Trim and Tilt Cylinder Alignment via Spherical Bearings
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Solution Overview
Problem
Conventional trim and tilt systems for outboard motor propulsion units on marine crafts experience undue stress on trim cylinder units due to the unitary construction, leading to wear and fatigue as the angle of trim rods changes with respect to the swivel bracket during trimming and tilting, causing transverse stress.
Innovation Solution
A trim and tilt system with a stem bracket, swivel bracket, tilt cylinder unit, and trim cylinder units where the trim rods are aligned to transmit the weight of the propulsion unit substantially along their longitudinal axis, using ball bearings and trim receivers to guide the force, and pads to limit pivotal range, reducing stress on the trim cylinder units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a unitary trim and tilt cylinder apparatus is used, then the system structure is simplified and space is saved, but undue stress and wear are applied to the trim cylinder units during trimming operations
Solution Approach 1:
The patent divides the unitary trim and tilt cylinder apparatus into separate trim cylinder units and tilt cylinder units. Each trim cylinder unit is independently mounted to the swivel bracket, allowing the trim function to be separated from the tilt function. This segmentation eliminates the stress concentration problem in the unitary design while maintaining space efficiency through compact arrangement of the separate components.
2Adaptability or versatility
If the trim rod angle changes with respect to the swivel bracket during trimming, then the outboard propulsion unit can be trimmed, but transverse stress is applied to the trim rods leading to wear and fatigue
Solution Approach 1:
The patent employs spherical bearings in the swivel bracket that allow the trim rods to dynamically adjust their angle relative to the swivel bracket during trimming operations. The spherical bearings accommodate angular changes while maintaining force alignment along the longitudinal axis of the trim rods, preventing transverse stress. This dynamic adaptation enables full trimming capability while protecting the trim rods from wear and fatigue.
3Reliability
If the force is transmitted along the longitudinal axis of the trim cylinder unit, then stress on the trim cylinder unit is minimized, but alignment mechanisms are required
Solution Approach 1:
The patent introduces spherical bearings as intermediary elements between the trim rods and the swivel bracket. These spherical bearings serve as mediators that automatically align the force transmission path with the longitudinal axis of the trim cylinder units. The spherical geometry provides self-alignment capabilities, ensuring force is transmitted axially without requiring complex external alignment mechanisms, thus reducing stress while maintaining simplicity.
Data Source
AI summary
A trim and tilt system for use with an outboard propulsion unit on a marine craft having a transom. The trim and tilt system comprises a stern bracket configured to be mounted on the transom of the marine craft and a swivel bracket for supporting the outboard propulsion unit. The swivel bracket is pivotally supported on an upper end of the stern bracket. There is also a tilt cylinder unit that has a lower end supported by the stern bracket and an upper end in pivotal engagement with the swivel bracket. The tilt cylinder unit pivotally supports a pair of trim cylinder units. Each of the trim cylinder units is on an opposite side of the tilt cylinder unit. Each said trim cylinder unit has a longitudinal axis, a lower end in pivotal arrangement with the tilt cylinder unit and a trim rod for engagement with the swivel bracket. The swivel bracket has means for aligning the trim rods therewith, whereby the force exerted by the swivel bracket on the trim cylinder unit is substantially along the longitudinal axis. There is also means for actuating the tilt cylinder unit and the trim cylinder units.