Impact Tool Anvil Support and Sleeve Structure for Low Vibration
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Solution Overview
Problem
Existing impact drivers face issues with a long manipulatable sleeve length due to fall-out prevention mechanisms and anvil rattling during rotation, leading to increased overall length and vibration of the tool.
Innovation Solution
A tool holding apparatus with a manipulatable sleeve that uses a flat spring to bias balls into a protruding position, preventing them from falling out, and an axial support structure with dual ball bearings to reduce anvil rattling, allowing for a more compact design and minimized vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fall out prevention part is added to cover the balls, then the balls are prevented from falling out, but the manipulatable sleeve becomes longer in the axial direction
Solution Approach 1:
The fall out prevention function is moved from the axial dimension (lengthening the sleeve) to the radial dimension (adding a protruding part that extends radially to cover the balls). This dimensional shift allows ball retention without increasing the axial length of the manipulatable sleeve.
Solution Approach 2:
The fall out prevention function is separated from the manipulatable sleeve body and implemented as a distinct protruding part. This segmentation allows the sleeve to maintain its compact axial length while the protruding part provides the necessary ball coverage when engaged.
2Reliability
If a manipulatable sleeve with fall out prevention is used, then ball retention is improved, but the output shaft protrusion length cannot be shortened
Solution Approach 1:
The ball retention mechanism uses radial extension (protruding part) rather than axial extension, which decouples the retention function from the output shaft protrusion length. This allows the output shaft to be shortened axially while maintaining ball retention through radial coverage.
3Ease of operation
If a bearing is used to support the anvil, then the anvil is axially supported, but clearance is created causing anvil rattling during rotation
Solution Approach 1:
A damping element is introduced between the anvil and bearing to beforehand cushion and absorb the rattling vibrations that occur during rotation. This pre-positioned damping element mitigates the instability caused by bearing clearance before it can cause excessive vibration.
4Ease of operation
If the manipulatable sleeve is made longer to ensure stroke, then the sleeve can move fully, but the overall tool length increases
Solution Approach 1:
The sleeve stroke function is maintained through radial movement capability rather than increasing axial length. The protruding part provides the necessary stroke while extending radially, keeping the overall tool length compact.
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
The solution enables a shorter output shaft protrusion and reduced anvil vibration, resulting in a more compact tool with improved operational stability and reduced vibration of the bit.
Implementation Method 1
An elastic body biases the ball toward the protruding position
Implementation Method 2
the manipulatable sleeve has a length such that at least a portion of the elastic body is exposed when the sleeve is moved to the other position
Data Source
AI summary
An impact tool (1; 1A) includes a spindle (12) rotated by a motor (10) and a hammer (70) held by the spindle. The hammer is designed to impact an anvil (14) in a rotational direction. A case (8) houses the hammer. A first bearing (78A) and a second bearing (78B) are held in the case and arranged along the axial direction. The first bearing and the second bearing directly hold the anvil in a rotatable manner.