There’s a Kickstarter for a widget to slice plastic bottles into long thin strips, which can then be used for a variety of purposes.
The cutting action of this widget seems to be performed by two wheels that overlap slightly. If you don’t want to click on the link, I’ll try to describe the setup:
Take parallel axles, and place one wheel on each axle. The wheels have broad, flat metal ‘tires’ like on an old-fashioned wagon wheel. The edges of the metal ‘tires’ have a hard 90 degree angle, probably ground so as to be flat on the sides. The two wheels are staggered on the axles, and arranged such that the rim of one wheel slightly overlaps the rim of the other wheel, and the wheels are in contact along their sides. If you feed a sheet of material into the wheels, one wheel pushes the sheet down and the other wheel pushes the sheet up, and the sheet gets sheared or sliced at the point where the two wheels touch each other. It’s kind of like a pair of scissors of infinite length, with two blades always sliding past each other.
Is there a name for this kind of setup? The widget on Kickstarter looks like it’s made of off-the-shelf parts, but googling ‘rotary cutter’ or ‘rotary shear’ doesn’t seem to pull up the right sort of mechanism.
I’d just call it a rotary shear. We had a larger version in sheet metal shops years ago and I’m sure still today. I have a plastic handled small version used for cutting wrapping paper that I bought in WalMart or maybe Hobby Lobby.
A Google search for “rotary shear” brings up thousands of images from massive machines to handheld electric or smaller.
It’s often an additional feature for a bead roller used to make impressions in metal. Slightly larger wheels cut the metal instead of just bending it. Rotary shear sounds like a good name.
At the 1:23 point the text says “Can be used for demonstration purposes only and not for advertising or sales promotion.” Why? What kind of demonstration purposes might one use it for? What kind of advertising or promotion might one use it for? What’s the problem with using it for the latter?
I assume they don’t mean demonstration, advertising, or promotion of the product itself in the context of trying to sell it, as it seems totally nonsensical to have such a prohibition.
It doesn’t say “Can be used”, it says “Cans used”. They’re promoting a device for cutting plastic bottles and plastic cans and inform you that this part of the video, where they are cutting metal cans, has been included for demonstration purposes, and is not meant to advertise and promote the device as suitable for cutting metal cans.