Foldable Propeller Pivot Pin Nesting for Assembly Stability
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Solution Overview
Problem
Existing foldable propellers for boats do not adequately address the issue of fouling and corrosion, and their assembly can be complex and unstable.
Innovation Solution
A foldable propeller design featuring a hub with pivot pins and hub flanges that allow blades to pivot between operative and inoperative orientations, using a simplified assembly method with locking members and a galvanic anode for corrosion protection, and optionally incorporating gears for balanced engagement with the drive shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional foldable propeller designs are used, then the propeller can be folded to minimize drag, but the assembly becomes complex and stability is compromised
Solution Approach 1:
The patent combines multiple components (blade, blade root, pivot pin, locking member) into an integrated assembly where the locking member is directly formed as part of the blade root structure. This merging reduces the number of separate parts and simplifies assembly while maintaining the foldable functionality for drag minimization.
Solution Approach 2:
The pivot pin is inserted through the hub flange and into the blade root, with the locking member nested within the blade root structure. This nested arrangement allows compact integration of multiple functional elements without increasing overall assembly complexity.
2Adaptability or versatility
If traditional foldable propeller designs are used, then the propeller can fold, but fouling and corrosion issues are not adequately addressed
Solution Approach 1:
The patent extracts the corrosion protection function by incorporating a sacrificial anode that is electrically connected to the hub structure. This separate corrosion protection element is taken out from the blade assembly itself, allowing the blades to be removed and folded without carrying corrosion protection components that could become fouled.
Solution Approach 2:
The hub flange is designed with specific local features including a recess for the pivot pin and a channel for receiving grease. This localized quality improvement at critical interfaces protects against corrosion and fouling at the most vulnerable points without requiring complete redesign of the entire propeller system.
3Ease of manufacture
If simple assembly methods are used, then assembly is simplified, but stability of the blade-to-hub connection is compromised
Solution Approach 1:
The locking member is pre-formed as an integral part of the blade root structure during manufacturing. This preliminary action ensures that the connection geometry is precisely defined before assembly, providing stable blade-to-hub connection while simplifying the assembly process to only require insertion and engagement of the pre-configured locking member.
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 design enhances stability, simplifies assembly, reduces fouling and corrosion, and ensures balanced blade engagement, resulting in a more effective and durable propeller.
Implementation Method 1
Galvanic corrosion can be limited by using sacrificial anodes that will be corroded instead of the propeller hub and blades
Data Source
AI summary
The present invention relates to a foldable propeller (1) for a boat, e.g. for a sailboat or a multihull yacht, where the foldable propeller (1) comprises a hub (2) with a plurality of blades, each blade comprising a blade root arranged to pivot around a separate pivot pin in order to be either in a first operative orientation, where the blade (4) is pointing mainly in a radial direction, or in a second inoperative orientation, where the blade is pointing mainly in an axial direction. The hub (2) comprises a number of hub flanges (28) for holding the pivot pins (9). The pivot pin (9) comprises at its second end (21) a head (26) with a recess (24) that accommodates the first end (20) of another of the pivot pins (9) inside the head (26).