Power Tool Output Shaft Alignment and Locking
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Solution Overview
Problem
Existing motorized power tools with elongated output shafts face issues with axial alignment of shaft extensions, leading to imprecision and potential misalignment during multiple disc tool arrangements, and existing solutions fail to ensure secure locking mechanisms.
Innovation Solution
The output shaft features a constant outer diameter thread with a flat thread design for precise alignment and a secondary inner thread for secure attachment, along with cams to prevent rotation and ensure proper locking, allowing for reliable alignment and secure mounting of multiple disc tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a hollow cylindrical shaft extension is provided with inner thread for securing multiple disc tools, then the quantity of tools that can be mounted increases, but the axial alignment precision deteriorates due to large distances between tools
Solution Approach 1:
The output shaft is divided into functionally distinct sections: a tool receptacle section with outer thread for single tool mounting, and a separate centering section with inner thread for multiple tool mounting. This segmentation allows each section to be optimized for its specific function, ensuring precise alignment even when multiple tools are mounted at large distances apart.
Solution Approach 2:
The centering section acts as an intermediary element between the tool receptacle and the mounted tools. It provides a dedicated threading interface that mediates the connection, ensuring that the shaft extension remains properly aligned with the output shaft rotational axis regardless of the positions of individual disc tools.
2Adaptability or versatility
If the output shaft length is increased to accommodate multiple disc tools, then the adaptability improves, but the ease of operation deteriorates due to limited application region in hand-held tools
Solution Approach 1:
The output shaft is segmented into a tool receptacle portion and a centering section, allowing multiple tool mounting capability without requiring a proportionally long overall shaft length. The centering section can be compact while still providing sufficient threading engagement for secure attachment.
Solution Approach 2:
Instead of extending the shaft length in the axial direction to accommodate multiple tools, the invention utilizes the radial dimension by providing a centering section that projects beyond the tool receptacle radial projection. This allows multiple tools to be mounted in the axial direction while maintaining a compact overall footprint.
3Adaptability or versatility
If the outer thread has variable diameter to accommodate different tool positions, then the adaptability improves, but the manufacturing precision deteriorates
Solution Approach 1:
The output shaft is divided into distinct functional sections: the tool receptacle with its outer thread maintains a constant diameter for precise single-tool mounting, while the separate centering section provides the necessary variability in diameter to accommodate multiple tools at different positions. This segmentation allows each section to be optimized independently.
Solution Approach 2:
Different sections of the output shaft have different geometric properties tailored to their specific functions. The tool receptacle section has constant diameter for precision, while the centering section has variable diameter to accommodate different tool arrangements. This local differentiation of geometric quality resolves the contradiction between adaptability and precision.
Data Source
AI summary
A motorized power tool includes an output shaft (11) including a tool receptacle (13) for receiving a disc-shaped tool (7) and having an outer thread with a constant outer diameter (D) and that forms a first securing element (14) for a locking element (8), a centering section (16) adjoining the tool receptacle (13) and extending beyond a radial projection of the tool receptacle, and a second securing element (15) provided at the free end (12) of the output shaft (11) for receiving an attachment element (9) for securing a shaft extension (21) to the output shaft (11).