Abstract: A gear reduction system is provided including two-stage gear reducers that may be converted to three-stage gear reducers by addition of a modular input stage. The modular input stage converts the input stage of the two-stage reducers to an intermediate stage of the three-stage reducers. Gearing, preferably including both drive pinions and driven gears, of the input stages of the two-stage reducers are used in the intermediate stages of the three-stage reducers, thereby reducing the overall number of parts needed for a family or series of reducers. Gearing is also common between input (and intermediate) stages of smaller gear reducers and modular input stages used with larger gear reducers, further reducing the number of different parts. The two-stage reducers and modular input stages of the three-stage reducers are preferably driven by modular transmission adapters that support the drive pinions of the input stages.

Abstract: An X-Y positioning machine has a forcer, with armature coils, that moves around on a platen, supported by an air bearing. Magnets embedded in the motor platen generate a fixed magnetic field with which the armature coils interact. Perpendicular elongated coils interact with the fields of magnets in columns and rows. When a traditional rectangular pattern of the magnets is provided, a packing density and average peak magnetic flux intercepted by the coils are limited to 50%. The present invention provides magnet configurations that provide greater than 50% maximum peak flux density and up to 100% packing density. Several magnet arrangements are provided: a first in which round magnets are used instead of square, and a second in which diamond shaped magnets are used. The latter can be used at 100% packing density arrangement. In addition to high peak flux density for a narrow coil, these embodiments exhibit low cogging forces. A method of making the magnet is also provided.

Abstract: A redundant controller employs two controller chassis having replaceable functional modules interconnected electrically within the chassis. System back up modules in the chassis coordinate the switching of control from a primary to a secondary chassis according to chassis redundancy state information of the chassis stored in the backup modules and module redundancy state information stored in the modules unique to the modules.