Floor Surfacing Machine Torque Detection for Wheel-Lock Safety

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Solution Overview

Problem

Remotely controlled floor surfacing machines pose safety risks when operators forget to lock the drive wheels, leading to unintended movement during grinding operations.

Innovation Solution

A safety arrangement that includes a detecting unit connected to the control unit to determine the torque required for operating each drive wheel, preventing the surfacing apparatus from operating if the torque is below a predetermined limit, ensuring the wheels are locked before starting the grinding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If locking pins are used to lock drive wheels to drive axles, then the drive wheels can be secured before operation, but it is difficult to verify whether the locking pins are in their locked position and operators may forget to arrange them correctly

Engineering Contradiction:
ImprovesafetyVSAvoidverification of locking position
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces the purely mechanical locking pin system with an electrical detection system. Hall effect sensors detect the position of locking pins (which have magnetic elements) relative to the drive axles, converting mechanical position information into electrical signals that can be reliably monitored by the control unit, thus solving the verification difficulty while maintaining safety

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

Solution Approach 2:

The control unit receives feedback from Hall effect sensors about the locking pin positions and uses this information to determine whether to enable the surfacing apparatus. The system provides continuous monitoring and feedback to ensure wheels are properly locked before allowing operation, preventing safety accidents

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the surfacing apparatus can be operated independently from the drive wheels, then remote control and monitoring is enabled, but the machine may start moving on its own if wheels are not properly locked

Engineering Contradiction:
Improveremote controlVSAvoidunintended movement
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The control unit performs preliminary verification of wheel locking status before allowing the surfacing apparatus to operate. The Hall effect sensors check the position of locking pins in advance, and only when proper locking is confirmed does the system enable the surfacing motors, preventing unintended movement during remote operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control unit acts as an intermediary between the drive wheel locking system and the surfacing apparatus. It mediates the connection by requiring verification of proper wheel locking through Hall effect sensors before permitting the surfacing motors to operate, thus preventing harmful unintended movement while enabling remote control

Inventive Principle:
Principle #24Intermediary (Mediator)

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 safety by preventing hazardous scenarios caused by unlocked wheels, ensuring the machine only starts operation when the wheels are securely locked, thereby protecting the operator from potential accidents.

Implementation Method 1

the detector comprises a Hall sensor being configured for detecting the speed of at least one output axle of said motor arrangement

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

the detector comprises a current measuring unit being configured for detecting the current supplied to said motor arrangement, said current being indicative of the torque required for operating each drive wheel

Methodology Applied
Scientific EffectElectrical current measurement: Ohmmeter

Data Source

PatentEP3525985B1Safety arrangement and method for a floor surfacing machine
Publication Date: 2023.06.14 HUSQVARNA AB
  • EP3525985B1 patent drawingFigure 1
  • EP3525985B1 patent drawingFigure 2
  • EP3525985B1 patent drawingFigure 3~4

AI summary

The present invention relates to a safety arrangement for a floor surfacing machine (1) comprising at least one drive wheel (3, 4), a motor arrangement (5, 6) for propelling said drive wheel (3, 4), a surfacing apparatus (13) and a control unit (10, 11a) for controlling the operation of said motor arrangement (5, 6) and said surfacing apparatus (13). The arrangement comprises at least one detecting unit (55; 56, 57) connected to said control unit (10,11a) and adapted for determining a torque required for operating each drive wheel (3, 4) wherein said control unit (10,11a) is configured for preventing operation of said surfacing apparatus (13) if said required torque is lower than a predetermined limit value. The invention also relates to a method for obtaining safety in a floor surfacing machine (1).