Removable Actuation Key Safety Contact with Movable Hook
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Solution Overview
Problem
Electrical safety contacts with removable actuation keys face challenges in ensuring high waterproofing, accurate actuation range, and structural simplicity, particularly in mass production, due to issues with partial welding and complex assembly processes.
Innovation Solution
The design incorporates a movable bridge and shuttle mechanism with elastic means and a hook system, allowing for a wide actuation range and reliable electrical continuity interruption, while simplifying the structure and reducing dimensions through fluid-tight cable glands and sealing elements, and a desmodromic coupling mechanism for smooth key insertion and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuation channel height is limited to ensure key insertion, then key insertion reliability is improved, but the actuation range is reduced
Solution Approach 1:
The movable hook is designed to dynamically change position between a first position (allowing key insertion) and a second position (obstructing insertion). The hook moves to the first position during normal operation to permit key insertion, and to the second position after actuation to prevent accidental re-insertion, thus resolving the contradiction between ensuring key insertion reliability and maintaining proper actuation range limitation.
Solution Approach 2:
The movable hook performs periodic motion between two positions in synchronization with the actuation cycle. During the insertion phase, the hook is in the first position permitting key insertion. After the actuation key pushes the bridge to open the contact, the hook moves to the second position to obstruct further insertion. This periodic action ensures both reliable key insertion when needed and prevention of improper insertion afterward.
2Ease of manufacture
If a removable bridge design is used, then ease of assembly is improved, but waterproofing capability deteriorates
Solution Approach 1:
The actuation key is extracted as a separate removable component from the contact body, while the bridge remains permanently integrated. The key is inserted through a sealed actuation channel to actuate the bridge without requiring openings in the contact body. This extraction approach maintains waterproofing by keeping the bridge and contact body as a sealed unit, while still allowing easy actuation through the removable key.
Solution Approach 2:
The actuation key serves as an intermediary element that transfers force from the outside to the bridge without creating permanent openings. The key is inserted through a sealed channel, acts on the bridge to open the contact, and is then removed. This intermediary approach allows the bridge to remain permanently sealed within the contact body while still enabling easy actuation through temporary insertion of the key.
3Device complexity
If the shuttle structure is simplified, then device complexity is reduced, but reliability of electrical continuity interruption worsens
Solution Approach 1:
The system is segmented into distinct functional components: the shuttle for mechanical actuation, the movable bridge for electrical contact, and the movable hook for positioning control. The shuttle itself is kept simple in structure, while the movable hook is added as a separate segment to ensure reliable electrical continuity interruption. This segmentation allows the shuttle to remain simple while the hook provides the necessary reliability for contact interruption.
Solution Approach 2:
The movable hook automatically moves to the second position after actuation to self-ensure that the key cannot be improperly re-inserted, and the elastic means automatically return the shuttle to its initial position after actuation. This self-service mechanism ensures reliable electrical continuity interruption without requiring complex additional control systems, maintaining simplicity while ensuring reliability.
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 design ensures high waterproofing, reliable electrical continuity interruption, and simplified assembly, allowing for a greater actuation range and reduced dimensions compared to prior art, while preventing undesired contact closures and facilitating easy assembly.
Implementation Method 1
elastic means (12) acting between said body (2) and said shuttle (10) to push said shuttle (10) towards said retracted limit stop position
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
An electric safety contact (1) with a removable actuation key (18) comprises a movable hook (11) for engaging the actuation key (18) when inserted into the body (2) of the electrical contact (1), wherein the front end (14) of said movable hook (11) is inclined in a manner to determine a lifting of the movable hook itself if during an initial phase of insertion of the actuation key (18) into the body (2) of the electrical contact (1), this movable hook (11) is in a position not completely lifted in which it interferes with the removable key (18) during its insertion into the body (2).