A New Piano Action
by Clarence N. Hickman
Ampico Research Laboratory

 
This text is a draft for a sales brochure by Dr. Hickman, written probably in early 1929.  The writing style closely resembles the style of  "The Ampico Service Manual 1929" which he also wrote.

  At last a grand piano action has been designed which eliminates over half of the intricate levers and triggers which have been common to these actions for the last fifty years! The simplicity of the action is apparent.  There are less than half the number of moving parts that are present in the usual grand action.  (See Figures 1 and 2.)

  The number of screw adjustments has been reduced from 8 to 4.  These 4 adjustments may be easily, quickly and accurately made.

  The construction is of such a nature that after the adjustments have once been made they remain in proper regulation for an unlimited number of years.  This is a great contrast to what may be expected from the old action.  In many cases the old action will not stay in proper regulation for as long as 24 hours.

Tests which have been made in the Research Laboratory of the American Piano Company to determine the durability of the new action have shown that it will last over a life time.  After being subjected to endurance tests in which two of the old actions were completely worn out, the new action was still found to be in perfect condition both from the standpoint of durability and regulation.  This endurance test was equivalent to over a hundred years of average use of a piano.

  The parts of the new action are connected with suitable pin joints in such a manner that frictions are reduced in many cases to 1/10th the amount present in the old action.  There are no rubbing parts whatsoever!

  Figures 3, 4 and 5 show chart diagrams obtained by a touch analyzer which was developed in the Research Laboratory.  Figure 6 shows a photograph of this touch analyzer.  This instrument was of great value in testing and developing this new action.

  This system of connecting the various parts of the action also eliminates the necessity of felt pads and silencers, which have always been a source of so much trouble in the old action.  This in turn eliminates the packing and swelling of these pads, and assures permanence of adjustments.

  The new action is designed especially to withstand severe moisture conditions.  It will remain in perfect regulation and without developing undue friction in climates where the humidity rises so high that the old action will swell up and completely refuse to operate.

  Special features have been added to the action which prevent what is known as blocking, and also prevent the hammer from being driven into the back check and becoming locked in this position.

  The simplicity of the action and the great reduction in the number and weight of the moving members has reduced the inertia to such an extent that a great deal of the noise, especially on return of the key, has been completely eliminated.

  This reduction in the inertia of the moving parts also permits repetition, which has heretofore never been possible.

  The permanence of adjustment makes it possible to so regulate the action that the pianist has complete control of the hammer until it is within 1/32" of the string.  With the old type action it has been necessary on account of weather conditions, etc., to regulate the action so that control of the hammer is lost about the time it is as much as 1/8" from the string.  This improvement in hammer control makes it possible for a pianist to play with a pianissimo that has heretofore been impossible.

  The directness of the manner in which the hammer is driven and the great reduction in the inertia and frictions greatly increase the fortissimo effects which maybe obtained.  The absence of frictions and the directness with which the power is applied to the hammer results it a touch that is very pleasing to the artist.  The smoothness and evenness make possible a dynamic control which is quite wonderful.  Many pianists have remarked that "it makes me a better artist than I really am."

  The nature of the construction of the action improves the tone of the piano.  This is brought about by the rigidity with which the hammer is held in alignment, and also by the fact that the new action is provided with what is known as a driving member stop.  This stop, which is an added feature, insures that the hammer shall swing free of all other mechanism at the time that it strikes the string.

  The design of the action is such that any individual key may be removed without disturbing the rest of the action.  In a like manner keys may be leveled without removing the action assembly.

  Realizing that the individuality of the artist must be taken into consideration and knowing that each individual pianist has his own preferences, in regard to the heaviness of touch, an ingenious device has been applied to the action whereby it is possible for the pianist to regulate the heaviness of the touch to suit himself.  The small lever on the left hand-side of the keyboard may be moved into any position with an accompanying change in the heaviness of the touch.  When pushed all the way in, the touch is lightest.  When pulled all the way out, the touch is heaviest.  Any intermediate positions give various degrees of touch lying between the heaviest and lightest.


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Figure 1.  Hickman action.

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Figure 2.  Standard piano action (probably Knabe).
 

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Fig. 3.  Friction after soaking in high humidity.
 

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Fig. 4.  Same piano 24 hours later.
 

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Fig. 5.  Friction of Hickman action.
 

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Fig. 6.  Key force recording machine,


High resolution images, format Portable Network Graphics (PNG):

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fig5.png (89 Kb)


14 February 2002