Movable pivot bearing for changing key leverage in string keyboard instruments
OwnerDavid Stanwoodinventor
Life of this patent
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Abstract
A moveable key lever pivot bearing system for keyboard instruments in which the pivot bearing is provided with a longitudinal slot to enable mounting the bearing over a pivot pin disposed on a balance rail mounted within the case of the instrument. The key lever, pivot pin, and balance rail all remain in fixed relationship to one another resulting in a fulcrum point change when the bearing is longitudinally shifted back and forth with respect to the pianist. Means are provided to fix the bearing at a selected longitudinal position, extension arms for example, which may be manipulated to adjust the position of the bearings
Claims4
In a keyboard instrument having a case, a balance rail mounted within said case, a plurality of pivot pins vertically disposed along said rail, and a plurality of key levers each having a slot for receiving one of said pivot pins, said key levers disposed over said pivot pins through said slots, the improvement which comprises:
- A. a plurality of movable pivot bearings providing fulcrum points for said levers, each having a longitudinal port for receiving one of said pivot pins, each longitudinally slideably disposed over one of said pivot pins between one of said key levers and said balance rail, wherein the position of each of said pivot bearings is longitudinally adjustable in relation to one of said keys, one of said pivot pins, and said balance rail;
- and
- B. pivot bearing adjustment means mounted within said case and attached to said pivot bearings for longitudinally sliding said pivot bearings between said balance rail and said key levers to alter the fulcrum points of said key levers.
Dependencies are inferred from the claim text.