Forceps Handpiece Coupling With Force-Limiting Drive Shaft Assembly

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Solution Overview

Problem

Conventional medical devices with handpieces that actuate end effectors face challenges in reducing packaging space, simplifying design and manufacturing, improving user experience, and preventing damage, particularly in forceps used for surgical procedures.

Innovation Solution

The development of a medical device with a handpiece that includes a drive shaft motion transfer assembly, featuring a drive body, force-limiting spring, and clip, which transfers forces from the user to the end effector to control the jaws' opening, closing, and rotation, while preventing excessive force that could damage the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional handpiece design is used to actuate end effectors, then the device can perform basic surgical functions, but the packaging space is excessive and the design complexity is high

Engineering Contradiction:
Improvepackaging spaceVSAvoiddesign complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent combines the drive shaft motion transfer assembly with the handpiece housing into an integrated unit. The drive body is received within the housing and the actuator is integrated into the same structure, eliminating separate components and reducing overall packaging space while maintaining functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive body is nested within the handpiece housing, and the actuator is nested within the drive body structure. This nested arrangement allows compact packaging by placing smaller components inside the structural envelope of larger components, reducing the overall volume required.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If the handpiece is designed with simplified manufacturing, then production is easier and cost is reduced, but the stability and durability may be compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddevice stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The handpiece is segmented into distinct functional modules: the housing, the drive body, the actuator, and the force-limiting spring assembly. Each module can be manufactured separately using optimized processes and then assembled, simplifying manufacturing while maintaining the structural integrity and reliability of each component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The force-limiting spring acts as an intermediary element between the actuator and the drive shaft. It provides a mechanical means to limit excessive force without requiring complex electronic sensors or control systems, thereby simplifying manufacturing while ensuring device stability and preventing damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the force-limiting mechanism is added to prevent damage, then device durability is improved, but the device complexity increases

Engineering Contradiction:
Improvedevice durabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The force-limiting spring is designed to automatically engage and disengage based on the mechanical conditions within the handpiece. When excessive force is applied, the spring compresses to limit the force transmission to the drive shaft, and automatically returns to its original position when the force is removed, without requiring external control or complex mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The force-limiting spring is a simple, inexpensive mechanical component that can be easily replaced if worn or damaged. This approach prioritizes overall device durability by using a low-cost protective element rather than attempting to make the entire force-limiting mechanism highly durable and complex.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Volume of moving object

If the drive shaft motion transfer assembly is integrated into the handpiece, then packaging space is reduced, but the ease of repair becomes more difficult

Engineering Contradiction:
Improvepackaging spaceVSAvoidrepair accessibility
Core Design Contradiction:
Volume of moving objectVSEase of repair

Solution Approach 1:

The integrated design maintains segmental boundaries between the housing, drive body, and actuator components. These segments are designed with interfaces that allow for selective disassembly and reassembly, enabling repair personnel to access and replace specific components without having to disassemble the entire handpiece structure.

Inventive Principle:
Principle #1Segmentation

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 enhances the stability and durability of the forceps, simplifies manufacturing, and improves user experience by ensuring safe and effective actuation of the end effector without risking damage from excessive force.

Implementation Method 1

a force-limiting spring, which can be configured to limit a maximum amount of force that can be applied to the drive shaft

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3946091B1Forceps handpiece to driveshaft coupling
Publication Date: 2025.01.15 GYRUS ACMI INC
  • EP3946091B1 patent drawingFigure 1A
  • EP3946091B1 patent drawingFigure 1B
  • EP3946091B1 patent drawingFigure 2

AI summary

Forceps including a handpiece configured to transfer motion from an actuator to an end effector of the forceps. The handpiece including: a lumen extending through a portion of the handpiece; a sleeve affixed to the handpiece, the sleeve extending through at least a portion of the lumen; and a shaft extending into the sleeve and affixed to the sleeve.