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MECH 447 - Senior Design Capstone Project Prepared for: William Bill Dick Instructor of Mechanical Engineering University of Nebraska-Lincoln By: Rao, Manu Vengeta Kathirasen, Kathirgugan Kong, Liran Zhang, Dingwei LOAD-TRIGGERED WALKER

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Overview Objective Background Design Overall - Retractable Pen Mechanism - Arc Mechanism - Portability Force Analysis Cost

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Objective Madonna Rehabilitation Hospital identified need for load-triggered mechanism accidentally slips eliminate the need for person using the walker to use hand- triggered brake or any other type of manual braking mechanism Major considerations : 1) need for mobility 2) need for effective fall prevention mechanism

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Background Duro-Med 2-Button Adjustable Aluminum Folding Walker ($45.99) NOVA "GetGo" 4203 Rolling Walker ($99.99)

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Design

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THE ARC MECHANISM Force Angle()F-Tube 2211lb 2914lb 3617lb 4320lb 5022lb 5725lb * 20lb to disengage the magnet

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Mobility

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Step 1: Pull out the pins and disengage the brake tube and the rotating bar. Shows the pin mechanism that if pulled in the direction shown, would disengage and allow the walker to be folded

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Mobility Step 2: Disengage the Velcro strap to the horizontal bar, and push the tube and bar downwards. Shows the handle that is attached to the upper horizontal bar which has Velcro padding

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Mobility Step 3: The walker is folded and the user can hold the strap to move the walker

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Mobility

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Design for Manufacture

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Cost cam-ratchet mechanism = $ 62.70 walker = $ 222.58 Production costs (SAE guidelines) - cam-ratchet mechanism = $ 9.07 - walker amounted to = $ 56.65 total cost = $ 422.77 addition of overhead costs, bureaucracy, additional modification and profits = market value of $ 800