Ultrasonic Waveguide Thermal Expansion Coupling
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Solution Overview
Problem
Current ultrasonic surgical instruments face challenges in securely attaching end effectors to waveguides, with torque wrenches often becoming lost or misused, leading to inadequate acoustic coupling and potential device malfunction.
Innovation Solution
The use of an ultrasonic surgical instrument with a waveguide and engagement mechanism made from materials with different coefficients of thermal expansion, allowing for a selectively expandable interference fit when heat is applied, ensuring a secure and acoustically coupled attachment of the end effector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque wrenches are used to attach end effectors to waveguides, then attachment reliability is improved, but device complexity and risk of loss increase
Solution Approach 1:
The patent removes the external torque wrench from the system and integrates the attachment function directly into the end effector assembly. The end effector includes an engagement mechanism with teeth that directly engage with the waveguide, eliminating the need for separate torque wrenches and reducing device complexity while maintaining attachment reliability.
Solution Approach 2:
The end effector is designed with self-aligning engagement features including tapered surfaces and indexed teeth that automatically guide and secure the end effector to the waveguide without requiring external tools. The system performs its own attachment function through the engagement mechanism that provides automatic positioning and securing.
2Manufacturing precision
If torque wrenches are used to attach end effectors, then attachment precision is improved, but ease of operation deteriorates
Solution Approach 1:
The engagement mechanism features self-aligning tapered surfaces and indexed teeth that automatically position the end effector with precise orientation and spacing relative to the waveguide. This eliminates the need for clinicians to locate and use torque wrenches, making the attachment process intuitive and easy to perform while maintaining precise attachment geometry.
3Reliability
If interference fit with thermal expansion is used, then attachment reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The waveguide is designed with a radially expandable distal end that can be thermally expanded to facilitate end effector attachment. When heated, the waveguide material expands radially, allowing the end effector to be positioned and secured. Upon cooling, the waveguide contracts to create a secure interference fit, providing reliable attachment while accommodating normal manufacturing tolerances through the thermal expansion mechanism.
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
This solution provides a reliable and secure attachment of the end effector to the waveguide, ensuring optimal transmission of ultrasonic energy and reducing the risk of device malfunction, while also simplifying the attachment process and eliminating the need for torque wrenches.
Implementation Method 1
The attachment portion is configured to be selectively expandable into an acoustically coupled retaining engagement with the ultrasonic end effector by expanding faster than the proximal end of the ultrasonic end effector when heat is applied to establish an interference fit therebetween
Data Source
AI summary
An ultrasonic surgical instrument is disclosed including an ultrasonic transducer, an ultrasonic end effector comprising a proximal end formed of a first material having a first coefficient of thermal expansion, and a waveguide configured to transmit ultrasonic energy generated by the ultrasonic transducer to the ultrasonic end effector. The waveguide includes an attachment portion formed of a second material having a second coefficient of thermal expansion that is greater than the first coefficient of thermal expansion. The attachment portion is configured to be selectively expandable into an acoustically coupled retaining engagement with the ultrasonic end effector by expanding faster than the proximal end of the ultrasonic end effector when heat is applied to establish an interference fit therebetween.