Flexible Torque Shaft Alignment for Surgical Instruments
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Solution Overview
Problem
Current flexible surgical instruments for transmitting torque are difficult to align, hard to clean and sterilize, prone to breaking under high torque, and costly to manufacture.
Innovation Solution
A surgical instrument with a flexible shaft comprising torque transmitting elements coupled in series, each rotationally fixed and tiltable, and an alignment member made of a spring-elastic material like Nitinol, allowing reversible bending and alignment, with features like recesses and through-holes for alignment and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible shaft is used to reach hard-to-access positions, then adaptability is improved, but alignment precision deteriorates
Solution Approach 1:
The flexible shaft is divided into multiple discrete torque transmitting elements (first element, second element, third element) that can be independently positioned. Each element contains alignment features (protrusions, recesses, or magnetic elements) that enable precise angular alignment when the shaft is bent, resolving the contradiction between flexibility and alignment precision.
Solution Approach 2:
Magnetic alignment elements are introduced as intermediaries between the torque transmitting elements. These magnetic elements (permanent magnets or electromagnets) create magnetic fields that automatically align the elements angularly when the shaft is bent, providing precise alignment without mechanical constraints that would reduce flexibility.
2Adaptability or versatility
If a flexible shaft with multiple components is used, then adaptability is improved, but device complexity increases
Solution Approach 1:
Multiple functions are merged into single components. Each torque transmitting element simultaneously provides torque transmission, flexibility through tilting capability, and alignment through integrated alignment features. The coupling mechanism also serves dual purposes: mechanical connection and angular alignment, reducing the need for separate alignment components.
Solution Approach 2:
The torque transmitting elements are designed as universal components that can be repeatedly coupled in series to create flexible shafts of different lengths and configurations. The same element design with alignment features can be used in various positions and orientations, reducing overall system complexity through standardization.
3Adaptability or versatility
If traditional flexible shaft construction is used, then flexibility is improved, but reliability deteriorates due to breaking under high torque
Solution Approach 1:
The torque transmitting elements are designed with dynamic tilting capability relative to each other, allowing the shaft to flex and bend without creating stress concentration points. The elements can tilt to accommodate bending while maintaining torque transmission, and the magnetic alignment provides gradual force distribution rather than abrupt mechanical locking, reducing shock loads.
Solution Approach 2:
The invention uses a composite structure combining magnetic materials (for alignment), mechanical coupling features (for torque transmission), and tilting mechanisms (for flexibility). This composite approach allows each component to be optimized for its specific function while working together to provide both flexibility and high torque capacity without breaking.
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 precise alignment and torque transmission while reducing the risk of breakage and manufacturing costs, facilitating easier handling and sterilization.
Implementation Method 1
an elongate alignment member extending through the through-holes of the torque transmitting elements, wherein the alignment member is made from a spring-elastic material
Implementation Method 2
The spring-elastic material may be a superelastic or pseudoelastic material
Implementation Method 3
The spring-elastic material may be a shape memory material, such as a shape memory alloy
Implementation Method 4
The spring-elastic material may be a shape memory material, such as a shape memory alloy
Implementation Method 5
The spring-elastic material may be a nickel titanium alloy, for example Nitinol
Data Source
AI summary
A surgical instrument for transmitting torque is described. The surgical instrument comprises a torque receiving portion at a proximal end of the surgical instrument, a torque delivering portion at a distal end of the surgical instrument, and a flexible shaft extending between the torque receiving portion and the torque delivering portion. The flexible shaft comprises torque transmitting elements coupled in series along a longitudinal direction of the shaft such that one of the torque transmitting elements is rotationally fixed and tiltable relative to an adjacent one of the torque transmitting elements, wherein each of the torque transmitting elements comprises a through-hole. The surgical instrument also comprises an elongate alignment member extending through the through-holes of the torque transmitting elements, wherein the alignment member is made from a spring-elastic material. The present disclosure further provides a system comprising the surgical instrument and a method of using the surgical instrument.