Stroller Rocking via Partial Wheel Braking

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Solution Overview

Problem

Existing motor-assisted strollers lack a safe and practical automatic rocking function that mimics natural rocking motion without manual intervention.

Innovation Solution

A stroller with a frame and wheels, equipped with a drive mechanism and a braking device that allows partial rotation of at least one wheel in both directions, simulating a back-and-forth motion by limiting wheel rotation during braking, ensuring safety and control of the rocking motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the drive mechanism is activated for automatic rocking function, then the stroller can perform self-contained rocking motion, but safety control and prevention of unintentional movement becomes difficult

Engineering Contradiction:
Improveautomatic rocking functionVSAvoidsafety control
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

A braking device is introduced as an intermediary mechanism between the drive mechanism and the wheels. The braking device selectively applies friction to the wheel periphery, allowing controlled limitation of wheel rotation during automatic rocking while preventing unintended movement. This mediator enables both automation and safety control by regulating the transmission of motion from the drive to the stroller frame.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the braking device is engaged to limit wheel rotation, then safety and control of rocking motion is improved, but the ability to perform rocking motion is restricted

Engineering Contradiction:
Improvesafety controlVSAvoidrocking motion capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The braking device is designed to apply partial braking force rather than complete locking. The brake pads contact only a portion of the wheel periphery, allowing limited rotation (e.g., 10-30 degrees) while still providing sufficient friction to control the rocking motion. This partial action enables the stroller to perform rocking movements within a controlled range while maintaining safety.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If free wheel rotation is allowed for natural rocking, then the rocking motion is smooth and natural, but unintentional movement and safety hazards increase

Engineering Contradiction:
Improverocking motion smoothnessVSAvoidunintentional movement
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The braking device operates periodically during the rocking cycle, engaging and disengaging in rhythm with the desired rocking motion. During each rocking cycle, the brake is activated to limit rotation at specific phases (e.g., at the extremes of the rocking arc) while remaining inactive during phases where smooth motion is desired. This periodic application of braking force maintains both natural motion characteristics and safety control.

Inventive Principle:
Principle #19Periodic 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 solution provides a safe and controlled automatic rocking motion that mimics natural rocking, enhancing safety and comfort by preventing unintentional movement and ensuring smooth acceleration and deceleration.

Implementation Method 1

A braking device (14) for at least one wheel (12) is provided. The braking device (14) can be switched between a driving state with free wheel rotation and a braking state with at least one braked wheel (12).

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4384431B1Pram and method for automatic rocking
Publication Date: 2026.03.04 CYBEX GMBH
  • EP4384431B1 patent drawingFigure 1~2
  • EP4384431B1 patent drawingFigure 3~4

AI summary

A pram with a frame (10) which comprises a handlebar (11) and wheels (12) for moving the pram, with a drive (13) which is drive-connected to at least one of the wheels (12), and with a brake device (14) for at least one wheel (12), which brake device (14) can be transferred into a moving state with free wheel rotation and into a brake state with at least one braked wheel (12), wherein the drive (13) can be actuated for an automatic rocking function of the pram, wherein the wheel (12) which is braked by the brake device (14) can be rotated to a limited extent in both wheel circumferential directions in the braked state for automatic rocking of the pram.