The Frictionless Riverhawk Free-Flex® Pivot offers many advantages: infinite life, low center shift, and no friction. Yes, you read that right: no friction. Now, you may be saying to yourself “Well, that’s impossible. There is always some friction in a moving part”. Is the Free-Flex® Pivot truly as frictionless as we say?
What is friction?
Firstly, we must understand what friction is. Nearly 200 years before Newton defined what force was, Leonardo da Vinci, the esteemed painter of the Mona Lisa, was the first man to truly begin to study the phenomenon known as friction. Da Vinci realized that the way different parts interacted with one another when in contact was a pivotal part in the way machines could operate. Da Vinci then came up with two laws to describe the phenomenon known as friction.
- The force of friction between two sliding surfaces is proportional to the load pressing the surfaces together.
- The force of friction is independent of the apparent area of contact between the two surfaces.
To sum it up, this version of friction, known as dry friction, results when there is a force being applied to two surfaces in contact. When most people think of friction, this is the type they imagine. One of the more prevalent examples is trying to slide a box across a rough surface, like asphalt.
The Free-Flex® Pivot Design: Truly Frictionless
What does this have to do with the Free-Flex® pivot being frictionless? The answer is simple: the Free-Flex® pivot is designed so that moving surfaces are free from contact. Whether it be in the null position or rotated to 30 degrees, each and every surface of the Free-Flex® pivot remains independent of one another. This unique design means that the Free-Flex® Pivot is, in the classical sense, frictionless, and can function properly over millions of cycles without the need for any sort of lubrication.
What is hysteresis?
However, there is another kind of friction: one that is lesser known, and is always present within bending materials. This type of friction occurs at a molecular level within the steel springs themselves. Essentially, the bending of metal produces a miniscule amount of friction between molecules in the material. This friction is then dissipated in the form of heat energy, and results in a phenomenon we call hysteresis. Hysteresis effectively changes the null position of the pivot after rotation. This means the pivot itself does not return to exactly 0 degrees of rotation after every cycle.
Hysteresis in Free-Flex® Pivots? Not A Concern.
Is this phenomenon a cause for concern? The short answer is no. The long answer: also no. Not only are the effects of hysteresis incredibly miniscule and difficult to even measure, but the results are incredibly consistent and repeatable. While a pivot may not return to 0 after every cycle, it will return to the same place after cycle as long as the angle it is moving is consistent. Because this effect is so miniscule and has virtually no effect on any sort of pivot performance, our parts, in essence, can be called frictionless bearings.
The Free-Flex® Pivot Design In Action
If you wish to learn more about hysteresis or any other Free-Flex® Pivot design engineering characteristics a detailed page with all our product engineering data can be found here. If you have any questions regarding Frictionless Free-Flex® Pivots, or wish to get an idea about which pivot may be right for your application, please contact us and we would be happy to help you with all of your rotational motion needs.
