PIT Crew Design Review

By

Dan Chapman, Tim Wilson, and Jon Miller

January 24, 2003

Initial Concepts

Design Selection

Prototype

Exploded view

Piston Cylinder

Modified Ratchet

3-Way Valve

Regulator

Air Canister

Limit Switch

Bracing Attachment

Piston (Bimba)

Specifications:2.5 in Bore2 in StrokeSingle acting with a spring

returnWill deliver a force of 440 lbf

at 90 psi; this produces a lug torque of 185 ft*lb

Cost:Piston with a pivot mount is $115.60

Weight:32 oz or 2 lbs

Three-Way, Two-Position Valve (McMaster-Carr)

Specifications:

Max operating pressure of 150 psi

Actuated by a lever

Dimensions (2.16” x 2.48” x 1.26”)

Cost:

$73.09

Weight:

Unknown (estimated .5 lbs)

Regulator(Valin)

Specifications:

3000psi max inlet and 400psi max outlet

Cost:

$190.00

Weight:

1.5 lbs (est.)

Modified Ratchet(Sears)

Specifications:

– Craftsman ½” ratchet driver Model #44809

Cost:

– $21.00

Weight:

– 1.44lbs (excludes adapter and socket)

Prototype Parts List and Cost SummaryCategory Description Price ea. Total

Piston Housing $90.00 1 $90.00

Pivot Attachment $25.60 1 $25.60

Clevis Bracket w/ Pin $19.80 1 $19.80

Rod Pivot $10.85 1 $10.85

Regulator 0-3000psi inlet, 0-400psi outlet $190.00 1 $190.00

High Pressure Fittings Street 90's $14.60 2 $29.20

Hex nipple $2.70 2 $5.40

Needle Valve $62.70 2 $125.40

Low Pressure Hose Nipple $4.52 4 $18.08

3-Way Valve $73.09 1 $73.09

Ratchet $21.00 1 $21.00

HousingMounting Plate (.5" Aluminum) (12x20) $79.20 1 $79.20Angle Iron Piston Mount (3x3x.5) (3" length) $5.19 1 $5.19Automatic Triggor Connection (.09" Aluminum) (2x12) $1.44 1 $1.44Aluminum Mount for Ratchet (3" square aluminum x 3" long) $16.73 1 $16.73

Bottle High Pressure Air Canister

$710.98

Prototype Weight Summary

Piston Cylinder and Mounts 2.46 lbsRegulator 1.5 lbs3-way valve (est.) .5 lbsRatchet 1.44 lbsBottle 2.08 lbsHousing plate and

other attachments (est.) 17.7 lbsHP & LP fittings (est.) .75 lbsTOTAL ~25 lbs

Prototype Testing

Goals:– Actual vs. theoretical performance

• Operating pressure

• Torque output

• Safety of system

• Identify which components are overly conservative

– Size and weight reduction– Worst case scenarios

Testing Outcomes

Optimization of components – Pre-set regulator– Minimize number of valves– Smallest possible canister – Determine ideal bottle pressure– Custom piston-cylinder– Minimum size of total package

(What we anticipate will happen)

Prototype Testing Metric

Prototype 1Volume of prototype ~1152 in 3̂Pressure of the canister 2000psi

Operating Pressure of piston 100psi

Estimated Cost $710.98Weight 25 lbs

Time to remove a lug nut at 100 ft-lb

Time to remove a lug nut at 150 ft-lb

Maximum breaking torqueHuman factors (user friendly, how obvious to use is this?)Number of lugs with 1 tank 6

to be determinedto be determined via user testingto be verified with testing

approximateapproximate (we will optimize this)

to be determined

to be determined

Comments:it would fit in a box this size

maximum pressure (we will optimize)theoretical value (we will optimize this)

Biggest Safety Concerns

• High pressure—what is the minimum operating pressure that will give the desired result?

• Hazards analysis—what pinch-points exist, how can they be removed through design?

• Canister safety—can the system be packaged so that it cannot be misused?

Schedule

Task Week# 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2DesigningMachine Parts for Lock-boxMachine Ratchet & Adapter AttachmentMachine HousingTestingTesting Analysis & Re-designAdditional MachiningRe-TestingDocumentation &Wrap-upDesign Expo

May

Sp

ring

Break

AprilJan Feb March

Concept of Final Product

Addition of a safety trigger

Ergonomical layout

Optimized components