Walk-behind mower steering wheel universal joint

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing walk-behind mowers with rigid controls require operators to walk around obstacles and perform U-turns manually, leading to unnecessary walking and energy expenditure.

Innovation Solution

A walk-behind mower design featuring a frame with a selectively steerable drive wheel, follower wheels, and a steering wheel assembly connected via a universal joint, allowing for rotational force application to the frame about a vertical axis, enabling easy steering without the need to follow a push handle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rigid handle control system is used, then the structure is simple, but the operator must walk around obstacles and perform U-turns manually, increasing walking distance and energy expenditure

Engineering Contradiction:
ImproveSteering convenienceVSAvoidWalking time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The mower incorporates a steerable drive wheel that can rotate about a vertical axis, transforming the static rigid handle system into a dynamic steering system. This allows the mower to turn in place without requiring the operator to manually maneuver the handle around obstacles, reducing walking distance and time while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

2Productivity

If a steering wheel assembly with universal joint is added, then turning efficiency is improved and walking distance is reduced, but device complexity increases

Engineering Contradiction:
ImproveTurning efficiencyVSAvoidSteering mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The universal joint connects the steering wheel assembly to the frame, enabling the steering wheel to apply rotational force to the frame about a vertical axis. This multi-functional connection allows the steering wheel to control the steerable drive wheel while maintaining structural integrity, achieving improved turning efficiency without proportionally increasing complexity.

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

3Ease of operation

If the steerable drive wheel is made selectively steerable, then the turning radius is reduced and 180° turns are enabled without repositioning, but the control mechanism becomes more complex

Engineering Contradiction:
ImproveTurning maneuverabilityVSAvoidSteering control complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The steerable drive wheel is designed to rotate about a vertical axis, enabling dynamic steering adjustments. This dynamic capability allows the mower to perform 180° turns without repositioning and reduces the turning radius, improving maneuverability while the rotational symmetry of the wheel minimizes the complexity of the control mechanism.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3302021B1Walk-behind mower with steering wheel control
Publication Date: 2019.10.09 MTD PRODUCTS INC
  • EP3302021B1 patent drawingFigure 1
  • EP3302021B1 patent drawingFigure 2
  • EP3302021B1 patent drawingFigure 3

AI summary

A walk-behind mower (20) includes a frame (24) and a power source (50) attached to the frame (24). A selectively steerable drive wheel (46) and a set of follower wheels (70) are rotatably attached to the frame (24). The walk-behind mower (20) includes a steering wheel assembly (80) attached to the frame (24), the assembly including a steering column (84) and a steering wheel (86) attached to the steering column (84). The walk-behind mower (20) also includes a universal joint (90) connecting the steering wheel assembly (80) to the frame (24). The walk-behind mower (20) further includes a mower deck (34) attached to the frame (24) and a mower blade assembly (36) attached to the deck. In other examples, the walk-behind mower (20) includes a front section (26) and a rear section (28) that rotate relative to each other about a vertical axis (30).