1. P08002-Automated Parallel Bars
Ryan Hellems Project Lead
Justin Knowles ME
Justin Vowles ME
Jeff Osborne ME
Jessica Stalker ISE
Dr. B. DeBartolo Project Advisor
Customer: Nazareth Physical Therapy Clinic, JJ Mowder
Sponsor:

2. Project Description
The physical therapy clinic at Nazareth uses parallel bars to rehabilitate stroke and other neurological patients for walking.
Device needs to simplify raising and lowering of parallel bars, and insuring they remain level.
Key high level customer needs
Must be safe -Support 350 Lbs without drop
-No pinch points or sharp edges
-No trip or snag hazards
-Accurate height adjustment
Ease of use -<9 Lbs force to raise
-Reasonable time to adjust (90s)
-Bars remain level along full length
Reliable for 5 years of life

3. Current System

4. Project Rationale
Peg and pin system is difficult and time consuming to adjust
Safety concern from unlevel bars
Difficult to ensure right and left bar are same height
Need of accuracy to have consistent height in each session

5. Selected Concept
Hand Rail
Lifting System
Crank Tower
Drive Shaft

6. Key Calculations
0.5 inches height change per revolution (4:1 gear ratio)
Input force on handle is 2.19 Lbs.
Ergonomic max is 8.5 Lbs
Minimum bar height: 26 inches
Maximum bar height 44 inches
Ergonomic height of hand crank is 36 inches

7. Design Details

8. Design Details

9. Risk Assessment
Side-to-side deflection of uprights is too much, system wobbles
Resolution: Build one jack and measure. Reduce clearance, or add collar.
Use of a non-precision acme threaded rod could cause alignment or excessive torque issues.
Resolution: Build one jack and test for issues, if any, upgrade to precision threaded rod.
Using less expensive, jack miter gears could pose an excessive wear issue which would not be discovered until they fail in use.
Resolution: Testing has been completed comparing hardness of different miter gears. Results showed that jack miter gears will hold up for this application.
Unexpected frictional losses could cause the final system to be difficult to raise and lower.
Resolution: If losses present a torque issue gearing can be changed to make the system easier to raise and lower.

10. Budget Vertical Support Total – $399.35 Lifting System - $167.94
Drive Shaft System - $342.02
Hand Crank Tower – $460.33
Total Cost - $1,369.64

11. Current State Of Design
Design meets all customer needs
Design meets engineering specifications except:
2 inches less of range of motion, lower max height
Deflection at full-extension unknown, maybe an issue
Budget: Below target, extra funds for Powder Coating
Schedule:
Design completed on schedule, some analysis remaining (completed over break)
Long Lead items ordered (miter gears and pulleys)
Mitigations:
Build high-risk components early, and test. Alternative design options identified.
Modular design- main subsystems will be built independently

12. Milestones for MSD II Week 1-
Order initial parts for prototype and testing
Week 3-
Assemble one system, and begin tests.
Week 5-
Implement all possible test plans.
Manufacture additional components, pending successful testing; else redesign.
Week 7-
Fully assemble both sides of system at RIT
Test functionality of both systems
Week 8-
Install both sides in Nazareth PT clinic
Week 10-
Final Project Review
Poster Session

13. Questions?

14. Detailed Drawing of Hand Crank

15. Detailed Drawing of Lift Mechanism

16. Detailed Budget 1

17. Detailed Budget 2