Chris A Trivelas

US Patent:

50423541, Aug 27, 1991

Filed:

Jan 18, 1990

Appl. No.:

7/467023

Inventors:

Chris A. Trivelas - North Bend WA
Darrell G. Fandrich - Bellevue WA

Assignee:

Fandrich Design, Inc. - Seattle WA

International Classification:

G10C 318

US Classification:

84240

Abstract:

The subject action is a modification of the traditional upright action. The traditional jack spring is eliminated. Its function is assumed by a jack/repetition spring, which is a compression spring adjustably mounted between the jack near the end that engages the hammer butt and a pilot attached to a threaded shaft through the back stop portion of the hammer assembly. The hammer return spring mounting enables adjustment of the range of force applied by the spring to the hammer. The force range magnitude is such that the hammer return torque is commensurate to the torque that would be applied by gravity if the hammer shank were mounted horizontally instead of vertically. The operating force of the jack/repetition spring is related to that of the hammer return spring in such a way that re-engagement of the jack with the hammer butt is assured before hammer return beyond the back-checked point. The ends of the jack/repetition spring are geometrically located to allow the elements of the action to keep in intimate contact after re-engagement, making possible the elimination of the bridle tape and wire, and to provide a function that feels smooth and tight, not loose. The interaction between the springs as applied produces enough return force on the key to allow use of weights in the played end of the key to provide the desirable inertial resistance of a grand action to the player's touch on the keys.

US Patent:

48965774, Jan 30, 1990

Filed:

Oct 2, 1987

Appl. No.:

7/104277

Inventors:

Chris A. Trivelas - North Bend WA
Darrell G. Fandrich - Bellevue WA

International Classification:

G10C 318

US Classification:

84240

Abstract:

The subject action is a modification of the traditional upright action. The traditional jack spring is eliminated. Its function is assumed by a jack/repetition spring, which is a compression spring adjustably mounted between the jack near the end that engages the hammer butt and a pilot attached to the back stop portion of the hammer assembly. The hammer return spring mounting enables adjustment of the range of force applied by the spring to the hammer. The force range magnitude is such that the hammer return torque is commensurate to the torque that would be applied by gravity if the hammer shank were mounted horizontally instead of vertically. The operating force of the jack/repetition spring is related to that of the hammer return spring in such a way that re-engagement of the jack with the hammer butt is assured before hammer return beyond the back-checked point. The ends of the jack/repetition spring are geometrically located to allow the elements of the action to keep in intimate contact after re-engagement, making possible the elimination of the bridle tape and wire, and to provide a function that feels smooth and tight, not loose. The interaction between the springs as applied produces enough return force on the key to allow use of weights in the played end of the key to provide the desirable inertial resistance of a grand action to the player's touch on the keys.