Abstract: A keyboard including an upper casing which has a key-holder member for movably supporting keys with a movable electrode, and a lower casing which has an integrally formed upraised portion which defines a recess open in the bottom wall of the lower casing. A printed-circuit board is held in direct contact with the top wall of the upraised portion of the lower casing such that stationary electrodes on the printed-circuit board are opposite to the corresponding movable electrodes. The printed-circuit board may be a flexible film-like member on which an elastic sheet having elastically collapsible cap portions is disposed such that the cap portions cooperate with the film-like printed-circuit board to form enclosures in which the corresponding movable and stationary electrodes are accommodated, and such that the cap portions collapse upon operation of the keys for moving of the movable electrodes toward the stationary electrodes.

Abstract: A keyboard assembly having key-switches, comprising a key holder plate supporting multiple keys in plural rows and movably across the thickness of the plate, and further comprising an upper casing which has a rectangular aperture closed by the key holder plate. The key holder plate has holes through which the keys extend, and integral guide portions concentric with the holes and extend toward the rectangular aperture. Opposite right and left sides of the aperture perpendicular to the rows of the keys are defined by side walls of the upper casing each of which has a downward extension toward the key holder plate. The extension has a convex lower end profile with which the key holder plate is held in pressed contact by fasteners, with elastic deformation thereof following the convex lower end profile of the downward extension, such that a surface generally defined by top faces of the keys is curved in cross section across the rows of the keys.

Abstract: A keyboard switch arrangement mounted on a base plate and having a plurality of key stem holder blocks, each of which protects a key stem from slipping out and has coupling portions of ridges and grooves on the outer side walls coupled in contiguous relation to one another in a manner that one ridge in one block is fitted in one groove of the adjacent block.

Abstract: A keyboard assembly having key-switches, comprising a key holder plate supporting multiple keys in plural rows and movably across the thickness of the plate, and further comprising an upper casing which has a rectangular aperture closed by the key holder plate. The key holder plate has holes through which the keys extend, and integral guide portions concentric with the holes and .[.extend.]. .Iadd.extending .Iaddend.toward the rectangular aperture. Opposite right and left sides of the aperture perpendicular to the rows of the keys are defined by side walls of the upper casing each of which has a downward extension toward the key holder plate. The extension has a convex lower end profile with which the key holder plate is held in pressed contact by fasteners, with elastic deformation thereof following the convex lower end profile of the downward extension, such that a surface generally defined by top faces of the keys is curved in cross section across the rows of the keys.