Convertible Top Drive Self-Locking Gear Overload Protection

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Solution Overview

Problem

Existing convertible top drives for motor vehicles are prone to overload damage and lack manual operation capabilities in case of motor failure, with complex structures making manual operation difficult.

Innovation Solution

A structurally simple convertible top drive featuring a self-locking gear with automatic overload protection and an emergency unlocking mechanism, allowing automatic disengagement of gears to prevent damage and enabling manual operation if the drive motor fails.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a self-locking gear is used to prevent the convertible top from moving unintentionally, then the reliability of the drive is improved, but the drive becomes vulnerable to overload damage when the top encounters resistance

Engineering Contradiction:
Improveprevention of unintentional top movementVSAvoidresistance to overload damage
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The gear system transitions from a static self-locking state to a dynamic disengaged state when overload occurs. The guide element allows the first gear part to pivot automatically when excessive force is detected, transforming the rigid self-locking mechanism into a flexible system that can adapt to overload conditions by disengaging the gear teeth.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The overload protection mechanism operates automatically without external intervention. When the convertible top encounters resistance causing excessive force on the first gear part, the guide element pivots relative to the housing, causing the gear parts to disengage automatically. The system serves itself by detecting and responding to overload conditions through the spring element's deformation and the guide element's automatic movement.

Inventive Principle:
Principle #25Self-service

2Reliability

If the gear is designed to be self-locking for safety, then the top remains securely positioned, but manual operation becomes difficult or impossible when the drive motor fails

Engineering Contradiction:
Improvesecure positioning of the topVSAvoidmanual operability during motor failure
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The guide element acts as an intermediary between the first gear part and the housing. It provides a controlled path for the first gear part to move during both automatic overload protection and manual operation. The guide element's geometry and the stop element work together to allow intentional disengagement while maintaining secure positioning during normal operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system allows dynamic transition between locked and unlocked states. During normal operation, the spring element maintains the self-locking condition. During manual operation, applying force to the first gear part causes the guide element to pivot, dynamically changing the system from locked to unlocked state, enabling manual top operation.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the overload protection mechanism is made automatic, then the drive is protected without manual intervention, but the structure becomes more complex

Engineering Contradiction:
Improveautomatic overload protectionVSAvoidstructural complexity of the drive
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The overload protection function is merged with the existing self-locking gear mechanism. The guide element serves dual purposes: it guides the first gear part during normal operation and simultaneously acts as the overload sensing and response mechanism. The spring element integrates the locking force provision with the overload detection function, eliminating the need for separate protection mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The guide element performs multiple functions: it guides the first gear part's movement, acts as an overload sensor through its connection to the spring element, and provides the mechanical response path for automatic disengagement. The stop element on the housing serves both to limit guide element movement and to define the disengagement position, demonstrating multi-functionality that reduces overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively protects the drive from overload and allows for manual operation of the convertible top, ensuring reliable and safe operation without the need for complex structures.

Implementation Method 1

a spring element (22) acting on the guide element (23) and causing the guide element (23) to assume a first position, in which the two gear parts (14, 15) of the respective gear (11) are engaged with one another, or a second position, in which the two gear parts (14, 15) of the respective gear (11) are disengaged from one another

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP2325429B1Tarpaulin drive
Publication Date: 2018.09.12 DR ING H C F PORSCHE AG
  • EP2325429B1 patent drawingFigure 1
  • EP2325429B1 patent drawingFigure 2
  • EP2325429B1 patent drawingFigure 3

AI summary

The hood drive (10) has a self-locking transmission (11), over which the hood drive is coupled to a hood rod (12) of a motor vehicle hood. A transmission part (14) of the self-locking transmission is actuated by a drive motor (13). The actuation of the transmission part is transferable over another transmission part of the self-locking transmission on the hood rod.