Retractable Forceps Helical Spring Mechanism

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Solution Overview

Problem

Dental forceps require a convenient automatic retraction mechanism to reduce user effort and prevent contamination, but existing solutions often have springs that are either too strong or interfere with the forceps' operation, and lack effective cleaning access.

Innovation Solution

A helical spring is enclosed in a chamber within the forceps' connectors, encircling a pivot element, with grooves on the connectors' surfaces to guide retraction and allow for easy cleaning and sterilization, while a bolt secures the forceps with adjustable tightness to prevent spring contact and ensure balanced retraction force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a strong spring is used for automatic retraction, then the retraction force is sufficient to move jaws apart, but repeated and/or prolonged gripping becomes difficult or uncomfortable for the practitioner

Engineering Contradiction:
Improveretraction forceVSAvoidgripping comfort
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The force system is segmented into multiple components: a first spring providing retraction force on the jaws, a second spring providing retraction force on the handles, and a friction reduction element. This segmentation allows each spring to be optimized for its specific function with moderate force characteristics, preventing any single spring from being excessively strong and causing gripping discomfort.

Inventive Principle:
Principle #1Segmentation

2Extent of automation

If a spring is placed between the jaws and handles for automatic retraction, then the jaws retract automatically when grip is released, but the spring configuration may interfere with closing or retracting the forceps

Engineering Contradiction:
Improveautomatic retractionVSAvoidclosing motion
Core Design Contradiction:
Extent of automationVSEase of operation

Solution Approach 1:

The spring mechanism is extracted from the traditional single-location placement and distributed to two separate locations: one spring is positioned to act on the jaws independently, and another spring acts on the handles independently. This extraction allows each spring to perform its retraction function without interfering with the closing motion of the other component.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A friction reduction element (such as a bearing or low-friction coating) is introduced as an intermediary between the spring and the moving parts. This intermediary reduces frictional interference, allowing the spring to provide automatic retraction force while minimizing resistance to the closing and retracting motions of the forceps.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the spring is enclosed within the forceps, then the retraction mechanism is compact, but cleaning and sterilization access becomes difficult

Engineering Contradiction:
Improveforceps compactnessVSAvoidcleaning access
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The enclosure structure is designed with local quality variations: most of the spring mechanism is enclosed within the forceps body to maintain compactness, but specific portions (such as the spring ends or access channels) are left open or accessible. This allows cleaning solutions to reach critical areas while maintaining a compact overall structure.

Inventive Principle:
Principle #3Local quality

4Stability of the object's composition

If the spring force is applied equally to both jaws and handles, then the retraction is balanced, but the spring installation becomes more complex

Engineering Contradiction:
Improveretraction balanceVSAvoidspring installation
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The force application system is segmented into two independent spring arrangements: one spring configured to apply force to the jaws and another spring configured to apply force to the handles. This segmentation achieves balanced retraction forces on both components while simplifying installation, as each spring can be independently positioned and adjusted without complex multi-point attachment requirements.

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

The solution provides a balanced and automatic retraction mechanism that reduces user effort and allows for effective cleaning and sterilization of the forceps, preventing contamination and ensuring reliable operation in dental procedures.

Implementation Method 1

A spring, such as a helical spring, is enclosed in a chamber inside the connectors. The spring encircles a pivot element for the forceps

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A helical spring is enclosed in a chamber within the forceps' connectors, encircling a pivot element

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3531936B1Retractable forceps
Publication Date: 2024.02.21 SAJID HASEEB
  • EP3531936B1 patent drawingFigure 1
  • EP3531936B1 patent drawingFigure 2~5
  • EP3531936B1 patent drawingFigure 6~7

AI summary

A forceps having relative pivoting forceps joined by connectors and jaws retractable by action of a helical spring in a chamber inside the connectors of the two forceps. A passage from the spring chamber outward lo the exterior periphery of a first connector and opening in a space between the two jaws of the two forceps when the forceps and their jaws are retracted, permitting entry of cleaning materials into the interior of the forceps. The jaws being shaped and the passage into the interior of the forceps being so located and shaped that the passage into the interior of the forceps is blocked by at least one of the jaws when the forceps are gripped and the jaws are toward each other.