Self-Tightening Drill Chuck With Multi-Start Threads for Manual Release
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Solution Overview
Problem
Self-tightening drill chucks with single-start threads face issues with excessively large clamping forces and frictional forces, leading to inconvenient operation and potential blockages, requiring dedicated tools for loosening and often resulting in waste due to difficulty in manual opening.
Innovation Solution
A gear self-tightening drill chuck design featuring multi-start threads and driven bevel gears, allowing for convenient manual loosening and operation, with a lead angle range of 3.1° to 18.7° to balance clamping force and ease of opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single-start thread is used to transmit power to clamping paws, then the clamping force is large, but the frictional force becomes excessively large and may cause blockage, requiring dedicated tools for loosening
Solution Approach 1:
The thread is segmented into multiple starts (multi-start thread), dividing the single continuous thread path into multiple parallel thread paths. This segmentation reduces the lead angle and distributes the clamping force across multiple thread engagement points, thereby reducing frictional resistance and enabling manual loosening while maintaining adequate clamping force.
Solution Approach 2:
The thread parameters are changed from single-start to multi-start configuration, altering the lead angle and thread pitch characteristics. This parameter change reduces the frictional force and extrusion force between thread surfaces, allowing the drill chuck to be loosened manually without dedicated tools while still providing sufficient clamping force during operation.
2Manufacturing precision
If a self-tightening drill chuck with large clamping force is used, then the precision is high, but the operation becomes inconvenient and the drill chuck may be discarded due to inability to open
Solution Approach 1:
The thread structure is segmented into multiple starts, creating multiple parallel thread paths that share the clamping load. This segmentation maintains the self-tightening effect for precise clamping while reducing the frictional resistance enough to allow manual opening, preventing drill chuck abandonment.
Solution Approach 2:
The thread configuration parameters are changed from single-start to multi-start, modifying the lead angle and thread engagement characteristics. This parameter change enables the drill chuck to achieve both high clamping precision through self-tightening and ease of manual operation by reducing frictional forces to manageable levels.
3Ease of operation
If a multi-start thread is used, then the ease of manual loosening is improved, but the clamping force may be reduced
Solution Approach 1:
The thread is divided into multiple starts, creating multiple parallel load paths. While each individual thread path carries less load, the cumulative effect of multiple paths maintains adequate total clamping force while significantly reducing the frictional resistance in each path, enabling easy manual loosening.
Solution Approach 2:
The thread parameters are optimized by changing from single-start to multi-start configuration, adjusting the lead angle and pitch to achieve a balance point where frictional force is reduced enough for manual loosening while the multi-path engagement maintains sufficient total clamping force for precise operation.
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 multi-start thread design disperses clamping force over a larger contact area, reducing unit frictional force and enabling easy manual opening of the drill chuck, improving operational convenience and reducing the risk of blockages.
Implementation Method 1
the multi-start thread design disperses clamping force over a larger contact area, reducing unit frictional force
Implementation Method 2
A driving bevel gear is provided at one end of the rear body... The driving bevel gear is arranged in the main body, and is engaged with the driven bevel gears
Implementation Method 3
An inner hole of each of the driven bevel gears is provided with an internal thread. One end of each clamping jaw is provided with an external thread in cooperative use with the internal thread of each of the driven bevel gears
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A gear self-tightening drill chuck, relating to the field of machining instruments and the field of electric-powered tools, comprising a rear pressing cover (10) or a retaining ring (19), a rear body (9), a main body (3), a front sleeve (1), clamping jaws (7), and driven bevel gears (2); the rear body (9) is arranged inside the main body (3); one end of the rear body (9) is provided with a driving bevel gear (8), the large end thereof being arranged next to the rear body (9); the driving bevel gear (8) is arranged inside the main body (3), and is engaged with the driven bevel gears (2); a plurality of driven bevel gears (2) are arranged uniformly with the axis of the driving bevel gear (8) as the centre line; the driven bevel gears (2) have an inner screw thread; one end of the clamping jaw (7) has an outer screw thread for use together with the inner screw thread; the main body (3) is provided with clamping jaw holes (4) and bevel gear holes (18); one end of the main body (3) is provided with a drilling tool accommodating hole (20), the front sleeve (1) being arranged outside the drilling tool accommodating hole (20), and the front sleeve (1) may also be integrated with the main body (3); the other end of the main body (3) is provided with a rear hole (5) and the rear pressing cover (10) or retaining ring (19); the rear pressing cover (10) or the retaining ring (19), the rear body (9), the driving bevel gear (8), the main body (3), and the front sleeve (1) are coaxially arranged; and the inner screw thread and the outer screw thread are both multi-start screw threads. Thus, after the drill chuck has been clamped and closed and has finished operating, said drill chuck can be loosened by hand and conveniently released, achieving the aim of manually opening the clamping jaws; operation is simple and convenient.