AM Plactraction Tread Mounting System

Originally Posted by Chris is me

I wonder which is faster, switching a wheel on a WCD or pulling a tread with this method?

Wheel. A snap ring is VERY fast to remove, then the wheel slides off. Undoing four screws is much slower.

[Gdeaver]

In our pivot design it is very difficult to remove a wheel so we need something to do it in place.

[Stephen Kowski]

Originally Posted by CraigHickman

Wheel. A snap ring is VERY fast to remove, then the wheel slides off. Undoing four screws is much slower.

That's under the assumption the team that removes their entire wheel has nothing else holding the tread on. I have seen many robots that have snap ring wheel removal but still have something (rivets usually) to keep treads from falling off.

[Cory]

Originally Posted by Stephen Kowski

That's under the assumption the team that removes their entire wheel has nothing else holding the tread on. I have seen many robots that have snap ring wheel removal but still have something (rivets usually) to keep treads from falling off.

I think Chris is asking if it would be faster to swap an already prepared wheel or to change the tread on this wheel.

For what it's worth, we could probably remove the wheel from our bot, put the new wheel on, and put the new snap ring on in under 15 seconds. There's no comparison. Any method of retreading is going to take at least 5-10x that.

[Stephen Kowski]

Originally Posted by Cory

For what it's worth, we could probably remove the wheel from our bot, put the new wheel on, and put the new snap ring on in under 15 seconds. There's no comparison. Any method of retreading is going to take at least 5-10x that.

If you have an extra set of wheels I'd agree that is the case. I don't think most have those resources however.

[R.C.]

Originally Posted by Stephen Kowski

If you have an extra set of wheels I'd agree that is the case. I don't think most have those resources however.

If done properly, you honestly don't need a full back up set. I know most teams buy an extra 2 or 3 wheels.

How many wheels do teams go through per season on their competition bots?

-RC

[Andrew Schreiber]

I am undecided on this mounting system but I have to commend you on having a lot of information available there. Thank You!

[Stephen Kowski]

Originally Posted by R.C.

If done properly, you honestly don't need a full back up set. I know most teams buy an extra 2 or 3 wheels.

How many wheels do teams go through per season on their competition bots?

-RC

Good point. In a 6WD the center wheel treads are going to be replaced far more often than the other 4. Which in a season may not be very much anyway.

[efoote868]

Have you considered filing for a patent?

[Foster]

Originally Posted by efoote868

Have you considered filing for a patent?

I don't think so, and this would count as prior art, someone trying to do that would have a tough time.

I'm interested in the "replace in 15 seconds" replies. We have driven wheels, I'd like to see how your drive wheels are attached to let you do that.

Gary's design is super simple and would (could, have?) worked in a variety of tread styles. The comon rivet idea works until n+1 replacements where the hole becomes too large or the "quick change in the pit" fix where the hole also becomes too big.

My upgrade is to use glue to keep the insert in. Gary noted that the glue process had failue points:

• Glue spread keeping the wheels together
• Glue spread blocking the internal threads
• Glue melt (eating away) of the wheel material
• Lack of a good glue joint
• Hey, there will be 7 tread changes (2 season, 5 off season), why add risk

So YMMV. But it's another great Gary idea, which is why my forehead is flat from going "D'oh".

[NickE]

Originally Posted by Foster

I'm interested in the "replace in 15 seconds" replies. We have driven wheels, I'd like to see how your drive wheels are attached to let you do that.

The wheel is held on the shaft by a "snap" style external retaining ring. With snap ring pliers, one just needs to remove this ring and pull the wheel off of the shaft. The torque is transmitted through the hexagonal shaft into a broached wheel bore. This can be seen in the picture below from our 2010 robot.