Keyboard device of electronic musical instrument

[12. A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by said key and the other end stopped by said keyboard frame so as to bias said key toward a non-struck position;
• a plurality of pivot members each of which is disposed on said keyboard frame at an end of a longitudinal axis of said key to correspond to one of said keys, and has a circular surface to be brought into slidable contact with a back end portion of said key so as to allow said key to perform pivotal movement;
• said back end portion of said key being spring-biased against said circular surface of said pivot member by means of said return spring;
• and
• wherein said back end portion of the key has a bearing portion which is brought into slidable contact with said circular surface of said pivot member, said bearing portion being formed in an inner portion of an extended portion extending downward from said back end portion of said key;
• wherein said return spring engages with a portion of said key which is located in front of a stopper portion of said keyboard frame which stops said return spring so as to apply a biasing force to hold said bearing portion of said key against said circular surface of said pivot member;
• and
• wherein a vertical wall is formed at a back end of said keyboard frame, and a lock member is inserted between said vertical wall and said back end portion of said key to prevent said bearing portion from being removed from a hole formed in said keyboard frame.]

[13. A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by said key and the other end stopped by said keyboard frame so as to bias said key toward a non-struck position;
• a plurality of pivot members each of which is disposed on said keyboard frame at an end of a longitudinal axis of said key to correspond to one of said keys, and has a circular surface to be brought into slidable contact with a back end portion of said key so as to allow said key to perform pivotal movement;
• said back end portion of said key being spring-biased against said circular surface of said pivot member by means of said return spring;
• and
• wherein said pivot member is fixed at a keyboard frame portion which defines a back edge of a hole formed in said keyboard frame, has said circular surface formed by a combination of an upper semicircular portion and a lower semiconductor portion having the same radius as that of said semi-circular portion and a width smaller than that of said upper semicircular portion, and has a groove between said upper semicircular portion and said lower semicircular portion, said groove receiving said keyboard frame portion..THETA.

[17. A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by said key and the other end stopped by said keyboard frame so as to bias said key toward a non-struck position;
• a plurality of pivot members each of which is disposed on said keyboard frame at an end of a longitudinal axis of said key to correspond to one of said keys, and has a circular surface to be brought into slidable contact with a back end portion of said key so as to allow said key to perform pivotal movement;
• said back end portion of said key being spring-biased against said circular surface of said pivot member by means of said return spring;
• and
• wherein said pivot member is fixed at a keyboard frame portion which defines a back end of a hole formed in said keyboard frame, and a lock member extends to close said hole so as to prevent said back end portion of said key, which is partially fitted in said hole, from being removed
• from said]

[20. A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by said key and the other end stopped by said keyboard frame so as to bias said key toward a non-struck position;
• a plurality of pivot members each of which is disposed on said keyboard frame at an end of a longitudinal axis of said key to correspond to one of said keys, and has a circular surface to be brought into slidable contact with a back end portion of said key so as to allow said key to perform pivotal movement;
• said back end portion of said key being spring-biased against said circular surface of said pivot member by means of said return spring;
• and
• wherein said keyboard frame has a vertical wall bent downward at a back end thereof, said pivot member has an extended portion bent at said backward of said keyboard frame back end, and there is further provided a lock member disposed between a groove formed in said extended portion and a
• stopper portion formed in said vertical wall.]

[21. A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are algined on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by said key and the other end stopped by said keyboard frame so as to bias said key toward a non-struck position;
• a plurality of pivot members each of which is disposed on said keyboard frame at an end of a longitudinal axis of said key to correspond to one of said keys, and has a circular surface to be brought into slidable contact with a back end portion of said key so as to allow said key to perform pivotal movement;
• said back end portion of said key being spring-biased against said circular surface of said pivot member by means of said return spring;
• and
• wherein said circular surface has such a large radius of curvature that an imaginary center of the curvature is located on an imaginary plane behind
• said keyboard frame.]

A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys, which are aligned on said keyboard frame, and which are vertically pivotable, wherein each key of said plurality of keys has an arcuate surface at a back end portion of said each key,
• a plurality of return springs, each of which corresponds to one of said plurality of keys and biases its said corresponding one of said keys toward a nonstruck position;
• a plurality of pivot members, each of which corresponds to one of said keys and is disposed on said keyboard frame at an end of said corresponding one of said plurality of keys, each of said plurality of pivot members having an arcuate surface which is in slidable contact with said back end portion of said corresponding one of said plurality of keys, so as to allow each of said plurality of keys to perform pivotal movement,
• said each of said plurality of pivot members being immovably fixed to said keyboard frame when said corresponding one of said plurality of keys is struck and performs pivotal movement,
• said back end portion of each of said plurality of keys being spring-biased against said arcuate surface of its said corresponding one of said plurality of pivot members by means of its said corresponding one of said plurality of return springs;
• and
• regulating means, formed on opposing surfaces of said arcuate surface of each of said plurality of pivot members and said back end portion of said corresponding one of said plurality of keys, respectively, for regulating lateral movement of each of said plurality of keys in cooperation with each other.

