Pushbutton keyboard assembly having pole and inner contacts simultaneously engaged by a bridging contact

DETAILED DESCRIPTION Among the many objects of this invention may be noted the provision of a keyboard system which requires a minimal number of parts; the provision of such a keyboard system in which the switching stations may comprise single or multipole switches; the provision of such a keyboard system having multipole switching stations in which the poles are inherently switched simultaneously; and the provision of such a keyboard which is inexpensive to manufacture and easy to assemble.
Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.
Briefly, a keyboard system of this invention includes a substrate keyboard having a generally flat surface with a network of circuit paths thereon.
The board may be metallic with a dielectric layer thereon on which the circuit paths are disposed or it may be a conventional electrically insulative substrate.
In any event, switch contacts are provided at a plurality of switching stations on the substrate and are interconnected by conductive paths.
The network of circuit paths also provide interconnection with terminals.
The switch contacts comprise at least one inner and outer contact for each switch station with the top surface of the outer contact spaced from the substrate a greater distance than the top surface of the inner contact.
A switch actuating electrically conductive disc is placed over each switch station and is resiliently deformable between an initial position in which it is clear of the inner contact and an actuated position in which the disc bridges the outer and inner contacts to thereby complete a circuit therebetween.
Switching stations comprise a disc support which may be one or more pads, generally U-shaped staple like elements or an apertured insulative layer of material adapted to support the outer margin of the disc.
The support maintains the disc out of contact with both the outer and inner contacts in the unactuated position.
The pole contacts comprise the outer contacts of the switching station and are disposed intermediate the inner contact and the disc support