Spring Clip Locking Mechanism for Foldable Hand Crank

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Solution Overview

Problem

The handling of foldable or pivotable hand cranks for landing gear is complex, and there is a risk of injury due to detachment, as existing systems lack a reliable locking mechanism that simplifies operation and ensures secure attachment.

Innovation Solution

A locking element with a fastening section and a spring clip that securely fastens to the hand crank, providing a self-locking mechanism that prevents detachment and optimizes lever position, reducing the risk of injury by ensuring the hand crank remains locked in use position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a foldable hand crank is used for support jacks, then storage space is reduced and portability is improved, but the handling complexity increases and safety risks arise from potential detachment

Engineering Contradiction:
Improvestorage spaceVSAvoidhandling complexity
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The locking element is designed as a self-locking mechanism where the spring clip automatically engages with the input shaft when the hand crank is in the extended position, eliminating the need for manual locking operations and reducing handling complexity while maintaining the foldable design benefits

Inventive Principle:
Principle #25Self-service

2Volume of moving object

If a foldable hand crank is used for support jacks, then storage space is reduced and portability is improved, but reliability deteriorates due to risk of detachment

Engineering Contradiction:
Improvestorage spaceVSAvoidattachment security
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The spring clip is pre-loaded with elastic force that continuously exerts a locking action on the input shaft, creating a preliminary anti-action against any potential detachment forces. This ensures the hand crank remains securely attached during operation while allowing folding when not in use

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If a locking mechanism is added to secure the hand crank, then reliability and safety are improved, but device complexity increases

Engineering Contradiction:
Improveattachment securityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking element utilizes the existing motion of the hand crank itself to trigger the locking action. When the hand crank is extended, the locking element automatically engages with the input shaft through spring-loaded locking sections, eliminating the need for separate control mechanisms and minimizing added complexity while ensuring reliable attachment security

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring clip acts as an intermediary element that mediates between the hand crank and the input shaft. It translates the positional state of the hand crank into a locking or unlocking action, providing a simple yet effective connection mechanism that reduces overall system complexity compared to direct mechanical linkages

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The locking element simplifies handling, prevents detachment, and reduces the risk of injuries by ensuring the hand crank remains securely locked in the optimal position, enhancing safety and ease of use.

Implementation Method 1

a spring clip (33) connected to the fastening section (31), on which at least one locking section (34) is formed, which overlaps the end face of the input shaft (10) at least partially in a form-fitting manner when the hand crank (20) is in a folded-out use position and at the same time is prestressed or pulled against this end face of the input shaft (10) due to the spring force

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the spring clip (33) is deflected in a restoring or spring-elastic manner when the hand crank is pivoted from a rest position and the locking section on the spring clip automatically at least partially overlaps the end face of the input shaft in a form-fitting manner by springing back or resetting when the hand crank assumes a position of use

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2595846B1Actuating system for a support winch on a semi-trailer with a fixing element for locking a hinged hand crank on the input shaft of the support winch
Publication Date: 2014.08.20 SAF HOLLAND GMBH
  • EP2595846B1 patent drawingFigure 1a~1b
  • EP2595846B1 patent drawingFigure 2
  • EP2595846B1 patent drawingFigure 3

AI summary

The invention relates to a fixing element (30) for locking a hinged hand crank (20) on the input shaft (10) of a support winch for a semi-trailer, wherein the hand crank (20) is fastened to the input shaft (10) in an articulared manner and can pivot between at least one folded-in rest position and at least one folded-out usage position. According to the invention, said fixing element (30) has a fastening section (31) for fastening to the hand crank (20) and a spring bar (33) connected to the fastening section (31) on which at least one locking section (34) is formed, wherein the locking section (34) reaches over the end face of the input shaft (10) in a form-fitting manner in a folded-out usage position of the hand crank (20) and is simultaneously pulled against said end face of the input shaft (10) (F).