Dental Handpiece Radial Coupling for Secure Tool Retention
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Solution Overview
Problem
Existing dental-medical handpieces face challenges with the assembly and disassembly of tool holders, which are mechanically difficult due to screw-based couplings that can loosen during operation, making it hard to secure and tighten the tool holder effectively, and are cumbersome to handle.
Innovation Solution
A radially movable coupling element is integrated into the handpiece, allowing for automatic locking when the tool is inserted and easy release by pulling it out, utilizing inclined or rounded surfaces to facilitate smooth axial movement and ensure secure coupling without the need for additional handling measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw coupling is used to connect the tool holder to the drive shaft, then the connection can be securely fastened, but the assembly and disassembly process becomes mechanically difficult and time-consuming
Solution Approach 1:
The coupling element is designed to be radially movable between a coupling position (where it engages with the tool holder) and a release position (where it disengages). This dynamic mechanism allows automatic locking when the tool holder is inserted and easy release by pulling it out axially, eliminating the need for manual screw tightening and loosening operations.
2Device complexity
If the tool holder is arranged largely countersunk in the drive shaft, then the coupling structure is compact, but it becomes difficult to apply torque for tightening at the front end of the collet
Solution Approach 1:
The coupling element is moved from a static front-end position to a radially movable position within the drive shaft. The coupling action occurs in the radial dimension rather than requiring axial torque application at the front end. This allows the tool holder to be compactly arranged countersunk in the drive shaft while maintaining easy operation through axial insertion and extraction movements.
3Reliability
If manual screw tightening is required for the tool holder, then the connection can be secured, but additional handling measures and time are required for assembly
Solution Approach 1:
The coupling element is pre-positioned in the drive shaft in the release position, ready to automatically engage when the tool holder is inserted. This preliminary arrangement eliminates the need for subsequent manual tightening operations, reducing assembly time while maintaining secure connection through the automatic radial engagement of the coupling element.
Data Source
Figure 1
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Figure 3~5
AI summary
The unit has a drive shaft (3) rotatably supported in an oblong shaft (2), and a tool holder for a tool. A detachable coupling (17) is provided between the drive shaft and the holder. A locking unit (8b) is formed by the tool in such a way that the locking/unlocking of the coupling is effected by a relative movement between the holder and tool. The movement is a displacement in the longitudinal direction of the drive shaft.