1. Jonathan Brooks Matthew Piatkowski Spencer Herendeen

2. Ultimate Tailgate Prototype2

3.  Project Background and Scope ◦ Customer Needs ◦ Engineering Specifications ◦ Risk Management  Design Changes from MSD I  Final System  Budget  Project Shortfalls  Recommendations for future prototypes

4.  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

5.  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 V AC outlet power, and 12 V DC 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 A AC when vehicle is off and limited to 15 A AC when the vehicle is on.

6. Engr. Spec. #SourceSpecification (description)Unit of MeasureMarginal ValueIdeal Value ES31Mechanical Secure to a 2001 Chevrolet 2500 (interference) Binary00 ES33Mechanical Compatible with Cap or cover (interference) Binary00 ES34MechanicalTruck Bed Preservation (interference)Inches 6 0 ES35MechanicalWork surface level with bedinches± 0.500 ES26Mechanical Rigid work surface when in the down position inches< 10 ES27MechanicalLock in place while upDegrees< 10 ES28MechanicalLock in place while downDegrees< 50 ES36MechanicalWeight to supportlbs250500 ES29MechanicalBlack and Decker Workmate clamp forcelbs250500 ES30MechanicalAuxiliary clamp forcelbs100200 ES37MechanicalTie Down forcelbs250500 ES1ElectricalVoltage at tailgate plugV (AC)100 - 125120 ES8ElectricalInverter total harmonic distortion%<30%<25%

7. IDRisk ItemEffectCause Likelihood Severity Importance Action to Minimize RiskOwner Open/Clos ed? 17 Tailgate too heavy to lift manually Assistance required for lifting Components and features too heavy 339 Assisted lift mechanism designed externally as an independent study MP, JPClosed Drawer capacity too high 2 Tailgate too thin for drawers No storage bins Poor design, structure impedes space for drawer 326 Assess customer need for depth of storage bin JBClosed Customer need not metNeeds too restrictive Relocate Storage Reassess needs 13Excessive Losses in wire Battery drained prematurely Wire too long and/or thin 326 Choose proper wire diameter SHClosed Wire unable to carry sufficient power 22 Electrical draw from normal truck circuits is too high Inverter must be turned off earlier than expected Too many accessories running at once 122 Measure the draw of the truck with all accessories running SHClosed Design proper cutoff circuitry 4 Workmate interferes with work surface space Insufficient work surface Tailgate dimension limitations 122 Pop-up Workmate JBClosed More complicated design 30 Parts difficult to fabricate Excessive time spent creating parts Poorly designed parts122 Ensure all intricate parts are fabricated early JB, MPClosed

8.  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

9.  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.

10.  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

11.  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

12.  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

13.  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

14.  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

15.  Inverter was pre-designed and manufactured by the Whistler Group, Inc.  Inverter has a high power rating to tolerate up to a continuous 16 A AC 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.

16.  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 V AC, 20 A AC. ◦ All components have a low profile in order to reduce complexity of integration, cost, and space.

17.  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

18. Estimate Mechanical Total$995.61 Estimate Electrical Total$485.07 Estimate Total $1,480.68 Actual Total$1,141.32 Difference$339.36

19. 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

20. 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