Counter-Rotating Rotary Brooms for Large-Debris Surface Sweeping

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Solution Overview

Problem

Existing surface maintenance machines face challenges in effectively controlling adverse air currents generated during sweeping, leading to particulate being thrown off rather than collected, and often require front skirts that can obstruct the collection of large debris.

Innovation Solution

The use of a pair of counter-rotating brooms that generate air currents in opposite directions to draw particulate towards a chute and hopper, eliminating the need for a front skirt and improving airflow routing to collect larger debris.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a front skirt is used to control air currents and draw particulate toward the hopper, then vacuum system performance is improved, but large debris cannot be drawn inward and is thrown off (plowing)

Engineering Contradiction:
Improveparticulate collection efficiencyVSAvoidlarge debris collection capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The single broom is segmented into a pair of brooms (first and second brooms) positioned side-by-side. Each broom independently generates air currents that draw particulate inward, eliminating the need for a front skirt while maintaining effective particulate collection and enabling large debris collection

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a single broom rotates to sweep the surface, then sweeping function is provided, but adverse air currents are generated that are hard to control and throw particulate off

Engineering Contradiction:
Improvesweeping functionVSAvoidadverse air currents
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The pair of brooms rotates in opposite directions (counter-rotation), creating asymmetric air current patterns that draw particulate inward toward the hopper rather than throwing it off. The first broom rotates clockwise while the second broom rotates counter-clockwise, generating complementary air currents that work together to control particulate

Inventive Principle:
Principle #4Asymmetry

3Reliability

If front skirting is used to improve vacuum airflow routing, then particulate collection is enhanced, but the machine structure becomes more complex and large debris is obstructed

Engineering Contradiction:
Improvevacuum airflow routingVSAvoidfront skirt assembly
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The front skirt assembly is completely removed from the machine structure. Instead of using a physical barrier (skirt) to control airflow, the invention uses the counter-rotating brooms themselves to generate the necessary air currents that draw particulate inward, eliminating the complex front skirt structure while maintaining effective airflow routing

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

This solution enhances the collection efficiency of particulate, including larger debris, by utilizing counter-rotating brooms to direct air currents inward, reducing the need for front skirting and improving vacuum system performance.

Implementation Method 1

a vacuum system adapted to generate vacuum for drawing the particulate swept by the pair of brooms

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

The pair of brooms can rotate in a direction opposite to each other, whereby the counter-rotation of the pair of brooms can sweep the surface, including sweeping particulate located on the floor

Methodology Applied
Scientific EffectAir current generation through rotation: Turbulence

Data Source

PatentEP3410912B1Surface maintenance machine
Publication Date: 2023.04.05 TENNANT CO
  • EP3410912B1 patent drawingFigure 1
  • EP3410912B1 patent drawingFigure 2
  • EP3410912B1 patent drawingFigure 3

AI summary

Embodiments include a surface maintenance machine (100), comprising a maintenance tool chamber comprising a first side, a second side, a third side and a fourth side. A rotary broom (110, 112) is housed in the maintenance tool chamber and substantially enclosed by the first, second, third and fourth sides thereof. The rotary broom (110, 112) sweeps particulate from the surface. A vacuum system (150) generates vacuum for drawing particulate swept by the rotary broom (110, 112). The vacuum system is positioned proximal to the first side. A skirt assembly (200) extends substantially around the second, third and fourth sides of the maintenance tool chamber. The skirt assembly (200) has a vacuum passage defined therein and in fluid communication with the vacuum system to direct air flow into the vacuum passage, thereby drawing particulate into the vacuum passage and preventing particulate accumulation at portions of the second, third and fourth sides that are distal to the vacuum system (150).