Impact Tool Spindle Run-Off for Compact Axial Design
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Solution Overview
Problem
Existing impact tools face challenges in reducing size along the axial direction of the anvil due to the space requirements for the impact mechanism, particularly the hammer's stroke movement, which restricts design variations and increases production costs.
Innovation Solution
Incorporating a run-off portion on the spindle's front surface to set back the impact mechanism, allowing the hammer to move backward for a predetermined distance, thereby reducing the tool's axial length without compromising stroke length, and using engagement projections to restrict the coil spring's inner diameter, simplifying the structure and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the impact mechanism includes space for hammer stroke movement, then the impacting capability is ensured, but the axial length of the tool increases
Solution Approach 1:
The hammer's inner cylindrical portion is nested within the run-off portion formed by the engagement projections on the spindle. This allows the hammer to move backward during operation while being contained within the axial space of the spindle structure, effectively reducing the overall axial length of the tool while maintaining the necessary stroke movement for impacting capability
2Duration of action of moving object
If the impact mechanism uses traditional coil spring positioning, then the hammer stroke is maintained, but the structure becomes complex and production cost increases
Solution Approach 1:
The engagement projections on the spindle automatically perform multiple functions: they restrict the inner diameter of the coil spring, forms the run-off portion for the hammer's inner cylindrical portion, and guide the hammer's backward movement. This self-service design eliminates the need for separate positioning structures, simplifying the overall structure while maintaining the necessary hammer stroke for impacting capability
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 configuration enables a compact impact tool design with a simple structure and reduced production costs while maintaining the necessary impacting capability, allowing for a smaller axial size without sacrificing performance.
Implementation Method 1
a coil spring positioned between a large-diameter portion at a rear side of the spindle and the hammer so as to urge the hammer toward the advanced position
Implementation Method 2
the hammer being fitted onto a front side portion of the spindle and rotatable along with the spindle via rolling elements
Data Source
AI summary
In an impact tool including a spindle, an anvil, and an impact mechanism having a hammer and a coil spring, a restricting portion is provided at a front surface of a large-diameter portion of the spindle so as to receive a rear end of the coil spring and to restrict an inner diameter of the rear end of the coil spring. A ring-shaped groove is formed at a rear surface of the hammer to receive a front end of the coil spring, in a manner which provides an inner cylindrical portion at a rear side of the hammer. A run-off portion is formed in the restricting portion so as to allow the inner cylindrical portion of the hammer to move thereinto, so that the hammer can move backward for a distance corresponding to a depth of the run-off portion.