Self-Closing Hinge Cam Mechanism for Refrigerator Door

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Solution Overview

Problem

Existing refrigeration appliances lack a simple and compact self-closing hinge arrangement that effectively limits the maximum opening angle of the door leaf while ensuring durability and stability under high loads, and prevents unnecessary stress on the hinge mechanism.

Innovation Solution

A self-closing hinge arrangement featuring a cam mechanism with a radial slideway, where the engaging member has a planar counter-stop surface that meets a flat stop surface on the cam member perpendicularly, creating a rigid stop that limits the door's opening angle and integrates a self-closing mechanism within a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional hinge arrangement is used, then the door can be opened freely, but the maximum opening angle cannot be limited and the hinge is prone to lateral stresses

Engineering Contradiction:
Improvedurability of hinge arrangementVSAvoidcomplexity of hinge arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the stop function and self-closing function into a single integrated hinge arrangement. The cam mechanism with radial slideway serves both to limit the maximum opening angle (stop function) and to automatically close the door (self-closing function), eliminating the need for separate components and reducing overall complexity while improving reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam mechanism acts as an intermediary element between the door and hinge pin. Through the cam profile and radial slideway interaction, it mediates the door's movement to enforce the maximum opening angle limit and simultaneously generates the self-closing action, providing a sophisticated solution that addresses multiple requirements through a single mediating mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a rigid stop mechanism is added to limit maximum opening angle, then the door stop stability improves, but the hinge arrangement size increases

Engineering Contradiction:
Improvestability of door stopVSAvoidsize of hinge arrangement
Core Design Contradiction:
Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The stop mechanism is merged with the hinge pin itself through the cam profile integrated into the hinge assembly. The radial slideway and cam member form a compact stop mechanism that does not require separate external components, maintaining stability while minimizing volume increase

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cam mechanism utilizes curved surfaces and radial geometry to create the stop function. The radial slideway and cam profile employ curved geometries that provide effective stopping action within a compact space, avoiding the need for large linear extensions that would increase the hinge arrangement volume

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Volume of stationary object

If the counter-stop surface meets the stop surface at an angle, then the stop is more compact, but lateral forces create unnecessary stress

Engineering Contradiction:
Improvecompactness of hinge arrangementVSAvoidstress on hinge mechanism
Core Design Contradiction:
Volume of stationary objectVSStress or pressure

Solution Approach 1:

The patent applies a specific geometric configuration where the counter-stop surface and stop surface meet perpendicular to their approach direction. This local geometric quality ensures that the stopping force is applied purely in the axial direction without generating lateral components, eliminating unnecessary stress on the hinge mechanism while maintaining compact dimensions

Inventive Principle:
Principle #3Local quality

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 stable and durable door stop that prevents the door from being opened beyond the permissible angle, even under high forces, while minimizing material usage and avoiding lateral stresses, resulting in a smaller and lighter hinge arrangement.

Implementation Method 1

The holder and thus the roller is supported against the radial slideway of the cam by means of a spring coil

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a cam mechanism, which has an engaging member and a cam member cooperating with the engaging member, which comprises a radial slideway on which the engaging member runs along

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP2522798B1Household cooler with a self-closing hinge assembly
Publication Date: 2020.10.28 BOSCH SIEMENS HAUSGERATE GMBH
  • EP2522798B1 patent drawingFigure 1
  • EP2522798B1 patent drawingFigure 2
  • EP2522798B1 patent drawingFigure 3~4

AI summary

The device i.e. household cooling device (1), has a heat-insulating inner container (2) arranged in a body (7) and forming a storage area (3) for cooling goods. A door leaf (4a) is pivotably attached to the body around a vertical axis (A) and supported by a self-locking hinge arrangement (8) to open and close the area. The arrangement has a cam mechanism with an engaging member and a cam unit, where the member has a thrust ring surface. The cam unit has a fixed stop surface limiting a maximum opening angle of the leaf, where the ring surface is attached to the stop surface during the angle.