Walk-behind Mower Speed Control Assembly with Multi-Position Selector

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Solution Overview

Problem

Existing self-propelled walk-behind lawn mowers lack a convenient and ergonomic speed control mechanism that allows independent actuation of the transmission by the operator and fails to optimize speed for individual operators, making it difficult to navigate obstacles and maintain suitable travel speed.

Innovation Solution

A speed control assembly with a plurality of selectively rotatable levers and a knob that allows the transmission to be actuated between engaged and disengaged positions and adjusted between multiple speeds, enabling operators to control the speed of the lawn mower effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-speed self-propelled transmission is used, then the transmission structure is simple, but the operator cannot adjust the speed to match individual needs or navigate obstacles effectively

Engineering Contradiction:
Improvespeed adjustment capabilityVSAvoidtransmission control structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a multi-speed transmission system that allows dynamic adjustment between different speed levels (high, medium, low) through a selector mechanism. This enables the transmission to adapt to varying operational conditions and operator preferences, resolving the contradiction between adaptability and complexity by providing adjustable speeds within a manageable control structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the speed parameter of the transmission by incorporating a multi-position selector that adjusts the transmission ratio or engagement level. This allows the system to operate at multiple speed levels rather than a fixed single speed, thereby improving adaptability while maintaining a relatively simple control mechanism through discrete parameter settings.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the self-propelled transmission is engaged, then the lawn mower can move autonomously, but the operator loses control over navigation speed and obstacle avoidance

Engineering Contradiction:
Improveoperator control over speedVSAvoidspeed control mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments the speed control function into distinct selectable levels (high, medium, low speeds) through a multi-position selector mechanism. This segmentation allows the operator to choose the appropriate speed level for different operational scenarios, providing ease of operation while keeping the control mechanism simple through discrete, clearly-defined speed options.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the transmission operates at fixed speed, then the control mechanism is simple, but the operator cannot optimize speed for different operating conditions

Engineering Contradiction:
Improveoperational efficiencyVSAvoidmulti-speed control system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a dynamically adjustable transmission system that allows the operator to select from multiple speed levels based on operational requirements. This dynamic capability enables optimization of productivity for different mowing conditions while maintaining relatively simple control through a straightforward selector mechanism that switches between predefined speed settings.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2760268B1Speed control assembly for a self-propelled walk-behind lawn mower
Publication Date: 2017.11.08 MTD PRODUCTS INC
  • EP2760268B1 patent drawingFigure 1
  • EP2760268B1 patent drawingFigure 2
  • EP2760268B1 patent drawingFigure 3

AI summary

A speed control mechanism for controlling selective engagement of the self- propelled transmission assembly for a walk-behind lawn mower is provided. The speed control mechanism is also configured to control the relative output speed of the transmission assembly. The speed control mechanism includes a speed engagement assembly (33)and a speed adjustment assembly (32), wherein the speed engagement assembly (33) includes a pair of rotatable levers (34,36) for causing the transmission assembly to actuate between a disengaged position and an engaged position and the speed adjustment assembly (32) includes a rotatable knob (42) for causing the relative output speed of the transmission assembly to the wheels of the lawn mower to increase or decrease.