Abstract: A composite keyboard musical instrument comprises an acoustic piano and a silent system, and the silent system includes a hammer stopper split into two parts assigned to higher/middle pitched parts and a lower pitched part, respectively, and a timing changer for accelerating escape of jacks; although the two parts are independently rotatably supported by bearing units, two transmission mechanisms are used in parallel for transmitting torque from only one electric motor to the two parts and timing changer so that the power transmission system is simple.

Abstract: A composite keyboard musical instrument comprises an acoustic piano and a silent system, and the silent system includes a hammer stopper split into two parts assigned to higher/middle pitched parts and a lower pitched part, respectively, and a timing changer for accelerating escape of jacks; although the two parts are independently rotatably supported by bearing units, two transmission mechanisms are used in parallel for transmitting torque from only one electric motor to the two parts and timing changer so that the power transmission system is simple.

Abstract: A jig is used in an assemblage between key sensors and an acoustic piano, and the jig has a shutter guide assembled with a casing of optical sensor array for aligning slits with target trajectories of shutter plates and pieces of adhesive double coated tape adhered to the shutter plates for aligning the shutter plates with associated white/black keys, wherein the shutter plates are inserted into the slits so that the shutter plates are placed on the target trajectories, and the white/black keys are moved along the target trajectories until they are brought into contact with the pieces of adhesive double coated tape for temporality tacking the shutter plates to the associated white/black keys.

Abstract: A keyboard musical instrument is a combination of an acoustic piano, a silent system and an electronic sound generating system, and the silent system includes a change-over mechanism and a shank stopper connected to the change-over mechanism so as to be changed between a free position and a blocking position, wherein a change-over mechanism gives rise to a rotation of the shank stopper around vertical axes spaced apart from each other on a horizontal virtual plane so that the hammer stopper is free from a twist.

Abstract: A jig is used in an assemblage between key sensors and an acoustic piano, and the jig has a shutter guide assembled with a casing of optical sensor array for aligning slits with target trajectories of shutter plates and pieces of adhesive double coated tape adhered to the shutter plates for aligning the shutter plates with associated white/black keys, wherein the shutter plates are inserted into the slits so that the shutter plates are placed on the target trajectories, and the white/black keys are moved along the target trajectories until they are brought into contact with the pieces of adhesive double coated tape for temporality tacking the shutter plates to the associated white/black keys.

Abstract: An acoustic piano is equipped with a shank stopper moved into and out of trajectories of hammer assemblies and a change-over mechanism for changing the shank stopper, and the change-over mechanism has a pedal, a transmitter connected to the pedal and another transmitter held in contact with the transmitter for transmitting force exerted on the pedal to the shank stopper, wherein the transmitters are only restricted in the direction to transmit the force from the pedal to the shank stopper so that the transmitters are independently disassembled and regulable.