Abstract: A brushless slip ring includes a housing, a plurality of annular spaces disposed in the housing and spaced apart along a common longitudinal axis, and a cageless assembly of electrically conductive spherical balls freely rotatably disposed in each of the spaces. Each of the spaces is formed between radially inner and outer electrically conductive surfaces of a rotor and stator, respectively, and a pair of axially spaced retainer rings. The spherical balls conduct electrical current between the outer and inner surfaces. The balls are rigid and harder than the inner and outer surfaces and are arranged in an annular row. The balls occupy substantially the entire circumference of the space and are freely circumferentially movable relative to one another within the space for making contact with one another.

Abstract: A moving coil linear actuator including an elongated permanent magnet having a cross-sectional width substantially greater than its edge height and having an elongated length of soft magnetic material disposed along one or both edges of the permanent magnet to enhance the magnetic field strength in the gap through which the moving coil translates.