Cooking Appliance Lid Interlock for Safe Cover Positioning

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Solution Overview

Problem

Culinary preparation appliances face safety and design challenges, including the need for wider housings and additional switches to prevent operation without a working container, which complicates the fitting and usage of the cover.

Innovation Solution

A safety device that uses a lower safety member to prevent the cover's peripheral edge from moving into the control element's operating position when inclined, ensuring the cover is correctly positioned and allowing rotation of the rotary working tool only when properly aligned, thus avoiding dangerous operation without the working container.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cover height is increased to prevent operation without the working container, then safety is improved, but the housing width and fitting height requirements increase

Engineering Contradiction:
ImprovesafetyVSAvoidhousing width
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent introduces a radial dimension constraint through the grooved cylindrical surface that engages with the control element. Instead of relying solely on vertical cover height, the safety mechanism operates in the radial dimension where the groove geometry prevents the control element from reaching the actuating position when the cover is improperly positioned or removed.

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

Solution Approach 2:

The grooved cylindrical surface acts as an intermediary mechanism between the cover and the control element. This intermediate structure translates the cover's angular position into a radial constraint, allowing the control element to be actuated only when the cover is correctly positioned, thereby enabling safety without increasing overall housing dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If two switches spaced apart angularly are used to prevent operation with inclined cover, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidnumber of switches
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the safety detection function into the single control element actuation mechanism. The grooved cylindrical surface simultaneously serves as both the control element's guide and the safety interlock, eliminating the need for separate switches. The geometry of the groove itself provides the safety function by physically preventing actuation when the cover is improperly positioned.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grooved cylindrical surface performs multiple functions: it guides the control element's radial movement, provides the safety interlock mechanism, and translates angular cover position into radial constraint. This multi-functional design replaces what would otherwise require multiple separate safety switches, reducing device complexity while maintaining safety.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If the cover fitting height is reduced to match the reception area, then ease of operation is improved, but safety is compromised without additional switches

Engineering Contradiction:
Improvecover fittingVSAvoidsafety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent compensates for reduced vertical fitting height by introducing a radial dimension constraint through the grooved cylindrical surface. The control element's radial movement within the groove provides the safety function, allowing the cover to fit within the standard reception area height while maintaining safety through the radial-angular coupling mechanism.

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

Data Source

PatentEP2008559B1Cooking appliance comprising a simplified safety system
Publication Date: 2010.09.15 SEB SA
  • EP2008559B1 patent drawingFigure 1
  • EP2008559B1 patent drawingFigure 2~4
  • EP2008559B1 patent drawingFigure 5~6

AI summary

The appliance has a lid (4) that covers a working container, and has a control unit (15) that exhibits mobility between a raised rest position and a lowered operating position. The control unit is formed by a lower peripheral edge (41) of the lid. The lip has a lower security unit (43) that freely rotates a rotary working tool (3), when the lid is placed on a housing (1). The security unit cooperates with an upper part (35) of the tool to cause inclination of the lid on the housing for separating the lower peripheral edge from a lowered operating position of the control unit.