Rotary Locking Coupling for Low-Force Secure Trailer Connection

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Solution Overview

Problem

Existing coupling technologies for bicycle trailers and similar applications are either too stiff, limiting force and moment absorption, or require high forces for connection, making them difficult to handle and use.

Innovation Solution

A coupling system with a locking shaft that engages in a locking groove, allowing for secure connection with low required forces, featuring a compact and robust design, and can be easily released by simple rotation, along with a spring or manual actuator for automatic locking and unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a locking shaft with locking groove is used to connect coupling parts, then the connection becomes secure with low required forces, but the coupling stiffness increases which limits force and moment absorption

Engineering Contradiction:
Improveconnection forceVSAvoidforce and moment absorption
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The coupling system incorporates a rotatable locking shaft that can transition between locked and unlocked positions, allowing the coupling to dynamically adjust its state. The locking groove and locking section design enables the coupling to accommodate both secure connection and controlled movement, resolving the contradiction between connection security and flexibility for force absorption.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a locking shaft is designed to engage in a locking groove for secure connection, then connection security is improved, but the device complexity increases

Engineering Contradiction:
Improveconnection securityVSAvoidcoupling structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking shaft integrates multiple functions into a single component: it provides the locking mechanism through the locking section engaging with the locking groove, serves as a rotational actuator for locking and unlocking, and works with the spring element to provide automatic locking. This merging of functions reduces the number of separate components needed while maintaining connection security.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring element automatically pushes the locking shaft into the locked position when the coupling parts are connected, providing self-locking functionality without requiring manual intervention. The system uses its own operational forces to achieve locking, reducing the need for additional complex locking mechanisms.

Inventive Principle:
Principle #25Self-service

3Reliability

If a locking mechanism is designed to prevent unintentional detachment, then reliability is improved, but the ease of operation for releasing the coupling decreases

Engineering Contradiction:
Improveprevention of unintentional detachmentVSAvoidreleasing operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking shaft can be rotated to transition between locked and unlocked states, providing a simple dynamic operation for releasing the coupling. The rotatable design allows the user to easily change the state of the locking mechanism through a small rotational motion, maintaining ease of operation while ensuring secure locking during normal use.

Inventive Principle:
Principle #15Dynamics

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

Enables easy and secure connection of various parts with low operational forces, suitable for multiple applications, including bicycle trailers and buggy wheel suspensions, while preventing unintentional detachment due to vibrations.

Implementation Method 1

— in particular with the aid of a spring

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The locking shaft (4) is designed and mounted in such a way that its locking section (31) can engage in the locking groove (22)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3135574B1Coupling
Publication Date: 2021.11.24 CROOZER GMBH
  • EP3135574B1 patent drawingFigure 1~3
  • EP3135574B1 patent drawingFigure 2
  • EP3135574B1 patent drawingFigure 4a~4d

AI summary

The invention relates to a coupling for connecting and/or holding together two parts, in particular for a bicycle trailer, comprising a first and a second coupling part which cooperate and are detachable from one another, one of which has an insert connected to one of the parts and the other an a sleeve connected to the other of the parts, the sleeve being adapted to at least partially enclose the insert, and the first coupling part having at least one locking groove (22, 103). In order to achieve a structurally simple coupling that is easy to handle, at least one locking shaft (4, 96) is mounted on or in the second coupling part, which has at least one locking segment which has at least one locking section (31, 131) and one unlocking section ( 32, 132), wherein the locking section (31, 131) has a greater radial extension than the unlocking section (32, 132). The locking shaft (4, 96) is arranged in such a way that the locking section (31, 131) can engage in the locking groove (22, 103) when the insert piece is inserted into the sleeve, and the unlocking section (32, 132) cannot the locking groove (22, 103) can engage. Means are also provided for rotating the locking portion (31, 131) to the locking position, for holding the locking portion (31, 131) in the locking position and for releasing the locking portion (31, 131) from the locking position.