Impact Tool Hammer Drive With Variable Spindle Groove Depth
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Solution Overview
Problem
Existing impact tools lack the capability to increase fastening speed and impact force effectively, leading to inefficiencies in screw tightening.
Innovation Solution
The impact tool design incorporates a spindle groove with varying depth along its axial direction, a ball mechanism, and a spring system to enhance the rotational speed and impact force of the hammer, allowing for earlier and more forceful impacts on the anvil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impact force is increased to improve fastening speed, then the productivity is improved, but the device complexity increases due to additional components
Solution Approach 1:
The patent combines the ball bearing mechanism and impact mechanism into a single integrated structure. The ball is positioned within the spindle groove such that it simultaneously serves as both a bearing element for supporting the spindle and an impact element for delivering rotational impact to the anvil. This merging eliminates the need for separate bearing and impact components, thereby increasing productivity without proportionally increasing device complexity.
Solution Approach 2:
The spindle groove serves multiple functions: it guides the ball bearing during rotation, provides the impact surface for the hammer, and controls the rotational speed of the hammer through its varying depth. The ball itself serves dual purposes as both a bearing element and an impact element. This multi-functionality allows the system to achieve high impact force while maintaining a relatively simple overall structure.
2Productivity
If the hammer rotational speed is increased to improve impact force, then the productivity is improved, but the tool size increases
Solution Approach 1:
The spindle groove depth is varied dynamically along the axial direction, creating different radial positions for the ball at different axial locations. This dynamic geometry allows the ball to be positioned optimally for both bearing and impact functions at different stages of rotation, enabling high impact force within a compact radial space. The varying depth creates a dynamic impact mechanism that achieves high speed without requiring a proportionally large tool volume.
Solution Approach 2:
The patent utilizes the axial dimension to control the radial position of the ball through the varying spindle groove depth. By changing the groove depth in the axial direction, the system achieves different impact forces and rotational speeds without increasing the radial or axial dimensions of the tool body. This dimensional approach allows high impact force while maintaining a compact tool size.
3Productivity
If a ball mechanism with varying depth spindle groove is used to increase impact force, then the productivity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The spindle groove is designed with locally varied depth along its axial length, with different sections providing different radial positions for the ball. This local quality variation allows the groove to serve multiple functions at different locations: deeper sections provide greater impact force while shallower sections maintain proper bearing clearance. The local variation is designed to be manufacturable using conventional machining techniques, balancing performance improvement with manufacturing feasibility.
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 increases the rotational speed and impact force of the hammer, reducing the likelihood of cam-out phenomena and enabling faster screw tightening with reduced tool size.
Implementation Method 1
a spring, which biases the hammer forward
Implementation Method 2
a hammer supported on the spindle via the ball
Data Source
AI summary
An impact tool (1) includes: a motor (6); a spindle (8) rotated by the motor; a spindle groove (8D) formed in the spindle; a ball (48) held in the spindle groove; a hammer (47) supported on the spindle via the ball; a spring (49, 50), which biases the hammer forward; and an anvil (10) configured to be impacted by the hammer in a rotational direction. The depth of the spindle groove (8D) differs in accordance with the location thereof in an axial direction of the spindle.