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.