Retractable Boat Ladder Locking Mechanism
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Solution Overview
Problem
Existing watercraft steps lack a reliable locking mechanism to secure the step in the deployed position, which can lead to accidental retraction and injury, and existing solutions either fail to lock the step in the use position or require gravitational assistance, which is insufficient for boat ladders.
Innovation Solution
A locking mechanism featuring a rod, bent plate, and washers that automatically locks the U-shaped ladder in the use position using torsion springs, preventing retraction until manually released by the user, ensuring safety during boarding and exiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to secure the step in the deployed position, then user safety is improved, but device complexity increases
Solution Approach 1:
The locking mechanism automatically engages when the step is deployed to the use position, eliminating the need for manual locking operations. The cam surface and pin work together to self-lock the step in place, reducing operational complexity while enhancing safety.
Solution Approach 2:
A cam surface is introduced as an intermediary element between the step and the locking pin. The cam surface converts the rotational motion of the step into linear motion that drives the pin into the locked position, simplifying the overall locking mechanism while ensuring reliable engagement.
2Ease of operation
If a manual unlocking mechanism is provided, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The unlocking function is extracted as a separate, simple manual operation from the automatic locking function. Users can easily disengage the pin from the cam surface by applying slight force, allowing simple manual control over the locking state without complicating the automatic locking mechanism.
3Ease of operation
If the step is designed to be easily released, then ease of operation is improved, but reliability decreases
Solution Approach 1:
The cam surface is designed with specific geometric characteristics that provide strong engagement in the locked position while allowing easy release. The shape and positioning of the cam surface create local areas of high contact pressure for reliable locking, while the overall geometry permits straightforward manual disengagement when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mechanism securely locks the ladder in the use position, preventing accidental retraction and allowing safe use until manually unlocked, enhancing user safety and preventing injuries.
Implementation Method 1
The ladder is rotationally biased to in the storage position. The bias is created from a pair of torsion springs that are in each bracket.
Implementation Method 2
Another smaller torsion spring biases the bent plate in the opposite rotational direction as the ladder.
Data Source
AI summary
A retractable U-shaped ladder assembly preferably for a craft such as a watercraft has a rotatably retracted ladder which is attached to the craft by brackets. A torsion spring is used to bias the ladder into the retracted position. While the ladder is in an in-use position, the ladder is locked into place by a locking mechanism. The locking mechanism includes a bent plate which presses against four rings that are fixed to a rod, which rod extends from each bracket. Each ring has a notch that is located in the same position. In the use position, the bent plate will fit into the notches of the rings and lock the step. When the user is finished using the ladder, the user can manually unlock the step by pressing the bent plate. The bent plate moves out of engagement with the notches in the rings, thereby allowing the torsion springs in the brackets to rotate the step to the retracted position.