Brush Vacuum Overload Shutdown Using Eddy Current Torque Sensing

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Solution Overview

Problem

Existing floor care devices with single motors for blower and brush drive face complexity and cost in ensuring long-term stability and operational reliability during overload conditions, requiring additional switches and extensive electronic controls for effective shutdown.

Innovation Solution

Incorporating a torque detection unit in the drive train with an eddy current disk and a pivotable carrier, controlled by a magnetic field, which engages a clutch element to trigger a safety shutdown via a switching mechanism when torque exceeds a threshold, allowing for simple mechanical overload protection and compensation for torque peaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electronic control systems with microcontrollers and monitored performance are used for overload protection, then operational reliability is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improveoperational reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex electronic control systems with a purely mechanical overload protection mechanism. The mechanical system uses a spring-loaded latch that engages with a cam surface on the drive shaft. When overload occurs, the spring releases the latch, allowing a centrifugal weight to move outward and disengage the drive belt, providing automatic overload protection without any electronic components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mechanical overload protection system is self-actuating and requires no external control. The spring-loaded latch automatically engages during normal operation and automatically releases when overload conditions occur, with the centrifugal weight providing the triggering mechanism. The system serves itself by using the mechanical energy already present in the drive train to detect and respond to overload conditions.

Inventive Principle:
Principle #25Self-service

2Reliability

If additional switches and electronic control components are added for overload protection, then safety shutdown functionality is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvesafety shutdown functionalityVSAvoidease of manufacture
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for additional switches and electronic control components by implementing a purely mechanical overload protection system. The mechanism uses a spring-loaded latch, cam surface, and centrifugal weight that work together to automatically disengage the drive belt during overload, simplifying manufacturing while maintaining safety shutdown functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If mechanical overload protection mechanisms are simplified, then ease of manufacture is improved, but operational reliability may worsen

Engineering Contradiction:
Improveease of manufactureVSAvoidoperational reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The mechanical overload protection system combines multiple simple mechanical components (spring-loaded latch, cam surface, centrifugal weight, drive belt) into an integrated mechanism that provides reliable overload protection. The combination of these components creates a system that is both simple to manufacture and highly reliable in detecting and responding to overload conditions.

Inventive Principle:
Principle #40Composite materials

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 enables a straightforward and cost-effective mechanical overload protection mechanism that ensures reliable shutdown during excessive torque, enhancing the operational stability and simplicity of floor care devices by using a magnetic field to control a switching element for safety shutdown.

Implementation Method 1

an associated rotary body as an eddy current disc made of electrically conductive material, and that the eddy current disk is assigned at least one magnet which is pivotably positioned on a stationary, movable carrier and the carrier is adjusted by a magnetic field formed by the generated eddy current of the coupled eddy current disk

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP2944244B1Floor cleaning device
Publication Date: 2017.05.24 STEIN & CO GMBH
  • EP2944244B1 patent drawingFigure 1
  • EP2944244B1 patent drawingFigure 2~3
  • EP2944244B1 patent drawingFigure 4

AI summary

Floor care device is disclosed as a brush vacuum cleaner, with a brush attachment facing the floor for receiving a driven brush roller with an overload protection, the brush attachment having at least one electric motor for a suction fan and for driving the brush roller, which is assigned a unit for torque detection, and a safety shutdown a switching arrangement takes place above a torque threshold due to overload, with a driven element of the unit for torque detection being arranged in the drive train, which element can be coupled above the torque threshold via a clutch element that can be engaged with an associated rotating body as an eddy current disc made of electrically conductive material, with at least one magnet being assigned to the eddy current disc is, which is pivotally positioned on a stationary mounted movable carrier, and an adjustment of the carrier by a magnetic field formed by the generated eddy current de r coupled eddy current disc takes place, the carrier controls a corresponding circuit arrangement, such as a switching element, as a safety shutdown.