Keyboard simulation with vertical inversion indexes
Patent 4295407 Issued on October 20, 1981. Estimated Expiration Date: 
April 18, 2000. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
April 18, 2000. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3350973 3431885 3903783 InventorApplicationNo. 06/141577 filed on 04/18/1980US Classes:84/471R, Charts or boards235/89R, Sheet84/481Plurality of cardsExaminersPrimary: Franklin, Lawrence R.Attorney, Agent or FirmInternational ClassG09B 15/00 (20060101)AbstractA teaching aid simplifies the understanding and practicing of the inversions of the major triads of the diatonic scale by utilizing a series of insert cards which slide into a simulated keyboard and read up vertically duplicate sets of the scale tones of the triad beginning with the underlying keyboard tone. In contrast with the usual method of inversion indication, wherein sequential indicia point out inversions on the keyboard itself, or on a horizontal scale, by reading up vertically rather than horizontally the student is able to easily see the inversion arrangement without confusing it with the keys that he is playing. | |
