Method and apparatus for altering actuator drive in a reproducing piano
AssigneeKimball International, Inc.
InventorWayne L. Stahnke
Life of this patent
Estimating the term…
Abstract
A method and apparatus for altering the solenoid drive during playback in a reproducing piano to prevent double hammer strikes. The key is depressed by a solenoid under constant velocity until the point of let-off, and the velocity is then increased to accelerate the continued movement of the key and action so that the hammer rebounding from the string will fall without rebounding from the action against the string a second time. In a preferred embodiment, a microprocessor evaluates the key velocity drive value, and if the velocity called for is above a predetermined level, then no boost is applied to the solenoid.
Claims16
A reproducing piano comprising:
- a plurality of keys,
- piano action means actuated by said keys to move hammers into contact with respective strings when the pertaining keys are depressed, said hammers being positively engaged by said action means until let-off occurs after which the hammers travel in free flight toward the strings, and
- key actuation means including actuators in engagement with said keys for selectively moving said keys at a controlled velocity until let-off occurs and moving said keys at a second higher velocity after let-off occurs, whereby the action is accelerated after let-off to prevent double hammer strikes.
A reproducing piano comprising:
- a plurality of keys,
- piano action means actuated by said keys to move hammers into contact with respective strings when the pertaining keys are depressed, said hammers being positively engaged by said action means until let-off occurs after which the hammers travel in free flight toward the strings,
- an actuator means in engagement with each of said keys for actuating the respective key when the actuator means is energized, and
- a control means including a closed-loop current supply circuit means connected to said actuator means to energize said actuator means at a first controlled velocity during a first portion of the hammer actuating travel of the pertaining key and to energize said actuator means at a second velocity higher than the first velocity during a second portion of the hammer actuating travel of the key.
A reproducing piano comprising:
- a plurality of keys
- a piano action mechanism connected to each key including a hammer, a repetition roller connected to the hammer, and a jack positioned in engagement with the repetition roller and in the path of the repetition roller for moving the hammer toward a string when the pertaining key is depressed and moving out of the path of movement of the repetition roller after the hammer commences to travel in free flight toward the string,
- actuator means in engagement with said key for selectively moving said key in a direction to actuate said action to move said hammer against the string, and
- control means electrically connected to said actuator means for producing a current flow in said actuator means to move said key in said direction with a first controlled velocity and for producing a current flow through said actuator means to move said key in said direction with a second higher velocity after said hammer is in free flight toward said string thereby to cause said jack means to move out of the path of said repetition roller more quickly and prevent double hammer strikes of the string.
In a reproducing piano having a plurality of keys, a piano action connected to each key and in engagement with a pertaining hammer adapted to move the hammer to strike a respective string when the key is depressed, and a key actuator connected to each key, a method of depressing the key by actuator action in a manner to prevent double hammer strikes on the strings comprising:
- passing a current through the actuator to depress the key at a first controlled velocity thereby causing the action to move the hammer in continuous positive engagement until the point of let-off at which time the hammer begins to travel in free flight toward the string, and
- subsequently passing a current through the actuator to depress the key at a second velocity higher than the first velocity beginning at about the point of let-off to accelerate a portion of the action out of a return path of the hammer as the hammer rebounds from the string thereby preventing double strikes of the hammer on the string caused by rebound from the action.
In a reproducing piano having a plurality of keys, a piano action connected to each key and having a hammer propelled against a string by the action when the key is depressed, and a key actuator connected to the key, a method of controlling the energization of the actuator comprising:
- passing a current through the actuator to depress the key at a first controlled velocity and cause the action to continuously, positively engage the hammer to move the hammer toward the string, and subsequently passing a current through the actuator to depress the key at a second velocity higher than the first velocity after the hammer commences to travel in free flight toward the string.
In a reproducing piano having a plurality of keys, a piano action connected to each key and having a hammer propelled against the string by the action when the key is depressed, and a key actuator connected to the key, a method of depressing a key during playback comprising:
- retrieving a first actuator drive value from a non-volatile memory,
- converting the drive value to a first control current and energizing the actuator under the control of the first control current to cause the key to be depressed with a first velocity,
- determining if the first drive value is greater than a predetermined level,
- detecting when let-off in the action has occurred and installing a second actuator drive value corresponding to a higher current only if the first drive value is greater than the predetermined level, and
- converting the installed second value to a second control current and energizing the actuator under the control of the second current to cause the key to be depressed with a second velocity higher than the first velocity following let-off if the second drive value is installed.
Dependencies are inferred from the claim text.