Withdrawable Unit Housing Sealing and Position Locking
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Solution Overview
Problem
Existing withdrawable unit systems for electric switching devices fail to provide superior protection against dust and water while allowing safe and easy movement of power circuit breakers between operating, test, and withdrawn positions, often compromising on sealing and ease of operation.
Innovation Solution
A withdrawable unit system with a housing featuring a control side access door that seals densely, a locking device with a lever and notch mechanism, and a carriage for power transmission, allowing automatic securing in three positions and easy unlocking, while maintaining protection against dust and water according to IP 40 standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If access openings are provided in the withdrawable unit housing for controlling locking mechanisms, then ease of operation is improved, but protection against dust and water deteriorates
Solution Approach 1:
The patent employs a flexible membrane seal (membranenabdichtung) that covers the access opening in the housing. This membrane allows control elements to be actuated from the outside while maintaining dust and water tightness. The membrane acts as a flexible barrier that permits mechanical interaction through it while preventing ingress of harmful substances, thus resolving the contradiction between accessibility and protection.
2Reliability
If a locking device with multiple securing positions is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking device is designed with automatic positioning and securing features. The lever (Hebel) automatically engages with notches (Noppen) at specific positions during the movement of the withdrawable unit, providing self-locking without requiring additional actuators or complex control systems. This self-service mechanism achieves reliable multi-position securing while minimizing device complexity.
Solution Approach 2:
The patent introduces a slide (Schieber) as an intermediary element that controls the engagement between the lever and the notches. The slide acts as a mediator that can release or engage the locking positions in a controlled manner, simplifying the overall locking mechanism while maintaining reliable multi-position securing. This intermediary component reduces complexity by centralizing the control function in a single element.
3Object-affected harmful factors
If the housing is sealed to pass IP 40 protection tests, then protection against dust and water is improved, but ease of operation deteriorates
Solution Approach 1:
The patent replaces traditional mechanical access openings with a membrane-based sealing system. Instead of providing physical openings that compromise sealing, the control elements are coupled to the membrane, allowing actuation through the sealed barrier. This substitution maintains the integrity of the sealed housing while preserving operational accessibility.
Data Source
AI summary
The invention relates to a withdrawable unit system for an electric switching device. The invention overcomes the disadvantages of known such systems by disclosing a withdrawable unit system with a housing (11) containing a access door (13), which gives access to all control elements of the unit and which can be closed as densely as it meets the requirements of international standards such as DIN EN 60529 for example. In further embodiments the current invention suggests a moveable unit (30) with an effective and reliable possibility for blocking and releasing the electrical switching device in and from at least three defined positions withdrawn, test and plugged-inby using a slide (150), a lever (120) and notches (131, 132, 133) with dedicated notch blocking devices (140).