Patent ID: 8766076
Filing Date: 2014-07-01
Classification: G10H

Abstract:
1. A keyboard device for an electronic keyboard instrument, comprising: a key configured to be capable of swinging; a hammer configured to pivotally move in accordance with depression of said key, said hammer having a pressure-applying surface having a convexed shape; and a key switch configured to detect key depression information on said key, wherein said key switch comprises: a substrate having a plurality of fixed contacts provided thereon, a switch body formed of an elastic material and, having a pressure-receiving surface having a concaved shape on the sides along a longitudinal axis of the hammer and flat sides along a lateral axis of the hammer, said switch body being formed to be hollow and configured on said substrate in a manner to cover said plurality of fixed contacts, and a plurality of movable contacts provided inside said switch body in a manner opposed to said plurality of fixed contacts with respective different spacings therefrom, and configured to be sequentially brought into contact with said plurality of fixed contacts, respectively, as the pressure-receiving non-flat surface of said switch body is pressed by the pressure-applying non-flat surface of said hammer in accordance with depression of said key, to cause compressive deformation of said switch body, wherein the pressure-receiving surface of the switch body covers the plurality of movable contacts, and wherein the concaved shape of the pressure-receiving surface of said switch body, in a state not pressed by the pressure-applying surface of said hammer is shaped to be complementary identical and conform to and tightly fit within the convexed shape of the pressure-applying surface of said hammer, and wherein said switch body is disposed such that an orientation of the concaved shape of the pressure-receiving surface conforms to an orientation of the convexed shape of the pressure-applying surface of said hammer after said plurality of movable contacts are brought into contact with said plurality of fixed contacts, respectively to bring said plurality of movable contacts into stable contact with said plurality of fixed contacts, respectively to accurately detect said key depression information.