Foot Pedal Position Detection with Pressure Interlock

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Solution Overview

Problem

Existing foot pedals in machines, particularly in construction and agricultural vehicles, can be inadvertently actuated by dirt residues from footwear, leading to safety issues as they may continue to operate without intentional input, posing life-threatening risks.

Innovation Solution

Incorporating a magnet and Hall probe or potentiometer as a position transmitter, combined with pressure-sensitive sensors, ensures that the foot pedal can only be actuated when a foot is detected, with the position transmitter only sending signals if a threshold value is reached, and arranging pressure-sensitive sensors between a carrier and pedal layer for protection against wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a foot pedal is used to control machine operation, then the machine can be operated conveniently, but dirt residues from footwear can cause accidental actuation leading to safety hazards

Engineering Contradiction:
Improveconvenience of machine operationVSAvoidsafety of machine operation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent combines two independent detection systems: a position transmitter (Hall probe detecting magnet position) and a pressure-sensitive sensor (detecting foot presence). Both systems must confirm valid input conditions simultaneously - the position indicates pedal deflection while the pressure sensor verifies actual foot contact. This merging of detection methods prevents dirt residues from causing false actuation while maintaining operational convenience.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pressure-sensitive sensor acts as an intermediary verification layer between the foot pedal and machine control. It mediates by providing an additional confirmation signal that must be present alongside position changes, ensuring that only genuine foot actuation (with pressure) triggers machine operation, thereby blocking false signals from dirt residues.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If pressure-sensitive sensors are exposed on the foot pedal surface, then foot presence can be detected, but the sensors are susceptible to wear and damage

Engineering Contradiction:
Improvedetection accuracy of foot presenceVSAvoiddurability of pressure-sensitive sensor
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The pressure-sensitive sensor is nested within the foot pedal structure, positioned between the pedal surface and the mounting device. This nested arrangement protects the sensor from direct exposure to external elements like dirt and physical damage, while still allowing it to detect foot pressure effectively through the pedal structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The foot pedal incorporates a pedal surface layer that acts as a protective film over the pressure-sensitive sensor. This thin film structure allows pressure transmission from the foot to the sensor while providing mechanical protection and environmental sealing, maintaining sensor durability without compromising detection precision.

Inventive Principle:
Principle #30Flexible shells and thin films

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 prevents accidental operation due to dirt residues, enhancing safety by ensuring the foot pedal can only be actuated when a foot is present, thus preventing unintended machine operation.

Implementation Method 1

The position transmitter contains a magnet on the foot pedal (10) and a Hall probe (28), with the magnet acting on the Hall probe (28) when the foot pedal (10) is actuated to detect the position of the foot pedal (10)

Methodology Applied
Scientific EffectHall effect: Hall Effect

Implementation Method 2

a pressure-sensitive sensor (38) for detecting a foot on the foot pedal (10), wherein the pressure-sensitive sensor (38) is formed by a pressure-sensitive resistance element (38)

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 3

the pressure-sensitive sensor (38) is formed by a pressure-sensitive resistance element (38) or by a piezoelectric element

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2927776B1Foot pedal
Publication Date: 2018.11.14 FERNSTEUERGERAETE KURT OELSCH GMBH
  • EP2927776B1 patent drawingFigure 1~2
  • EP2927776B1 patent drawingFigure 3~4

AI summary

The invention relates to a foot pedal (10) for operating a machine. The foot pedal (10) is pivotably mounted in a mounting device (12) about a pivot axis (22). A return mechanism (35) returns the foot pedal (10) to its initial position after actuation. A position sensor (29) detects the position of the foot pedal (10) and controls the machine accordingly.