That is pretty much what I'm doing.
I'm basing it on a scissor jack, kind of.

Just trying to think of a way to attach clamps to either end.
I want to make them removable, so that I can have several sizes to fit the various pipe diameters.

have latching straps with the sizes. and reinforce the base attatching to the scissor mechanism

That's a good idea, what kind of material should I use for the straps? Some sort of rubber? I feel like it needs to have a lot of friction,
And what do you mean by "Reinforce the base attaching to the scissor mechanism?"

Metal strap with rubber on the inside
What I really meant was to reinforce the strap's base for rigidity
2 straps attached to scissor jack, that is the basis of the device
I don't see it weighing more than 10 lbs

Honestly, there are hundreds of ways going about it :/

This post was edited by saber_x3 on Apr 5 2013 07:42pm

The only problem I'm seeing with straps is you probably wouldn't be able to tighten them enough to get the friction needed to hold on. Unless you used another tool for that.

I think I'm just going to do a clam kinda think that bolts together (two halves) around the pipe, then inside each clamp have different sized flanges.
I'll have to make more parts, but shouldn't be too bad.

Ratchet straps

That really depends on your locking mechanism
Azrad's idea is good
The way I view it, all you need is to meet the criteria, and hopefully your design is easy to draw