Brush Head Retention Rings With Projections

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Solution Overview

Problem

Existing brush head assemblies often fail to securely retain bristle tufts, leading to potential separation under dynamic conditions and a time-consuming, costly manufacturing process.

Innovation Solution

The use of retention rings with transverse projections embedded within an elastomeric matrix improves adhesion and retention, with the proximal ends of bristle tufts optionally joined together for enhanced stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If retention rings are used to secure bristle tufts in the brush head, then the bristle tufts can be retained during assembly, but the retention rings are not firmly secured within the brush head under dynamic conditions, leading to potential separation

Engineering Contradiction:
Improveretention of bristle tuftsVSAvoidsecurement strength of retention rings
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies preliminary action by forming projections on the retention rings before assembly into the brush head. These projections are pre-configured to engage with recesses in the brush head body, ensuring firm securing of the retention rings during dynamic conditions. This preliminary structural preparation prevents subsequent separation of bristle tufts during toothbrush operation.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If traditional cooling methods are used to fix bristle tufts in place, then the brush head material sets to retain the tufts, but the process is time-consuming and expensive

Engineering Contradiction:
Improvefixing of bristle tuftsVSAvoidmanufacturing cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the traditional thermal cooling system with a mechanical interlocking system. Instead of relying on cooling to solidify and fix the bristle tufts in place, the design uses geometric interlocking features (projections and recesses) that mechanically secure the retention rings and bristle tufts during assembly. This eliminates the time-consuming cooling step while maintaining precise positioning and fixation of the bristle tufts.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If retention rings without additional features are used, then the structure is simple, but the adhesion surface area between the retention ring and brush head material is insufficient, leading to loose bristle tufts

Engineering Contradiction:
Improveretention strengthVSAvoidadhesion surface area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies dimensionality change by adding vertical projections to the retention rings that extend into recesses of the brush head body. This transforms the adhesion interface from a simple planar contact to a three-dimensional interlocking structure. The projections increase the effective contact area and create mechanical engagement in the vertical dimension, significantly enhancing retention strength without complicating the overall design.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3294089B1Brush head arrangements
Publication Date: 2024.08.21 KONINKLIJKE PHILIPS NV
  • EP3294089B1 patent drawingFigure 1~2
  • EP3294089B1 patent drawingFigure 3~4
  • EP3294089B1 patent drawingFigure 5~6

AI summary

A brush head (32) including: a plurality of bristle tufts (21), each of which comprises a plurality of bristle strands having a free end (25) and a proximal end (23); a plurality of retention rings (50) each comprising an upper portion (51), a lower portion (53), an exterior wall (55) and an interior wall (57), and each configured to receive the proximal end of at least one of the plurality of bristle tufts, wherein at least one of the plurality of retention rings comprises a transverse projection (71, 72) extending from the exterior and/or interior wall of the retention ring; and an elastomeric matrix (30) comprising at least a portion of each of the plurality of retention rings and the proximal end of each of the plurality of bristle tufts.