Abstract: Method of constructing an assembly having as one element a right circular cylinder with center bore and accurately machined and lapped circular surfaces and perpendicular end faces, and as another element a hollow shaft fitted and joined within said center bore in a manner unable to transmit distorting strain to said cylinder when said shaft has a coefficient of expansion greater than that of said cylinder. The shaft either has an interrupted exterior with severely limited contact areas for joining adhesively to the bore surface or is of other structure that is incapable of straining the cylinder.

Abstract: Gas bearing of the hydrodynamic self-acting type in which replenishment gas for the support film is drawn by the operating bearing through filter means as required to assure entrapment of potentially damaging particles before they can enter the gas film in the narrow clearance between the rotating and stationary bearing members. To further increase the flow of filtered gas, the bearing elements may optionally be equipped with supplemental gas pumping apparatus.

Abstract: Method of determining cylindricity and squareness of mating shaft and bearing members by rotating one member with respect to the other stationary member while using a fluid film as a stiff supporting lubricant to establish a stable and dynamic reference axis, and placing a sensing transducer in the stationary member to measure the variation in distance between the transducer and surface of the rotating member at predetermined increments of rotation and to measure the deviation in squareness in a thrust bearing arrangement. The rotating member is axially translated relative to the transducer and cylindricity measurements made at regular intervals during each of a plurality of revolutions during the axial translation to precisely map the variations in distance to the surface of the rotating member. Squareness measurements are also made under dynamic thrust loading to establish deviations from a true right cylinder.

Abstract: Rotary gas bearing and seal apparatus is disclosed which seals a region between the two planar bearing surfaces that is radially offset from the axis of rotation of the bearing. In the preferred embodiment, two arcuate gas sink channels sink the gas of the bearing away from the region. The gas outside the region and the two channels coact to effect the seal. A gas bearing and vacuum seal embodiment using air or alternatively nitrogen as the bearing gas is described.

Abstract: A vacuum-to-vacuum entry system which uses a rotary transport to transfer workpieces between two vacuum environments in a direction parallel to its axis of rotation and through the interface of a combination rotary gas bearing and seal. The combination gas bearing and seal seals off a zone in the gap between its two planar bearing surfaces that is radially offset from the axis of rotation of the bearing which is coincidental with the transport axis. Two arcuate gas sink channels on one of the bearing surfaces sink the gas of the bearing away from the zone. The bearing gas outside the zone in the gap and the two channels coact to effect a peripheral seal about the zone allowing the two vacuum environments when appropriately aligned to be in sealed communication with each other through the zone. A preferred embodiment is described for the transfer of ceramic substrates with circuitized surfaces between two vacuums environments.