Electric Toothbrush Brush Head Reciprocating Rotation Fixation

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Solution Overview

Problem

Existing electric toothbrush brush heads often experience disengagement of the bristle holder from the support tube due to production errors or wear, leading to potential injury from loose fixation, which can result in the bristle holder being swallowed or stuck in the throat, causing breathing issues.

Innovation Solution

A reciprocally rotatable brush head design where the driving shaft is restricted to rotate around a specific axis by the housing's top and central holes, preventing movement along the rotation axis and ensuring the brush disc remains securely attached, thus preventing disengagement and ensuring safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a restriction pin is used to fix the bristle holder to the support tube, then the brush head can be assembled, but the restriction pin may become loosened due to production errors or wear, causing the bristle holder to disengage

Engineering Contradiction:
Improveassembly easeVSAvoidfixation reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The restriction pin is nested within the bristle holder structure, with the pin passing through the bristle holder and being retained by a corresponding hole in the support tube. This nested configuration ensures the pin remains securely positioned during assembly and operation, preventing disengagement while maintaining ease of manufacture.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The restriction pin is pre-positioned within the bristle holder before assembly with the support tube. This preliminary positioning ensures proper alignment and secure fixation from the start, preventing loosening during subsequent use while keeping the assembly process simple.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the bristle holder is securely fixed to prevent disengagement, then safety is improved, but the structure becomes more complex

Engineering Contradiction:
Improvefixation reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The restriction pin and corresponding hole create a nested fixation system where the pin passes through the bristle holder and is retained by the support tube structure. This nested design provides secure fixation without adding external components or complex mechanisms, maintaining structural simplicity while ensuring reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The restriction pin structure is designed to be self-retaining, where the pin's positioning within the bristle holder and its interaction with the support tube hole create an automatic locking effect. This self-service mechanism ensures secure fixation without requiring additional fastening elements or complex assembly steps.

Inventive Principle:
Principle #25Self-service

3Device complexity

If the brush head is designed to be compact and simple, then manufacturing is easier, but the fixation mechanism may not be reliable enough to prevent disengagement

Engineering Contradiction:
Improvestructure simplicityVSAvoidfixation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The restriction pin is integrated into the existing bristle holder and support tube structures through a nested configuration. The pin passes through the bristle holder and is retained by a hole in the support tube, creating a secure fixation that adds minimal structural complexity while significantly improving reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The fixation mechanism uses the existing structural elements of the brush head (bristle holder and support tube) to create a self-retaining restriction pin system. This self-service approach ensures reliable fixation without requiring additional components, maintaining structural simplicity while enhancing safety.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3298985B1Brush head capable of performing reciprocating rotation
Publication Date: 2020.06.03 SHANGHAI SHIFT ELECTRIC CO LTD
  • EP3298985B1 patent drawingFigure 1
  • EP3298985B1 patent drawingFigure 2
  • EP3298985B1 patent drawingFigure 3

AI summary

A brush head (2, 50) capable of performing reciprocating rotation comprises a brush head housing (22, 52) and a driving wheel (27, 37A, 37B, 57). A top hole (221, 521) and/or a central through hole (223, 523) are/is distributed on the brush head housing (22, 52) in a centering manner. The center line(s) of the top hole (221, 521) and/or the central through hole (223, 523) and a revolution axis (L1) of a brush head driving shaft are located at a same line, and the brush head driving shaft (26, 56) penetrates through the central through hole (223, 523). Driving wheel through holes (272, 372A, 372B, 572) are distributed on the driving wheel (27, 37A, 37B, 57). After part of the brush head driving shaft (26, 36A, 36B, 56) passes through the driving wheel through holes (272, 372a, 372b, 572), the fitted region of the brush head driving shaft (26, 36A, 36B, 56) and the driving wheel (27, 37A, 37B, 57) enters the driving wheel through holes (272, 372A, 372B, 572), so as to enable the brush head driving shaft (26, 36A, 36B, 56) and the driving wheel (27, 37A, 37B, 57) to be fixedly linked. A brush plate protrusion (245, 345) formed along a revolution axis (L2) of the brush plate and towards the direction far away from a cleaning element (25, 55A, 55B) is distributed on a brush plate (24, 34, 54A, 54B). A driven wheel driven part (243, 343) matching a driving wheel driving part (271, 371A, 371B) is distributed on the brush plate protrusion (245, 345). A brush plate hollow region (241, 341, 541A, 541B) is formed on the brush plate protrusion (245, 345) along the direction of the revolution axis (L1) of the brush head driving shaft. The brush head driving shaft (26, 56) penetrates through or enters the brush plate hollow region (241, 341, 541A, 541B) and limits the brush plate (24, 34, 54A, 54B) to move along the revolution axis (L2) of the brush plate and towards the direction of the cleaning element (25, 55A, 55B). The brush plate (24, 34, 54A, 54B) is incapable of performing reciprocating rotation when the brush head driving shaft (26, 56) is not installed or is damaged.