Appliance Door Lock Slider Jaw Design Against Heat Deformation

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Solution Overview

Problem

The existing locking mechanisms for electric household appliances, such as electric clothes dryers, face issues with plastic deformation due to elevated temperatures, leading to a decrease in elasticity and eventual failure of the latch to snap the slider jaw, causing the door to remain unlocked after prolonged use.

Innovation Solution

The mechanism separates the slider body and jaw into distinct parts, allowing them to be made of different materials, with form-locking and using axle pins and holes for secure attachment, and incorporates a hindering element within the housing to ensure the slider jaw opens under spring force, preventing reliance on junction area elasticity for locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the slider jaw and slider body are made as one piece from plastic material, then the structure is simple and easy to manufacture, but the elasticity of the junction area decreases due to plastic deformation at elevated temperatures, causing locking failure

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The slider jaw (23) and slider body (22) are separated into distinct components. The slider jaw can be made from material with appropriate elastic properties for reliable locking, while the slider body can be made from different material. They are connected via axle pins (24) through axle holes (25), allowing independent material selection for each component to optimize both manufacturability and reliability.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the slider jaw is held closed by the cam lobe, then the locking mechanism is simple, but the elasticity of the junction area is required to open the jaw, which fails after prolonged use

Engineering Contradiction:
Improvedevice complexityVSAvoidreliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

An opening finger (232) is introduced as an intermediary element on the slider jaw. This finger engages with a hindering element (131) on the housing to actively open the slider jaw when needed. This mediator mechanism replaces the reliance on junction area elasticity, providing a positive opening action that ensures reliable operation regardless of material degradation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the tooth of the slider jaw snaps the latch head to lock the door, then the locking function is achieved, but plastic deformation of the junction area prevents the tooth from snapping the latch after extended use

Engineering Contradiction:
Improvelocking functionVSAvoidstructural stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

Separating the slider jaw from the slider body eliminates the vulnerable junction area. The slider jaw can be manufactured from material optimized for maintaining structural stability and elastic properties under thermal conditions, ensuring the tooth (231) reliably snaps the latch head (31) for extended operational life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanism allows different materials to be used for the slider jaw and slider body. The slider jaw can be made from materials with superior thermal stability and elastic recovery properties, while the slider body can use materials optimized for other requirements, creating a composite structure that maintains locking functionality.

Inventive Principle:
Principle #40Composite materials

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

This design prevents plastic deformation and maintains consistent locking functionality across varying temperatures, ensuring the door remains securely locked and unlocked as intended, even after extended use.

Implementation Method 1

a spring 4. The slider 2 is translatory movable in the housing 1 by means of an assembly of a guiding groove 21 and a guiding cam 11 in the direction against the force of the spring 4 during closing the door of an electric household appliance and in direction of the force of the spring 4 during opening the door of an electric household appliance

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The housing 1 is provided with a cam lobe 12 lifting and supporting a rear side 233 of the slider jaw 23 (Figs. 2a and 5a) as well as closing and supporting it (Figs. 2b and 5b), when the latch 3 thrusts the slider 2 in direction against the force of the spring 4

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2297417B1Mechanism for locking a door of an electric household appliance
Publication Date: 2015.01.07 ITW METALFLEX D O O TOLMIN
  • EP2297417B1 patent drawingFigure 1~2b
  • EP2297417B1 patent drawingFigure 3~5b

AI summary

A mechanism for locking a door of an electric household appliance is improved in that a slider jaw (23) is hinged to a body (22) of a slider (2) in such manner that, by its tooth (231), it snaps or releases a head (31) of a latch (3) and that the slider jaw (23) is provided with an opening finger (232), and a mechanism housing (1) is provided with a hindering element (131), which thrusts the opening finger (232) of the slider jaw (23), when the slider (2) moves in direction of the force of the spring (4), so that the slider jaw (23) gets open. The slider body (22) and the slider jaw (23) are preferably made of different materials: the slider body (22) of a polyoxymethylene copolymer and the slider jaw (23) of a polyamide or of a ZL4 alloy having a composition Zn:A14:Cul. The proposed mechanism is not susceptible to plastic deformation of the junction area between the slider body and the slider jaw.