Wegmans Bread Tray Lift Assist Wegmans Bread Tray Lift Assist

Design Review 2

Wegmans Bread Tray Lift Assist

• Goal:

Improve ergonomics

for operator during

the task of stacking the task of stacking

loaded bread trays

at the Wegmans

Bakery

Needs

• Enable good ergonomic

practices in terms of lifting

and body position

• Meet Wegmans safety

requirements in terms of

Specs

• Maintain a loading

height at 33 inches

• Allow for food to

descend no closer

And

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

descend no closer

to the floor than ½

foot

• Allow max load of

5 trays at 115 lbf

Updated Design

30.00

35.75 59.75

87.00

44.00

DO NOT SCALE DRAWING

whole assemblySHEET 1 OF 1

UNLESS OTHERWISE SPECIFIED:

SCALE: 1:32WEIGHT:

REVDWG. NO.

ASIZE

TITLE:

NAME DATE

COMMENTS:

Q.A.

MFG APPR.

ENG APPR.

CHECKED

DRAWN

FINISH

MATERIAL

INTERPRET GEOMETRIC

TOLERANCING PER:

DIMENSIONS ARE IN INCHES

TOLERANCES:

FRACTIONAL

ANGULAR: MACH BEND

TWO PLACE DECIMAL

THREE PLACE DECIMAL

APPLICATION

USED ONNEXT ASSY

PROPRIETARY AND CONFIDENTIAL

THE INFORMATION CONTAINED IN THIS

DRAWING IS THE SOLE PROPERTY OF

<INSERT COMPANY NAME HERE>. ANY

REPRODUCTION IN PART OR AS A WHOLE

WITHOUT THE WRITTEN PERMISSION OF

<INSERT COMPANY NAME HERE> IS

PROHIBITED.

5 4 3 2 1

Whole Assembly

Updated Design Continued

Lift Tray Cart

Features:

• V groove wheels

• Redesigned as skeletonskeleton

• Cotter Pin

• End Caps

• Gussets

• Double Support Bar

• Locating Wedge

51.25

12.50

13.00

33.25

26.25

25.25

12.00

DO NOT SCALE DRAWING

BoxSHEET 1 OF 1

UNLESS OTHERWISE SPECIFIED:

SCALE: 1:32WEIGHT:

REVDWG. NO.

ASIZE

TITLE:

NAME DATE

COMMENTS:

Q.A.

MFG APPR.

ENG APPR.

CHECKED

DRAWN

FINISH

MATERIAL

INTERPRET GEOMETRIC

TOLERANCING PER:

DIMENSIONS ARE IN INCHES

TOLERANCES:

FRACTIONAL

ANGULAR: MACH BEND

TWO PLACE DECIMAL

THREE PLACE DECIMAL

APPLICATION

USED ONNEXT ASSY

PROPRIETARY AND CONFIDENTIAL

THE INFORMATION CONTAINED IN THIS

DRAWING IS THE SOLE PROPERTY OF

<INSERT COMPANY NAME HERE>. ANY

REPRODUCTION IN PART OR AS A WHOLE

WITHOUT THE WRITTEN PERMISSION OF

<INSERT COMPANY NAME HERE> IS

PROHIBITED.

5 4 3 2 1

Start

3 way valve opens to pressure

line

Dolly and trays loaded

Air goes into cylinder

Forks lower

Forks lockForks lock

Forks raise to home position

Restart ProcessIs switch

activatedButton

pressedYes

YesNo

No

Adjustable

needle

valve

Air cylinder

(2 inch bore and max

3 way

valve

Emergency

relief ball valve

Air regulator

Air from line

Muffler

(2 inch bore and max

of 125 lbs to lower

requires ~40psi)

5th has been

placed and is

descending

3 Way Normally

Open to

Atmosphere

Push-Valve

Line is unpressurized

5th tray has

fully descended

Switched pressed,

wheels on ground

Line is pressurized

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 AnalysisDeflection 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

• End Caps on Forks

• Brush Guard System

• Removable forks (use in place)

• Foot being crushed

by forks

(use in place)

• Hard stop at 2 inches (normal use leaves 2.75 inch

clearance)

Updated Risks Updated Mitigations

• Springs failing

• Materials not arriving on time/correct material

Air drop installation

Designed with factor

safety

BOM finished and ready

to order

Verify with Mike• Air drop installation

• Air piston damper failing

• Not used correctlyor at all

Verify with Mike

Designed with factor

safety involved

Asked operators what

they want/expect

Ergonomic Analysis

• NIOSH Lifting Equation:– When setting tray on ground: 1.7

– With Bread Tray Lift Assist: 1.4

» Analysis of only 36 inch and below

• Percent improvement: • 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 – 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 – 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• Air Drop

• Planning shop fabrication time

• Receiving

• Air Cylinder Maintenance

• Build and Test