Endoscope Control Wire Tensioning to Eliminate Slack Hysteresis
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Solution Overview
Problem
The slack in control wires of medical devices, such as endoscopes, causes hysteresis and inaccurate positioning of the distal end, leading to incorrect placement of medical instruments.
Innovation Solution
A tensioner mechanism, comprising a cantilever spring and wire guide, is used to maintain continuous tension on the control wires, ensuring immediate movement of the distal end in response to actuator manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If control wires are used to manipulate the distal end of the flexible shaft, then the medical device can achieve flexible positioning, but slack in the wires causes hysteresis and inaccurate positioning
Solution Approach 1:
The control wires are pre-tensioned during assembly and operation to eliminate slack before positioning is required. The tensioning mechanism applies initial tension to the wires, ensuring they are taut and ready for immediate responsive movement when the actuator is manipulated, thereby eliminating hysteresis and improving positioning accuracy.
2Speed
If the actuator manipulates control wires to move the distal end, then directional control is achieved, but slack must be taken-up before movement occurs causing delay
Solution Approach 1:
The control wires are pre-tensioned during assembly and operation to eliminate slack before positioning is required. The tensioning mechanism applies initial tension to the wires, ensuring they are taut and ready for immediate responsive movement when the actuator is manipulated, thereby eliminating hysteresis and improving positioning accuracy.
3Measurement precision
If control wires have slack to accommodate movement, then flexibility is maintained, but hysteresis results in incorrect positioning
Solution Approach 1:
The control wires are pre-tensioned during assembly and operation to eliminate slack before positioning is required. The tensioning mechanism applies initial tension to the wires, ensuring they are taut and ready for immediate responsive movement when the actuator is manipulated, thereby eliminating hysteresis and improving positioning accuracy.
Solution Approach 2:
A tensioning mechanism serves as an intermediary component between the control wires and the actuator. This intermediary applies and maintains tension on the wires, ensuring they remain taut during operation. The tensioning mechanism translates actuator movement into precise distal end positioning by eliminating wire slack and hysteresis.
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 tensioner mechanism eliminates slack, enhancing the responsiveness and accuracy of the distal end movement, thereby improving the precision of medical device positioning.
Implementation Method 1
A tensioner mechanism, comprising a cantilever spring and wire guide, is used to maintain continuous tension on the control wires
Data Source
AI summary
A method and apparatus for tensioning a control wire in a medical device, wherein the apparatus comprises a lug adapted to be fixedly attached to a housing of the medical device; a wire guide defining an aperture through which the control wire extends; and a cantilever spring having a first end coupled to the lug and a second end coupled to the wire guide for applying force to the control wire. The apparatus is used in a medical device such as an endoscope.