Bayonet Housing Mounting Ring for Tool-Free Field Device Closure

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Solution Overview

Problem

The use of screws for attaching enclosure lids in field devices complicates maintenance and poses a risk of lost screws, compromising safety in industrial environments.

Innovation Solution

A ring-shaped fastening element with bayonet slots and ribs, eliminating the need for screws, provides a secure and easy attachment mechanism using complementary bayonet teeth and grooves, ensuring robust and tool-free closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If screws are used to attach the lid to the housing body, then the enclosure can be securely closed, but maintenance becomes more complicated and screws can be lost

Engineering Contradiction:
Improvesecure closureVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent removes screws entirely from the fastening system and replaces them with an integrated bayonet mechanism where the lid itself contains the fastening elements (bayonet slots and ribs). This extraction of the fastening function from separate screw components into the lid structure eliminates the need for separate fasteners that can be lost, while maintaining secure closure through the bayonet engagement system

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the lid and fastening mechanism into a single integrated component. The bayonet slots and ribs are directly formed in the lid, merging the covering function with the fastening function. This integration eliminates separate screws and simplifies maintenance to a single rotational motion for both opening and closing operations

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If screws are used for fastening, then the enclosure can be closed, but additional tools are required and handling becomes less convenient

Engineering Contradiction:
Improvefastening capabilityVSAvoidtool-free handling
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The bayonet mechanism is designed to be operated directly by hand without requiring external tools. The rotational insertion motion allows users to engage and disengage the lid using only their fingers, making the fastening system self-service capable and eliminating the need for screwdrivers or other fastening tools

Inventive Principle:
Principle #25Self-service

3Reliability

If multiple screws are used to secure the lid, then the enclosure is securely closed, but the number of parts increases and handling becomes more difficult

Engineering Contradiction:
Improvesecure enclosureVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple fastening functions into a single lid component with integrated bayonet slots and ribs. Instead of using multiple separate screws distributed around the enclosure, the bayonet mechanism provides comprehensive secure closure through a unified rotational engagement system, reducing the total part count while maintaining enclosure security

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4399490B1Mounting part for a housing and housing for a field device
Publication Date: 2026.03.25 ENDRESS HAUSER FLOWTEC AG
  • EP4399490B1 patent drawingFigure 1~2
  • EP4399490B1 patent drawingFigure 3~4
  • EP4399490B1 patent drawingFigure 5~6

AI summary

The invention relates to a securing part (10) for a housing, wherein the securing part (10) is ring-shaped and extends around a longitudinal axis (A1), wherein the securing part (10) has a first edge (11) and a second edge (12) opposite the first edge (11), wherein the first edge (11) has at least two bayonet grooves (20, 200) which are suitable for securing the securing part (10) to the housing, wherein the bayonet grooves (20, 200) extend along the longitudinal axis (A1) and about the longitudinal axis (A1) transverse to the longitudinal axis (A1), wherein the bayonet grooves (20, 200) each have an inlet (21, 221), a ridge, a stop and a groove base with a groove depth, wherein the stop limits the bayonet grooves (20, 200) in their extension about the longitudinal axis (A1), wherein the ridge is arranged on the groove base between the inlet (21, 221) and the stop and extends from the groove base radially relative to the longitudinal axis (A1) and at a predetermined height.