pic: Floating Zip Tie Chain Tensioner

This is our way of tensioning our chain next year. It requires three zip ties and is very easy to tension. We invested about 300 bucks worth of the original floating chain tensioners from mcmaster carr #5973K2. They were great but problems we had

  1. Pricey
  2. Sometimes over tensioned the chain
  3. Took to long to put them back together and taking them off was a major hassle.
  4. Last but not least, the clamps got lost very easily forcing us to buy whole new sets. (32.69)

This way we could tension chain with uhmw and zipties. Also we wouldn’t have to buy so many and we have about a million zip ties anyway. So what do you guys think. Any suggestions?

1 Like

Thats sweet. How do yall make sure all the zipties are in place. Does it work as well as mcmasters? Did yall ever have problems with zipties breaking and the tensioners falling off?

Ha! That is a neat idea!

The zip ties fall in the three slots on the top and bottom and they actually worked better than mcmaster’s for us. The reason being is that tensioning them meant replacing a zip tie. So if you didn’t have enough tension, pull the zip ties. Too much, cut them and put a new one. The zip ties never broke because they were rated at 75 lbs each. We implemented them after I saw that mcmaster’s were giving us way too much trouble. These can be made by buying u channel of uhmw or by cncing out blocks of uhmw.

We replaced the mcmaster’s during Nationals with our new ones.

very nice, were there any problems at the championship?

The only one was that we did not cut the ends of the zip ties so they got stuck to the chain. That was a nightmare.


Here’s a darker render.

hmm i would expect that was second nature, were you in a rush?

Yes we were, it was a minute before our 4th match at nationals.

patent it.

i’m serious.


I am sure there are a ton of guides on how to do that online, Google it!

Like try this, http://www.uspto.gov/web/patents/howtopat.htm

You’ve got to file an official patent.


but the first thing to do is to have a researcher do a patent search…where somebody searches through all the previously issued patents to see if there is an invention that currently exists.

if there isn’t then you can file for a patent which tend to take several years to issue.

Patenting this could get pricey, but it may be something your team is interested in.

I think it is a great little idea, and great little ideas should be taken care of.

Back in '07 I saw Team 8 put a zip-tie around a chain on their roller-claw :yikes: Now there’s a simple method!

I’m curious about what happens when the blocks twist around. I mean, the zip-ties aren’t gonna hold them perfectly flush like that. What happens when they twist and jam into the side of the chain?

We had these kinds of problems when we used delrin tensioners in our '06 drive train. The chain was always grinding against the sides of the slots we cut in the delrin. Wasted a lot of power that way.

Very creative though. I like the way you think :cool:

You just gave everyone here a “Why didn’t I think of that?” moment.

Great Idea.

If you go along with Brandon’s Idea to patent, and possibly sell it, may I suggest small Hose clamps as an alternative to zipties? It would make it larger and heavier, but also possible to adjust in two directions. It would also keep the tensioner in one piece, so that users cannot lose the second half of it. Finally, it would make it more robust. This would help its use in applications with larger chain/greater power use than FIRST.

do remember that if you patent it you have to give everyone due credit and a piece of the pie

Wow. This made my day. My only question is: is the uhmw that you use tough enough and how thick is it? Does it wear down after a few matches? I’m guessing that it’s easy enough to make plenty of extras out of a hunk of u channel. Did you replace the tensioner often(every match)?

This really is a great idea!!

Not to get too off-topic, but while developing a patent for this idea can be very pricey and time-consuming, there is another option. You have to remember what a patent is for: to document that this is your idea and you came up with it before anyone else so that no one else can profit from it (except for you, of course).

First, create a white paper on your tensioner, or a detailed document describing the device and its development. Be as detailed as possible, and include as many options as your team can think of (BTW, I like the hose clamp idea). Include drawings, photgraphs, names, etc. Once you have that, file an application for a copyright on the document (I think it’s about $40 for the application fee). Now, if anyone else takes your idea and goes to market with it, you have proof (with a critical government timestamp, no less) that you came up with the idea first. With that document, you could give that to any lawyer who would gladly sue that person/company that’s using your idea for a piece of the profit. I know of several people who do this regularly with ideas they develope.

Sure, if you’re going to take it to market yourself, a full-blown patent might be the way to go. But, if all you want to do is protect your future rights to your invention, a copyright is a whole lot cheaper. To top it off, if I remember correctly, while an expensive patent lasts only a few years (relatively speaking), a copyright lasts the lifetime of the filer plus 70 years.

But getting back on topic, I agree that this tensioner idea could be something that you and/or your team might want to protect.

This is why I love Madtown’s designs. simple and effective.

There is a major flaw in your idea. There is something called the “public disclosure clause” for patents. Basically as soon as you show your idea in a public place (a regional, or chiefdelphi would defiantly count) you have started a one year clock. If you don’t file a patent within that time frame then it is considered public domain and regardless of your time proof. That being the case anyone could come to market with this thing and you would have no protection.

If you don’t wish to do a full fledged patent at this time you can always file a provisional patent which adds one year of protection to give you the time to file a patent if you want.

In my honest opinion I wouldn’t worry about patenting this. If you go do a quick patent search for “chain tensioner” you will see literally hundreds of different methods. While what you have made has quite alot of use in the robotics community the use for industry is minimal, where size and weight constraints don’t really exist in many of the applications.

I don’t mean to discourage you and I think that everyone should try for a few patents in their lives but you need to decide if getting a patent will be worth the effort and experience. If your interest is selling this tensioner then just do it, and you don’t need a patent. For example look at andymark, they sell loads of items and don’t have patents on most of them.

As for the design I like the concept alot, I would make sure that you add a chamfer or round on the lead in edges both on the zip tie holders and the chain channel. UHMW is great for it’s lubricity but may not stand up under alot of use which is up to you because these will be cheap and easy to replace. I would look at delrin or some other harder plastics.

Or you could creative commons license it, preventing someone from stealing your idea for profit, but allowing anyone to copy it for their own use. I am even thinking of how this could be used in my own designs. thanks!