| 摘要 |
<p>The keyboard for pianos and similar musical instruments has key shanks (levers) formed of structural foam containing glass fibers, there being only one shank construction for all the white keys and another for all the black. The shanks are connected, at their outer ends, to self-positioning hollow key caps. Each shank rests, at a laterally thickened central portion, on a synthetic resin balance rail from which an integral balance pin projects into a slot in such central portion. The outer end of each shank rests on a synthetic resin guide rail having a guide pin formed integrally therewith and extending into the shank. The laterally thickened central portions of the shanks are sufficiently close to each other to provide a strengthening effect creating much resistance to side forces such as occur, for example, during shipment. The balance rail and guide rail, with their integral pins, are injection molded of solid synthetic resin and are mounted in strengthening rails which are metal extrusions. These, and also extruded pivot rails and side rails, create such strength and rigidity that they are mounted directly on the bottom wall of (for example) a "suitcase" electric piano instead of requiring a separate frame or sheet which is in turn mounted on such wall. The strengthening rails are keyed into slots in the bottom wall, for precise relative positioning of the rails. There are two balance-pin holes in each thickened shank portion, and two correspondingly spaced slots in the wall, the result being that assembly or adjustment for either light or heavy touch may he achieved at almost no added manufacturing cost.</p> |
