Mechanical Engineer — Compact Twist-Actuated Lift-and-Return Mechanism (CAD + Prototype)

About the project

Overview I'm developing a small consumer hardware product and need a talented, creative mechanical engineer to design the internal mechanism. The concept is a compact, hand-held device with an outer shell that the user twists. That twisting motion must drive an internal mechanism that raises a small output lever/arm approximately 90° and then returns it back to its original resting position — a single, smooth "raise-and-return" cycle per actuation. What you'll design A mechanism that converts rotary input (a twist about the central axis) into a controlled oscillating lift of a small output arm (up ~90°, then back to home). An outer shell / inner mechanism arrangement that self-locates and indexes repeatably onto a target surface each time it's placed. Sufficient mechanical advantage to deliver a moderate output force at the lever through the stroke (target on the order of ~30 N; final value to be confirmed against measured data I'll provide). Requirements Compact cylindrical envelope (roughly 70 mm diameter class), hand-operated, no motor or electronics — purely mechanical. Positive, driven return (not gravity-dependent). Open to your best mechanism choice — cam, scotch yoke, four-bar linkage, or something more creative. I'd like a short trade study and your recommendation. Designed for a resin (SLA) 3D-printed prototype first, then scalable toward production. Deliverables Concept sketch(es) + a brief mechanism trade study with your recommendation. Parametric 3D CAD with a native STEP export (plus STL for printing). A simple kinematic analysis showing the lever reaches ~90° and returns, with an estimate of the required input torque. A dimensioned drawing and print-ready files for the prototype. Skills Mechanism/kinematic design, parametric CAD (SolidWorks, Fusion 360, Onshape, or similar with STEP output), design-for-3D-printing, and ideally hands-on prototyping experience. To apply Please share 2–3 examples of mechanism or small-mechanical-product work you've done (cams, linkages, compact assemblies). Tell me briefly which mechanism approach you'd lean toward and why. I'll provide exact target dimensions and a measurement dataset after we connect. An NDA will be required before I share the full application and specifications.

Skills required