Wegmans Bread Tray Lift Assist Design Review 2

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

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

Updated Design

Whole Assembly

Updated Design Continued

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

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

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)

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

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

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

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

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

Piston raises, acting as air damper Open to ATM again

Deflection and Force Analysis Deflection seen by max force of Forks W Max Deflection: 0.0171 inch

Deflection and Force Analysis Deflection seen by max force of top bar F Max Deflection: 0.00166 inch

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)

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

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%

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: 30-36 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

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

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

Bill of Materials

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