Cooking appliance lamp

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Solution Overview

Problem

Existing luminaire designs for kitchen appliances face challenges in ease of assembly and light loss due to circumferential cutouts and friction locking connections, which compromise the stability and efficiency of light transmission.

Innovation Solution

A luminaire design featuring a light guide rod with a circumferential projection, such as a flange, that is positively locked in a corresponding recess of the holder, ensuring secure fit and defined orientation, while minimizing light loss through optimized light emission surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a circumferential cutout is incorporated into the light bar to achieve positive locking, then the light bar can be securely anchored in the holder, but the cross-section for light transmission is reduced and light loss occurs

Engineering Contradiction:
Improvelight bar anchoring stabilityVSAvoidlight loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The light bar is segmented into two functional zones: a locking zone with a circumferential cutout that receives the locking element, and a continuous light-transmitting zone that maintains full cross-sectional integrity for optimal light transmission without interruptions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking function is extracted from the light bar itself and transferred to a separate locking element that engages with the holder, allowing the light bar to maintain its continuous cross-section for light transmission while still achieving secure anchoring

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If spring clips or locking tabs are used to anchor the light guide rod, then positive locking connection is achieved, but the assembly structure becomes more complex

Engineering Contradiction:
Improvelight guide rod anchoringVSAvoidassembly structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element is merged with the light bar as an integrated component rather than a separate part, and the locking mechanism is merged with the holder structure, reducing the total number of components and simplifying assembly while maintaining reliable anchoring

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a clamping ring presses the sleeve walls against the light guide rod to create friction connection, then the light guide rod is held in place, but the assembly requires higher installation force and may damage components

Engineering Contradiction:
Improvelight guide rod fixationVSAvoidinstallation force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

Instead of applying radial clamping force to achieve axial retention (as in the friction connection), the design applies axial locking force through the locking element that engages with the holder, inverting the direction of the locking action to achieve secure fixation without excessive installation force

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

Data Source

PatentEP4339517B1Cooking appliance lamp
Publication Date: 2025.12.10 BJB GMBH & CO KG
  • EP4339517B1 patent drawingFigure 1
  • EP4339517B1 patent drawingFigure 2
  • EP4339517B1 patent drawingFigure 3

AI summary

The invention relates to a lamp, primarily a household appliance lamp, in particular a cooking appliance lamp, with a light source formed by a circuit board with an LED arranged thereon, with a light guide rod having a light entry surface for the light emitted by the LED, with a holder having a circuit board receptacle on a bottom side and a fixing element for receiving the light guide rod on a top side opposite the bottom side, with an opening in the holder in the area of ​​the fixing element through which the emitted light from the LED arranged on the bottom side passes to the light guide rod arranged on the top side, and is characterized in that the light guide rod forms a circumferential projection in a radial plane, in particular at least one substantially circumferential annular projection.The light guide rod is positively locked in place by means of the circumferential projection in the fixing element of the holder.