pic: Rage 173 cross section of robot in SolidWorks

[TriggsJr]

Thanks John for the complement !!!
I was very shocked we didn’t get a design award. With in our peers we were picked first for an Alliance partner. This was our goal, because the qualifying rounds have too much luck involved with them. I was very happy to take 2nd place in the UTC regional. We have one more regional and then the national to show at. So maybe we can pull out a win somewhere. But all of our goals for design were met and went a little farther then we expected. For next year if theirs lifting to do again you’ll definitely see this unit again.

Ok the design is all based around an item I use all the time at work. Its called cable chain, others call it wire way, or cable way. Cable chain was designed to have cables and hoses run through it. The chain is then connected to a stationary object and the other end is attached to an object that moves back and forth. As the moving object goes from one end to other the chain either unrolls or rolls back up. This is all the product was designed to do. The chain has this other property that the chain is stiff in one direction and the other the chain rolls up. Kind of like a Fat Max tape measure rolled out correctly the tape measure is stiff. Flip the tape over and the tape falls. This concept allows the tape measure to be rolled up. So I said if I can feed this chain into a set of telescoping tubes with a custom drive sprocket I can push the tubes out and pull them back in. And a bonus is I can run all the pneumatic lines and sensor wires right in the chain making a very clean setup.

We were very afraid the chain links would not take the pushing stress. So we prototyped an arm with the chain I wanted to use. As we ran the prototype we were all like this is the greatest thing since sliced bread. No more wire cables and pulleys or camper lifts.

Unloaded our arm can rise a total from ground to the end 13 ft in 4.8 seconds. Now we found at UTC you never have to reach that high most times its only about 10 to 11 feet.

The arm is made of 1/16 aluminum that has been laser cut and cnc bent. All sections of the 1/16 material took up a 4’x6’ sheet. A smaller tube was put on one side of the telescope to collect the cable chain it was made of 1/32 aluminum. The whole arm with motor and end affector weighed around 23 lbs. This gave us a great center of gravity. We have never tipped the machine over in competition or practice.

I offer a challenge for next year for some team to use this method. A Company called Igus makes the chain. Their on the web. It sure beats the making all those pulleys up.