Explosion-Proof Actuator Adapter Mechanism

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Solution Overview

Problem

Existing explosion-proof housings with actuating devices face challenges in transmitting movements while ensuring explosion protection, requiring high technical complexity and manufacturing effort, especially for bushings and feedthroughs, which are costly and require extensive testing and certification.

Innovation Solution

An actuating device with a mechanical actuating unit, a switching unit, and an adapter device that converts rotary motion into axial motion using a gear mechanism, featuring adapter tappets and channels to ensure flameproof gaps and reduce the need for complex certification of individual components, allowing for flexible and cost-effective implementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional actuating devices with shafts and coupling pieces are used to transmit movement through the housing wall, then rotational movement can be transmitted, but the device complexity increases and manufacturing effort rises due to explosion-proof requirements

Engineering Contradiction:
Improvemovement transmissionVSAvoidactuating device complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts the complex explosion-proof transmission mechanism from the actuating device and replaces it with a simple adapter tappet that moves linearly through the housing wall. The actuating unit and switching unit are separated, with only the simple adapter tappet penetrating the housing, thereby removing the complexity of eccentric slots and coupling pieces while maintaining movement transmission functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of transmitting rotational movement directly through the housing wall using complex eccentric mechanisms, the invention inverts the approach by converting rotational actuation into linear movement of the adapter tappet. The adapter tappet moves linearly through the housing wall, and the switching element is actuated in the same linear direction, eliminating the need for complex rotational transmission through the wall.

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

2Reliability

If flameproof gaps are formed in the area of bushing to ensure explosion protection, then safety is improved, but manufacturing effort and cost increase significantly

Engineering Contradiction:
Improveexplosion protectionVSAvoidmanufacturing effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the geometric parameters of the adapter tappet and housing opening to create a standardized flameproof gap configuration. By defining specific dimensional relationships between the adapter tappet diameter, housing opening size, and gap length, the design achieves explosion protection through simple dimensional control rather than complex manufacturing processes, making it easier to manufacture while maintaining safety.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If extensive testing and certification of individual actuating devices is performed to ensure explosion-proof compliance, then safety certification is achieved, but time and cost increase

Engineering Contradiction:
Improveexplosion-proof certificationVSAvoidcertification time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention creates a universal adapter device that can be used with various actuating units and switching units. By designing the adapter tappet and housing opening with standardized dimensions that satisfy explosion-proof requirements, the same adapter design can be certified once and then applied to multiple different actuating and switching unit combinations, eliminating the need for separate certification of each individual actuating device assembly.

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

4Ease of operation

If complex actuating devices with multiple components are used to transmit movement, then movement transmission is achieved, but the quantity of parts and assembly complexity increases

Engineering Contradiction:
Improvemovement transmissionVSAvoidnumber of parts
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The invention merges the functions of the adapter, flameproof gap provision, and movement transmission into a single integrated adapter tappet component. The adapter tappet simultaneously serves as the movement transmission element, the explosion-proof barrier, and the connection between actuating and switching units, eliminating the need for separate coupling pieces, shafts, and other intermediate components.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2881959B1Actuation device for an explosion-proof housing
Publication Date: 2016.10.12 R STAHL SCHALTGERATE GMBH
  • EP2881959B1 patent drawingFigure 1~3
  • EP2881959B1 patent drawingFigure 4
  • EP2881959B1 patent drawingFigure 5

AI summary

The invention relates to a fastening device (11) for an explosion-proof housing (10) of the ignition protection type "flameproof enclosure". The actuating device (11) has an actuating unit (15) with a manually operable actuating element (16). The actuating element (16) is movable in an axial direction (A). The actuating device (11) also has a switching unit (14) with at least one switching element (14) for switching at least one associated electrical contact. The actuating unit (15) is located outside the housing (10), while the switching unit (14) is arranged inside (12) the housing (10).An adapter device (22) mechanically connects the actuating unit (15) and the switching unit (13) and has at least one adapter plunger (38) mounted to be axially displaceable (A) in order to transmit the movement of the actuating element (16) via the adapter plunger (38) to the at least one switching element (14). The adapter plunger (38) is arranged to be axially displaceable in an adapter channel (39), forming a flameproof gap (53).