A scrollerwheel is a mechanical device composed of a number of rollers (four or more) and connective bands under tension, 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. Types of friction include dry, fluid, lubricated, skin, and internal -- an incomplete list. The study of t ...

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 A Rolamite is a technology for very low friction bearings developed by Sandia National Laboratories in the 1960s. It consists of two cylindrical rollers held captive in a channel by an S-shaped metal strip. The strip is under tension, which keeps ...

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 Ba ...

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 and engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **A ...

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 of mathematics (projective geometry, technical drawing, etc.), it is given a more precise definition, which may inc ...

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

cam Cam or CAM may refer to: Science and technology * Cam (mechanism), a mechanical linkage which translates motion * Camshaft, a shaft with a cam * Camera or webcam, a device that records images or video In computing * Computer-aided manufacturin ...

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 defined by an equation that allows ...

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,ISO 15 is a bearing (mechanical), bearing which carries a load by placing rolling elements (such as balls, cylinders, or cones) between two concentric, Groove ...

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-lubr ...

. 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, ...

s: underwater, in a

vacuum A vacuum (: vacuums or vacua) is space devoid of matter. The word is derived from the Latin adjective (neuter ) meaning "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressur ...

(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), a comic book character from ...

, and they are not fouled by gritty particulates.

Disadvantages

Scrollerwheels cannot have an

aspect ratio The aspect ratio of a geometry, geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side—the ratio of width to height, when the rectangl ...

(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