Driving Tool Interference Fit Hardness Gradient
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Solution Overview
Problem
Conventional two-piece driving tools with a bit and bit holder often disengage due to distortion under centrifugal force when rotated by a power tool, as the bit holder is made from a material with less hardness than the bit, leading to instability during use.
Innovation Solution
A driving tool design featuring a coupling component with a first compartment and a driving component, where the connecting portion is inserted into a tight interference fit within the compartment, ensuring the components remain firmly coupled without a securing member, utilizing materials with different hardness levels to prevent disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bit holder is made from material with less hardness than the bit, then the bit holder is easier to manufacture, but the bit holder distorts under centrifugal force and disengages from the bit
Solution Approach 1:
The patent changes the hardness parameter of the connecting portion to be less than the hardness of the driving component. This parameter change allows the connecting portion to deform elastically under centrifugal force, absorbing the stress that would otherwise cause disengagement, while still maintaining a secure connection during normal operation
Solution Approach 2:
The connecting portion acts as an intermediary element between the driving component and the bit holder. It mediates the stress and force transmission, using its lower hardness to provide a buffer zone that prevents direct stress transfer that would cause disengagement
2Device complexity
If the connecting portion is made with lower hardness than the driving component, then the components can be firmly coupled without securing members, but the connecting portion must withstand high centrifugal forces
Solution Approach 1:
The patent utilizes parameter changes by setting the hardness of the connecting portion lower than the driving component. This creates a controlled deformation characteristic where the connecting portion can elastically deform under centrifugal force, absorbing stress without permanent damage, thereby preventing disengagement without requiring additional securing members
Solution Approach 2:
The connecting portion is designed with lower hardness to serve as a pre-built cushioning element. Before the centrifugal force causes disengagement, the softer connecting portion deforms to absorb and distribute the stress, providing beforehand cushioning that prevents the more critical driving component from failing
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 driving tool components remain securely coupled, preventing disengagement during use, even under centrifugal force, enhancing stability and usability without the need for additional securing mechanisms.
Implementation Method 1
The connecting portion and the second receiving section are forced into a tight interference fit with each other such that the connecting portion and the second receiving section are unable to detach from each other
Implementation Method 2
The connecting portion and the second receiving section are forced into a tight interference fit
Data Source
AI summary
A driving tool includes a coupling component defining a compartment and a driving component received by the compartment. The compartment includes a first receiving section and a second receiving section. The driving component includes a first driving body portion, a second driving body portion, and a connecting portion. The connecting portion is inserted through the first receiving section and is fixedly disposed in the second receiving section. The connecting portion and the second receiving section are forced into a tight interference fit with each other. The second driving body portion includes a length inserted and disposed in the first receiving section. The first and second driving body portions are made to have a first hardness, and the connecting portion is made to have a second hardness respectively. The second hardness is less than the first hardness.