United States Patent  [li] Patent Number: 4,706,536
Sanders  Date of Patent: Nov. 17, 1987
 MEMBRANE KEYBOARD FOR SONGBOOK TONE GENERATOR
 Inventor: Sam Sanders, Nashville, Tenn.
 Assignee: JTG of Nashville, Inc., Nashville, Tenn.
 Appl. No.: 826,299
 Filed: Feb. 5,1986
 Int. CI.4 G10H 1/34; G10H 5/00
 U.S. CI 84/1.01; 84/423 R;
84/433; 84/471 R; 84/483 R; 84/DIG. 7; 200/5
 Field of Search 84/1.01, 423 R, 433,
84/471 R, 483 R, DIG. 7; 200/5 R, 5 A, 6 R
 References Cited
U.S. PATENT DOCUMENTS
3,592,098 7/1971 Zadig 84/DIG. 7
4,276,538 6/1981 Eventoffetal 84/DIG. 7
4,366,463 12/1982 Barker 84/DIG. 7
Primary Examiner—Stanley J. Witkowski
Attorney, Agent, or Firm—David B. Harrison
A membrane keyboard for e.g. a low cost electronic tone generator of the type affixed to the binding of a songbook is disclosed. The keyboard includes a base carrying a set of interdigital upwardly facing printed circuit contacts for each key. A membrane overlay is vacuum formed of a thin plastic sheet to define a horizontal row of playing keys, each key being formed as a plateau area, with a vertical depression spring rib separating each key. Each key includes an elastomeric foam pad affixed to its underside area which carries a conductive lower surface aligned with with the interdigital traces of the key. The conductive surface bridges the traces to complete an electrical circuit when the membrane is depressed downwardly from its top surface.
7 Claims, 7 Drawing Figures