Surgical Handle Toggle Lever Spring Integration

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Solution Overview

Problem

Existing surgical handles for tubular instruments are limited by complex mechanics that prevent disassembly, suboptimal tactile feedback, and difficulty in cleaning, often requiring additional spring elements that increase weight and reduce control, particularly when the tool is almost closed.

Innovation Solution

A surgical handle design that integrates a resilient toggle lever mechanism, where the toggle lever itself acts as the return spring, eliminating the need for a separate spring element, allowing for easier disassembly, improved cleaning, and enhanced tactile feedback by using a leaf spring that combines the functions of a toggle lever and a spring in a single component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate axial compression spring is built into the handle housing to generate return force, then the handle can return to starting position, but the spring requires additional space and the spring force effect is greatly reduced when the tool is almost closed

Engineering Contradiction:
Improvereturn force generationVSAvoidhandle housing space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The toggle lever is designed to perform dual functions: it acts as both the mechanical linkage for force transmission and as the spring element that generates return force. By integrating the spring function into the toggle lever itself, the patent eliminates the need for a separate axial compression spring in the handle housing, thereby saving space while maintaining reliable return force generation throughout the full range of motion

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a separate axial compression spring is used in the handle housing, then return force is provided, but the spring force effect drops sharply when the tool is almost closed leading to uncontrolled snapping shut

Engineering Contradiction:
Improvereturn force controlVSAvoidtool control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

By combining the toggle lever and spring element into a single integrated component, the return force is generated at the correct point in the mechanism's motion sequence. The integrated design ensures that the spring force acts directly on the force transmission train before the toggle lever translation, maintaining consistent control authority throughout the entire range of motion including when the tool is almost closed

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If multiple separate components (handle housing, spring, toggle lever, slide) are used in the handle mechanism, then each component can be optimized for its specific function, but the overall device complexity increases and disassembly becomes difficult

Engineering Contradiction:
Improvecomponent optimizationVSAvoidhandle mechanism structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent integrates the spring element and toggle lever into a single component, reducing the number of parts in the handle mechanism from four separate components (handle housing, spring, toggle lever, slide) to fewer integrated components. This simplification maintains functional optimization while reducing assembly complexity and facilitating easier disassembly for cleaning and maintenance

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If additional spring elements and complex mechanics are added to the handle, then return force and mechanical advantage are improved, but the handle weight increases and tactile feedback is reduced

Engineering Contradiction:
Improvemechanical advantageVSAvoidhandle weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

By integrating the spring function into the toggle lever itself, the patent eliminates redundant components and reduces overall handle weight. The integrated design maintains full mechanical advantage and return force generation capabilities while removing the weight penalty associated with separate spring elements and complex mounting structures

Inventive Principle:
Principle #5Merging (Combining)

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 simplifies the handle's construction, reduces weight, enhances tactile feedback, and improves control by eliminating the need for additional components, allowing for easier manipulation and maintenance while maintaining effective force transmission to the tubular shaft tool.

Implementation Method 1

a resilient element, in particular a leaf spring (9), which is curved in the sense of an arc and has a first end (A) and a second end (B) which forms a toggle lever with the lever/handle (1) in order to transfer force on the lever/handle (1) into an axial force on the slide (5)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2941211B1Surgical handle for a tool having a tubular shaft
Publication Date: 2016.09.21 AESCULAP AG
  • EP2941211B1 patent drawingFigure 1
  • EP2941211B1 patent drawingFigure 2
  • EP2941211B1 patent drawingFigure 3

AI summary

Disclosed is a surgical handle for a surgical instrument, in particular a shaft-type instrument for actuating a tool that is distally arranged on an instrument shaft, said surgical handle comprising a handle housing on which at least one handle is mounted so as to be movable relative to the handle housing. The handle is coupled, via a toggle mechanism, to a sliding element that is axially movable in the handle housing in order for the sliding element to be moved as the handle is actuated from the starting position against the restoring force of a spring element, said spring element being embodied by the toggle mechanism.