New Handle CAD Design Latch Mechanical Analysis J. Dzionara-Norsen

Handle Redesign New handle design to be used with standard crutch frame Differences from previous crutch design: – Longer shaft cuffs to account for misalignment during use – Slide handle onto shaft by removing axillary pad – Modified design handle frame to accommodate pad – Shorter handgrip to fit standard crutch frame

Handle CAD

Latch Mechanical Analysis Cantilevered beam where b=0.2”, h=0.5” AISI 304 steel YS = 31,200 psi F=150 lbf. F.O.S = 1.73 b h 1” F

Tearout, Bearing Stress, Shear Tearout: Bearing Stress: Compressive stress due to surface contact Shear of Bolt: = 2500 psi = 4167 psi = 5895 psi n = 5.3 n = 7.5 n = 12.5

Crutch Misalignment Most severe angle is 45 degrees Maximum y = 1.57” Handle cuff length and sliding button length take this into account 1.57” y