Locking Gear Predetermined Break Point for Overload Protection

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Solution Overview

Problem

Existing locking devices face the risk of housing breakage due to overload, which can lead to loose parts, harmful substance leakage, and loss of self-locking functionality, especially when stops are not optimally arranged outside the housing.

Innovation Solution

A predetermined breaking point is introduced within the drive train of the locking device, limiting the force transmitted to the gear mechanism and allowing for compact design with reduced risk of housing breakage, and optionally incorporating a self-locking gear to maintain position in case of breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If stops are arranged inside the housing to enable compact design, then device complexity is reduced, but the housing may break due to overload forces

Engineering Contradiction:
Improvehousing structureVSAvoidhousing integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The drive train is segmented into modular components (drive shaft, intermediate shaft, output shaft) with a predetermined breaking point at the weakest link. This segmentation allows the system to fail safely at a controlled location rather than causing catastrophic housing failure, resolving the contradiction between compact design and housing integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A predetermined breaking point is intentionally created in the drive train at a location with controlled strength. This breaking point acts as a safety mechanism that will fail first under overload conditions, protecting the housing from breakage. The breaking point is designed beforehand to absorb or redirect excessive forces away from the housing.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If stops are arranged outside the housing to protect from overload, then housing integrity is maintained, but device complexity increases

Engineering Contradiction:
Improvehousing integrityVSAvoidhousing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stop function and drive train are merged into a single integrated unit where the drive train components (shafts, gears) serve both as power transmission elements and as the stopping mechanism. The predetermined breaking point in the drive train replaces the need for separate external stops, reducing device complexity while maintaining housing integrity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a predetermined breaking point is introduced in the drive train, then housing protection is achieved, but the drive train may break under overload

Engineering Contradiction:
Improvehousing protectionVSAvoiddrive train strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The potential harm of drive train breakage is converted into a benefit by deliberately creating a predetermined breaking point at a controlled location. Instead of allowing random or catastrophic failure that could damage the housing, the system is designed to fail safely at the weakest link, protecting the housing while accepting controlled drive train failure. The harm (breakage) is redirected to a harmless location.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If a self-locking gear is used to maintain position after breakage, then operational reliability is improved, but device complexity increases

Engineering Contradiction:
Improveposition maintenanceVSAvoidgear mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The worm gear mechanism provides self-locking functionality automatically without requiring additional components or active control systems. The inherent friction and gear geometry of the worm drive prevent back-driving, automatically maintaining the position of the shut-off structure even after drive train breakage. This self-service mechanism improves reliability while adding minimal complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3388716B1Closing device
Publication Date: 2021.09.08 AUMA RIESTER GMBH & CO KG
  • EP3388716B1 patent drawingFigure 1~2

AI summary

In the case of locking devices (1) with gears (2, 18), overloading of the drive train can result in damage to the same and consequently in the housing breaking. In order to provide effective overload protection, the invention therefore proposes interrupting the drive train of the locking device (1) in the event of an overload, preferably by creating a predetermined breaking point (4) in the gear (2, 18) and as close as possible to the drive Drive train is formed, wherein the transmission (2) is preferably designed to be self-locking. In the event of an overload, which can be in the form of a torsional moment in particular, the predetermined breaking point (4) breaks and thus interrupts the power flow from the drive to a fitting or to a shut-off structure. In this way, further consequential damage, in particular a broken housing, can be effectively avoided