A scrollerwheel is a mechanical device composed of a number of rollers (four or more) and connective bands under

tension Tension may refer to: Science * Psychological stress * Tension (physics), a force related to the stretching of an object (the opposite of compression) * Tension (geology), a stress which stretches rocks in two opposite directions * Voltage or el ...

, which wrap around and weave between the rollers forming a self-supporting cluster possessing a central roller. The cluster of rollers is bound by the connective bands in such a way that the

static friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of tw ...

between the rollers and bands prevent the rollers from slipping as they roll and orbit the central roller.Canadians Reinvent the Wheel
'Business Week'' August 14, 1995 Scrollerwheels are related in operational principle to

rolamite Rolamite is a technology for very low friction bearings developed by Sandia National Laboratories in the 1960s. It is the only elementary machine discovered in the twentieth century and can be used in various ways such as a component in switches, ...

linear bearings (developed at

Sandia National Labs Sandia National Laboratories (SNL), also known as Sandia, is one of three research and development laboratories of the United States Department of Energy's National Nuclear Security Administration (NNSA). Headquartered in Kirtland Air Force Bas ...

in the late 1960s), and like them, they display only rolling friction, and not the kinetic friction inherent in most mechanical bearings. The rollers can have a

cross section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Ab ...

in a variety of shapes other than circular, such as:

oval An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas (projective geometry, technical drawing, etc.) it is given a more precise definition, which may include either one o ...

s (which with a single oval roller as the central roller, or one of the outer rollers, results in a

cam Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bin ...

med motion), various varieties of

superellipse A superellipse, also known as a Lamé curve after Gabriel Lamé, is a closed curve resembling the ellipse, retaining the geometric features of semi-major axis and semi-minor axis, and symmetry about them, but a different overall shape. In the C ...

s and

Reuleaux polygon In geometry, a Reuleaux polygon is a curve of constant width made up of circular arcs of constant radius. These shapes are named after their prototypical example, the Reuleaux triangle, which in turn, is named after 19th-century German engineer ...

Advantages

Unlike conventional

rolling-element bearing In mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two concentric, grooved rings called races. The relative m ...

s, they do not require

lubrication Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubrication mechanisms such as fluid-lubric ...

. Consequentially, they can be employed in environments hostile to

lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ...

s: underwater, in a

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often di ...

(where grease will boil) and at elevated temperatures. They can be constructed from a wide variety of materials, have zero

backlash Backlash may refer to: Literature * '' Backlash: The Undeclared War Against American Women'', a 1991 book by Susan Faludi * ''Backlash'' (Star Wars novel), a 2010 novel by Aaron Allston * Backlash (Marc Slayton), comic book character * ''Backl ...

, and they are not fouled by gritty particulates.

Disadvantages

Scrollerwheels cannot have an aspect ratio (diameter compared to thickness) as high as conventional mechanical bearings.

References

External links

U.S. Patent #5,462,363
Simple machines Rolling-element bearings Wheels {{tech-stub

Advantages

Disadvantages

See also

References

External links