Automatically moving floor treatment device and wheel for such a device

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Solution Overview

Problem

Self-propelled soil cultivation devices face challenges in efficiently overcoming obstacles due to the limitations of traditional profiled wheels, which often require multiple attempts to successfully navigate overtures like door sills, leading to inefficiencies in cleaning time and area coverage.

Innovation Solution

The wheel features a heterogeneous peripheral surface with tread blocks of varying shapes, heights, distances, orientations, and materials, ensuring a higher probability of successful power transmission and traction by providing multiple contact points and adaptive frictional resistance when encountering obstacles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional homogeneous profiled wheels are used, then the structure is simple and easy to manufacture, but the ability to overcome obstacles efficiently is poor

Engineering Contradiction:
Improveability to overcome obstaclesVSAvoidprofile structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wheel profile is designed with locally different characteristics - profile blocks with varying heights, shapes, and spacing distributed around the circumference. This local heterogeneity ensures that regardless of the wheel's rotational position when encountering an obstacle, there is always a suitable profile block configuration available to effectively engage with and overcome the obstacle, thereby resolving the contradiction between obstacle-overcoming ability and structural simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention introduces asymmetric and heterogeneous profile block arrangements instead of uniform symmetric patterns. Profile blocks differ in height, shape, and spacing, creating an asymmetric tread pattern that increases the probability of successful obstacle engagement from any rotational position, thus improving reliability while accepting increased design complexity.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If homogeneous profile blocks are used, then manufacturing is easier, but traction on various surfaces is insufficient

Engineering Contradiction:
Improvetraction on various surfacesVSAvoidwheel manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Different profile blocks are designed with locally optimized characteristics - varying heights, shapes, and materials - to address different surface conditions. This local quality differentiation improves traction across diverse surfaces (carpets, hard floors, thresholds) while requiring more complex manufacturing processes to produce the heterogeneous profile structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The wheel incorporates profile blocks made from different materials or material combinations with varying hardness and friction characteristics. This composite approach allows the wheel to adapt to different surface types through material diversity, enhancing traction reliability while increasing manufacturing complexity due to the need for multi-material processing.

Inventive Principle:
Principle #40Composite materials

3Power

If the wheel spins on obstacles, then power transmission is lost, but this occurs frequently with regular profiles

Engineering Contradiction:
Improvepower transmission to obstacleVSAvoidtime to overcome obstacle
Core Design Contradiction:
PowerVSLoss of time

Solution Approach 1:

The invention changes the geometric parameters of the profile blocks - varying heights, shapes, and spacing - to create a heterogeneous pattern that increases the likelihood of finding a suitable engagement configuration when encountering an obstacle. This parameter diversity reduces wheel spin by ensuring that at least some profile blocks can effectively transmit power to the obstacle, thereby reducing time loss while maintaining efficient power transmission.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If profile blocks repeat circumferentially, then the design is simpler, but the probability of encountering a suitable profile block for power transmission is lower

Engineering Contradiction:
Improvepower transmission probabilityVSAvoidprofile pattern complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The profile pattern deliberately avoids circumferential repetition, instead featuring locally unique profile block configurations at different positions around the wheel. This non-repeating local quality ensures that regardless of the wheel's rotational position during obstacle encounter, there is always a diverse range of profile block geometries available to transmit power effectively, thereby increasing power transmission probability while accepting increased pattern complexity.

Inventive Principle:
Principle #3Local quality

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

This design enhances the device's ability to quickly overcome obstacles, minimizing marks on surfaces and preventing wheel spin, thereby increasing the cleaning area covered per charge and improving traction and climbing capabilities.

Implementation Method 1

The heterogeneous tread pattern minimizes the marks left by the soil cultivation equipment when driving over damp or dirty surfaces... This results in a higher probability, compared to homogeneous profiles, of encountering a profile block that can bear against the obstacle and enable sufficient power transmission.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3449789B1Automatically moving floor treatment device and wheel for such a device
Publication Date: 2020.01.29 VORWERK & CO INTERHOLDING GMBH
  • EP3449789B1 patent drawingFigure 1
  • EP3449789B1 patent drawingFigure 2~3

AI summary

The invention relates to a self-propelled soil cultivation implement (1) with at least one wheel (4) rotatable about an axis of rotation (2) and having a circumferential surface (3), wherein the circumferential surface (3) comprises a plurality of profile blocks (5, 6, 7, 8) extending radially outwards with respect to the axis of rotation (2) and arranged one behind the other in the circumferential direction. To facilitate the soil cultivation implement (1) overcoming obstacles, it is proposed that the profile blocks (5, 6, 7, 8) form a completely heterogeneous profile of the circumferential surface (3) in the circumferential direction, so that the structure of the profile does not repeat in the circumferential direction.