Hitachi, Ltd.

Yukitaka Hayashi

Nagaharu Hamada

Yoshihiro Moribe

Toshitaka Hara

Masahiro Iwamura

Hideo Maekawa

Masahiro Mitamura

Kunitsugu Tsukui

Norio Murayama

Mitsuo Kikkawa

A head loading system including a head support mechanism supporting heads for at least reproducing information in juxtaposed relation to a recording medium, and a loading actuator driving the head support mechanism to move the heads toward and away from the recording medium. The loading actuator include motion converting arrangement for converting a linear motion of a solenoid into a rotary motion which is capable of increasing the amount of motion when the linear motion is converted into the rotary motion, thereby enabling the loading actuator to drive the heads with a small amount of linear motion. The motion converting arrangement includes a rotary member connected to a plunger of the solenoid and formed with grooves, a frame juxtaposed against the rotary member and formed with grooves and a bearing fitted between the grooves. The linear motion of the plunger is converted into a rotary motion of the rotary member by the action of the bearing performed in cooperation with the grooves.

Head loading system

A positioning method and apparatus for precisely positioning a magnetic head on a desired track of a magnetic disc includes stepping motor having a plurality of stationary pole windings adapted to be rotated stepwise, and a mechanism for moving the magnetic head by a rotational movement of the stepping motor. By rotating the stepping motor stepwise by an integral multiple of the number of stationary pole windings of the stepping motor, the magnetic head is moved by one track width of the magnetic disc. By driving the stepping motor by the integral multiple of the number of stationary windings, the magnetic head is positioned by the same stationary pole windings without being affected by an assembling tolerance of the stationary pole windings. The stepping motor may also be driven so as to overrun a desired track by at least one step and then rotated in a reverse direction by the same number of steps so that a positioning error due to forward and reverse rotations of the stepping motor is eliminated.

Positioning method and apparatus therefor

A cathode ray tube having a viewing screen on which time points represented by a plurality of points spaced from one another with a predetermined time interval are displayed in the raster direction, while display quantities of trend graphs are displayed as functions of the time points in the direction perpendicular to the raster direction by a plurality of points spaced from one another with a predetermined interval. A raster scanning is effected by sweeping the viewing screen with a scanning point whereby the scanning lines thus produced are correlated to the spaced points representing the display quantities. Apparatus stores the display quantities of the trend graph corresponding to the time points, sequentially reads out the display quantities from the memory apparatus in the order of the time points, and compares the display quantities read out from the memory apparatus with a display quantity represented by an instant scan line. The comparison apparatus compares the display quantity read out corresponding to an instant time point and an instant position of the scanning spot of the instant scan line with a display quantity represented by an instant scan line, supplies a video signal to the cathode ray tube when the instant display quantity represented by the instant scan lines lies in a range delimited by the display quantity at the instant time point and the display quantity at the select one time point of the time points immediately preceding and following the instant time point.

Trend graph display system

A data display control system for displaying respective data memorized in a plurality of refresh memories which is operable in various display modes including a selective picture display, a superimposed picture display and a shifting picture display. Individual data memorized in respective refresh memories contain each a display control bit adapted to determine whether or not the individual data are to be displayed on the screen. The data display control system reads out from the respective refresh memories a data information to be picture-displayed and only when the contents of a display control bit contained in the data information designate a display, it converts this data information into a video signal for a picture display. The contents of the display control bit are changeable for individual data.

Data display control system with plural refresh memories

A light pen detection system used for a display system using a cathode ray tube (CRT) in which the operation for detecting the character display position on the CRT face is started when the operation switch of the light pen is turned on, and repeatedly progresses in synchronism with the picture repetition rate, and when a position marker is displayed at the character display position detected through such detecting operation, the operation switch of the light pen is turned off thereby to stop such detecting operation, whereby the character display position detected is obtained as the up-to-date one indicated by the light pen.

Light pen detection system

In a magnetic memory which has thereon 2.sup.q tracks (q = positive integer) and in which each band consists of 2.sup.p sectors (p = positive integer) and the addressing of the magnetic memory is performed by addressing the bands and sectors, each track is designed to contain a plurality of bands so that one band can be constituted by 2.sup.p sectors while each track contains sectors whose number is not equal to 2.sup.p .sup.' (p' = positive integer).

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Hitachi, Japan

Yukitaka Hayashi