Abstract: This invention is directed to a boring machine provided with a spindle supported rotatably in a spindle housing, a driving means for rotating the spindle, and a spindle feed mechanism supporting the spindle housing so that the spindle housing can be moved up and down. This boring machine includes a means for detecting the level of axial displacement of the spindle in boring motion with the detecting means not contacting the spindle, and a comparator for comparing the level of the actual axial displacement of the spindle or the thrust force applied thereto and corresponding to this displacement with a predetermined threshold level of axial displacement or a threshold level of thrust force. The spindle feed mechanism is controlled in response to the output from the comparator.

Abstract: In effecting positioning of a workpiece relative to a working tool, indexing is carried out by obtaining precision measurement of the relative distance between the workpiece and the working tool by using a laser beam. Positioning can be effected with improved precision and working can be achieved with improved dimensional accuracy.

Abstract: A positive feedback amplifier circuit for possible use with a semiconductor memory device includes first and second MOS transistors whose current paths are connected together between two power source terminals, the gate of the first MOS transistor being connected to a clock. A third MOS transistor has a current path connected between one of the power source terminals and the gate of the second MOS transistor and also has a gate connected to the junction between the first and second MOS transistors and to a resistive means whose other end is connected to one of the power source terminals.

Abstract: A semiconductor memory device includes a plurality of memory cells arranged in a matrix fashion, word lines each connected commonly to the memory cells arranged on the same row, plural pairs of data lines each pair connected commonly to the memory cells on the same column line, and a row decoder connected to the word lines. The semiconductor memory device further includes positive feedback amplifiers connected to the work lines, which respond to voltages on the word lines at a preset or higher level to pull up the potential on the word lines to a higher level.

Abstract: A centerless grinding method and a device using same, in which: a work having a cylindrical stem portion and a flange portion is supported on a supporting plate; a regulating wheel is provided with a lead angle so as to feed the work in its axial direction; the regulating wheel is fed in the direction substantially perpendicular to the axis of the grinding wheel, with the axis of the regulating wheel being inclined in a manner the peripheral surface of the regulating wheel may be maintained in parallel with a given conical peripheral surface of the grinding wheel which has a square or right-angled edge in its cross section; and the aforesaid grinding wheel has peripheral surfaces consisting of two continuous frusto-conical surfaces; whereby the stem portion and an inner face of the flange portion of the work may be ground at the same time.