Forklift Speed Sensor Roller Layout for Cleaner Wheel Sensing

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Solution Overview

Problem

Existing speed sensors for forklift trucks are prone to maintenance challenges, space inefficiency, and sensitivity to pollution, with exposure to floor objects and vertical extension complicating service and increasing susceptibility to contamination.

Innovation Solution

A speed sensor arrangement for forklift trucks featuring a roller that rotates around a second axis perpendicular to the wheel's axis of rotation, secured on a sensor shaft, and pressed against the wheel's side surface, with adjustable pressure via elastic members, ensuring compact design and protection from pollution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor is protected by a guard from objects on the floor surface, then the sensor is protected from some damage, but the sensor remains exposed to objects on the floor surface and replacement needs to lift the truck

Engineering Contradiction:
Improvesensor protectionVSAvoidsensor replacement
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The sensor arrangement is extracted from the traditional protected-but-inaccessible position and repositioned to be easily accessible for maintenance while maintaining protection through the side-surface mounting approach

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sensor arrangement enables easy self-service maintenance through its compact design that allows replacement without requiring truck lifting, making the system easier to maintain independently

Inventive Principle:
Principle #25Self-service

2Ease of repair

If a rotational speed sensor arrangement uses a second wheel disc close to the wheel tread for friction transmission, then easy maintenance is achieved, but the arrangement extends vertically and takes up a lot of space

Engineering Contradiction:
Improvemaintenance serviceVSAvoidvertical space
Core Design Contradiction:
Ease of repairVSVolume of moving object

Solution Approach 1:

The sensor arrangement transitions from a vertical extension approach to a compact lateral mounting approach by pressing against the side surface of the wheel, reducing vertical space occupation while maintaining maintenance accessibility

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The sensor arrangement is nested within the compact space between the wheel and the forklift truck body, utilizing the side surface area rather than extending vertically outward

Inventive Principle:
Principle #7Nested doll (Nesting)

3Speed

If the second wheel disc is very close to the wheel tread for friction transmission, then the wheel can rotate the sensor easily, but the second wheel disc can be polluted

Engineering Contradiction:
Improvewheel rotation transmissionVSAvoidpollution sensitivity
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The sensor arrangement uses the wheel's side surface as an intermediary contact point instead of the tread surface, maintaining rotational transmission capability while avoiding direct contact with polluted tread areas

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The arrangement exploits the cleaner local area of the wheel's side surface rather than the polluted tread area, maintaining functional effectiveness while reducing exposure to harmful contaminants

Inventive Principle:
Principle #3Local quality

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

The solution provides a compact, easily serviceable speed sensor arrangement that is resistant to pollution and geometric inaccuracies, with adjustable pressure and balanced efforts, enhancing reliability and simplicity.

Implementation Method 1

a roller (35) secured on the sensor shaft (37) and configured to rotate around the second axis of rotation (R2) and to press on one side surface (47) of the supporting wheel (29)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

at least one elastic member (69) configured to act on the movable plate (61) to press the roller (35) against the side surface (47) of the at least one supporting wheel (29)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4657078A1Speed sensor arrangement and forklift truck comprising such an arrangement
Publication Date: 2025.12.03 STAUBLI WFT GMBH
  • EP4657078A1 patent drawingFigure 1
  • EP4657078A1 patent drawingFigure 2
  • EP4657078A1 patent drawingFigure 3

AI summary

A speed sensor arrangement (31) for a forklift truck having a frame and at least one supporting wheel (29) articulated on the frame around a first axis of rotation (R1). The speed sensor arrangement comprises an angular sensor (33) comprising a sensor shaft (37) configured to rotate around a second axis of rotation (R2) and a roller (35) secured on the sensor shaft and configured to rotate around the second axis of rotation. The second axis of rotation is included in a first plane perpendicular (P2) to the first axis of rotation (R1), the second axis of rotation intersects the first axis of rotation (R1) and the roller is configured to press on one side surface (47) of the supporting wheel of the forklift truck.