Walk-Behind Power Tool Speed Control for Adaptive Self-Propulsion

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Solution Overview

Problem

Existing rear-moving power tools require users to adjust their walking speed to match the tool's preset speed, leading to inconvenience and inefficiency in operation.

Innovation Solution

A rear-moving power tool with a control module and sensing module that allows users to switch between self-propelled modes, including a first state where the motor speed adapts to the user's walking speed and a second state where the tool walks at a constant speed set by the user, facilitated by operating members and a speed adjustment mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the walking assembly is driven by the motor to walk automatically at a preset speed, then the labor of the user is reduced, but the user cannot walk at a constant speed suitable for themselves and must adjust their step to match the tool's speed

Engineering Contradiction:
Improveuser convenienceVSAvoidspeed adaptability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the motor speed adjustable and adaptable. The control module enables the motor to operate at different speeds based on user selection, transforming a fixed-speed system into a dynamic, flexible system that can adapt to different user walking speeds and operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by allowing the motor speed parameter to be varied. The control module receives user input to change the motor's rotational speed parameter, enabling the walking assembly to move at different speeds. This resolves the contradiction by making the speed parameter adjustable rather than fixed.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the motor operates at a fixed preset speed, then the device structure is simple, but the user experience is poor as the speed cannot be adjusted to suit different users or conditions

Engineering Contradiction:
Improvecontrol system complexityVSAvoidoperational flexibility
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The control module serves multiple functions: it receives user input, processes speed adjustment commands, and controls the motor accordingly. This multi-functional component adds operational flexibility without proportionally increasing overall system complexity, as a single integrated module handles multiple control tasks.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control module incorporates feedback mechanisms where user input (such as operating member actuation) is detected and processed to adjust motor speed. This feedback loop enables the system to respond to user needs dynamically, improving operational flexibility while maintaining a relatively simple control architecture.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4393288B1Walk-behind power tool
Publication Date: 2025.12.31 NANJING CHERVON IND
  • EP4393288B1 patent drawingFigure 1
  • EP4393288B1 patent drawingFigure 2
  • EP4393288B1 patent drawingFigure 3

AI summary

Provided is a rear-moving power tool, including a walking assembly including walking wheels; and a motor configured to drive the walking assembly. The rear-moving power tool has a self-propelled mode, where the self-propelled mode includes a first self-propelled state and a second self-propelled state; and in the second self-propelled state, the motor is capable of rotating at at least one constant rotational speed set according to a parameter of the rear-moving power tool during walking in the first self-propelled state. The rear-moving power tool is convenient to operate, and the working efficiency of a user can be improved.