Riding Mower Tamper Detection Circuit

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Solution Overview

Problem

Existing riding mower safety systems are vulnerable to tampering, as operators can simulate the presence of an operator by removing protective means and short-circuiting switches, leading to unsafe operating conditions.

Innovation Solution

A control tamper apparatus that includes a transducer to detect the operator's presence, a microcontroller to convert the signal into a reference voltage, and a control unit to manage the mower's movement, ensuring safe operation by recognizing tampering attempts and sending a control signal to stop the mower's blades or motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If protective means are removed and switch contact is short-circuited to simulate operator presence, then the mower can be operated without an operator present, but safety conditions are compromised and unauthorized operation becomes possible

Engineering Contradiction:
Improvemower operationVSAvoidsafety condition
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces an intermediary control apparatus between the simple switch and the mower's control system. This intermediary device monitors the switch signal and implements additional verification logic, preventing tampering attempts from compromising safety. The intermediary acts as a mediator that validates whether the operator presence signal is genuine before allowing mower operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control apparatus implements feedback by continuously monitoring the switch contact state and comparing it against expected operational patterns. When tampering is detected (such as unauthorized short-circuiting), the system provides feedback by preventing mower operation or alerting the operator, thereby maintaining safety conditions even when the simple switch is manipulated.

Inventive Principle:
Principle #23Feedback

2Ease of manufacture

If a simple switch with protective means is used to detect operator presence, then the system is easy to manufacture and understand, but it is vulnerable to tampering and can be bypassed

Engineering Contradiction:
Improvesafety device manufacturingVSAvoidanti-tamper capability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the safety system into multiple functional components: a simple switch for basic detection, a control apparatus for signal processing and verification, and the mower's control system for execution. This segmentation allows the switch to remain simple and easy to manufacture, while the control apparatus provides the necessary anti-tamper intelligence without complicating the overall manufacturing process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control apparatus serves as an intermediary layer between the simple switch and the mower's control system. It receives the basic switch signal, performs verification to detect tampering attempts, and only allows operation when genuine operator presence is confirmed. This intermediary approach maintains ease of manufacture for the switch while adding reliability through intelligent verification.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the motor is automatically switched off when operator is absent, then safety is maintained, but the system can be bypassed by tampering with the switch contact

Engineering Contradiction:
Improvesafety enforcementVSAvoidcontrol system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control apparatus implements feedback monitoring of the switch contact state and compares it against valid operational patterns. When tampering is detected, the system maintains safety enforcement by preventing motor operation. The feedback mechanism allows the system to distinguish between genuine operator presence and tampering attempts without requiring complex additional hardware.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control apparatus performs self-verification by monitoring its own input signals for consistency with expected operational patterns. It automatically detects tampering attempts and adjusts its control output accordingly, maintaining safety enforcement without requiring external intervention or complex additional safety systems.

Inventive Principle:
Principle #25Self-service

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

Effectively prevents unsafe operation by recognizing tampering attempts and implementing safety measures such as grounding spark plug coils or blocking blades, maintaining the mower in a safe condition.

Implementation Method 1

a transducer (2) adapted to detect the presence of the operator on the seat (101) and to provide a first electrical signal V0 as a response

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP2929772B1Riding mower with control tamper apparatus
Publication Date: 2016.11.23 GGP ITAL
  • EP2929772B1 patent drawingFigure 1
  • EP2929772B1 patent drawingFigure 2~3

AI summary

A riding mower (100) is described, comprising at least one driving seat (101), a safety device (102) which includes a transducer (2) adapted to detect the presence of the operator on the seat (101) and to provide a first electrical signal (V0) as a response, and a control unit (3) adapted to electronically manage the movement of the riding mower (100). The riding mower (100) comprises a control tamper apparatus (1) configured to convert said first electrical signal (V0) into a second electrical signal (V) and, if said second electrical signal (V) is equal to a reference value (Vref), to provide said control unit 3 with a control signal (STOP) as a response. (Fig.3).