Handheld Power Tool Shiftable Gear Detent Locking
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Solution Overview
Problem
Existing handheld power tools with shiftable gears lack secure detent locking mechanisms, leading to potential unintended gear shifts, which can compromise operating safety and require additional detent elements.
Innovation Solution
A transmission member, such as a wire clip, is used to transmit and convert the positioning motion of a user control element into a gear component, also serving as a detent lock to secure each gear step, eliminating the need for additional detent elements and enhancing safety by combining positioning travel and detent functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional detent elements are added to secure gear steps, then detent locking reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the detent locking function with the transmission member (wire clip) that already exists in the gear shifting mechanism. The transmission member is given a dual function: it transmits positioning motion from the user control element to the gear component, and simultaneously secures each gear step as a detent position through detent portions that engage with detent recesses in the housing. This merging eliminates the need for separate detent elements, reducing device complexity while maintaining reliable detent locking.
2Reliability
If the positioning travel distance of the wire clip and detent springs are precisely adapted, then secure detent positioning is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The transmission member (wire clip) serves itself by incorporating detent portions directly into its structure. As the wire clip moves to transmit positioning motion, its detent portions automatically engage with the detent recesses in the housing to secure the gear step. This self-service mechanism eliminates the need for separate detent springs that would require precisely adapted positioning travel distances, thereby reducing manufacturing precision requirements while ensuring secure detent positioning.
Data Source
AI summary
A handheld power tool is provided with a shiftable gear that has at least two gear steps which are meant to be selected via a user control element disposed adjustably on the housing, in which the user control element actuates a transmission member that acts upon an adjustable gear component, and the user control element is intended to be adjusted between at least two detent positions that correspond to the gear steps of the gear. The transmission member is intended to be adjusted into the detent positions, which can be transmitted to the user control element via the coupling between the user control element and the transmission member.