Endoscope Tip Portion Diameter Reduction via Axial Cap Connection
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Solution Overview
Problem
Existing endoscopes face a challenge in reducing the diameter of the tip portion of the insertion unit due to the thickness of annular walls or cylindrical flange portions, which increases the outer diameter and affects the device's functionality.
Innovation Solution
The design features a plate-like cap body with a mounting portion and extending portions that connect to the tip portion body without forming an annular wall or flange, using a stringy or belt-like fixing member to secure the engagement between the cap and tip portion bodies, and an arc-shaped outer surface for improved airtightness and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an annular wall or cylindrical flange portion is formed on the cap body to connect to the tip portion body, then the connection between cap and tip portion body is secured, but the outer diameter of the tip portion is increased
Solution Approach 1:
The invention transitions from a radial connection structure (annular wall extending radially outward) to an axial connection structure (extending portion projecting axially toward the tip portion body). This dimensional change allows the cap to connect to the tip portion body without increasing the outer diameter, as the connection is achieved through axial projection and engagement rather than radial extension.
Solution Approach 2:
The extending portion of the cap is nested within the space defined by the tip portion body's outer peripheral surface. The extending portion projects into the axial space available without requiring radial clearance, effectively nesting the connection structure within the existing dimensional envelope of the tip portion.
2Strength
If the annular wall is made thick to ensure engagement strength, then the connection reliability is improved, but the outer diameter of the tip portion is further increased
Solution Approach 1:
The invention moves the engagement strength requirement from the radial dimension (thickness of annular wall) to the axial dimension (length of extending portion and engagement depth). The extending portion achieves sufficient engagement strength through its axial projection length and the engagement relationship with the tip portion body, eliminating the need for thick radial walls.
Solution Approach 2:
The invention changes the critical geometric parameter for engagement strength from radial thickness (annular wall thickness) to axial dimensions (extending portion length, engagement depth). This parameter transformation allows achieving the required strength without increasing the outer diameter constraint.
3Ease of manufacture
If a traditional cap structure with annular wall is used, then the cap can be easily manufactured, but the tip portion diameter is increased
Solution Approach 1:
The invention modifies the cap structure from a radially-extending annular wall to an axially-projecting extending portion. This design change maintains manufacturing simplicity through standard molding techniques while achieving the required compact outer diameter, as axial projection is equally straightforward to manufacture as radial extension.
Solution Approach 2:
The invention changes the critical geometric parameter from radial thickness to axial length for the cap's connecting feature. This parameter substitution allows maintaining ease of manufacture (both radial and axial features are easily molded) while achieving the compact diameter requirement through axial rather than radial extension.
Data Source
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AI summary
There is provided an endoscope of which a tip portion of an insertion unit can be reduced in diameter. A flat surface of an extending portion of a cap body is in contact with a planar mounting surface of an outer peripheral surface of a tip portion body and a second engagement portion is engaged with a first engagement portion in an endoscope of the invention, so that the tip portion body and the cap body are connected to each other. Further, a stringy or belt-like fixing member is disposed on an outer peripheral surface of a coating member, which covers a connecting portion between the tip portion body and the cap body, in the endoscope of the invention to fix engagement between the first and second engagement portions.