Bicycle Trailer Suspension with Adjustable Elastomer Precompression

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Solution Overview

Problem

Existing bicycle trailer suspension systems face challenges in providing optimal springing and damping across varying loads, from a baby to multiple children and luggage, as they either bottom out with low loads or fail to respond with high loads, and require complex adjustments, with limited damping and durability issues due to weather exposure.

Innovation Solution

The use of a flexible polyurethane foam material, such as Sylomer®, for the wheel swing arm suspension, which provides progressive springing and high damping, maintaining effectiveness across different load ratios without needing weight-based adjustments, and is weather-stable and maintenance-free.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a soft spring is used for optimal suspension with low load (baby), then the suspension responds sensitively with low load, but the bicycle trailer bottoms out when fully loaded

Engineering Contradiction:
Improvesuspension responsivenessVSAvoidsuspension performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies the dynamics principle by making the spring rate adjustable through a mechanism that allows the user to change the precompression force on the elastomer body. This enables the suspension to adapt its characteristics dynamically - softer for light loads and harder for heavy loads - resolving the contradiction between responsiveness and reliability across different loading conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the precompression force parameter of the elastomer body. Through an adjustable mechanism, the precompression can be varied to change the effective spring rate, allowing optimal suspension performance whether transporting a baby or multiple children with luggage

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a hard spring is used to prevent bottoming out with maximum load, then the bicycle trailer does not bottom out when fully loaded, but the spring system has no effect on low load (baby)

Engineering Contradiction:
Improvesuspension performanceVSAvoidsuspension responsiveness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The adjustable precompression mechanism allows the spring to transition from a hard state (precompressed) that prevents bottoming out to a softer state (less precompressed) that provides responsive suspension for light loads, making the system adaptable to different operational requirements

Inventive Principle:
Principle #15Dynamics

3Reliability

If a weight-dependent adjustment of spring rate is implemented, then optimal suspension is achieved for various loads, but the setting becomes complex and cumbersome

Engineering Contradiction:
Improvesuspension performanceVSAvoidadjustment mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The adjustment mechanism is segmented into discrete, easily manageable positions that correspond to different loading scenarios. This segmentation simplifies the user interface while maintaining the ability to provide optimal suspension performance across various weight conditions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The suspension system is designed to be self-adjusting within a range, where the user simply needs to select from pre-defined adjustment positions rather than making precise measurements, reducing the complexity and effort required for proper setup

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If a two-layer leaf spring with adjustable clamping device is used, then the spring rate can be adjusted, but the setting elements corrode during normal use due to weather effects

Engineering Contradiction:
Improvespring rate adjustmentVSAvoiddurability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses an elastomer body as the spring element, replacing traditional metal leaf springs. This composite material approach provides both the desired adjustability and weather resistance, as elastomers are inherently more resistant to corrosion from weather effects while maintaining elastic properties

Inventive Principle:
Principle #40Composite materials

5Reliability

If a torsion bar suspension is used, then suspension is provided, but the design is complex and requires precise adjustment

Engineering Contradiction:
Improvesuspension performanceVSAvoidsuspension structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the complex torsion bar mechanism and replaces it with a simpler elastomer body-based suspension system. This extraction maintains the essential suspension function while eliminating the complexity and adjustment requirements associated with torsion bar designs

Inventive Principle:
Principle #2Taking out (Extraction)

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 offers consistent and comfortable suspension and damping for both low and high loads, reducing vibration stress, especially for children, without requiring load-specific adjustments, and is durable and easy to maintain.

Implementation Method 1

an elastic element made of at least one dimensionally stable flexible polyurethane foam material

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

which provides progressive springing and high damping, maintaining effectiveness across different load ratios

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

via which the wheel swing arm relative to the chassis is supported

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2842855B1Suspension for a bicycle trailer or buggy
Publication Date: 2018.02.14 CROOZER GMBH
  • EP2842855B1 patent drawingFigure 1~2
  • EP2842855B1 patent drawingFigure 3~5

AI summary

The invention relates to a wheel suspension for a non-motorized vehicle, in particular a stroller or a bicycle trailer for transporting children, which has a chassis (1) and at least two wheels (8), each mounted on a wheel swing arm (11, 15), wherein at least one elastic element (21) is provided for each wheel swing arm (11, 15) by means of which the wheel swing arm (11, 15) is supported against the chassis (1). In order to provide such a wheel suspension, which is based on a simple construction and enables optimal suspension and damping of the non-motorized vehicle, it is proposed that both wheel swing arms (11, 15) project laterally beyond the chassis (1) and can pivot past a lateral frame member (3, 4) of the chassis (1).