1. Bonneville Power Administration Spacer Cart Progress Report #2
Portland State University
Spring of 2016
ME CAPSTONE Project
Presenters: Austin F. and Carlos J.
Team members: Austin F., Joshua P., Mackenzie L., Bao P., Rob L., Sam L. Stephen R.

2. BACKGROUND INFO Aerial Line Cart [Spacer Cart]
Used for repairs of high voltage transmission lines.
Created in-house by BPA.
Capstone team tasked with redesign to address safety/ergonomic problems.

3. Product Design Specification Revisited
Main Design Criteria [PDS]
Redesign of Cart Arms
Redesign of Squeeze Wheel Assembly
Redesign of Cross Bar
FEA Analysis of Cart
Determination of Factor of Safety

4. CART ARMS
Current Cart Arm Design

5. New Cart arm design

6. SQUEEZE WHEEL ASSEMBLY
Current Design

7. Design A & B

8. DESIGN C
Combines features of A & B for mounting and height adjustment

9. Final Design

10. Squeeze Wheel Mounted

11. Cross Bars
BPA has approved the bolt action lock, but they have not made the final decision on whether they will install them yet. We will create drawings and provide them to BPA, who will decide whether to send them for fabrication.

12. CROSS BARS [cont.]

13. FEA Analysis – Current Design
Analysis performed with a 500 lbf static load on arms.
Maximum deflection is 1.26”
Horizontal displacement
Vertical displacement

14. FEA Analysis – New Design
Analysis performed with a 500 lbf static load on arms.
Maximum deflection is 0.16”
Horizontal displacement
Vertical displacement

15. FEA Analysis – Dynamic load
We are currently conducting a more in-depth FEA analysis to ensure that the cart will not fracture due to any dynamic loading that may be encountered in the field.

16. FACTOR OF SAFETY
BPA currently specifies an 8:1 FoS for the Spacer Cart
Capstone team researched using standard: 29 CFR Sub Part L
Based on research done through various standards, specifically, the standard above which defines Safety and Health Regulations for Construction, subsection for Scaffolds, the Capstone team decided that this unit qualifies under the definition of a “scaffold”. The “standard” factor of safety used for scaffolding in industry is 4:1. As a team, we have recommended to BPA to switch to a 5:1 FoS instead of 8:1.

17. NEXT STEPS… Pinch Wheel Assembly Cart Arms Cross-bar
Finalize drawings for fabrication [Tentative 5/20/16]
Cart Arms
Complete drawings for fabrication. [Tentative 5/20/16]
Complete FEA analysis for impact loading on arms. [Tentative 5/27/16]
Make a decision on need for Cross-bar based on FEA results.
Cross-bar
Create drawings for fabrication. [Tentative 5/20/16]

18. Questions? No?
SUCCESS!!