Cab Door Holding Member Relocation for Operator Space
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Solution Overview
Problem
Conventional hydraulic excavators face issues with door holding members protruding into the operator's room, reducing living space and workability, and risking interference with obstructions when the door is opened.
Innovation Solution
The design features a left front pillar with a stepped surface and a retreating recessed portion on the door to prevent the engaging member from protruding into the operator's room, allowing the door holding member to be positioned closer to the outer surface, thus minimizing the door's thickness and extension when closed, and providing a seal member to prevent dust and noise intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the door holding member is extended to the operator's room side from the inside of the door, then the door can be held at a closed position, but the thickness of the inner surface side of the door increases and the door holding member gives a feeling of oppression to the operator's room
Solution Approach 1:
The door holding member is repositioned from the inner surface side to the outer surface side of the door, changing its spatial dimension. This relocation moves the holding mechanism outside the operator's room, eliminating the feeling of oppression while maintaining the door closed position holding function through the engaging member on the pillar.
Solution Approach 2:
An engaging member is introduced as an intermediary component mounted on the pillar. This engaging member includes an engaging ring that works with the door holding member to secure the door in the closed position, distributing the holding function between the door assembly and the pillar structure, thereby reducing the need for thick door construction.
2Reliability
If the door holding member largely extends to the inside of the door, then the door can be held securely, but the door holding member can be easily brought into contact with obstructions when the door is opened
Solution Approach 1:
The door holding function is extracted from the door body itself and relocated to the pillar structure via the engaging member. By taking out the holding mechanism from the door and mounting it on the pillar, the door can open freely without the holding member extending into the path where obstructions may occur.
Solution Approach 2:
The engaging member on the pillar serves as an intermediary that decouples the door holding function from the door body. This allows the door to move independently during opening operations without the holding member interfering with obstructions, while still providing secure closed position holding through the engaging ring mechanism.
3Reliability
If the engaging member is mounted on the rear surface portion of the left front pillar, then the door holding function is provided, but the mounting plate protrudes to the door side and may interfere with the door when closed
Solution Approach 1:
The mounting plate is designed with a protruding portion that extends to the door side in advance, and the door is correspondingly provided with a retreating recessed portion. This preliminary design of the protruding structure allows the engaging member to be mounted on the pillar while pre-configuring the door to avoid interference during closure.
Solution Approach 2:
Instead of making the door thinner to avoid the protruding mounting plate, the solution inverts the approach by making the mounting plate protrude and corresponding the door with a retreating recessed portion. This reversal of the conventional thinning approach allows the mounting plate to protrude while still avoiding interference through the complementary recessed design.
Data Source
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AI summary
A cab (8) is provided with a cab box (13) in which a space between each of pillars (14 to 18) is covered by each of surfaces (13A to 13F) and the inside becomes an operator's room (13G) and a door (24) mounted on the left intermediate pillar (16). On a rear surface portion (14D) of the left front pillar (14), a protruding portion (23A1) of a mounting plate (23A) is provided in a state protruding to the door (24) side. On a mounting opening (24E) on the inner surface side of the door (24), a door holding member (28) engaged with an engaging member (23) and holding the door (24) at a closed position is provided. On the door (24), a retreating recessed portion (29) for avoiding interference with the protruding portion (23A1) of the mounting plate (23A) is provided on the front side from the door holding member (28).