The authors present a simple design for a magnetically coupled manipulator capable of grabbing small samples in an ultrahigh vacuum environment. The opening and closing of the sample grabber is accomplished by the relative rotation of independent rings of magnets. This manipulator provides high values of axial force (30 lb) and azimuthal torque (23 in. lb).
REFERENCES
After designing, building and testing this manipulator, and further writing this paper, we found relevant patent literature. Apparently there are only two patents on this subject. The first is “Linear and rotary positioning device,” U.S. patent 5,105,925, (21 April 1992) and the second is “Magnetic feedthrough manipulator,” U.S. patent 5,514,925 (7 May 1996). Surprisingly, the second patent makes no reference to the first. We believe the design presented here is much simpler to implement.
High-strength type 321 stainless steel tubing 2 in. OD, 1.96 in. ID, 0.02 in. wall.
Extension spring, 302 stainless steel, 0.75 in. long, 0.063 in. OD, 0.009 in. wire size. Spring constant: 0.75 lb/in.
