← Back to Projects
Mechanical Design

Actuator Cable Disengagement Mechanism

Compact service mechanism for jam recovery and latch release under strict packaging and load constraints

Actuator Cable Disengagement Mechanism
Free Body Diagram and Stress Analysis
Prototype Assembly
1 / 3

Overview

Timeframe: 2024-2025

Institution: University of Toronto - MIE442 (Mechanical Design)

Team Size: 5 members (Sam Bahrami, Kelvin Cao, Clive Fellows, Mo Taban, Batu Tibet)

Role: Mechanical Design and Structural Validation Engineer

Designed a manual service mechanism that slackens a jammed actuator cable and releases the latch from one pull while fitting within an 80 x 80 x 30 mm envelope and holding a 2.0 safety factor.

The Problem

Stalled actuators keep the latch locked by holding cable tension. The mechanism needed to create slack and release the latch with a single input, stay under 50 N pull force, and survive 250 N abuse loads.

Constraints

  • 80 x 80 x 30 mm package
  • Single 50 N manual pull
  • 250 N abuse load with ≥2.0 safety factor
  • Repeated service cycles and elevated temperature
  • Both slack generation and latch release from one motion

Solution

I led concept and validation work:

  • Lever and pulley layout that generates slack and triggers the latch in the same stroke
  • Service lever geometry sized for 50 N input and hard stops for repeatability
  • Steel pins with polymer housings and torsion springs for reset and durability
  • Compact stack-up optimized for manufacturability and tolerance control

Analysis

  • Free body and contact stress checks on service, jam, and abuse cases
  • Beam and pin stress sizing with Modified Goodman fatigue review
  • ANSYS static runs to confirm hand calculations within acceptable agreement
  • Iterative geometry tweaks to remove stress concentrations

Tools & Technologies

ANSYS FEA Analytical Mechanics Fatigue Analysis Contact Stress Design for Manufacturing

Design Validation

≤50 N
Service Force
≥2.0x
Safety Factor
<30 mm
Packaging Height

Results:

  • Met the 50 N pull target with margin through mechanical advantage
  • Cleared 2.0 safety factor across service and abuse cases
  • Validated cyclic life for pins and springs
  • Kept the full assembly inside the 80 x 80 x 30 mm volume

Key Learnings

  • Hand calculations first made FEA setup faster and more trustworthy.
  • Tight packaging forced a cleaner architecture that combined functions.
  • Designing for manufacturing early avoided costly geometry changes later.