Wedge-Stop Floating Latch for Gasket Aging Compensation

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Solution Overview

Problem

Existing latching mechanisms for household appliances, such as dishwashers and washing machines, face issues with gasket aging, where the latch mechanism may allow water leakage as the gasket compresses more over time, requiring adjustments in the stop position to maintain a sealed door.

Innovation Solution

A wedge-shaped stop mechanism that automatically accommodates the inboard movement of a floating latch design by variably bridging axial separations between the latch frame and the carriage, using lateral motion and teeth engagement to ensure secure sealing without high contact forces, and can be manufactured from thermoplastic materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed stop position is used in floating latch mechanisms, then the latch can be manufactured with simple structure, but water leakage occurs as the gasket ages and compresses more

Engineering Contradiction:
Improvesealing performanceVSAvoidstop mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stop mechanism is made adjustable rather than fixed, allowing it to adapt to changing gasket compression characteristics over time. The stop can be repositioned along the latch mechanism to maintain proper engagement as the gasket ages and compresses more, thereby preventing water leakage without requiring a completely complex system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stop position parameter can be changed or adjusted to compensate for gasket aging. By modifying the stop's location along the latch mechanism, the system maintains reliable sealing performance despite changes in gasket compression over time, resolving the contradiction between simple structure and long-term reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the stop is positioned to engage with the floating latch mechanism for a new gasket, then the latch structure remains simple, but the door can open slightly as the gasket ages

Engineering Contradiction:
Improvedoor closure assuranceVSAvoidsealing reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The stop mechanism allows for dynamic adjustment of the engagement point on the floating latch mechanism. As the gasket ages and the latch mechanism moves, the stop can be repositioned to maintain proper engagement, ensuring the door remains securely closed without requiring complex additional components.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a wedge-shaped stop with lateral motion is used, then the stop can accommodate axial separations effectively, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveaccommodation of axial separationsVSAvoidlateral motion precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The stop uses lateral motion (one dimension) to accommodate axial separations (another dimension). By moving the stop laterally along the latch mechanism, it can compensate for variations in axial separation caused by gasket aging, providing adaptability without requiring extremely tight manufacturing tolerances in the axial direction.

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

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 effectively prevents water leakage as the gasket ages by adjusting to changing axial separations, allowing for zero-force engagement and disengagement, and is suitable for use with thermoplastic components, ensuring a compact and reliable locking mechanism.

Implementation Method 1

A variation on the over-center spring mechanism stores energy in a spring as the door is opened and holds that energy until the door is closed again

Methodology Applied
Scientific EffectSpring energy storage and release: Spring

Implementation Method 2

A wedge-shaped stop mechanism that automatically accommodates the inboard movement of a floating latch design by variably bridging axial separations between the latch frame and the carriage, using lateral motion

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Data Source

PatentEP2147176B1Gasket-compensating latch mechanism
Publication Date: 2012.08.15 ILLINOIS TOOL WORKS INC
  • EP2147176B1 patent drawingFigure 1~4
  • EP2147176B1 patent drawingFigure 2~3
  • EP2147176B1 patent drawingFigure 5~6b

AI summary

A latch for an appliance or the like provides a floating bolt assembly (22, 30) spring biasing a door (16) against a sealing gasket in different positions depending on gasket compliance. A lock provides a stop (60, 68) that may adjustably bridge a distance between the latch frame (42) and the floating bolt assembly as the gasket ages thereby providing positive locking of the door over the life of the appliance.