Torque Limiting Coupling for Phaco Needle Mounting
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Solution Overview
Problem
Existing methods for mounting and demounting hollow needles on phaco instrument handpieces are complex and involve torque limitation, which complicates the process.
Innovation Solution
A device with a manually operable housing and a rotary shaft equipped with a torque limiting and non-return coupling, allowing for easy mounting and demounting of hollow needles without torque limitation, using a spring-loaded coupling mechanism with complementary projections and recesses to manage torque and direction of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque-limiting manually operable tools are used to screw the hollow needle onto the handpiece, then the mounting process is controlled and secure, but the device design becomes elaborate and complex
Solution Approach 1:
The device is divided into distinct functional components: a housing for manual operation, a rotary shaft for rotation, and a torque-limiting coupling mechanism with separate driver element. This segmentation allows each component to perform its specific function while keeping the overall design manageable and avoiding excessive complexity.
Solution Approach 2:
The torque-limiting coupling acts as an intermediary mechanism between the manually operated housing and the hollow needle. It mediates the torque transmission, providing controlled mounting while simplifying the interface between the user's manual operation and the precise torque requirements of needle attachment.
2Reliability
If torque limitation is implemented for mounting the hollow needle, then secure attachment is ensured, but the demounting process becomes restricted and more complex
Solution Approach 1:
The coupling mechanism dynamically adapts its behavior based on the direction of rotation. During mounting (clockwise rotation), the spring-loaded coupling engages to limit torque and ensure secure attachment. During demounting (counter-clockwise rotation), the coupling allows free rotation without torque limitation, enabling easy removal. This dynamic behavior resolves the contradiction between secure attachment and easy demounting.
Solution Approach 2:
The coupling mechanism periodically engages and disengages based on the rotation direction. The spring-loaded design allows the coupling to engage during tightening phases and disengage during loosening phases, creating a periodic pattern of torque application that facilitates both secure mounting and easy demounting.
3Ease of operation
If a simple device design is used for mounting and demounting, then ease of operation is improved, but torque control and prevention of unintended unscrewing are reduced
Solution Approach 1:
The spring-loaded torque-limiting coupling is self-regulating and does not require external control mechanisms. The spring automatically engages and disengages based on the applied torque and rotation direction, providing torque control and prevention of unintended unscrewing through the device's own mechanical properties rather than complex external controls.
Solution Approach 2:
The device changes the torque parameter dynamically based on rotation direction. During mounting, the spring-loaded coupling limits torque to a predetermined safe value. During demounting, the coupling allows torque to vary freely. This parameter change enables both simplicity and reliability without requiring complex control systems.
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
Enables simple and efficient mounting and demounting of hollow needles, providing clear torque limits during screwing and preventing unintended unscrewing, thus simplifying the process while ensuring secure attachment and detachment.
Implementation Method 1
a torque limiting and non-return coupling which has two coupling surfaces resiliently pressed against each other
Data Source
AI summary
The device (10) for mounting and demounting a hollow needle (12) on or from a phaco instrument handpiece (14) comprises a housing (16) having a torque limiting and non-return coupling (34). The coupling (34) is provided with corresponding coupling release projections (58) and coupling recesses (56) on two coupling surfaces (36), (38). Said coupling surfaces (36, 38) further have corresponding non-return projections (62) and non-return recesses (60). The coupling (34) is formed by a driver element (32) and a rotary shaft (18) having a plug-on end (22) for plugging on the hollow needle (12) to be mounted and demounted, respectively.