Hand Tool Blocking Device for Eccentric Spindle Play
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Solution Overview
Problem
Hand-held power tools with eccentric grinding or polishing functions face challenges in securely holding the tool spindle in place during tool changes due to excessive play, especially when using tools with threads or bayonets, which complicates the mounting and dismounting process.
Innovation Solution
A blocking device is implemented with sequential engagement of locking projections and receptacles on a locking device and a blocking part, allowing for precise alignment and secure locking of the tool spindle, even with eccentric movements, using a combination of first and second blocking arrangements that engage in a specific order to minimize play and ensure tool spindle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single locking device is used to block the tool spindle, then the structure is simple, but the tool spindle has excessive play and cannot be securely held
Solution Approach 1:
The blocking device is segmented into multiple locking arrangements (first and second locking arrangements with respective locking projections and receptacles). Each locking arrangement independently contributes to securing the tool spindle, reducing total play through cumulative constraint. This segmentation allows the system to achieve higher reliability without requiring a single overly complex locking mechanism.
2Adaptability or versatility
If the blocking part is made stationary relative to the housing, then the structure is simple, but the tool spindle cannot accommodate eccentric movements
Solution Approach 1:
The blocking part is designed to be movable relative to the housing, capable of executing eccentric movements that follow the tool spindle's motion. This dynamic design allows the blocking part to maintain proper engagement with the locking device while accommodating the eccentricity of the tool spindle, preventing binding and ensuring smooth operation throughout the eccentric cycle.
3Ease of operation
If the locking device is made linearly adjustable, then the sequential engagement of blocking arrangements is enabled, but the device complexity increases
Solution Approach 1:
The locking device is designed with linear adjustability that enables preliminary positioning for sequential engagement. The first locking arrangement engages first to establish an initial stable connection, then the locking device can be further adjusted to enable engagement of the second locking arrangement. This preliminary action approach simplifies the overall engagement process by breaking it into manageable sequential steps.
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
A manual machine tool has a motor (11) for driving a machine tool spindle (12) and is interlocked in an interlock position, where with movement of the retainer device (76) in the interlock position, a first interlock salience (80) and a first interlock location (79) engage a first interlock arrangement (78). The first interlock salience (80) and the first interlock location (79) mutually engage and remain in engagement, when a second interlock salience (83) and second interlock part engage a second interlock arrangement (81).