Sunday, March 01, 2009

convertible manipulator/sheer

A manipulator with four or six ‘fingers’ positioned symmetrically around a central axis might also serve as a sheer, able to snip along two or three planes. The cutting edges would be the edges of basal segments to which the fingers were mounted. Four-fingered manipulators would be mechanically simpler and more robust. Six-fingered manipulators would have sharper edges and therefore make more efficient sheers. In either case, to act as a sheer the fingers would have to reach past the object (stem) to be cut, so it could be grasped by their basal segments.

An alternative to the above would be a four fingered manipulator with basal segments angled at less than 90 degrees, possibly as little as 45 degrees, with space between them, and the ability to rotate into that space. In the case of 45 degree angled basal segments, each finger should be able to rotate 22.5 degrees in either direction from its rest position. This would result in both a manipulator with two sets of opposed digits, 45 degrees apart on either side, arranged along either of two axes, as well as a more effective sheer.

The basal segments to which I've been referring would appear, from anywhere along the central axis, like simple blocks of metal presenting a distinct edge. However, from the outside, with those edges hidden, they would look more like the links in multi-jointed digits that they would also be.

keeping dust off optics

Whether lenses for machine vision, or lenses and mirrors to direct laser light, the need to keep dust off their surfaces should be obvious.

One likely solution is to surround the lens with a doughnut-shaped (toroidal) trough, with an outer opening at least as large as the lens itself. Compressed, filtered air would be introduced tangentially, through a jet positioned along the trough's widest circumference, causing the air within to spin. The rate of spin would increase as the air climbed the inner wall of the trough toward the opening, and continue to increase approaching the axis of the lens.

There would also be a net movement of air outward through the opening. Once outside the confines of the trough, air would spray outward in an approximate disk shape. Any dust that happened to come close to the opening would be pushed off by this disk-shaped, laminar outflow, with essentially no chance that it would end up inside where it might come in contact with the lens.