Challenges and Engineering
The magnetic discs that are central to PolarityGear are called "Polymagnets" and are manufactured by CMR (Correlated Magnetics, polymagnet.com). Polymagnets are nothing short of amazing. CMR has proprietary technology that allows them to place concentrated magnetic forces in very precise locations on magnetic material. The results create unique behavior and much stronger magnetic forces than otherwise possible with magnets.
We use a pair of CMR's 2240 disc Polymagnets in PolarityGear. There are 12 detents of North and South poles around the circumference. As you pull paper from the roll you feel a resistance due to the magnetic poles trying to stay in alignment with the opposite pole on the other disc. The paper will continue to dispense until you are ready to rip it and pull a little quicker when a tear forms at the perforation.
CMR's 2240 (pair from Polymagnet.com left, photo from magnetic viewing film right)
PolarityGear has been in development for more than three years and during that time we have tested it on all kinds of paper products. We wanted users to have a good experience with PolarityGear and the only way to ensure that was to make the torque resistance adjustable. A typical thin, single ply toilet paper rips much easier than a thick 2 ply. If the resistance is too much for the thin, single ply then it would rip at the first perforation, as it's being pulled-out leaving you with one sheet and frustrated with the new product. The opposite could also be the case, if the resistance is too easy, it doesn't do anything for thicker paper.
Then the question became how do we make it adjustable. We wanted it to be easy to adjust with no tools. We could have made the adjustment visible or hidden when the roll is loaded. In the end we came up with an undulating helix shaped mechanism. We're not aware of anything else out there like it. The wavy pattern provides enough friction between the two mating parts to keep it in the current setting during use. By having three sets of the helix instead of two or four, it keeps everything true and in balance.
Our Undulating Helix Mechanism
When you first see the paper towel holder, you’re probably wondering what is going on with the ends of the wires. This is another first of its kind. The wires intersect using the central intersection point as support to help keep its structure. The wires need that support in order to provide enough force against the cardboard tube inside the roll. Without it, the roll would spin around the wires because of the resistance the magnetic discs provide. There is a spring that attaches to the wires at the intersection point to keep them aligned.
The intersection of the wires
We think that PolarityGear will be popular with geeks like us who appreciate creative solutions.