Oven Lamp Glass Bayonet Locking to Prevent Burning and Fume Leakage

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Solution Overview

Problem

Oven lights face issues with the lamp glass burning due to high temperatures and dirt accumulation, making it difficult to remove and replace, and allowing fumes to escape through the mounting opening, leading to soiling and technical problems.

Innovation Solution

The design incorporates radially acting spring tongues that rest in transverse grooves for secure bayonet-like fixing, providing frictional connection and preventing unintentional loosening, while a reverse rotation lock and axial positioning features ensure easy assembly and disassembly without vapor leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lamp glass is screwed in tightly to prevent loosening, then the lamp glass is secured against unintentional loosening, but the contact surface burns to the flange edge due to high temperatures and tightening torque

Engineering Contradiction:
Improvesecuring against looseningVSAvoidburning of contact surface
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional threaded mechanical connection with a bayonet-style rotational locking mechanism. The lamp glass collar has locking protrusions that engage with corresponding grooves in the flange, allowing secure fixation without excessive tightening torque that causes burning. This mechanical system substitution eliminates the screw thread contact that generates heat and burning while maintaining reliable anti-loosening through positive mechanical engagement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the connection parameter from threaded fastening with high clamping force to bayonet engagement with controlled insertion depth and rotational locking. The bayonet connection specifies a precise insertion distance and rotational angle to achieve locking without excessive force, thereby preventing the contact surface burning while maintaining secure fixation against loosening.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the lamp glass is tightly fastened to prevent loosening, then the lamp glass remains secure during operation, but it becomes difficult to remove for maintenance purposes

Engineering Contradiction:
Improvesecuring against looseningVSAvoidremoval for maintenance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a dynamic bayonet connection that transitions from a loose insertion state to a locked state through rotational movement. During installation, the collar is inserted axially and then rotated to engage the locking protrusions with grooves, providing secure fixation. For maintenance removal, the reverse rotational movement disengages the locks, allowing easy extraction. This dynamic mechanism enables both secure operation and easy maintenance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection mechanism is segmented into distinct functional elements: an axial insertion phase and a rotational locking phase. The collar features separate locking protrusions that engage with grooves at specific positions. This segmentation allows the connection to be established in steps, making it easy to install by simple rotation and easy to remove by reversing the rotation, while maintaining secure fixation during operation.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If a small distance is provided between the stop surface and housing flange surface to prevent burning, then burning is reduced, but fumes escape through the mounting opening into the cavity

Engineering Contradiction:
Improveburning preventionVSAvoidfume escape
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary sealing mechanism between the lamp glass and housing flange. The bayonet connection includes a sealing element or sealing surface that prevents fume escape through the mounting opening. This intermediary sealing structure allows the stop surface to be positioned at an optimal distance that prevents burning while the sealing mechanism blocks the pathway for fume leakage into the cavity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different functional qualities to different regions of the connection interface. The stop surface area is positioned to prevent burning by maintaining appropriate distance from the flange, while a separate sealing region provides local sealing quality to prevent fume escape. This local differentiation of functional qualities allows simultaneous prevention of both burning and fume leakage.

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

This solution allows for maintenance-friendly removal of the lamp glass without vapor escape, prevents burning and deformation, and ensures secure sealing against fumes, thus addressing the challenges of high-temperature issues and dirt accumulation.

Implementation Method 1

the spring force of the spring tongues ensures a frictional connection between the lamp glass and the housing part, which is secured against unintentional loosening

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP1811227B1Electrical lamp, in particular for kitchen appliances
Publication Date: 2008.07.23 BJB GMBH & CO KG
  • EP1811227B1 patent drawingFigure 1
  • EP1811227B1 patent drawingFigure 2
  • EP1811227B1 patent drawingFigure 3

AI summary

The lamp has a housing part with a locking member directed into an interior of the housing part, where the locking member is provided for bayonet-shaped fixing or screw fastening of a lighting glass (11). The glass forms a collar (27) for surrounding an opening (26) of the glass, where the collar inserts the glass into the housing part. The collar has plugging grooves (29) arranged axial to the locking member, and transverse grooves (30) attached to the plugging grooves. The locking member is designed as a radial spring tongue and is fitted with the glass at the transverse grooves.