Abstract: A hinge device comprising a shaft, a coil spring, a shaft holder, and a bracket. The coil spring has a coiled portion wound around the main portion of the shaft. The shaft holder is secured to a first member and holds one end of the shaft, thus preventing the shaft from rotating. The bracket supports both end portions of the shaft, and is secured to a second member. The bracket, therefore, allows the first and second members to rotate relative to each other around the shaft. The main portion of the shaft has a cross section having a short diameter and a long diameter. The coiled portion is formed of a plurality of turns contacting one another. Each turn extends at a predetermined pitch angle to a line which extends at right angles to the axis of the shaft. The turn therefore looks elliptical when viewed in the axial direction, and has a short diameter greater than that of the main portion of said shaft, and a long diameter substantially equal to that of the main portion of said shaft.

Abstract: A portable computer has a base unit and a flat panel display unit. The base unit has a keyboard and a turntable rotatably connecting to the base unit in a horizontal direction. A display support is fixed to the turntable. The flat panel display unit is pivotally connected to the display supporter. The flat panel display unit rotates in the vertical direction between a closed position for covering the keyboard and an open position for operating the keyboard. The flat panel display unit rotates with the turntable in a horizontal direction between the open position and a twisted position for twisting the flat panel display unit. A display stopper prevents the flat panel display from rotating in the vertical direction when it is in the twisted position.

Abstract: An expansion device includes a box-like device body and a second battery pack. The body includes a hard disc drive therein, a fitting recess open to the outer surface of the body, power-receiving terminals provided in the fitting recess and connected to the hard disc drive, and a second connector adapted to be connected to a first connector of a personal computer. The second battery pack is designed to be removably mounted in a battery mount portion, in place of a battery pack of the computer, and includes a coupling portion removably fitted in the fitting portion, the first and second power-supply terminals. When the second battery pack is mounted in the mount portion while the coupling portion is fitted in the fitting recess, the device body is coupled to the computer in a state where the second connector is connected to the first connector and the first and second power-supply terminals contact power-receiving terminals of the computer and the power-receiving terminals of the device body.