Flexible Hinge Medical Instrument Jaw Mechanism
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Solution Overview
Problem
Current surgical instruments with jaws face challenges in precision and efficiency, particularly as they decrease in size, due to high friction and hysteresis issues, which lead to uneven motion and increased force requirements, complicating minimally invasive procedures and micro-surgery.
Innovation Solution
A medical instrument with a unitary jaw structure and wrist mechanism formed from a single piece of material, featuring flexible hinges that reduce friction and hysteresis, allowing for precise positioning and movement with lower effective drive train compliance and mechanical advantage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the diameter of surgical instruments is reduced to minimize incision size and post-operative trauma, then patient recovery is improved and cosmetic outcomes are enhanced, but the friction and hysteresis in jaw mechanisms increase leading to reduced precision and increased force requirements
Solution Approach 1:
The patent replaces traditional pivot pin-based mechanical hinge mechanisms with a flexible hinge mechanism. This substitution eliminates the need for pivot pins and associated friction, allowing the jaw structure to achieve smooth motion through material flexibility rather than mechanical joint rotation. The flexible hinge is formed from a continuous piece of material that bends to enable jaw opening and closing without the friction and hysteresis inherent in pin-based systems.
Solution Approach 2:
The patent employs a flexible hinge mechanism that utilizes the flexibility of a thin-walled tubular structure. The hinge is formed by creating a bend in the tubular wall that allows controlled flexing motion. This flexible structure enables the jaw to move smoothly without mechanical joints, eliminating pivot pin friction and reducing hysteresis while maintaining the compact size required for minimally invasive surgery.
2Ease of operation
If traditional pivot pin hinge mechanisms are used in small-diameter instruments, then jaw actuation is achieved, but pivot pin friction increases requiring greater actuating force and causing uneven motion
Solution Approach 1:
The patent replaces the pivot pin hinge mechanism with a flexible hinge mechanism. Instead of using a mechanical joint with a pivot pin that creates friction, the invention uses the elastic deformation of a flexible material to enable hinge rotation. This substitution dramatically reduces the actuating force required because there is no static friction to overcome, and the motion is smooth and continuous throughout the range of motion.
3Force
If block and tackle mechanisms are used to increase mechanical advantage, then jaw actuation force is reduced, but the number of parts and assembly complexity increase
Solution Approach 1:
The patent integrates the flexible hinge mechanism directly into the jaw structure itself, merging what would traditionally be separate components (hinge mechanism, jaw, actuator) into a single integrated assembly. The flexible hinge is formed as an integral part of the tubular jaw structure, eliminating the need for separate pivot pins, bearings, and associated fastening hardware. This integration reduces parts count while maintaining the mechanical advantage needed for effective jaw actuation.
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 solution enables smaller, smoothly functioning surgical instruments with reduced hysteresis and friction, improving precision and accessibility in minimally invasive procedures by eliminating pivot pin friction and allowing for precise control and reduced patient trauma.
Implementation Method 1
a first jaw portion flexibly integral with the connector portion... allowing for precise positioning and movement with lower effective drive train compliance and mechanical advantage
Data Source
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AI summary
A medical instrument includes a unitary jaw structure having: a connector portion, a first jaw portion flexibly integral with the connector portion, a first arm portion integral with the first jaw portion, and an actuator portion flexibly integral with the first arm portion for causing rotating motion of the first jaw portion upon linear motion of the actuator portion. The medical instrument includes a unitary wrist structure having: a first connector portion having a lower stop surface, a compact flexure integral with the first connector portion, and a second connector portion integral with the compact flexure with the second connector portion having an upper stop surface integral with the compact flexure below the lower stop surface and forming an angle with the lower stop surface.