Swingable Front Guard Structure for Loader and Hood Interference

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Solution Overview

Problem

Existing work vehicles, such as tractors, are prone to damage from erroneous operations where the front guard and vehicle parts come into contact, particularly when the hood is opened or the front loader is raised/lowered while the upper frame is in the wrong position.

Innovation Solution

A front guard with a lower frame and an upper frame that can swing between a standing and forward-leaning posture, featuring a protruding portion that contacts the hood to prevent damage during erroneous operations, and an elastic member to facilitate posture change.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the upper frame is fixed in the guard position, then the protective function is improved, but the risk of damage from erroneous hood opening operations increases

Engineering Contradiction:
Improveprotective functionVSAvoiddamage from erroneous operation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The upper frame is designed to be swingable between a guard position and a retracted position, allowing it to dynamically adjust based on operational conditions. This dynamic capability enables the front guard to maintain protective function while avoiding damage from erroneous hood opening operations by automatically retracting when the hood is opened.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The protruding portion on the upper frame is positioned to contact the hood before the hood can collide with the upper frame. This preliminary contact prevents harmful collision by guiding the hood's movement and triggering the upper frame to swing to the retracted position in advance, avoiding damage from erroneous operations.

Inventive Principle:
Principle #9Preliminary anti-action

2Object-affected harmful factors

If the upper frame is made swingable to prevent damage, then the resistance to erroneous operation damage is improved, but the structural complexity increases

Engineering Contradiction:
Improvedamage from erroneous operationVSAvoidswing mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The front guard is divided into a lower frame and an upper frame that can swing independently. This segmentation allows the upper frame to be positioned and supported separately, enabling the swing function while maintaining overall structural simplicity. The upper frame's ability to swing is achieved through simple pivot connections rather than complex mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The upper frame automatically swings between guard and retracted positions based on forces generated during normal operations (hood opening, front loader movement). This self-service mechanism eliminates the need for motors, sensors, or complex control systems, achieving damage prevention through passive mechanical response to operational forces.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If the protruding portion is positioned to contact the hood, then the prevention of erroneous operation damage is improved, but the risk of interference with normal hood operation increases

Engineering Contradiction:
Improvedamage from erroneous hood openingVSAvoidhood opening operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The protruding portion acts as an intermediary element between the hood and the upper frame. It contacts the hood first during opening operations, serving as a mediator that triggers the upper frame to swing to the retracted position. This intermediary contact prevents direct collision between the hood and upper frame while guiding the protective response without interfering with normal hood operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The potential harmful contact between the hood and upper frame during erroneous opening operations is converted into a beneficial triggering mechanism. The protruding portion's contact with the hood, which could be harmful, is instead used to initiate the protective swing motion of the upper frame, transforming the harmful interaction into a useful safety function.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4033037B1Front guard and work vehicle
Publication Date: 2026.03.11 KUBOTA CORP
  • EP4033037B1 patent drawingFigure 1
  • EP4033037B1 patent drawingFigure 2
  • EP4033037B1 patent drawingFigure 3

AI summary

A work vehicle (1) includes a vehicle body (2), a front guard (30) attached to a front portion of the vehicle body, and a front loader (12) that is attached to the front portion of the vehicle body and can be raised or lowered. The front guard has a lower frame (31) attached to the vehicle body and an upper frame (41) that is attached to the lower frame (31) so as to be swingable around a shaft oriented in a vehicle width direction and a posture of which can be changed between a standing posture and a forward leaning posture by swinging with respect to the lower frame, and the upper frame has a vertical part (42) that extends upward, an upper portion of the vertical part is formed with an upper curved portion (42a) that is curved backward as it goes upward, and the upper curved portion has a first upper region (42a1) that is located on a movement trajectory of a part of the front loader when the front loader is lowered while the upper frame is located in the forward leaning posture and a second upper region (42a2) that is curved forward as it goes downward from the first upper region.