Endoscopic Control Spool for Flexible Shaft Tensioning
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Solution Overview
Problem
Endoscopic surgical devices face challenges in controlling tension within flexible shafts, which affects the flexibility and articulation of the working end, particularly due to the elongate nature of the shaft and the interference of control wires that do not pass through the center, leading to undesired flexing and reduced precision.
Innovation Solution
A control mechanism with a spool and biasing elements that allows for slack in the tensioning element during insertion and engages to apply tension when needed, enabling free movement and precise articulation of the working end, using a driver and trigger to move the spool between positions and apply tension to the tensioning elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control wires are used to articulate and actuate the working end, then precise control is achieved, but the wires become longer or shorter as the shaft is flexed, interfering with flexibility
Solution Approach 1:
The control mechanism allows dynamic adjustment of wire tension through a spool system that can engage or disengage from the wire. The spool moves between a first position where it provides slack to the wire, allowing free flexion, and a second position where it engages the wire to apply tension for precise control. This dynamic state change resolves the contradiction by adapting the control mechanism's behavior to the operational context.
Solution Approach 2:
The system changes the tension parameter of the control wire by moving the spool between positions. In the first position, the wire has minimal tension allowing flexibility. In the second position, the spool engages the wire to increase tension for precise articulation and actuation control. This parameter change enables the system to optimize performance for different operational requirements.
2Reliability
If tension is applied to the control mechanism during insertion, then control is maintained, but the shaft flexibility is restrained or undesired flexing occurs
Solution Approach 1:
The spool system dynamically adjusts tension application based on operational needs. During insertion, the spool is in the first position providing slack to the control wire, allowing the shaft to flex freely without restrained flexibility. When control is needed at the working end, the spool moves to the second position to engage the wire and apply tension. This dynamic behavior resolves the contradiction by decoupling insertion flexibility from operational control stability.
3Ease of operation
If control wires do not pass through the center of the flexible shaft, then articulation is enabled, but the wires become longer or shorter as the shaft is flexed
Solution Approach 1:
The spool acts as an intermediary mechanism between the control wire and the shaft. It provides a reference point that maintains consistent geometric relationship with the shaft while allowing the wire to be tensioned or relaxed. The spool's ability to move between positions enables it to compensate for wire length changes during flexion while maintaining effective control of the working end articulation.
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 allows for improved flexibility and precise control of the endoscopic device, enabling effective articulation and actuation of the working end without interfering with the shaft's flexibility, enhancing the precision and effectiveness of endoscopic procedures.
Implementation Method 1
The spool can also include a biasing element (e.g., a wave spring) disposed between each pair of plates and adapted to bias the plates to one of the first and second positions
Data Source
AI summary
Control devices and methods are provided for controlling tension applied to a tensioning element extending through a flexible shaft, such as on an endoscopic device. In one exemplary embodiment, the methods and devices are configured to allow free movement and optionally provide slack to a control mechanism on an endoscopic device during insertion to allow free flexion of the shaft of the device, and to tension the control mechanism when desired to actuate, articulate, or otherwise control the working end or other portion of the device disposed within a patient's body.