History of Reverse Action Design on the Autoharp
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James S Back
New and Useful Improvements in Autoharps
Filed September 27th 1895 and Granted May 5th 1896
United States Patent Office: 559764
“Be it known that I, James S. Back of the city of Ottawa .. in the Dominion of Canada, have invented certain new and useful improvements in Autoharps; and I do hereby declare that the following is a full, clear and exact description..”
The instrument described by Back innovates upon an otherwise unchanged autoharp, and unlike the Wigand design, the proportions in this drawing do appear entirely realistic. Twelve, full size keys appear on the keyboard and the action is built above the strings of the instrument, and oriented perpendicular to the string face (similar to Wigand).
“..My improved autoharp is provided with mechanism which by means of a piano keyboard (or, more strictly, an organ-keyboards) permits any chord in any key or the octaves of any single note to be sounded…”
However, unlike Wigand, the damping mechanism is top sprung, in the manner of an autoharp (providing upward force on the damper bars), the reverse action provided by feet, which extend between the strings and damp the underside of individual strings. The drawing above right, shows the mechanism with key depressed and feet extending to undamped position below the strings. The reverse damping is thus provided from underneath the strings, and thus requires a downward force to release the dampers. Keys are coupled directly to the corresponding damper bars, but this time before the pivot-point, and provide the necessary force. From pianistic perspective, an advantage of this design is the long length, key to pivot point — a similar length to piano key length (to pivot point) that would provide adaptive keyboard feel.
There is some sophisticated thinking with regard to adaptation of the piano sustain. The mechanism is more complex than the simple “damp by bar return” of other reverse actions (including mine) or the addition of a key crook which lifts all the damper bars simultaneously (Wigand, Millington/Young). By means of a rocking mechanism, a 13th full damping bar (designed to damp all strings) provides damping and release in combination with the octave occurrences. The effect of this is that in legato mode, strings of the last played keys (or combination of keys) continue to vibrate. A crook changes the instrument behaviour to behave in non-legato mode, where the strings will vibrate as long as the key is held, and then damp on release of the key. Discussion as to the wisdom of incorporating sustain pedals will follow later — suffice to say, at the moment, that this sustain effect adds a lot of complexity to the system.
The complexity of the mechanism and also the description renders this device quite difficult to assess. For a flavour of the language consider Claim 1 (the first of 6) below.
“In an autoharp, the combination with the body of a casing secured above the sound-board, of a series of damper-bars pivoted in said casing at one end above and parallel to the strings and each carrying a damper at the other or free end each adapted to press upward against one of the strings, a cross-bar in said casing carrying a series of springs each holding up one of said bars, a series of presser-bars placed transversely above said damper-bars and provided with pins each adapted to bear upon one of the damper-bars, a spring at each end of each of said presser-bars holding the same up, a board above said bars provided with guides for vertical pins and forming the bottom of a keyboard, a series of pins in said bottom adapted to move vertically and each in contact with one of the presser-bars, a series of keys arranged in the manner of an organ-keyboard suitably pivoted, and each bearing upon one of the aforesaid pins, a muffler-bar similar to the presser-bars but without pins and bearing bodily upon the free ends of the damper-bars, a rocking bar pivoted to the bottom of the keyboard under the rear end of the keys and adapted to have its rear edge depressed by the keys, an arm or lever at one end of said rocking bar bearing with its forward end upon one of the vertical pins which move in said bottom and which is in contact with said muffler-bar and a spring holding up the rear end of said arm or lever, substantially as set forth."
Certainly the design is ingenious, but perhaps over-engineered. The inclusion of the sustain mechanism suggests pianistic thinking, but the keyboard integration on Back’s prototype is very involved indeed. Overall this prototype probably contains the most parts and also the most moving parts of any conception of reverse action autoharp design.