Slotted Hinge Structure for Low-Force Steerable Instruments
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Solution Overview
Problem
Existing steerable surgical instruments face limitations in bendability, requiring high bending forces and having limited fatigue life due to elastic deformation or separation of parts, making handling and assembly difficult.
Innovation Solution
A cylindrical element with a hinge structure featuring a slotted design that allows for improved bendability, enabling high deflection without fatigue and maintaining structural integrity, using techniques like laser cutting to create flexible zones that can rotate freely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional steering cables or elastic deformation methods are used, then the instrument can achieve bending capability, but the bending force required is high and the fatigue life is limited
Solution Approach 1:
The cylindrical element is divided into multiple portions that can rotate freely relative to each other at the hinge location. This segmentation allows each portion to move independently, reducing the force required for bending and eliminating fatigue issues associated with elastic deformation of a single continuous structure.
Solution Approach 2:
The invention changes the physical state of the hinge from an elastic deformation mechanism to a rigid rotation mechanism. By creating a hinge with a slotted structure that allows free rotation between portions, the system transitions from relying on material elasticity to relying on mechanical articulation, thereby reducing required bending force and eliminating fatigue limitations.
2Ease of operation
If elastic deformation is used to provide flexibility, then the instrument can bend, but the bending capability is limited and handling becomes difficult
Solution Approach 1:
The cylindrical element is segmented into multiple rotatable portions at the hinge, enabling greater and more controlled bending capability compared to elastic deformation. This segmentation allows the instrument to achieve larger deflection angles and improves handling by providing predictable, mechanical articulation rather than limited elastic bending.
3Strength
If the hinge structure is made robust to maintain structural integrity, then the instrument can withstand forces, but the bendability and flexibility are reduced
Solution Approach 1:
The hinge structure is segmented into multiple portions that rotate relative to each other. Each portion can be designed with sufficient strength to maintain structural integrity, while the articulation between portions provides the necessary bendability. This resolves the contradiction by distributing structural requirements across multiple strong components rather than requiring a single continuous structure to be both strong and flexible.
Solution Approach 2:
The hinge employs a composite structure combining rigid portions with a slotted configuration that allows rotation. This composite design maintains structural integrity through the rigid portions while achieving bendability through the articulated slotted structure, eliminating the need to choose between strength and flexibility.
4Ease of manufacture
If conventional hinge designs are used, then the instrument can achieve flexibility, but the assembly complexity increases and manufacturing becomes difficult
Solution Approach 1:
The hinge structure is merged into a single cylindrical element as an integral feature rather than being assembled from separate components. The slotted structure that enables rotation is formed directly in the cylindrical element, eliminating the need for separate hinges, pins, or connectors, thereby simplifying assembly and manufacturing while maintaining flexibility.
Solution Approach 2:
The invention replaces complex mechanical hinge assemblies with a slotted structure that provides rotation through its geometry alone. This substitution eliminates the need for multiple mechanical components (pins, bushings, retainers) and simplifies both manufacturing and assembly while preserving the required flexibility and bendability.
Data Source
AI summary
A cylindrical element with a hinge structure has:a first portion (524; 1124; 522(n−1); 1122(n−1));a second portion (522(1); 1122(1); 522(n); 1122(n)) which is rotatable relative to the first portion (524; 1124; 522(n−1); 1122(n−1)) about two rotation sections (530(1); 1130(1); 530(n); 1130(n)) arranged at locations 180° rotated relative to one another viewed in a tangential direction of the cylindrical element;an attachment element (502(1); 1006; 502(n)).The rotation sections (530(1); 1130(1); 530(n); 1130(n)) are implemented by:either the first portion (524; 1124; 522(n−1); 1122(n−1)) or the second portion (522(1); 1122(1); 522(n); 1122(n)) is provided with an opening accommodating a pin (556(1); 1156(1); 556(n); 1156(n));the pin (556(1); 1156(1); 556(n); 1156(n)) is attached to a portion of the attachment element (502(1); 1006; 502(n));the other one of the first portion (524; 1124; 522(n−1); 1122(n−1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) is attached to another portion of the attachment element (502(1); 1006; 502(n));such that the first portion (524; 1124; 522(n−1); 1122(n−1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) cannot move relative to one another in a longitudinal direction, a tangential direction and a radial direction but are configured to rotate relative to one another about a center of rotation.