spring components are incorporated into the same housing and operational envelope as the trigger, allowing the locking function to be added without requiring separate controls or significantly increasing overall device complexity. The trigger and locking mechanism share common structural elements and mounting points.
Solution Approach 2:
The locking mechanism is designed to be self-actuating through a simple manual operation. When the trigger is pulled to the ON position, the operator simply presses a button or releases a latch to engage the locking member with the cam surface. The spring automatically maintains the locked state without requiring additional power or complex control systems. Disengagement is achieved through a simple manual action that releases the locking member, allowing the trigger to return to the OFF position.
3Object-affected harmful factors
If the locking mechanism is designed to require additional movement distance, then accidental activation is prevented, but the ease of operation decreases
Solution Approach 1:
The locking mechanism employs a dynamic engagement system where the locking member moves along a cam surface rather than requiring linear travel through a fixed aperture. The cam surface is positioned and angled to provide mechanical advantage, allowing the locking member to engage with minimal additional movement distance. The dynamic cam-based engagement provides sufficient travel to prevent accidental activation while maintaining ease of operation through mechanical leverage.
Data Source
AI summary
A trigger mechanism for a power tool having a trigger and a locking mechanism, the trigger being moveable between an ON and an OFF position, the locking mechanism being moveable between a LOCKED-ON, a LOCKED-OFF and a NEUTRAL position.