Spaced Pivot Assembly for Surgical Forceps
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Solution Overview
Problem
Existing dual-action jaw sets for surgical instruments often lose mechanical advantage as they close due to central pivot pins and actuation mechanisms that align on centerline, limiting the force applied during grasping or cutting operations.
Innovation Solution
A push-to-close actuated, dual-action, spaced pivot assembly with two separate moving jaws that pivot about fulcrum points on opposite sides of the centerline, maximizing crank angle and force by positioning pivot and drive force points far apart, allowing for simultaneous jaw movement and enhanced cutting or grasping capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a central common pivot pin is used for both jaws, then the structure is simplified and easier to manufacture, but the mechanical advantage is limited due to restricted crank arm distance
Solution Approach 1:
The invention divides the single central pivot into two separate spaced pivot fulcrum points, one for each jaw. This segmentation allows each jaw to have its own pivot location optimized for mechanical advantage while maintaining structural simplicity through the shared jaw retaining body.
Solution Approach 2:
The pivot points are positioned in a spaced arrangement transverse to the centerline of the jaw retaining body, moving from a single-point (0D) or collinear (1D) arrangement to a distributed (2D) configuration. This dimensional change maximizes the crank arm distance between pivot and drive force points.
2Ease of operation
If link arms are used to connect center pivoting jaws to actuation drive, then jaw movement is achieved, but mechanical advantage is lost as jaws close and components align on centerline
Solution Approach 1:
The invention employs asymmetric positioning of the pivot fulcrum points relative to the jaw geometry and drive force application points. This asymmetric arrangement ensures that the crank arm maintains an optimal angle throughout the jaw closing motion, preventing alignment on the centerline that would eliminate mechanical advantage.
Solution Approach 2:
The spaced pivot configuration enables dynamic optimization of the crank angle during jaw actuation. As the jaws close, the geometry maintains favorable force transmission angles, allowing the system to adaptively preserve mechanical advantage throughout the motion range rather than losing it at the closing position.
3Force
If pivot points are positioned far apart, then maximum crank angle and jaw force are achieved, but structural complexity increases
Solution Approach 1:
The invention merges the support function for both spaced pivot points into a single integrated jaw retaining body. This consolidation allows the pivot points to be positioned far apart for maximum mechanical advantage while avoiding the structural complexity of two separate mounting structures, as both pivots are accommodated within one unified component.
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
This design provides maximum force leverage and efficient tissue cutting and grasping, enabling reliable biopsy and surgical procedures, particularly suited for delicate tissues like heart and lung biopsies, with a locking mechanism to securely hold and remove tissue samples.
Implementation Method 1
by positioning the pivot point fulcrum and drive force point as far away from each other as the structure allows, the maximum crank angle at any point of the jaw actuation is produced, to maximize the force of the jaws
Data Source
AI summary
A push-to-close actuated, dual-action, spaced pivot, assembly for jaws, blades, and forceps devices. The assembly is structured for use with a push rod, cable, or solid wire forceps actuator surgical instrument. A jaw receiving body of the assembly is adapted to receive a wide variety of types of jaws performing different surgical functions. Two separate moving jaws each pivot about a separate spaced pivot pin, on opposite sides of the jaw body centerline. A handle with a pushing actuating rod provides a pushing motion to a drive rod, cable, or solid wire within a cable sheath to push a connected yoke in the assembly to push against the jaws to close the jaws together.