I need an updated cabin design for my fold-away bicycle trailer. The chassis, front wheel, wheel base, and bicycle hitch are already engineered; what remains is a robust yet lightweight cabin that folds flat for cargo mode and opens into a roomy pet compartment. Top priority The folding mechanism must feel effortless—one smooth, intuitive motion that a single person can manage without tools. Strength and compact stowage still matter, but usability comes first. Material preference Aluminum is the material of choice to keep weight down and corrosion resistance high. If you see clear functional gains with selective steel or composite inserts, I’m open to hearing the rationale, but the core frame should stay aluminum. Must-have features • Ventilation windows for proper airflow when pets are onboard • Integrated storage compartments that remain accessible in both modes Scope of work – Engineer the folding frame and hinge system, including latch locations and safety stops – Provide 3D CAD models (SolidWorks or compatible STEP) and assembly drawings – Detail BOM with aluminum profiles, fasteners, and any proprietary hardware – Supply clear user instructions/illustrations for folding-unfolding sequence – Advise on manufacturability: tube sizes, bend radii, weld joints, or extrusion specs Acceptance criteria 1. Cabin folds to the footprint shown in my sketch while staying under 15 kg frame weight. 2. One-handed operation demo (video or animation) proves the mechanism meets the ease-of-use goal. 3. Vent windows and storage remain functional in both configurations. 4. All files and drawings open cleanly in SolidWorks 2022 or later. Share any past examples of folding furniture, trailers, or similar mechanisms if available; it will speed up our discussion. I’m ready to supply the current wheel-base CAD the moment we start.