Endoscope Bending Section Control Cable Design
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Solution Overview
Problem
Existing endoscopes with Bowden cables face issues such as space constraints within the insertion tube, potential buckling of control cables under push forces, and increased manufacturing costs, which affect the maneuverability and longevity of the device.
Innovation Solution
A single force transfer member with a reduced cross-sectional area is used to control the bending section of the endoscope, allowing for efficient deflection and minimizing space usage, while being cost-effective and durable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Bowden cables with plastic guide tubes are used to control the bending section, then the control mechanism is reliable and prevents cable buckling, but the insertion tube occupies more space and manufacturing costs increase
Solution Approach 1:
The patent removes the plastic guide tube from the Bowden cable assembly, extracting only the essential control function. The control cable is allowed to run freely through the bending section without the enclosing tube, significantly reducing the space occupied while maintaining control reliability through the cable's inherent flexibility and tension-transmission properties
Solution Approach 2:
The control cable is divided into functional segments: a tensioned portion in the handle for control input, a flexible intermediate section in the bending section that can buckle and bend, and an attachment portion at the distal tip. This segmentation allows different portions to perform different functions, with the intermediate section accommodating buckling while maintaining overall control effectiveness
2Reliability
If two control cables are used to prevent buckling, then the bending section deflection is maintained, but the space requirement and device complexity increase
Solution Approach 1:
The patent combines the functions of two separate control cables into a single Bowden cable assembly. By allowing the control cable to buckle under compression and bend with the articulation, one cable performs both the push and pull control functions that previously required two cables, simplifying the overall control system
Solution Approach 2:
The control cable's physical state is changed from a rigid, tension-only element to a flexible element that can undergo buckling and bending. This parameter change allows the single cable to accommodate compressive forces by buckling while maintaining tension-transmission capability, replacing the need for two cables
3Volume of stationary object
If a single control cable is used to reduce space, then the insertion tube becomes narrower, but the cable may buckle under push forces reducing deflection
Solution Approach 1:
The control cable is designed with dynamic flexibility in its intermediate section, allowing it to adapt its shape during operation. The cable can buckle and bend dynamically as the bending section articulates, maintaining control effectiveness throughout the range of motion while occupying minimal space in the insertion tube
4Ease of operation
If Bowden cables are used in disposable endoscopes, then the control mechanism is effective, but manufacturing costs increase
Solution Approach 1:
The patent simplifies the Bowden cable assembly by removing the plastic guide tube, creating a cheaper, disposable control mechanism suitable for single-use endoscopes. The simplified cable assembly can be easily manufactured and discarded with the endoscope, eliminating the need for expensive, reusable components while maintaining adequate control functionality for the intended application
Data Source
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AI summary
An endoscope having a proximal end and a distal end (4). The endoscope comprises a handle at the proximal end and an insertion tube (3) extending from the handle towards the distal end (4) where the insertion tube (3) terminates in a tip section. The tip section comprises a bending section (5) and an articulated tip part (7) and the bending section (5) comprises a number of articulated segments (6) each comprising a guide passage (14) for a control member (11). The elongated control member (11) has a proximal end and a distal end (13). The proximal end of the elongated control member (11) is attached to an operating member arranged (8) at the handle (2) and the distal end (13) of the elongated control member (11) is attached to the most distal articulated segment (6, 7) of the bending section. An intermediate section (15) of the elongated control member (11) between said proximal end of the elongated control member (11) and the distal end (13) of the elongated control member (11) passes through said guide passages (14). The intermediate section (15) has a reduced overall cross-sectional area as compared to the majority of said elongated control member (11).