Posted by Justin Rolnick at 02/24/2001 11:04 PM EST
Student on team #702, Blue Streak, from Culver City High Robotics Magnet and Nasa/JPL.
I am the captain of a rookie team. I would like to know where the teams who use tank treads get them or how they make them. I would also like to know where the teams with special traction wheels get them.
Posted by Jake at 02/24/2001 11:34 PM EST
Student on team #365, Miracle Workerz, from Avon Grove High School and DuPont Engineering.
In Reply to: Tank treads and specialty wheels
Posted by Justin Rolnick on 02/24/2001 11:04 PM EST:
The secret to Li’l MOE’s tread system is really not that big of a secret. We used the timing belts that came in the kit for our treads. We also used the timing pulleys that came in the additional hardware list to drive the belt. The trick to having a tread design is having enough torque to spin in one place and not burn out a motor, or to have enough slip to allow you to spin with less torque. Another trick to tread sytems is the bogey wheels. They just spin without power to make sure the tread doesn’t slack or fall off the timing belt. We custom machined our bogey wheels, but you could also use regular pulleys. If you need any other help, feel free to E-mail me or walk up to our pits (Team 365 - bright green shirts) and ask for Captain Jake. We will be at the J&J Mid-Atlantic Reagional, Philadelhia Alliance Reagional, and the Nationals in Orlando.
Another useful bit of information from the vast knowledge banks of~
~ Captain Jake
Posted by Patrick Dingle at 02/25/2001 11:35 AM EST
Coach on team #639, Red B^2, from Ithaca High School and Cornell University.
In Reply to: Li’l MOE’s tread system
Posted by Jake on 02/24/2001 11:34 PM EST:
Okay… now I’m confused.
Timing belt comes with the kit???
Patrick, who has been through the kits about 8.4*10^31 times
: The secret to Li’l MOE’s tread system is really not that big of a secret. We used the timing belts that came in the kit for our treads. We also used the timing pulleys that came in the additional hardware list to drive the belt. The trick to having a tread design is having enough torque to spin in one place and not burn out a motor, or to have enough slip to allow you to spin with less torque. Another trick to tread sytems is the bogey wheels. They just spin without power to make sure the tread doesn’t slack or fall off the timing belt. We custom machined our bogey wheels, but you could also use regular pulleys. If you need any other help, feel free to E-mail me or walk up to our pits (Team 365 - bright green shirts) and ask for Captain Jake. We will be at the J&J Mid-Atlantic Reagional, Philadelhia Alliance Reagional, and the Nationals in Orlando.
: Another useful bit of information from the vast knowledge banks of~
: ~ Captain Jake
Posted by Anton Abaya at 02/25/2001 1:53 PM EST
Coach on team #419, Rambots, from UMass Boston / BC High and WHO NEEDS SPONSORS WHEN YOU HAVE DETERMINATION!.
In Reply to: Re: Li’l MOE’s tread system
Posted by Patrick Dingle on 02/25/2001 11:35 AM EST:
i’m so sick of that kit i wanna puke in it.
-anton
ps. hmm, i’m gonna paint our kits for fun!
Posted by Elliot Johnson at 02/25/2001 11:15 PM EST
Student on team #218, HP Robotics Team, from Highland Park High School and Double-E Inc…
In Reply to: Re: Li’l MOE’s tread system
Posted by Patrick Dingle on 02/25/2001 11:35 AM EST:
: Okay… now I’m confused.
: Timing belt comes with the kit???
I think he means that black plastic window mechanism tape.
later,
Elliot
Posted by Justin Rolnick at 02/26/2001 2:09 AM EST
Student on team #702, Blue Streak, from Culver City High Robotics Magnet and Nasa/JPL.
In Reply to: Li’l MOE’s tread system
Posted by Jake on 02/24/2001 11:34 PM EST:
I mean the actual tank treads. Where do you get them or how do you make Them.
Thanks
EOM
Posted by Jim Meyer at 02/26/2001 8:24 AM EST
Engineer on team #67, HOT Team, from Huron Valley Schools and GM Milford Proving Ground.
In Reply to: Tank treads and specialty wheels
Posted by Justin Rolnick on 02/24/2001 11:04 PM EST:
: I am the captain of a rookie team. I would like to know where the teams who use tank treads get them or how they make them. I would also like to know where the teams with special traction wheels get them.
A few tank treads are double sided timing belt. Some, like the Techno-Cart, appear to use small metal plates fastened to a roller chain. I have no idea how the super wide tracks on a robot in the gallery were made.
Double sided timing belt is available because it is on the additional hardware list. You are allowed 20’ of this stuff, from any source you can find, as long as they don’t custom make it specially for you. I’m sure you already know this, but stuff in the additional hardware list can cost as much as you can afford to pay.
Custom wheels are typically made from materials on the additional hardware list. We made ours mostly from 1/4" thick aluminum plate. Once these custom wheels are made the teams usually wrap some sort of traction material around them. I have seen some teams use timing belt with the toothed side out for this.
Our custom wheels were built on a CNC mill. The students did most of the work but they worked very closely with an experienced machinist. You could make a simpler version from wood by using a circle cutter to cut a bunch of disks from plywood and then gluing them together to make a wheel. Team 122 had very cool wood wheels last year.
I hope this helps,
Jim
Posted by Andy Baker at 02/26/2001 9:09 AM EST
Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.
In Reply to: Re: Tank treads and specialty wheels
Posted by Jim Meyer on 02/26/2001 8:24 AM EST:
: A few tank treads are double sided timing belt. Some, like the Techno-Cart, appear to use small metal plates fastened to a roller chain.
This is the second year for team 45 to use metal treads. We used them back in '99. Ours for this year are drastically different. Here’s how we did it:
We took 35 chain from Small Parts, and welded on steel angles on either side of the chain at every 6th full link. This was not easy. We had to first make a welding fixture, and then do some practicing to get some decent welds and figure out if the welds would hold.
At the same time, we took 0.060 steel sheet, cut it into 1.5" squares, and then bent up the sides to look like a shallow “U” shape. The corners were ground off and the entire “cleat” was sanded to make it smooth.
The cleats have two clearance holes in them that match up with two holes on the steel flanges on the chain, and we used #6 button heads with nylock nuts to fasten them on.
One note… we had to de-grease the chain before welding and then re-oil it after all of the flanges were put on.
After much practicing, we noticed no carpet damage. We stared to see some wear on the ramp where we are continuously driving over it… kinda like a discoloration of the carpet threads to a lighter color… but I suspect that this is typical for any team’s bridge that got alot of traffic.
These treads do cause splinters to the 4x6 under the center barrier, but only if we are really banging into the boards. If we take it easy while going over the board, then a few marks are made, but splinters are few and very small. It is not good for our robot to be banging against the board anyway, so our drivers are told to take it easy.
We have noticed some damage to the treads and welds. So far, we’ve just taken a pair of pliars and bent the damaged parts back into position. We made two sets of backup treads, so if the treads on the 'Kart get too bad, we’ll swap the whole track out for new ones.
I don’t know if our efforts will be worth it… but we had fun making these treads, that’s for sure. One great thing about the chain/treads is that efficiency losses are low, in comparison to a timing belt. I don’t know exact numbers, but I would assume that there are less losses in a chain drive system compared to a timing belt system.
Andy B.