A keyboard device of an electronic musical instrument, comprising;

• a key pivotally supported on a key support member;
• a return elastic member for applying a return force to bias said key in a non-operative state;
• a pivot point portion having a predetermined width larger than a width of a sidewall of said key in a direction of width of said key and formed such that a sectional surface thereof parallel to a surface perpendicular to the direction of width within the predetermined width is an arcuate portion, respectively;
• a pivot point abutment portion located behind a performance portion of said key and having an arcuate portion brought into slidable contact with said arcuate portion of said pivot point portion within the predetermined width, the arcuate portion of said pivot point abutment portion having the same radius of curvature as that of said arcuate portion of said pivot point portion;
• a projection formed on a circumferential surface of said pivot point portion and said pivot point abutment portion along a circumferential direction of contact circumferential surface portions of said pivot point portion and said pivot point abutment portion;
• and
• a fitting groove corresponding to said projection formed on the other
• circumferential surface.

A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by its said corresponding one of said keys and an other end stopped by said keyboard frame so as to bias each said corresponding one of said keys toward a non-struck position;
• a plurality of pivot members each of which corresponds to one of said keys and is disposed on said keyboard frame at an end of a longitudinal axis of said corresponding one of said keys, and has an arcuate surface to be brought into slidable contact with a back end portion of said corresponding one of said keys so as to allow each of said keys to perform pivotal movement;
• said back end portion of each of said keys being spring-biased against said arcuate surface of its said corresponding pivot member by means of its said corresponding return spring;
• and
• wherein said back end portion of said each key has a bearing portion which is brought into slidable contact with said arcuate surface of its said corresponding pivot member, said bearing portion being formed in an inner portion of an extended portion extending downward from said back end portion of said each key;
• wherein each of said return springs engages with a portion of said corresponding one of said keys which is located in front of a stopper portion of said keyboard frame which stops said each of said return springs so as to apply a biasing force to hold said bearing portion of said corresponding one of said keys against said arcuate surface of its said corresponding pivot member;
• and
• wherein a vertical wall is formed at a back end of said keyboard frame, and a lock member is inserted between said vertical wall and said back end portion of said each key to prevent said bearing portion from being
• removed from a hole formed in said keyboard frame.

A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by its said corresponding one of said keys and an other end stopped by said keyboard frame so as to bias each said corresponding one of said keys toward a non-struck position;
• a plurality of pivot members each of which corresponds to one of said keys and is disposed on said keyboard frame at an end of a longitudinal axis of said corresponding one of said keys, and has an arcuate surface to be brought into slidable contact with a back end portion of said corresponding one of said keys so as to allow each of said keys to perform pivotal movement;
• said back end portion of each of said keys being spring-biased against said arcuate surface of its said corresponding pivot member by means of its said corresponding return spring;
• and
• wherein each of said pivot members is fixed at a keyboard frame portion which defines a back edge of a hole formed in said keyboard frame, has said arcuate surface formed by a combination of an upper arcuate portion and a lower arcuate portion having the same radius as that of said arcuate portion and a width smaller than that of said upper arcuate portion, and has a groove between said upper arcuate portion and said lower arcuate portion, said groove receiving said keyboard frame portion.

A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by its said corresponding one of said keys and an other end stopped by said keyboard frame so as to bias each said corresponding one of said keys toward a non-struck position;
• a plurality of pivot members each of which corresponding to one of said keys and is disposed on said keyboard frame at an end of a longitudinal axis of its said corresponding one of said keys, and has an arcuate surface to be brought into slidable contact with a back end portion of said corresponding one of said keys so as to allow each of said keys to perform pivotal movement;
• said back end portion of each of said keys being spring-biased against said arcuate surface of its said corresponding pivot member by means of its said corresponding return spring;
• and
• wherein said each pivot member is fixed at a keyboard frame portion which defines a back end of a hole formed in said keyboard frame, and a lock member extends to close said hole so as to prevent said back end portion of said its corresponding one of said keys, which is partially fitted in
• said hole, from being removed from said hole.

A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by its said corresponding one of said keys and an other end stopped by said keyboard frame so as to bias each said corresponding one of said keys toward a non-struck position;
• a plurality of pivot members each of which corresponds to one of said keys and is disposed on said keyboard frame at an end of a longitudinal axis of said corresponding one of said keys, and has an arcuate surface to be brought into slidable contact with a back end portion of said corresponding one of said keys so as to allow each of said keys to perform pivotal movement;
• said back end portion of each of said keys being spring-biased against said arcuate surface of its said corresponding pivot member by means of its said corresponding return spring;
• and
• wherein said keyboard frame has a vertical wall bent downward at a back end thereof, each of said pivot members has an extended portion bent at said keyboard frame back end, and there is further provided a lock member disposed between a groove formed in said extended portion and a stopper
• portion formed in said vertical wall.

A keyboard device of an electronic musical instrument, comprising:

• a keyboard frame;
• a plurality of keys which are aligned on said keyboard frame and which are vertically pivotable;
• a plurality of return springs each of which corresponds to one of said keys and has one end stopped by its said corresponding one of said keys and an other end stopped by said keyboard frame so as to bias each said corresponding one of said keys toward a non-struck position;
• a plurality of pivot members each of which corresponds to one of said keys and is disposed on said keyboard frame at an end of a longitudinal axis of said corresponding one of said keys, and has an arcuate surface to be brought into slidable contact with a back end portion of said corresponding one of said keys so as to allow each of said keys to perform pivotal movement;
• said back end portion of each of said keys being spring-biased against said arcuate surface of its said corresponding pivot member by means of its said corresponding return spring;
• and
• wherein said arcuate surface has such a large radius of curvature that an imaginary center of the curvature is located on an imaginary plane behind said keyboard frame.