Collet Chuck Magnetic Coupling to Limit Drill Slippage and Wear
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Solution Overview
Problem
Existing clamping systems in dental handpieces fail to prevent premature wear and separation of the drill and clamp during rotation due to excessive torque, leading to reduced precision and reliability.
Innovation Solution
A selective angular coupling mechanism between the clamp and guide bush, utilizing magnetic or mechanical coupling to maintain angular holding torque below the slip threshold, minimizing separation risks and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clamp is rigidly coupled to the guide bush or drive shaft, then angular holding torque is maximized, but the drill may slip inside the clamp during sudden load changes due to excessive inertia forces
Solution Approach 1:
The coupling between the clamp and guide bush is made dynamic rather than rigid. The clamp can rotate relative to the guide bush when torque exceeds the magnetic coupling threshold, allowing the system to absorb sudden load changes and inertia forces while maintaining reliable angular holding during normal operation.
Solution Approach 2:
The magnetic coupling strength is carefully selected to be between the maximum transmission torque and the slip threshold. This parameter optimization ensures that the coupling is strong enough to maintain angular position during normal operation but weak enough to allow controlled slippage during abnormal high-torque events, protecting the drill-clamp interface from wear.
2Ease of operation
If the clamp is made resilient to grip the drill, then clamping function is improved, but the clamp wears prematurely due to repeated slippage during rotation under load
Solution Approach 1:
The magnetic coupling acts as an intermediary between the clamp and guide bush, providing a controlled interaction that allows the clamp to maintain its resilient clamping function while protecting it from premature wear. The magnetic field transmits torque without requiring rigid mechanical contact that would cause wear during slippage events.
3Reliability
If additional components are added to improve coupling, then reliability is enhanced, but assembly complexity increases
Solution Approach 1:
The mechanical coupling between the clamp and guide bush is replaced with a magnetic coupling system. This substitution eliminates the need for additional mechanical components such as keys, splines, or interlocking features, thereby maintaining assembly simplicity while achieving reliable torque transmission and controlled slippage protection.
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 solution significantly reduces the risk of drill and clamp separation, enhances service life, and maintains reliability without increasing assembly complexity.
Implementation Method 1
a selective angular coupling mechanism between the clamp and the guide bush or respectively the drive shaft directly, the selective angular coupling mechanism exerting an angular holding torque
Data Source
AI summary
A handpiece suitable for dental or chirurgical applications, including a device for clamping a drilling tool, able to be actuated in rotation about an axis of rotation by a drive mechanism. The drive mechanism has a drive shaft rotatable about the said axis of rotation. The clamping device includes a clamp disposed inside the drive shaft for axially securing the drilling tool with respect to the axis of rotation, the clamp co-operating with a plunger for releasing the drilling tool, as well as a radial guide bush of the drilling tool, rotating integrally with the drive shaft. A selective angular coupling mechanism exerting an angular holding torque between the clamp and the guide bush or respectively the drive shaft, the value of which being inferior to that corresponding to the slip threshold between the said clamp and the drilling tool.