Keyboard for initiating switching operations or switching signals associated with respective symbols on the surfaces of the keys

Claim 1

A keyboard for initiating switching functions or switching signals, said keyboard having alpha-numeric symbols imprinted thereon and comprising: an electrically insulative contact set carrier plate; a plurality of conductive path regions arranged in a regular repetitive pattern on said carrier plate; a guide matrix structure mounted above said carrier plate, said matrix having a plurality of guiding bores formed therein in a rectangle arrangement of rows and columns, said guide matrix structure being formed with apertures spaced from said guiding bores; axially movable key means extending through and being guided within each of said guiding bores, said key means comprising: an elastic switch actuating diaphragm in juxtaposition with said carrier plate; a snap-action cup portion of said diaphragm normally spaced above said carrier plate; a contact set actuating plunger integrally formed with said cup portion and extending upwardly therefrom; and a cylindrical guide stem positioned to engage said plunger; an electrically conductive bridging element mounted to at least some of said key means, said bridging element being normally spaced from and in juxtaposition with one of said conductive path regions, each said bridging element and conductive path regions comprising a contact set, said bridging element being mounted to the side of said cup portion opposite said plunger for selective actuation of said contact set; a keyhead extending laterally from each said key means and forming a gap separating said adjacent keyheads, each said keyhead being formed with a recess at each corner thereby forming an aperture at each crossing of the gaps between keyheads in the rows and columns; a synchronizing pin freely axially movably mounted in each said aperture, said axial movement being parallel to the direction in which said key means are movable, each said synchronizing pin being formed with a flange engaging that portion of said keyheads surrounding said aperture so that axial movement of said synchronizing pin causes movement of all said key means forming said aperture; an elastic covering layer over the tops of said keyheads and synchronizing pins, said layer being imprinted with symbol-carrying inscription fields, said symbols being the alpha-numerical symbols of said keyboard, one of said symbols being associated with each said aperture and synchronizing pin, said synchronizing pins and at least portions of said covering layer being substantially transparent; and a miniature signal lamp in said apertures, one said lamp being associated with each said symbol, said lamps being adapted to be connected so as to light upon depression of the respective symbol; whereby when one of said symbols is depressed, all of the keys at that crossing are depressed and at least two of said contact sets are actuated to initiate a switching function associated with said depressed symbol.