# US 9,040,807 B2 · Keyboard apparatus for an electronic musical instrument > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,807 B2 - Document ID: US9040807B2 - Status: Granted - Kind: B2 - Application number: 14/499,498 - Filed: 2014-09-29 - Published: 2015-04-02 - Granted: 2015-05-26 - Earliest claimed: 2014-09-29 - Assignees: Yamaha Corporation - Applicants: Yamaha Corporation - Inventors: Ichiro Osuga; Hiroshi Harimoto - Web page: https://patentgrep.com/patent/US9040807B2 ## CPC - G10H 1/346: {Keys with an arrangement for simulating the feeling of a piano key, e.g. using counterweights, springs, cams} - G10H: ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE ## Abstract Reaction force generation members 21w, 21b are made of elastic body to be shaped like domes, respectively, so that the reaction force generation members 21w, 21b can be elastically deformed by depression exerted in directions of axis lines Yw, Yb, respectively, to increase their respective reaction forces from the beginning with the increasing amount of elastic deformation to buckle after respective peaks of the reaction forces to reduce the respective reaction forces. By varying the directions of the axis lines Yw, Yb of the reaction force generation members between a white key 11w and a black key 11b, the respective directions in which the reaction force generation members 21w, 21b are depressed at the peaks of the reaction forces are made close to the directions of the axis lines Yw, Yb of the reaction force generation members 21w, 21b, respectively. ## Claims ### Claim 1 A keyboard apparatus for an electronic musical instrument, the keyboard apparatus comprising: a plurality of keys composed of a white key and a black key, each key pivoting about a corresponding pivot axis so that a front end of the key can move up and down, and a plurality of reaction force generation members which are provided for the plurality of keys, respectively, and each of which is depressed by a depression of a corresponding key to generate a reaction force against the depression of the corresponding key, wherein each of the reaction force generation members is made of an elastic body to be shaped like a dome, and is configured to be elastically deformed by being depressed in an axis line direction to increase the reaction force from a beginning with an increasing amount of elastic deformation to buckle after a peak of the reaction force to reduce the reaction force; and the plurality of reaction force generation members are arranged such that the axis line direction of the reaction force generation members is varied between the white key and the black key so that a direction in which each of the reaction force generation members is depressed at the peak of the reaction force is close to the axis line direction of the reaction force generation member. ### Claim 2 (depends on 1) The keyboard apparatus for an electronic musical instrument according to claim 1, wherein the plurality of reaction force generation members are placed to face depression portions of the keys, respectively, so that the reaction force generation members can be depressed by the depression portions of the keys, respectively, or the plurality of reaction force generation members are provided on the plurality of keys, respectively, so that the reaction force generation members can be depressed by depression portions provided to face the reaction force generation members, respectively; and a first angle between the axis line direction of the reaction force generation member corresponding to the white key and the axis line direction of the reaction force generation member corresponding to the black key is set to be smaller than double a second angle between a straight line which is situated on a plane orthogonal to the pivot axis of the white key and passes through a depression point of the reaction force generation member depressed by a depression of the white key at the peak of the reaction force and the pivot axis of the white key, and a straight line which is situated on a plane orthogonal to the pivot axis of the black key and passes through a depression point of the reaction force generation member depressed by a depression of the black key at the peak of the reaction force and the pivot axis of the black key. ### Claim 3 (depends on 2) The keyboard apparatus for an electronic musical instrument according to claim 2, wherein the first angle is set to be equal to the second angle. ### Claim 4 (depends on 2) The keyboard apparatus for an electronic musical instrument according to claim 2, wherein the respective depression portions of the plurality of keys, or the respective depression portions placed to face the plurality of reaction force generation members are configured such that respective normal lines of depression surfaces of the depression portions of the keys, or respective normal lines of depression surfaces of the depression portions placed to face the plurality of reaction force generation members become parallel to the axis lines of the reaction force generation members at respective peaks of the reaction forces, respectively. ### Claim 5 (depends on 1) The keyboard apparatus for an electronic musical instrument according to claim 1, wherein the plurality of reaction force generation members are configured to face respective depression portions of a plurality of pivoting bodies operating in conjunction with the plurality of keys, respectively, so that the reaction force generation members can be depressed by the depression portions of the pivoting bodies, respectively, or the plurality of reaction force generation members are provided on a plurality of pivoting bodies operating in conjunction with the plurality of keys, respectively, so that the reaction force generation members can be depressed by depression portions placed to face the reaction force generation members, respectively; and a first angle between the axis line direction of the reaction force generation member corresponding to the white key and the axis line direction of the reaction force generation member corresponding to the black key is set to be smaller than double a second angle between a straight line which is situated on a plane orthogonal to a pivot axis of the pivoting body corresponding to the white key and passes through a depression point of the reaction force generation member depressed by a pivot of the pivoting body corresponding to the white key at a peak of the reaction force and the pivot axis of the pivoting body corresponding to the white key, and a straight line which is situated on a plane orthogonal to a pivot axis of the pivoting body corresponding to the black key and passes through a depression point of the reaction force generation member depressed by a pivot of the pivoting body corresponding to the black key at a peak of the reaction force and the pivot axis of the pivoting body corresponding to the black key. ### Claim 6 (depends on 5) The keyboard apparatus for an electronic musical instrument according to claim 5, wherein the first angle is set to be equal to the second angle. ### Claim 7 (depends on 5) The keyboard apparatus for an electronic musical instrument according to claim 5, wherein the respective depression portions of the plurality of pivoting bodies, or the respective depression portions placed to face the plurality of reaction force generation members are configured such that respective normal lines of depression surfaces of the depression portions of the pivoting bodies, or respective normal lines of depression surfaces of the depression portions placed to face the plurality of reaction force generation members become parallel to the axis lines of the reaction force generation members at respective peaks of the reaction forces, respectively. ### Claim 8 A keyboard apparatus for an electronic musical instrument, the keyboard apparatus comprising: a plurality of keys composed of a white key and a black key, each key pivoting about a corresponding pivot axis so that a front end of the key can move up and down, and a plurality of reaction force generation members which are provided for the plurality of keys, respectively, and each of which is depressed by a depression of a corresponding key to generate a reaction force against the depression of the corresponding key, wherein each of the reaction force generation members is made of an elastic body, and is configured to be elastically deformed by being depressed to increase the reaction force from a beginning with an increasing amount of elastic deformation to buckle after a peak of the reaction force to reduce the reaction force; and the plurality of reaction force generation members are arranged such that a direction in which each of the reaction force generation members exerts a reaction force at the peak of the reaction force is varied between the white key and the black key so that a direction in which each of the reaction force generation members is depressed at the peak of the reaction force is close to the direction in which the reaction force generation member exerts the reaction force.