1. Wegmans Bread Tray Lift Assist
Design Review 2

2. Wegmans Bread Tray Lift Assist
Goal: Improve ergonomics for operator during the task of stacking loaded bread trays at the Wegmans Bakery

3. Needs And Specs Maintain a loading height at 33 inches
Enable good ergonomic practices in terms of lifting and body position
Meet Wegmans safety requirements in terms of mechanical operation and physical aspects
Meet Wegmans requirements in terms of cleaning and food contamination risks
Ease of use for operator
The unit should be durable and reliable
Maintain a loading height at 33 inches
Allow for food to descend no closer to the floor than ½ foot
Allow max load of 5 trays at 115 lbf

4. Updated Design

5. Whole Assembly

6. Updated Design Continued

7. Lift Tray Cart Features: V groove wheels Redesigned as skeleton
Cotter Pin
End Caps
Gussets
Double Support Bar
Locating Wedge

10. 3 way valve opens to pressure line
Start
Air goes into cylinder
3 way valve opens to pressure line
Forks lower
Dolly and trays loaded
Forks lock
Is switch activated
Restart Process
Button pressed No
Yes No
Yes
Forks raise to home position

11. Adjustable needle valve
3 way valve
Air from line
Muffler
Air regulator
Adjustable needle valve
Emergency relief ball valve
Air cylinder
(2 inch bore and max of 125 lbs to lower requires ~40psi)

12. 5th has been placed and is descending
Line is unpressurized
3 Way Normally Open to Atmosphere Push-Valve

13. 5th tray has
fully descended
Line is pressurized
Switched pressed, wheels on ground

14. Piston Pressurized, lowering piston slowly
Forks lower,
trays in contact with floor only

15. Filled until 40 psi is reached and cylinder is locked in down position

16. Open to ATM closed to pressurized line
Compressed air released to ATM

17. Piston raises, acting as air damper
Open to ATM again

18. Deflection and Force Analysis
Deflection seen by max force of Forks W
Max Deflection:
inch

19. Deflection and Force Analysis
Deflection seen by max force of top bar F
Max Deflection:
inch

20. Problems and Solutions from Last meeting
Dolly Sliding off
Hand Guarding
Piston Failure
Foot being crushed by forks
End Caps on Forks
Brush Guard System
Removable forks (use in place)
Hard stop at 2 inches (normal use leaves 2.75 inch clearance)

21. Updated Risks Updated Mitigations
Designed with factor safety
BOM finished and ready to order
Verify with Mike
Designed with factor safety involved
Asked operators what they want/expect
Springs failing
Materials not arriving on time/correct material
Air drop installation
Air piston damper failing
Not used correctly or at all

22. 17.6% Ergonomic Analysis NIOSH Lifting Equation: Percent improvement:
When setting tray on ground: 1.7
With Bread Tray Lift Assist: 1.4
Analysis of only 36 inch and below
Percent improvement:
17.6%

23. Ergonomics Continued Release button height: 45 inches from floor
Height based up elbow height for 95th percentile male according to ANSUR database
Tray stack height: inches from floor
Based upon height of hand at rest calculated from ANSUR database
Reduces bending at waist
Lower risk of back strain
No detriment to higher lifts
Additional suggestion: add anti-fatigue mat to floor where operator stands

24. Safety Features Bright colored forks for visibility
Powder Coated Yellow
Hard stop for forks at 2 inches above floor
Prevent foot from being crushed in a failure situation
Removable forks removes collision hazard when device is not in use

25. Simulated Floor Plan
30”
30”
18”
36”
Operator

26. Bill of Materials

27. Next Steps Procurement of materials Regulator Floor Location Air Drop
Planning shop fabrication time
Receiving
Air Cylinder Maintenance
Build and Test