Abstract: An input keyboard (1) contains a switching device (3) for pushbuttons (22) wherein the contact linings (11.1, 11.2) on a printed circuit board (10) are bridged by a countercontact (16) operated by the pushbutton (22). The countercontact (16) consists of a carbonized plastic foil (14) and an electrically conducting layer (17) on the side facing away from the contact linings. By virtue of this arrangement there comes into being a bridging resistance between the bridged conductor strips (12.1, 12.2) that depends on the operating pressure (P) applied to the pushbutton, this resistance being then used to cause a control circuit arrangement (6) to generate a control command (Bf) for setting a particular function and an adjustment command (Bw) for setting a particular value or adjustment rate.

Abstract: A push button variable resistor device includes a hollow push button seat member confining a receiving space, and at least one resistor piece fixed inside the seat member. The resistor piece has a contact portion and at least one leg portion projecting outward through a base portion of the seat member. A spiral spring resistor is disposed inside the receiving space of the seat member above the resistor piece. The spring resistor has a plurality of concentric turns of varying diameters. A push button is slidably fitted through a button opening of the seat member. The spring resistor hs a topmost turn cooperatively associated with the push button. The push button is externally pushed to compress the spring resistor to cause the concentric turns to contact the resistor piece. The contact area between the spring resistor and the resistor piece varies according to the degree of depression of the push button to correspondingly vary the output resistance of the variable resistor device.

Abstract: A typewriter keyboard instrument wherein the keyboard is arranged as a standard typewriter with only letters, numbers, and symbols of the standard keyboard wherein the key with the letter N is assigned to play the note middle C, and wherein each succeeding key to the right plays a note which is a half-step higher than the note played by the preceeding key, and two expanded keyboards; the first expanded keyboard having five additional keys on each end of each row, wherein each additional key plays a note one half-step lower or higher than the adjacent key; and the second expanded keyboard having five additional keys on the right hand end of each row of keys and seven additional keys on the left end of each additional row wherein each additional key plays a note which is one half-step higher or lower than the adjacent keys, and wherein the music for the standard and the expanded keyboards is written with a key designation in the clef and wherein the dark notes have a light letter corresponding to the key to be