Abstract: In a rotating mirror scanner, a polygonal mirror is fixed between a pair of journals of a spindle. A rotor is fixed on the spindle, and a rotor magnet constituting a magnetic thrust bearing is fixed to one end of the spindle. One bearing of a dynamic pressure type and a ring-shaped stator magnet which constitutes the magnetic thrust bearing are both fixed in a hollow housing having an opening. The spindle is inserted into the housing through the opening thereof so that the outer peripheral surface of the rotor magnet faces the inner peripheral surface of the stator magnet, and that one journal is fitted in the one bearing. Thus, the spindle is set in the housing. A cover having the other bearing is fitted in the opening of the housing so that the other journal is supported by the other bearing.

Abstract: A precise feeding table apparatus which comprises an XY-table assembly including a Y-table and an X-table mounted thereon. Electric motors for supplying a driving force to feed the X- and Y-tables are set on a base of the table apparatus. A driving shaft of the electric motor for the Y-table takes the form of a ball screw to cause a guide carriage supported by the driving shaft to make a minute reciprocation. A moment derived from the reciprocation of the guide carraige is not directly transmitted to the Y-table. A connection rod moving jointly with the guide carriage is connected to an output shaft fitted to the Y-table by means of a coupling including a fluid bearing. The fluid bearing supports the connecting rod in contactless relationship, thereby preventing the vibrations and moments of the connecting rod from being transmitted to the output shaft.

Abstract: The apparatus comprises a drill power meter for producing an electric signal representing the drilling resistance of a workpiece, a filter for shaping the waveform of the electric signal, an integrator for integrating the output of the filter, a comparator for comparing the output from the integrator with a reference signal for producing a pulse when the former is larger than the latter, a first counter for counting the pulse, a second counter for counting the total number of measurements of the drilling resistance of the workpiece performed by the drill power meter, and means for comparing the counts of the first and second counters for judging the useful life of the drill.

Abstract: A bearing device comprising a rotatable shaft, a spherical body fixed to said shaft, a bearing body having a spherical concave bearing face corresponding to said spherical body, and a radial bearing for supporting said shaft at a position spaced apart from said bearing body.