Dental Prophy Angle Self-Aligning Locking Mechanism

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Solution Overview

Problem

Conventional dental prophy angle and handpiece systems suffer from instability, leading to wobbling and rocking during use, and broken drive shafts that are difficult to remove, necessitating repair or replacement.

Innovation Solution

A dental prophy angle with an elongated tubular body and self-aligning locking mechanism, featuring a drive shaft with beveled gear teeth and a hinged closure, securely attaches to a handpiece with a keying mechanism that prevents rotation and shifting, ensuring stability and easy removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional dental prophy angle and handpiece systems are used, then the basic cleaning function is provided, but instability occurs leading to wobbling and rocking during use

Engineering Contradiction:
ImprovestabilityVSAvoidwobbling and rocking
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The prophy angle is divided into separate components including a drive shaft, a body with head portion, and a hinged closure. The drive shaft can be independently inserted and secured within the handpiece, while the body and closure form a separate removable assembly. This segmentation allows each component to be optimized for stability and ease of removal independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drive shaft is nested within the body of the prophy angle, and the hinged closure covers the head portion while allowing access to the nested drive shaft. The locking mechanism features nested elements where locking tabs engage with corresponding recesses in the handpiece, creating a stable nested configuration that prevents wobbling.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Strength

If conventional locking mechanisms are used, then attachment is achieved, but broken drive shafts are difficult to remove

Engineering Contradiction:
Improvesecure attachmentVSAvoidremoval of broken components
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The drive shaft is designed as a separate extractable component that can be independently removed from the body. The hinged closure provides access to the drive shaft, allowing it to be extracted without removing the entire prophy angle assembly. This extraction capability facilitates easy removal of broken drive shafts.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hinged closure provides dynamic access to the drive shaft, allowing the operator to open the hinge and remove the drive shaft when needed. The locking mechanism includes movable locking tabs that can be engaged or disengaged, providing dynamic control over the attachment strength and facilitating easy removal of components.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If a secure locking mechanism is implemented, then stability is improved, but ease of operation for replacement is reduced

Engineering Contradiction:
ImprovestabilityVSAvoideasy replacement
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The prophy angle is pre-assembled with the drive shaft inserted into the body and the hinged closure attached. This preliminary assembly allows the operator to simply attach the complete assembly to the handpiece without having to manually insert or align multiple components, maintaining ease of operation while ensuring stable attachment through the locking mechanism.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The locking mechanism incorporates movable locking tabs that can be easily engaged during attachment and disengaged during removal. The hinged closure provides dynamic access, allowing the operator to quickly open the hinge and remove the drive shaft or entire assembly without complex manipulation, balancing secure attachment with ease of replacement.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If the drive shaft is made long to reach the handpiece motor, then functionality is achieved, but the risk of breakage and difficulty of removal increases

Engineering Contradiction:
Improvefunctional connectionVSAvoiddrive shaft breakage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The connection between the prophy angle and handpiece motor is segmented into the drive shaft component and the body component. The drive shaft can be a shorter, more robust element that fits into the handpiece, while the body provides the necessary structural support and housing. This segmentation reduces the overall length and flexibility of the drive shaft, minimizing breakage risk while maintaining functional connection.

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 system provides a stable and ergonomic dental prophy angle and handpiece assembly that minimizes lateral and angular movement, allowing for secure attachment and easy replacement of the prophy angle, and facilitates easy removal of broken components without requiring professional repair.

Implementation Method 1

The drive shaft (20) has a driving gear (22) at its forward facing end which intermeshes with a driven gear (24) in the head (18) of the prophy angle

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

The drive shaft (58) includes at least one self-aligning locking tab (80, 81) that defines a recessed locking surface (82) adapted for receiving an interlocking drive member (96) in the handpiece (85)

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP2222245B1Dental prophylaxis angle and handpiece assembly
Publication Date: 2017.08.09 DENTSPLY SIRONA INC
  • EP2222245B1 patent drawingFigure 1
  • EP2222245B1 patent drawingFigure 2
  • EP2222245B1 patent drawingFigure 3

AI summary

A dental prophylaxis angle and handpiece assembly for cleaning and polishing teeth is provided. The dental prophylaxis angle is removably attached to the dental handpiece by an interlocking mechanism that includes extension locking tabs, a locking annular member, and an interlocking drive member in the handpiece. The prophy angle is securely snap-fitted onto the handpiece and locked in place so that it has minimal lateral movement. After the prophy angle has been used to treat a patient, it can be removed easily from the handpiece and disposed thereof.