Pyrolytic Oven Door Locking with Electromagnet and Rotary Lobe

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Solution Overview

Problem

Existing door blocking devices for electric household appliances, such as pyrolytic ovens, are expensive, bulky, and complex, making them unsuitable for high-temperature applications, and often require multiple microswitches for operation.

Innovation Solution

A compact door blocking device using a retaining member with elastic means, a rotary member with radially projecting lobes, and an electromagnet for controlled actuation, which allows for straightforward operation and high reliability, eliminating the need for expensive microswitches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If known door blocking devices are used for pyrolytic ovens, then the door can be locked during operation, but the devices become extremely expensive and bulky due to servomotor operation requirements

Engineering Contradiction:
Improvedoor locking reliabilityVSAvoidblocking device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex servomotor-based mechanical system with a simpler electromagnet-actuated mechanism. The electromagnet (35) directly actuates the rotary member (20) through magnetic force, eliminating the need for complex mechanical transmission components like servomotors, gears, and multiple linkages while maintaining reliable door locking functionality during high-temperature operation

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

Solution Approach 2:

The invention extracts and eliminates unnecessary complex components from the blocking device. By removing the servomotor and its associated mechanical transmission system, the patent retains only the essential elements (electromagnet, rotary member with lobe, retaining member) needed for reliable door locking, thereby simplifying the overall device structure and reducing cost

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If servomotor-based blocking devices are used, then door locking can be achieved, but the devices become extremely expensive

Engineering Contradiction:
Improvedoor locking reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive components that can be easily manufactured and replaced if needed. The electromagnet (35), rotary member (20) with simple lobe structure, and retaining member (10) are designed as straightforward mechanical elements without complex electronics or precision mechanisms, significantly reducing manufacturing cost while maintaining functional reliability for door locking during pyrolytic cycles

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By substituting the expensive servomotor system with a simple electromagnet-actuated mechanical mechanism, the patent dramatically reduces component cost. The electromagnet requires basic electrical components and the mechanical linkage consists of simple shaped members, making the overall device much more cost-effective while preserving the essential door locking function

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

3Measurement precision

If complex blocking devices with multiple microswitches are used, then door position detection can be achieved, but the device complexity increases

Engineering Contradiction:
Improvedoor position detectionVSAvoidblocking device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent removes the need for multiple microswitches and complex position detection systems. The electromagnet (35) and rotary member (20) mechanism inherently provides positional control through its mechanical design, eliminating the need for separate sensing elements and complex control circuitry while still achieving reliable door position detection and control

Inventive Principle:
Principle #2Taking out (Extraction)

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 cost-effective, reliable, and compact door blocking system suitable for high-temperature applications, reducing complexity and operational costs while ensuring safe door locking and unlocking mechanisms.

Implementation Method 1

an electrically controlled actuator, preferably defined by a straightforward electromagnet, for selectively moving the rotary member

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Implementation Method 2

elastic means for pushing the retaining member into the rest position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

preferably by means of a ratchet device, between a first angular position and a second angular position

Methodology Applied
Scientific EffectRatchet: Ratchet

Data Source

PatentEP1888971B1Blocking device for the door of a pyrolitic oven
Publication Date: 2008.11.26 ITW IND COMPONENTS SRL
  • EP1888971B1 patent drawingFigure 1
  • EP1888971B1 patent drawingFigure 2~3
  • EP1888971B1 patent drawingFigure 4~5

AI summary

A door blocking device (1) including a retaining member (10) movable, along a given path, between a work position and a rest position, in which it respectively cooperates with and does not cooperate with a coupling member (8) of the door (2) when the door is in a closed position; and controlled-actuation means (11) for controlled actuation of the retaining member, and which include elastic means (13) for pushing the retaining member into the rest position; means (14) for moving the retaining member into the work position in opposition to the elastic means; a rotary member (15) having at least one radially projecting peripheral lobe (16) ; and an electrically controlled actuator (18) for moving the rotary member selectively between a first angular position, in which the at least one lobe does not interfere with the given path (T) , thus allowing the retaining member to move between the work position and the rest position, and a second angular position, in which the lobe interferes with the given path to lock the retaining member (10) in the work position in opposition to the elastic means.