Self-locking Drill Chuck Spring Leaf Design
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Solution Overview
Problem
Existing self-locking drill chucks face reliability issues due to high load on the spring leaf and instability caused by centrifugal forces, leading to failure in maintaining the self-locking function during operation.
Innovation Solution
A self-locking drill chuck design where the nut is directly driven by the rotating sleeve without a spring leaf, incorporating a state switching part and limit clutch connecting structure, allowing the spring leaf to maintain a normally closed state with its locking end opposite to the teeth, enhancing the self-locking reliability and hand feeling during clamping operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring leaf is used to drive the rotating sleeve during nut rotation in the clamping direction, then the self-locking function is maintained, but the spring leaf is subjected to high load which easily causes failure of self-locking functions
Solution Approach 1:
The patent segments the functions of the spring leaf into two distinct components: the spring leaf itself maintains only the self-locking function by engaging with teeth on the drill body, while a separate rotating sleeve mechanism handles the driving function during nut rotation. This functional segmentation reduces the load on the spring leaf, preventing failure of the self-locking function while maintaining both self-locking and driving capabilities in the overall system.
2Reliability
If the spring leaf is made in a normally open state of sprung outwardly and pressed between teeth forcibly by the cam surface, then the self-locking structure is formed, but the spring leaf is always subject to centrifugal force during working which influences the stability of the self-locking function
Solution Approach 1:
The patent inverts the normal state of the spring leaf from the conventional outwardly sprung open state to an inwardly sprung closed state. The locking end of the spring leaf normally contacts the teeth on the drill body in a closed position, and opens only when actively actuated by the cam surface during idle running. This inversion eliminates the continuous centrifugal force problem because the spring leaf remains closed and locked during operation, with the locking force directed inward rather than outward against centrifugal effects.
3Reliability
If the locking end of the spring leaf is pressed between teeth forcibly by the cam surface on the rotating sleeve, then the self-locking structure is formed, but this influences the connecting structure of the rotating sleeve
Solution Approach 1:
The patent extracts the self-locking function from the rotating sleeve mechanism and assigns it to a separate spring leaf system that engages directly with teeth on the drill body. The rotating sleeve is relieved of the self-locking function and only performs its primary rotating drive function, connected to the nut through a simplified limit clutch structure. This extraction reduces the complexity of the rotating sleeve connecting structure while maintaining reliable self-locking through the dedicated spring leaf-teeth engagement.
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 design improves the reliability and efficiency of the self-locking mechanism by reducing the load on the spring leaf and counteracting centrifugal forces, ensuring consistent clamping and releasing operations.
Implementation Method 1
the spring leaf has a locking end matching with teeth, wherein under normal state, the locking end of the spring leaf is in a closed state against the teeth
Implementation Method 2
The nut is connected with the rotating sleeve by a limit clutch connecting structure, and the limit clutch connecting structure is set with a section of idle running of the rotating sleeve
Data Source
AI summary
A self-locking drill chuck is disclosed herein. Among the rotating sleeve, the spring leaf and the nut, the nut is rotated by the rotating sleeve without being driven by the spring leaf, the spring leaf is loaded on the nut to rotate with the nut synchronously, under normal state, the locking end of the spring leaf is in a closed state against the teeth, and the self-locking drill chuck is also provided with a state switching part which is connected with the rotating sleeve and rotates with the rotating sleeve synchronously; the spring leaf is provided with a state switching matching structure. The nut is directly driven by a rotating sleeve without the spring leaf during the rotating process in the clamping direction or the releasing direction, which can enhance the hand feeling and efficiency in the clamping operation; the spring leaf has self-locking functions which can be in normally closed and the elastic force is opposite to the centrifugal force, greatly enhancing the reliability of the drill chuck self-locking structure.