Steering Lock Fragile Portion Prevents Pull-Out Theft

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Solution Overview

Problem

Conventional steering lock devices can be compromised by illegal unlocking actions that involve detaching the frame cover, allowing the motor and other components to be removed, potentially leading to the lock member being pulled out and the steering lock being released, even if the slide plate is broken.

Innovation Solution

A steering lock device design that incorporates a fragile portion with a predetermined lower mechanical strength than other parts, which tears when a strong force is applied, preventing the lock member from being pulled out and enhancing stealing-proof capabilities by ensuring the lock member remains in the lock guide hole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the frame cover is made detachable for maintenance access, then ease of repair is improved, but reliability deteriorates because the lock member can be pulled out through the detached cover

Engineering Contradiction:
Improvemaintenance accessVSAvoidsteering lock security
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The fragile portion is pre-positioned in the lock member at a location that will fail under theft forces but not during normal operation. This preliminary placement ensures that when illegal unlocking forces are applied after cover detachment, the fragile portion tears first to prevent lock member removal, while maintaining reliable operation during legitimate maintenance access

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lock member is designed with non-uniform structural properties: most of the lock member has high strength for normal operation, while a specific localized region (the fragile portion) has deliberately reduced strength. This local quality differentiation allows the same component to exhibit different mechanical behaviors under different loading conditions - remaining intact during maintenance but failing safely during theft attempts

Inventive Principle:
Principle #3Local quality

2Reliability

If the lock member is made stronger to prevent pulling out, then reliability is improved, but the fragile portion concept cannot be applied

Engineering Contradiction:
Improveresistance to pulling outVSAvoidstructural uniformity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of uniformly strengthening the entire lock member, the invention applies local quality by creating a specific fragile portion with reduced strength at a predetermined location. This allows the majority of the lock member to maintain high strength while a localized weak point provides the necessary failure mechanism to prevent complete lock member removal during theft attempts

Inventive Principle:
Principle #3Local quality

3Reliability

If the slide plate is made breakable to prevent illegal unlocking, then reliability is improved, but ease of operation deteriorates because the lock mechanism may fail during normal use

Engineering Contradiction:
Improveprevention of illegal unlockingVSAvoidnormal lock operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The breakable feature is localized to a specific fragile portion rather than the entire slide plate. This localized weakness is positioned and dimensioned such that it only fails under the extreme forces of illegal unlocking attempts, while normal operational forces remain well below the failure threshold, ensuring reliable ease of operation during legitimate use

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fragile portion is pre-configured with specific dimensional characteristics that predict its failure behavior. By carefully designing the geometry and material properties of this localized region, the system ensures it will remain intact during normal operation but will tear to prevent illegal unlocking when excessive forces are applied

Inventive Principle:
Principle #10Preliminary action

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 design effectively prevents the lock member from being forcibly pulled out, enhancing stealing-proof and activation reliability by ensuring the lock member remains locked, even under strong force attempts, and maintaining the vehicle in an unsteerable state.

Implementation Method 1

By the spring member 111a, the holding shaft 113 is urged in a direction of being spaced apart from the slide plate 104

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a lock member 102 that is urged in a direction (upward direction of FIG. 1) of a steering shaft (not shown) of an automobile by a coiled spring 101

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2694337B1Steering lock device
Publication Date: 2017.08.02 ALPHA
  • EP2694337B1 patent drawingFigure 1
  • EP2694337B1 patent drawingFigure 2~3
  • EP2694337B1 patent drawingFigure 4~5

AI summary

An auxiliary lock mechanism that locks a lock member (6) at a steering lock position is provided. In the auxiliary lock member, a slide plate (91) thereof engages with an auxiliary engagement portion (95) of the lock member (6) located at the steering lock position in such a manner that engagement between a holding member (21) and a holding/receiving portion (93) thereof is disengaged. On a more rear end side of the lock member(6) than the auxiliary engagement portion (95), a fragile portion (74) is provided, in which a load is set smaller than a load tolerable by the slide plate (91). In a case where a load of a set value or more is applied to the lock member (6), the lock member (6) is torn at the fragile portion (74).