The anti-twister mechanism is a method of connecting a flexible link between two objects, one of which is rotating with respect to the other, in a way that prevents the link from becoming twisted. The link could be an electrical cable or a flexible conduit.
This mechanism is intended as an alternative to the usual method of supplying electric power to a rotating device, which is to use slip rings. The slip rings are attached to one part of the machine, and a set of fine metal brushes are attached to the other part. The brushes are kept in sliding contact with the slip rings, providing an electrical path between the two parts while allowing the parts to rotate about each other.
However, this presents problems with smaller devices. Whereas with large devices minor fluctations in the power provided through the brush mechanism are inconsequential, in the case of tiny electronic components, the brushing introduces unacceptable levels of noise in the stream of power supplied. Therefore, a smoother means of power delivery is needed.
A device designed and patented in 1971 by an American, D. A. Adams, (U.S Patent 3,586,413) and reported in The Amateur Scientist in December 1975, solves this problem with a rotating disk above a base from which a cable extends up, over and onto the top of the disk. As the disk rotates the plane of this cable rotates as well, at exactly half the rate of the disk, which allows the cable to remain twistless all along its length.
What helps make the device possible is the peculiar connectivity of the space of rotations, as discovered by P. A. M. Dirac and illustrated in his String Trick. This space can be represented by unit quaternions.
- C. L. Stong (December 1975). "Diverse Topics, Starting with How to Supply Electric Power to Something That Is Turning". Amateur Scientist.
- The Dirac String Trick