UHMW Kingpin Docking Interface for Low-Friction Trailer Pivoting
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Solution Overview
Problem
Existing methods for reducing rotational friction between a semi-tractor and an attached trailer, such as using grease or thin plastic sheets, are environmentally unfriendly, require frequent maintenance, and suffer from premature wear and tear, especially in varying weather conditions, leading to potential loss of control and safety hazards.
Innovation Solution
A low friction kingpin docking interface using a 36-inch diameter plastic disk with a snap-in design, clamped by a metal mechanism, which is easily replaceable and made of ultra-high molecular weight (UHMW) plastic, eliminating the need for fasteners and reducing friction through a resilient, durable material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If grease is used to reduce rotational friction between tractor and trailer, then friction is reduced, but environmental pollution increases and maintenance requirements increase
Solution Approach 1:
The patent introduces an intermediary substance - a plastic bearing material (such as UHMWPE - ultra high molecular weight polyethylene) - that mediates between the steel kingpin and the fifth wheel. This plastic intermediary replaces grease as the friction-reducing element, providing low friction without the environmental pollution and maintenance issues associated with grease application.
2Force
If thin plastic sheet is used to reduce friction, then friction is reduced, but the plastic suffers from premature wear and tear
Solution Approach 1:
The patent employs composite material construction for the plastic bearing, specifically using ultra high molecular weight polyethylene (UHMWPE) which combines the low friction properties of plastic with enhanced wear resistance. This composite approach maintains the benefits of plastic (low friction, no grease needed) while dramatically improving durability and resistance to premature wear and tear under heavy loads.
3Force
If thin plastic sheet is used to reduce friction, then friction is reduced, but maintenance complexity increases due to screw fastener issues
Solution Approach 1:
The patent extracts the fastening system from the rotation zone by using screws positioned on the outer perimeter of the plastic bearing, outside the 18-inch radius rotation area. This extraction prevents sand, dirt, and grease from clogging the screw holes during rotation, eliminating the maintenance complexity associated with accessing and maintaining fasteners in the high-wear rotation zone.
4Force
If thicker plastic is used to reduce friction, then friction is reduced, but the plastic exceeds conventional kingpin trailer vertical docking tolerances
Solution Approach 1:
The patent changes the material parameter from conventional plastic to ultra high molecular weight polyethylene (UHMWPE), which has superior mechanical properties including higher strength-to-weight ratio and better load-bearing characteristics. This material parameter change allows for a thinner bearing section (1/4 inch) to provide adequate friction reduction while remaining within the 18-inch radius vertical docking tolerances of conventional kingpin trailers.
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 interface significantly reduces rotational friction, enhances safety by preventing sudden rig locking, and extends the life of the plastic bearing, while being environmentally friendly and cost-effective, with minimal maintenance requirements.
Implementation Method 1
A low friction bearing structure shaped to surround a kingpin of a trailer reducing friction between a trailer and a docking system of a tractor vehicle
Data Source
AI summary
A mechanism attached to the trailer of a semi tractor trailer that uses a low friction UHMW or similar bearing sheet material as an interface between the two components. This wear item is easily replicable without the use of fasteners such as screws nuts or bolts. The invention uses a plug and play bayonetted snap in methodology and is easily installed on new or existing rigs such as 18/26-wheeler highway transports. The wearable bearing can be replaced by novice operators not skilled in technical installations in only a few minutes and at very low cost.