Roofrack Transverse Bar Adjustment Mechanism

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Solution Overview

Problem

Existing roof bars for motor vehicles lack adjustable center distance between transverse bars, making it difficult to accommodate after-sales accessories like bicycle racks, ski racks, or roof boxes.

Innovation Solution

Incorporating coupling means with longitudinal adjustment, such as a locking lug and runner system or ball joints, allowing the transverse bars to be adjusted along the length of the longitudinal bars, enabling quick positioning without tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If transverse bars are fixed at predetermined positions on longitudinal bars, then the structure is simple and stable, but the center distance between transverse bars cannot be adjusted to accommodate different accessories

Engineering Contradiction:

Improveadjustability of center distance between transverse barsVSAvoidcomplexity of adjustment mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the joint between transverse bars and longitudinal bars adjustable rather than fixed. The joint includes a locking lug that can be positioned at different locations along the longitudinal bar, allowing the center distance between transverse bars to be dynamically changed according to different accessory requirements, while maintaining structural stability when locked in position.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a locking mechanism is added to adjust transverse bar positions, then adaptability improves, but the operation becomes more complex and may require tools

Engineering Contradiction:

Improveability to accommodate different accessoriesVSAvoidease of adjusting transverse bar position

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies the self-service principle through the locking lug design that can be manually operated without requiring additional tools. The locking lug engages with corresponding features on the longitudinal bar to secure the transverse bar at the desired position, allowing users to independently adjust and lock the position through simple manual manipulation.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the transverse bars are made detachable for repositioning, then flexibility improves, but the risk of theft increases

Engineering Contradiction:

Improveflexibility in positioningVSAvoidsecurity against theft

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies the preliminary action principle by providing multiple predetermined locking positions along the longitudinal bars where the transverse bars can be secured. The locking mechanism is designed to be engaged at these pre-established positions, allowing flexibility in positioning while maintaining security through positive locking at each position.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP1728686B1Roofrack with adjustable transverse bars

Publication Date: 2009.04.15 RENAULT SA

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Figure 3~4
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AI summary

The rack has two longitudinal bars (2, 4) fixed on the roof of a vehicle and transverse bars (8, 10) fixed on the bars (2, 4) by articulations (20) to an articulated end. Each articulation of the bars (8, 10) on the bars (2, 4) has a pin bolt (22) which penetrates and quits a locking hole formed in the bar (2, 4) in respective lowered and raised positions. The bars (8, 10) are immobilized and adjusted longitudinally in a specific position according to the length of the bars (2, 4) in respective raised and lowered positions.