The Highway Department has been ordered by the Governor to lay off some personnel. The low man on their totem pole at present is Joe the traffic-cone-placer. Joe's job is to ride in the back of a pickup truck, lean out over the back and place traffic cones on the road at intervals to block off the "express lane" on the Southeast Slugway.

    The trickle-down theory allows the state to spend money on new equipment even when laying off low-salaried workers, so they have contracted with Framus Unlimited to design a machine to replace Joe. The only requirements I could get them to admit to were these:

- The cones are to be placed at 40 foot intervals along the highway regardless of truck speed.

- The cones should have approximately zero relative velocity with respect to the road in a horizontal direction at the moment they are released to drop onto the road. They  will survive up to 4" drop with no damage or tipping if their absolute velocity closely matches that of the road.

- The cones in the truck are arranged in a "magazine" which presents one cone at a time to a pickup station where your mechanism can grab it. Your mechanism should have close-to-zero velocity at the moment it picks a cone off the stack. Winsome Widgets Inc. got the contract for the magazine assembly so we don't have to design it.

- The truck has a power take-off (PTO) in the rear axle which can be used to power your mechanism.

    After meeting with our board of directors (at the Boynton) to discuss how to approach this lucrative state contract, we have added some constraints to those provided above.

- The device must be a pin jointed linkage, either a fourbar or a geared fivebar (so we can use the recently purchased software programs Fourbar and Fivebar.)

- A sample traffic cone has been purchased at great expense for your perusal and experimentation. It will be available in the Aptlab. The grippers which will grab the cone have already been designed and can exert a 25 lb force on the cone to accelerate it. The acceleration of your mechanism needs to be kept low enough so that the dynamic force exerted on the cone does not exceed this value.

    If we move quickly enough we can beat those bums at Winsome Widgets Inc. to the punch and define the location and orientation of the cones as presented from their magazine to suit our needs. Then they will have to design their magazine to our specs.

    You must follow the Design Process to fully define and constrain the problem. You must do Background Research into the problem and any existing solutions. You must create a general Goal Statement. You must generate a list of at least 15 additional Task Specifications. As with any design problem, there is an infinity of solutions possible. You are expected to come up with one solution which will work. To do so you will have to try out many alternate designs and iterate to your 'best' solution. You should expect to typically go through at least ten iterations before arriving at an acceptable one.

    There will be a need for extensive kinematic analysis in this project in addition to the synthesis activities. You are expected to do a complete velocity and acceleration analysis of your design to determine its feasibility and its effects on the payload. In order to make it possible for you to accomplish this task in the short time available, the National Highway Association has generously made available to you their computer programs, Fourbar, Fivebar and Sixbar. You may use these programs to analyze your potential design solutions. However, to ensure that you understand your results and to discourage a BFI approach, we require that you include a complete derivation of all equations necessary to the analysis of your design. These must be a general (non-numeric) derivation and you must use your derived equations to numerically check the computer program solutions for a minimum of two positions of your device.

    You are also required to document your solution in a professional engineering report which adheres to the Project Report Specifications document previously received. The background data should be written up in the Background Research section. The report will document the process by which you iterated to your final design as well as the design itself. Do not just describe the final result. Rather show me how you arrived at it, including the failures encountered along the way. This will demonstrate to me that you understand the engineering concepts and the relevant course material. Note that unreferenced and undiscussed computer or other illustrations will be considered to be report "filler" and be ignored. Do not put anything in the report unless you discuss its meaning. A working cardboard model of at least one plane (one side) of your design is required.

Some suggestions to get you started:

1. Do research before trying to solve the problem! Don't 'shoot from the hip'. Avoid BFI (Brute Force and Ignorance). Engineer it. Some suggested background research areas are:

- pickup truck dimensions

- traffic cone physical properties

2. There are two suggested linkage configurations to investigate, the fourbar and the geared fivebar. Consult the Hrones and Nelson 4-Bar atlas and the Zhang et al Geared 5-Bar atlas on reserve in Gordon Library, and select some linkages whose coupler curves look like they will do what you want. Note the link ratios and other parameters of these linkages. Note that you need a point of zero or near zero velocity to pick up the cone

3. Input these data to either program "Fourbar" or "Fivebar" in the Aptlab to investigate the velocities and accelerations of the cone on the coupler for various linkage positions.

4. Redesign the linkage as necessary to improve the desired output parameters. Cardboard models make designing much easier.

5. Pay particular attention to the polar velocity and acceleration diagrams for your coupler point. These will, along with the printed data, show you the velocity of the cone at any point of interest along its path.

6. Iterate steps 1-5 as necessary to obtain a reasonable solution.

7. Based on the maximum accelerations experienced by the cone during its trip on the coupler, and its mass, calculate the maximum positive and negative dynamic forces on the cone.

8. Check the computations of the computer program for velocity and acceleration of one point using any manual methods, graphics or analytical. Note that in engineering practice, you should never rely on the output of anybody's computer program being correct until you have personally checked it by another method.