Handheld Tool Lever Mechanism for One-Handed Trigger Unlocking
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Solution Overview
Problem
Electric handheld working machines face challenges in maintaining operationality comparable to engine-driven types while adhering to stricter safety standards, particularly in unlocking the trigger lever, due to complex and strength-depleting operations required by existing mechanisms.
Innovation Solution
An operating lever mechanism with a slide member and grip lever that allows the trigger lever to be unlocked through a single-handed operation involving a slide and a grip action, ensuring the lever remains locked unless intended, thus meeting safety standards without compromising grip strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a button on the side surface of the handle is pushed to unlock the trigger lever, then safety is improved by preventing accidental unlocking, but operational complexity increases requiring two actions in different directions
Solution Approach 1:
The grip lever and slide member are combined into a single integrated component that performs both functions: gripping the handle and sliding to unlock the trigger lever. This eliminates the need for separate button operation, reducing operational complexity while maintaining safety through the required two-step action of gripping and sliding in the same direction
Solution Approach 2:
The grip lever serves multiple functions: it acts as both the gripping surface for the operator's hand and the unlocking mechanism for the trigger lever. By integrating these functions into a single component, the design simplifies the operation sequence while ensuring safety through coordinated multi-action requirement
2Reliability
If the trigger lever is locked to prevent accidental activation, then safety is improved, but operational readiness becomes less recognizable compared to engine-driven machines
Solution Approach 1:
The trigger lever incorporates visual indicators (such as color changes or position indicators) that allow the operator to immediately recognize whether the working device can be started. The trigger lever's position and visual state provide clear feedback about the operational readiness, compensating for the absence of engine sound feedback
3Reliability
If a button mechanism is used for unlocking, then accidental unlocking is prevented, but grip strength decreases when the thumb must leave the handle to push the button
Solution Approach 1:
The grip lever integrates the gripping function and unlocking function into a single component, allowing the operator to maintain continuous grip on the handle while performing the unlocking action by sliding the grip lever. This eliminates the need to release the grip with the thumb, maintaining grip strength throughout the operation
Solution Approach 2:
The grip lever acts as an intermediary mechanism that translates the gripping motion into the unlocking action. By sliding the grip lever in the direction of handle extension, the operator can unlock the trigger lever while maintaining the gripping force, using the lever as a mediator between the grip and the lock mechanism
Data Source
AI summary
There is provided an operating lever mechanism including: a trigger lever to actuate an electric working device; a slide member provided to be able to slide in a direction in which the handle extends, the slide member being configured to lock the trigger lever when the slide member is not operated, and to unlock the trigger lever when the slide member is slid; and a grip lever operated by gripping the handle by one hand, the grip lever being configured not to allow the slide member to slide when the grip lever is not operated, and to allow the slide member to slide when the grip lever is operated. The slide member is slid while the handle is gripped by the one hand and the grip lever is operated, and therefore the trigger lever is unlocked.