Cab Door Layout That Stays Openable Under Frame Deformation

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Solution Overview

Problem

The door of a driver's cab in working machines, such as hydraulic shovels, can become unopenable when the cab frame is deformed due to contact with lumber, posing a risk of the operator being trapped inside.

Innovation Solution

The cab design features a door that is installed to oppose the side surface of the cab frame in a closed state, with a protruding edge of the window covering member protecting the door and a sealing member maintaining airtightness, and eaves above the door to prevent rain ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the door is fitted into a recessed portion on the side surface of the cab frame for airtightness and waterproofness, then sealing performance is improved, but the door may become unopenable when the cab frame is deformed by contact with lumber

Engineering Contradiction:

Improvesealing performanceVSAvoiddoor openability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The door is pre-installed to oppose the side surface of the cab frame rather than fitting into a recessed portion, establishing a clearance configuration before any deformation occurs. This preliminary positioning prevents the door from becoming trapped when the cab frame contacts lumber during operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The door is extracted from the recessed portion configuration and positioned to oppose the side surface of the cab frame. This separation removes the door from the deforming zone of the cab frame, allowing the door to maintain its openability even when the cab frame undergoes deformation during forestry operations.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If the door is installed to oppose the side surface of the cab frame to prevent trapping, then door openability is improved, but airtightness and waterproofness may be compromised

Engineering Contradiction:

Improvedoor openabilityVSAvoidsealing performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A sealing member is introduced as an intermediary element between the door and the side surface of the cab frame. This sealing member maintains airtightness and waterproofness while allowing the door to oppose the side surface with clearance, thus preserving both sealing performance and door openability simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If a wire mesh guard or polycarbonate shield is provided on the front surface to protect against lumber contact, then protection against deformation is improved, but the door may still become trapped if the cab frame deforms

Engineering Contradiction:

Improveprotection against deformationVSAvoiddoor openability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

Instead of protecting the door in the same dimension (front surface shields), the solution moves the door to a different spatial dimension by positioning it to oppose the side surface of the cab frame. This dimensional change places the door outside the primary deformation zone caused by front lumber contact, eliminating the trapping risk without compromising protection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11807310B2Cab

Publication Date: 2023.11.07 CATERPILLAR SARL

AI summary

To provide a cab in which opening and closing of a door is hardly inhibited even if a cab frame or a door is deformed. A cab comprises a cab main body having a cab frame and a doorway formed in the cab frame. The cab comprises a door that opens and closes the doorway of the cab main body. The door is installed to the cab main body so as to be opposed to the side surface of the cab frame in a closed state of the doorway.