Jaw Actuation Mechanism With Single-Driver Bidirectional Control
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Solution Overview
Problem
Existing surgical instruments with tendon-driven end effectors require four tendons and complex moving parts, limiting miniaturization and increasing manufacturing costs due to the need for antagonistic pairs of tendons for each jaw member actuation.
Innovation Solution
An actuation mechanism that uses a single driver with integrated antagonistic tendons to simultaneously rotate two jaw members through a pin and slot configuration, allowing for compact design and reduced component complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each jaw member is driven by a separate pair of antagonistic tendons, then reliable bidirectional actuation is achieved, but the number of tendons increases to four and device complexity increases
Solution Approach 1:
The patent combines two separate tendon systems into a single tendon that controls both jaw members. The tendon is routed through a pulley system where a single tendon creates opposing forces on two different pulleys, which in turn drive two jaw members in opposite directions. This merging reduces the tendon count from four to one while maintaining bidirectional actuation capability.
Solution Approach 2:
The single tendon serves multiple functions simultaneously: it actuates both the first jaw member and the second jaw member, provides bidirectional control for both jaws, and enables coordinated movement. The pulley system allows one tendon to perform the work that would traditionally require four separate tendons.
2Ease of operation
If four tendons and associated moving parts are used for each jaw member, then complete independent control is achieved, but miniaturization becomes difficult
Solution Approach 1:
The patent merges four separate control systems into a single tendon-pulley-jaw mechanism. By routing one tendon through two pulleys that are each connected to different jaw members, the system achieves independent control of both jaws while using minimal components. This dramatically reduces the volume required compared to four separate tendon systems.
Solution Approach 2:
The pulley system allows nested arrangement where the tendon passes through pulleys that are mounted on the jaw members themselves. The pulleys are positioned such that the tendon routing creates a compact, nested configuration where components are integrated into each other's space, minimizing overall instrument volume.
3Adaptability or versatility
If four tendons and motors are used to drive each jaw member, then full actuation capability is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines four motor-tendon assemblies into a single motor-tendon-pulley-jaw system. One motor drives a single tendon that, through the pulley mechanism, actuates both jaw members bidirectionally. This reduces component count, simplifies manufacturing, and lowers cost while maintaining full actuation capability.
Solution Approach 2:
The single motor and tendon system performs multiple functions: it drives both jaw members, provides bidirectional control for each jaw, and enables coordinated movement patterns. This multi-functionality eliminates the need for four separate motor-tendon assemblies, significantly reducing manufacturing complexity and cost.
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
Enables miniaturization of surgical instruments, reduces manufacturing costs, and enhances force amplification and responsiveness of jaw movement, suitable for minimally invasive procedures.
Implementation Method 1
Rotation of the driver about the drive axis causes rotation of the first jaw in a first sense and the second jaw in an opposite sense, wherein one of the first jaw engagement portion and the first drive engagement portion comprises a first pin, and the other one comprises a first radially extending slot
Data Source
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AI summary
An actuation mechanism comprising a first jaw rotatable about a jaw axis and comprising a first jaw engagement portion, a second jaw rotatable about the jaw axis and comprising a second jaw engagement portion, and a driver rotatable about a drive axis parallel to the jaw axis and comprising a first drive engagement portion and a second drive engagement portion; wherein the first jaw engagement and drive engagement portions are slidably engageable with one another and the second jaw engagement and drive engagement portions are slidably engageable with one another; whereby, when the first jaw engagement portion is engaged with the first drive engagement portion and the second jaw engagement portion is engaged with the second drive engagement portion, rotation of the driver about the drive axis causes rotation of the first jaw in a first sense and the second jaw in an opposite sense.