Rhino track failier?

[Andy Baker]

Originally Posted by Michael Corsetto

Just a thought.

If the tight fit between the bearing and the plastic hub is causing issues, could teams take a reamer to their existing plastic hubs and change a tight fit to a slip fit? Doesn't solve all the impact issues, but could reduce some of the stress in the hub.

Kudos to the AM crew for being on top of this. FRC teams are lucky to have so many dedicated suppliers!

-Mike

This could be reamed out, of course, but I really don't think that a too tight bore is the problem. We can press bearings into the current pulleys we have (existing design, Rev3) with a strong push of a thumb. It's not a tight press fit.

Here is an update with our current status:

1. So far, 5 teams have contacted us regarding cracks or fractures on their pulleys. We are sending emails to those 5 teams today. Oddly enough, all of these orders were shipped out on Jan. 10th or 11th.

2. We are continuing with an improved mold for our Rev4 pulley. It has all of the improvements listed above, AND we were able to change the interior (non-bearing) bore to 0.754. This bore would be able to accept a bushing if the user would like to install one. We don't think it will be needed with the other improvements.

3. We will send out improved pulleys to the 5 teams who have sent us input regarding cracks and fractures.

4. As you can see from Jason's post above, we are quite confused about how we can't break these pulleys like we broke our original test mule. We are still testing. The current testing shows that our existing design is very robust for climbing over things and for surviving drops on concrete floor from a considerable height (2 feet).

5. If more teams are seeing cracks and fractures, please send a note to sales@andymark.com, telling us which pulleys are breaking (1, 2, 3, or 4), your Rhino Track Drive order number, and with pictures of the breaks. We will replace these pulleys with pulleys from the new mold.

6. We are hesitant to send out new pulleys to all customers due to the positive results we are seeing in #4 above. If customers want to contact us to get replacement pulleys, please do so by sending an email to sales@andymark.com. You will need to tell us your AndyMark order number (this saves us time) and tell us the number of pulleys requested.

Andy B.

[ChuckDickerson]

Andy,

Do you have an estimate of when the new improved pulleys will be available and ready for shipment?

-Chuck

[BoilerMentor]

Originally Posted by Andy Baker

1. So far, 5 teams have contacted us regarding cracks or fractures on their pulleys. We are sending emails to those 5 teams today. Oddly enough, all of these orders were shipped out on Jan. 10th or 11th.

Andy B.

Andy,

Our pulleys would have gone out in that range of dates. We have yet to observe a failure. We've been checking them at fairly regular intervals.

I believe the reason we have yet to see a failure is related to our dead shaft design. We use a .375" OD tube between drive plates with a 1/4" bolt though the center, so the axle acts as a standoff. If spacers are fabricated properly it makes it impossible to put a clamping load on the inner race of the bearings in the pulley by tightening the bolt.

That's my two cents. I'll report back if we do see a failure.

This situation is an example of the world class customer service we've come to expect from Andymark.

Thank you.