Caddy Transport Cart
Full Assembly (with ~20° tipping stability cone model)
Rail Bearing Assembly
Custom Crank Shaft Bearing Assembly
Custom Carriage Plate Lead Screw Assembly
Counterbalance System
Overview
During my co-op at Alloy Enterprises, I redesigned a material handling cart to safely transport loads of more than 500 lb without external counterbalance support. I implemented structural optimization including bearing upgrades, steel carriage plate redesign, and an integrated counterbalance system. The design enabled 3x higher weight capacity with a 15° tipping safety factor while maintaining cart maneuverability.
Skills & Tools:
Mechanical design, structural analysis, deflection calculations, bearing selection, CAD modeling (SolidWorks), safety factor analysis, material selection, manufacturing coordination
Project Details:
Problem
The existing handling cart experienced significant tip deflection when transporting above 150lbs, creating safety concerns and operational inefficiencies. A temporary external counterweight solution was in use, but it compromised maneuverability and posed safety risks due to easy removability. Analysis identified multiple deflection sources: arm assembly, carriage plates, bearings, and end effectors. A permanent, integrated engineering solution was needed.
Main Objectives:
Redesign cart to safely carry more than 500 lb loads without external counterbalance
Eliminate deflection sources through engineering analysis and part upgrades
Maintain cart maneuverability and operational footprint
Implement integrated safety features preventing unsafe loading
Create manufacturable, cost-effective solution
Key Constraints:
Must fit within existing workspace and maintain range of motion
Compatible with existing build handling locations
All components must be serviceable
Structural Analysis & Optimization
I performed deflection analysis to identify and prioritize the main failure points: bearing compliance, carriage plate bending, and tipping instability and implemented a redesign for each deflection source:
Bearing system: Optimized spacing and upgraded to high-rigidity bearings with dual-bearing configuration, achieving 3x deflection reduction
Carriage plate: Analyzed bending mechanics and redesigned with steel material and optimized thickness for 10x rigidity improvement
Counterbalance system: Designed integrated steel weight distribution to achieve a 15° tipping safety factor with tool-removable mounting and preloading of top cart plate.
Supporting components: Created custom bearing supports, lead screw assemblies, and cart base improvements to accommodate new geometry
I coordinated manufacturing with machine shops, creating detailed drawings and specifications for all custom components including laser-cut plates, machined supports, and modified cart base.
Result:
Successfully handles over 500lb loads with compact counterbalance system
15° tipping safety factor achieved
Maintained cart form factor and maneuverability
Key Learnings:
Thorough analysis of problem is essential addressing root causes rather than symptoms
Design changes cascade through systems, requiring holistic planning
Integrated solutions outperform add-on fixes for both performance and usability
Safety factors must account for worst-case scenarios and potential misuse
