Power Tool Accessory Coupling to Prevent Spindle Twisting
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Solution Overview
Problem
The existing accessories for hand-held power tools often require users to rotate them relative to the tool to align the accessory spindle with the output shaft, leading to twisting and making coupling difficult.
Innovation Solution
A coupling element that adjusts between a rotationally fixed and a release position, with a coupling structure and counter-contour featuring teeth, prevents relative rotation between the accessory spindle and housing, simplifying alignment and coupling by ensuring a non-rotatable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accessory is rotated about the longitudinal axis to align the accessory spindle with the output shaft, then the alignment between accessory spindle and output shaft is improved, but the accessory spindle is twisted relative to the housing, making coupling more difficult
Solution Approach 1:
The coupling element is adjusted to the coupling position before the accessory spindle and output shaft are aligned, establishing a rotationally fixed connection in advance. This prevents twisting during the alignment process and enables straightforward coupling without operational difficulties.
Solution Approach 2:
The coupling element can be dynamically adjusted between a coupling position (rotationally fixed connection) and a release position (rotationally movable connection). This dynamic adjustment allows the system to transition between states: during coupling, the element is in the coupling position to prevent twisting; during alignment, it can be switched to the release position to allow rotation.
2Ease of operation
If the accessory spindle is allowed to rotate relative to the housing during alignment, then the alignment process is simplified, but the accessory spindle twists relative to the housing, preventing proper coupling
Solution Approach 1:
The coupling element is set to the coupling position before alignment begins, establishing a rotationally fixed connection that prevents unwanted twisting while allowing controlled rotation for alignment. After alignment is achieved, the rotationally fixed connection ensures proper coupling.
Solution Approach 2:
The coupling element provides dynamic control: in the coupling position, it allows controlled rotation during alignment while preventing unwanted twisting; in the release position, it enables free rotation if needed. This dynamic capability resolves the contradiction between allowing alignment rotation and preventing harmful twisting.
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
This solution allows for easy and secure coupling of the accessory to the hand tool, preventing twisting and enhancing operational reliability by maintaining alignment and ensuring a stable connection.
Implementation Method 1
at least one spring element is provided which acts on the adjusting sleeve in the release position
Data Source
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AI summary
The invention relates to an accessory (1) for a hand-held power tool, comprising a locking device (2) for releasably connecting an accessory spindle (4) defining an accessory longitudinal axis (3) to an output shaft (5) of the hand-held power tool. The locking device (2) comprises an adjusting sleeve (6) which is adjustably mounted on a housing (7) of the accessory (1) between a locking position and a release position, and at least one locking element (8) which is adjustably mounted on the accessory spindle (4) between a disengaged first position and an engaged second position for releasably connecting the accessory spindle (4) to the output shaft (5). A coupling element (9) is provided which is adjustable between a coupling position, in which the accessory spindle (4) is rotationally fixed to the housing (7), and a release position, in which the accessory spindle (4) is rotatable relative to the housing (7).