Swing Access Ladder Locking Mechanism for Earth Movers
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Solution Overview
Problem
The 'bounce' of retracted ladders in access systems for earth moving equipment, caused by shocks and vibrations from rough surfaces, leads to damage of pivot joints and associated components, as well as noise distractions for the driver.
Innovation Solution
An access system with a locking mechanism that restrains the ladder's movement during retraction, using an extendible linkage element and biasing means to prevent excessive movement, and a stop member to prevent movement away from the deployed position, reducing the impact of vibrations and shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ladder is left unrestrained in the retracted position, then the access means can move freely for deployment, but the ladder experiences excessive bounce and damage to pivot joints due to shocks and vibrations from rough surfaces
Solution Approach 1:
The locking means is designed to be dynamically switchable between locked and unlocked states. When locked, it restrains the ladder in the retracted position to prevent bounce damage. When unlocked, it allows free movement for deployment. This dynamic state change resolves the contradiction between preventing damage and maintaining operational freedom.
Solution Approach 2:
The system changes the positional parameter of the locking means between two states: engaged with the access means to restrain movement, and disengaged to allow movement. This parameter change enables the system to adapt between the conflicting requirements of damage prevention and operational flexibility.
2Reliability
If a locking mechanism is added to restrain the ladder, then bounce damage is reduced, but the device complexity increases
Solution Approach 1:
The locking means is integrated with the retraction mechanism rather than being a separate independent system. The locking means is moveable to an operative position wherein it restrains movement of the access means in the retracted position, combining multiple functions into a unified mechanism and reducing overall system complexity.
Solution Approach 2:
The locking means is designed to automatically engage and disengage based on the position and movement of the access means. The system self-regulates the locking state without requiring external control systems, operators, or complex actuation mechanisms, thereby adding minimal complexity while effectively preventing bounce damage.
3Reliability
If the locking means is always engaged, then bounce is prevented, but the access means cannot be deployed
Solution Approach 1:
The locking means transitions between engaged and disengaged states dynamically. In the engaged state, it prevents bounce by restraining movement in the retracted position. In the disengaged state, it allows the access means to swing to the deployed position. This dynamic behavior enables the system to adapt to different operational requirements.
Solution Approach 2:
The locking means operates periodically - engaged during transport when bounce prevention is needed, disengaged during deployment when movement is required. This periodic switching between states allows the system to satisfy both contradictory requirements at different times in the operational cycle.
Data Source
AI summary
An access system (10) for an earth moving equipment (100) to allow a person to travel from ground level to an elevated position, said access system (10) includes an access means (12) mountable on to the earth moving equipment (100), and a retraction mechanism (50) to move the access means (10) between a deployed position (14) wherein a person can ascend or descend on the access means and a retracted position (16) wherein the access means (10) is stowed, and a locking means (52) moveable to an operative position wherein the locking means (52) restrains movement of the access means (10) in the retracted position (16).