Jonathan BrooksMatthew PiatkowskiSpencer Herendeen

Ultimate Tailgate Prototype 2

Project Background and Scope◦ Customer Needs◦ Engineering Specifications◦ Risk Management

Design Changes from MSD I Final System Budget Project Shortfalls Recommendations for future prototypes

Project is to create a functional tailgate work surface with◦ Workmate style clamp◦ Auxiliary clamp◦ Storage Bins◦ 120 VAC power◦ 12 VDC power

The intention of this project is to generate an initial proof of concept. This is the main concern, and as such drives much of how the project progressed

Meet or exceed stock tailgate performance capabilities Flat work surface, level with truck bed Two clamps: one primary Workmate style, and one

auxiliary bar style Two storage drawers Structure to conform to a 2001 Chevrolet Silverado 2500 System capable of providing 120 VAC outlet power, and 12

VDC accessory power System power failsafe to shut down when vehicle is

engaged out of park or neutral and when vehicle battery voltage becomes too low.

System power to be limited to 10 AAC when vehicle is off and limited to 15 AAC when the vehicle is on.

Engr. Spec. # Source Specification (description) Unit of Measure Marginal Value Ideal Value

ES31 MechanicalSecure to a 2001 Chevrolet 2500 (interference)

Binary 0 0

ES33 MechanicalCompatible with Cap or cover (interference)

Binary 0 0

ES34 Mechanical Truck Bed Preservation (interference) Inches 6 0

ES35 Mechanical Work surface level with bed inches ± 0.50 0

ES26 MechanicalRigid work surface when in the down position

inches < 1 0

ES27 Mechanical Lock in place while up Degrees < 1 0

ES28 Mechanical Lock in place while down Degrees < 5 0

ES36 Mechanical Weight to support lbs 250 500

ES29 Mechanical Black and Decker Workmate clamp force lbs 250 500

ES30 Mechanical Auxiliary clamp force lbs 100 200

ES37 Mechanical Tie Down force lbs 250 500

ES1 Electrical Voltage at tailgate plug V (AC) 100 - 125 120

ES8 Electrical Inverter total harmonic distortion % <30% <25%

Mechanical◦ Drawer Slides have integrated catch to prevent drawer

from opening unexpectedly◦ Workmate Clamp has added rotation feature

Workmate can be rotated in 90 degree increments When operated parallel to the direction of truck, workmate is

elevated to allow work to extend into truck bed Workmate dimensions reduced to allow for rotation

◦ Automated actuation added as an independent study to work in conjunction with MSD II P10811 Drawers shortened to account for automated actuation

system◦ Tube structure made of 0.083 steel tubing instead of

0.065 due to availability

Electrical◦ No DC side relays were used in order to save on

implementation complexity, safety, and cost◦ No external low voltage shutdown circuitry was used

because the innate inverter circuitry was found to be sufficient

◦ No starter relay was used because the vehicle will draw current away from the inverter to start. The inverter has a shutdown mechanism if the current becomes too low.

Frame constructed as tube structure Tubes are 1-1/4 inch X 0.083 square mild

steel tube stock Tubes are cut to length and MIG welded

together to provide required strength External frame dimensions match those of

stock tailgate, except thickness which is increased to 4-1/2 inches to provide additional room for features

Drawers are constructed from 16 guage mild steel sheet

Drawer size is 15 X 12 X 2 inches Parts are cut to size with shears and bent if

required using a break Parts are MIG welded together Drawer slides are sourced from Ovis Online

and are 14 inch 100 lb load capacity Drawer slides are welded to drawer and

frame

Wood surfaces are milled to size Screw system is constructed on lathe Frame constructed from 16 gauge sheet

steel in same fashion as drawers Workmate mounts to frame by quarter turn

fasteners allowing easy changing of orientation in 90 degree increments

Irwin one handed bar clamp purchased from Lowes

Slots fabricated from mild steel to allow for insertion into frame for clamping directly to tailgate work surface

Clamp modified with stronger dowel pin to allow for mounting to slots welded on frame

Designed as an independent study Provides motors to raise and lower the

tailgate electronically Incorporates latching mechanism to prevent

tailgate from opening during vehicle operation

Inverter was pre-designed and manufactured by the Whistler Group, Inc.

Inverter has a high power rating to tolerate up to a continuous 16 AAC with a 94% efficiency under 66% load.

Inverter has safety shutdowns if the input and output voltages become too high or low.

Model has a robust mechanical design to tolerate temperature and above general usage.

The electrical relay system provides the failsafe conditions of◦ Immediate shutdown when the

vehicle is out of neutral or park◦ Switching of the allowable currents

dependent upon whether the vehicle is on or off 10 A for when the vehicle is off

and full draw (15 A) when the vehicle is on.

System is shutdown if current exceeds 10 A when vehicle is off

◦ Fast switching time of relays (< 1 s) and passable 10 A breaker cutoff time (~ 9 s)

◦ All components can tolerate at least a worst case maximum of 120 VAC, 20 AAC.

◦ All components have a low profile in order to reduce complexity of integration, cost, and space.

LED bank provides an interface between the tailgate and the rest of the electrical system

LEDs indicate whether the system is on or off, if the inverter is overloaded, when the truck should start, and what mode of current limit the system is in.

All LEDs are high intensity to provide a wide viewing angle, and far distance of sight.

All LEDs are fitted with a current limiting resistor for component protection

Estimate Mechanical Total $995.61

Estimate Electrical Total $485.07

Estimate Total $1,480.68

Actual Total $1,141.32

Difference $339.36

Mechanical Excessive weight when fully

loaded Self-actuated lifting subsystem

left to independent study Weatherproof enclosure for

electronic components not implemented

Interference with truck bed when closing tailgate

Electrical LED to indicate the right time to

start the truck is not included◦ Future Solution: The inverter

LED is a multi-purpose LED that indicates when the truck should be started.

LED to indicate an overload does not function properly◦ Future Solution: The inverter

LED also has the ability to indicate when an overload condition has occurred

Relay circuitry not placed in end user housing◦ Future Solution: Encase and

mount relay circuitry in non conductive housing

• Mechanical– Self-actuating lifting

subsystem integration– Lighter weight materials

for drawers– Weatherproof enclosure

for electrical components

– Reduce tubing size – Allow for more room for

tailgate features– Reduce tailgate weight

• Electrical– Isolated and devoted

battery– More robust relays– LCD interface to

replace LED interface bank

– Traced board for LED bank

– Removing inverter from cab for safety regulations

– Self-actuating lifting subsystem integration