Flexible Rotary Coupling Structure for Misalignment and Anti-Disassembly

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Solution Overview

Problem

Existing coupling units for personal care devices face challenges in efficiently transmitting rotary driving force while allowing for misalignment between components, and they often require complex assembly and may not prevent inadvertent disassembly during use.

Innovation Solution

A coupling unit design featuring a first coupling member with a curved bearing surface and a second coupling member with curved bearing surface segments, connected by elastically deformable elements that provide biasing forces to ensure engagement and prevent disassembly, allowing for rotation and pivoting while maintaining alignment and torque transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a coupling unit uses rigid connecting elements to transmit rotary driving force, then the structure is simple, but it cannot accommodate misalignment between coupling members

Engineering Contradiction:
Improvemisalignment accommodationVSAvoidcoupling unit structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs flexible connecting elements made of elastically deformable material that can bend and deform to accommodate misalignment between the first and second coupling members. These flexible elements replace rigid connections, allowing the coupling unit to adapt to angular and positional deviations while maintaining structural integrity and torque transmission capability.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The connecting elements are designed to be dynamically deformable rather than statically rigid. They can elastically deform during operation to accommodate misalignment, then return to their original shape, providing continuous adaptation to varying alignment conditions while transmitting rotational force.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a coupling unit uses elastic connecting elements to allow misalignment, then adaptability improves, but assembly complexity increases

Engineering Contradiction:
Improvemisalignment accommodationVSAvoidassembly process
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The blocking element is pre-configured in the first coupling member to guide the insertion and positioning of the flexible connecting elements. This preliminary structural feature ensures that during assembly, the connecting elements are automatically positioned correctly as they are inserted, reducing assembly complexity despite the elastic nature of the components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The blocking element serves as an intermediary structure that facilitates the assembly of the flexible connecting elements. It provides a mechanical guide and constraint system that simplifies the integration of elastic components into the coupling unit, making the assembly process more straightforward despite the complexity introduced by the flexible elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If a coupling unit allows easy assembly, then ease of operation improves, but it may permit inadvertent disassembly during use

Engineering Contradiction:
Improveassembly easeVSAvoidanti-disassembly capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The blocking element is designed with a geometry that prevents the flexible connecting elements from disengaging during normal operation. The element creates a mechanical interference fit or locking action that opposes any disassembly force, ensuring that while assembly remains simple, inadvertent disassembly is prevented through the preliminary design of the blocking structure.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The blocking element features curved or spherical surfaces that work with the flexible connecting elements to create a self-retaining mechanism. The curvature allows easy insertion during assembly but creates a mechanical lock that prevents reverse movement, enabling easy assembly while ensuring operational reliability and preventing inadvertent disassembly.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 enables efficient transmission of rotary driving force, prevents inadvertent disassembly, and allows for misalignment between components, enhancing the stability and usability of personal care devices by simplifying assembly and operation.

Implementation Method 1

at least one of the at least two connecting elements comprises an elastically deformable material in a first deformed condition providing a first biasing force urging the at least two second bearing surface segments into contact with the first bearing surface

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the elastically deformable material is provided such that, in a second deformed condition of the elastically deformable material, the elastically deformable material provides a second biasing force larger than the first biasing force

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3655673B1Coupling unit
Publication Date: 2021.05.26 KONINKLIJKE PHILIPS NV
  • EP3655673B1 patent drawingFigure 1
  • EP3655673B1 patent drawingFigure 2
  • EP3655673B1 patent drawingFigure 3

AI summary

There is disclosed a coupling unit (100) for transmission of a rotary driving force, comprising a first coupling member (110) having a curved first bearing surface (116) and a second coupling member (150) having a main coupling body (154) and a curved second bearing surface engaging the first bearing surface thereby enabling rotation of the second coupling member (150) relative to the first coupling member (110). The second coupling member comprises at least two carrying elements (158) which are each provided with a respective one of at least two second bearing surface segments (160) of the second bearing surface that engage the first bearing surface. At least two connecting elements (156) of the second coupling member (150) each connect a respective one of the at least two carrying elements (158) with the main coupling body (154) and comprise an elastically deformable material. In a first deformed condition the elastically deformable material provides a first biasing force urging the at least two second bearing surface segments (160) into contact with the first bearing surface. A blocking element (120) of the first coupling member (110) is arranged between the first bearing surface (116) and the main coupling body (154) and is configured to prevent passage of the carrying elements (158) along the blocking element at least in the first deformed condition. In a second deformed condition of the elastically deformable material, wherein the elastically deformable material provides a second biasing force larger than the first biasing force, the carrying elements (158) are able to pass along the blocking element.