Appliance Snap Joint Hinge with Elastomeric Bushing

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Solution Overview

Problem

Existing snap joint hinges for household appliances, such as dishwashers, face issues with hidden connection points during assembly, risk of damage under stress, rotation irregularities, noise, and axial clearance, making the connection process difficult and prone to errors.

Innovation Solution

A snap joint hinge device with a hooking mechanism featuring an elongated recess, a slot-like through recess, and elastic means to facilitate smooth and precise axial positioning of the hinge pin, ensuring secure engagement and silent rotation, and designed to be stress-resistant by using a hinge pin with an annular groove and a head that locks into a circular seat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the hinge uses a traditional support bush with expansion arms, then the connection is achieved, but the expansion arms are at risk of damage or breakage under stress

Engineering Contradiction:
Improvestress resistanceVSAvoidrisk of breakage
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent removes the vulnerable expansion arms from the support bush structure and replaces them with a solid bushing material having elastomeric properties. This extraction eliminates the weak points where breakage could occur while maintaining the stress-absorbing function through the elastomeric material itself.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state and properties of the support bush from a rigid structure with mechanical expansion arms to an elastomeric material that can deform elastically. This parameter change allows the bushing to absorb stress through material deformation rather than mechanical arm movement, eliminating breakage risks.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the hinge uses a downward-opening oblong hole and support bush, then the connection is achieved, but the connection points become hidden and difficult to align during assembly

Engineering Contradiction:
Improveassembly easeVSAvoidvisibility of connection points
Core Design Contradiction:
Ease of manufactureVSDifficulty of detecting and measuring

Solution Approach 1:

The patent inverts the opening direction of the oblong hole from downward to upward. This allows the alignment features and connection points to be visible to the assembler during the assembly process, eliminating the visibility problem while maintaining the functional connection between hinge components.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of operation

If the hinge allows axial clearance between brackets, then the components can move freely, but rotation irregularities and noises occur

Engineering Contradiction:
Improverotation smoothnessVSAvoidnoise and rotation irregularities
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent incorporates the elastomeric support bushing as a pre-designed cushioning element that compensates for axial clearance and misalignments before they can cause rotation irregularities or noise. The elastomeric material absorbs dimensional variations and maintains smooth rotation throughout the hinge's operational life.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If the hinge pin is inserted with force to flex the expansion arms, then the connection is secured, but damage or breakage of expansion arms occurs

Engineering Contradiction:
Improveconnection securityVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the installation mechanism from mechanical flexing of rigid expansion arms to elastic deformation of an elastomeric material. The hinge pin is inserted without force, and the elastomeric bushing naturally deforms to accommodate the pin, securing the connection without risking structural damage.

Inventive Principle:
Principle #35Parameter changes

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 stress-resistant, silent, and precise rotation mechanism that simplifies the assembly process, reduces the risk of damage, and minimizes axial clearance, ensuring a secure and smooth operation of the door connection.

Implementation Method 1

elastic means arranged to expand or contract to facilitate insertion of the hinge pin

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3658730B1Snap joint hinge device
Publication Date: 2021.10.27 C M I CERNIERE MECCANICHE IND
  • EP3658730B1 patent drawingFigure 1
  • EP3658730B1 patent drawingFigure 2
  • EP3658730B1 patent drawingFigure 3~5

AI summary

A snap join hinge device comprising a first element (3) intended to be fixed to a body of an appliance and a second element (5) intended to be fixed to a door of said appliance where said first (3) and second elements (5), in an assembled condition of the apparatus, are mutually connected for rotation of the door around a rotation axis. The second element (5) is provided with an elongated recess (7), having an open end (9) and a closed end (11), the second element (5) is also provided with a first connection (13) made near the recess (7). Said device (1) further comprises a hooking means (15) provided with a first seat (17) provided with an opening (19) and a second seat (18) almost facing the first seat (17) and delimited by one of its continuous edge and said hooking means (15) comprises a second connection (21) intended to engage in the first connection (13) to provide a fastening condition in which the opening (19) and the first seat (17) are aligned with the longitudinal axis of the recess (7) and facing the open end (9). Said first seat (17) and the recess (7) are designed to receive and house a stem of a hinge pin (23) fixed protruding from the first element (3) and defining said rotation axis. The second seat (18) is designed to receive and house a head (26) of this hinge pin (23). These first (3) and second (5) elements mutually separated and fixed to the chassis and the door, respectively, can be mutually connected rotatably, engaging the hinge pin (23) and its head (26) respectively in the first seat (17) and in the second seat (18) for hinging said door to the appliance chassis.