Action for upright piano

Disclosed is an action for an upright piano capable of expressing rich tone variation and improving the continuous press performance of the same key. In the action (1) for an upright piano, there are formed a guide member (67) fixed to a center rail (14) and continuing in the horizontal direction; and a member to be guided (73) sliding along the guide member (67). A hammer under rail (19) on which a hammer shank (45) abuts is affixed to a hammer rail (18), and butt flanges (41) are affixed to the member to be guided (73). The member to be guided (73) is connected to a pedal (77) via an upthrust bar (81) and a balance (79) such that the member to be guided (73) is slid to the right or left with the force of working the pedal (77) by the player.

This application is a national stage application of International Patent Application No. PCT/JP2011/003889, filed Jul. 7, 2011 (WO 2012/004999, published Jan. 12, 2012), which is herein incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to actions of an upright piano.

BACKGROUND ART

First, the terms used in the following description are defined. Unless otherwise notified, the directions of an upright piano are those seen from the piano player's side; that is, “front”, “back”, “left”, and “right” are the front, back, left and right, respectively of the upright piano, from the perspective of the piano player. “Clockwise” and “counter-clockwise” are the clockwise and counter-clockwise, respectively, from the perspective of the piano player. The term a “rest state” means a “state where no force is applied by a piano player to a key”. It also means that “the front of a key closest to a piano player is located at the highest point of its travel” The term a “ready state” means a “state of an action during the time when the key is in the rest state”. The expression that a “pedal is in the activated state” means that “a piano player is pressing a pedal” The expression that a “pedal is in the released state” means “no force is applied to a pedal by a piano player”

A typical upright piano has 88 actions. Each action comprises a key, a whippen, a jack, a hammer butt, a hammer and a strong. The typical upright piano also has a shift pedal (see, Patent Document 1). The shift pedal is connected to a half-blow rail through a trap lever and a pedal rod. The half-blow rail is rotatablyrotatably supported by a hammer-rest rail. When the action is in the ready state, the hammer is abutted to the half-blow rail.

A hammer-butt flange is secured to an action rail. The hammer butt is pivotall rotatably y supported by the hammer-butt flange. The hammer butt supports the hammer. The hammer butt also supports a back stop through a back stop shank. The whippen is rotatably supported by the action rail. The jack is rotatably supported by the whippen. A protruding end of the jack is configured in such a manner that it can pushes upward a pushed-up portion of the hammer butt. A bridle wire and a back-check wire are projected from the whippen. A back check is secured to one end of the hack-check wire.

Each string is composed of one to three piano wires. An action of an upright piano has a bridle strap (see, Patent Document 2). The bridle strap is a unique part of upright pianos. Grand pianos have no bridle strap. The bridle strap connects the back stop and the bridle wire. More specifically, the rear end of the bridle strap is connected to the junction between the back stop and the back stop shank. The front end of the bridle strap is connected to the end of the bridle wire.

Unless otherwise specified, a “length of the bridle strap” or an “expansion of the bridle strap” refers to a “length of a segment of the bridle strap extending between a point where the bridle strap is connected to the back stop and a point where the bridle strap is connected to the bridle wire”. Unless otherwise specified, a “minimum length of the bridle strap” has a similar meaning.

When the action is in the ready state, a piano player applies a force to a key to depress the key. The whippen rotates upward, the jack pushes up the hammer butt, and the hammer rotates backward. Then, the jack escapes from under the hammer butt and the hammer is disconnected from the motion of the key. The hammer returns back due to the moment of inertia to hit the string. After hitting the string, the hammer rotates forward. The back check then captures the back stop and the hammer is stopped.

Next, the piano player releases the key. The whippen rotates downward, and the back check releases the back stop. The whippen further rotates downward, and the bridle wire rotates downward along with the whippen. The distance between the back stop and the bridle wire is increased, and the bridle strap pulls the hammer butt forward. The hammer butt rotates forward along with the hammer. The rotated hammer is abutted against the half-blow rail. The time interval from the point when the back check releases the back stop to the point when the hammer is abutted against the half-blow rail is denoted by T1. In addition, when the whippen falls, the jack slips under the hammer butt. The action is returned to its ready state.

When the piano player depresses the key, the protruding end of the pushing-up portion of the jack pushes up the pushed-up portion of the hammer butt. The protruding end of the pushing-up portion of the jack is made of wood or plastic. Thus, the protruding end of the pushing-up portion is hard. The pushed-up portion of the hammer butt is covered with a piece of non-woven fabric or leather. Thus, the pushed-up portion is soft. Such a portion of the pushed-up portion that is hit by the protruding end of the pushing-up portion is pressed and become thin with time. As a result, the pushed-up portion has an uneven surface or difference in level at a boundary between a portion hit by the protruding end of the pushing-up portion and a portion that is not affected by the protruding end of the pushing-up portion.

When the piano player presses a shift pedal, the shift pedal is shifted from the released state to the activate state. The shift pedal pushes up the pedal rod through the trap lever, and the pedal rod in turn pushes up the half-blow rail. The half-blow rail rotates backward. The hammer is pushed up by the half-blow rail and rotates backward to a closer position to the string. This means that the hammer travels a shorter distance when it rotates to hit the string while the piano player is depressing the shift pedal. With the shorter rotation distance of the hammer, a weaker sound is produced when the hammer hit the string. Thus, the piano player can change degrees of loudness or softness of a note by using the shift pedal.

In the following description, a “state a” means a “state where the action is in the ready state, and the shift pedal is in the released state.” A “state b” means a “state where the action is the ready state and the shift pedal is in the activated state”. In the state a, the piano player depresses the shift pedal. The hammer rotates backward along with the hammer butt, and the back stop moves away from the bridle wire. This situation corresponds to the state b. In the state b, a distance between the back stop and the bridle wire is denoted by D9. The distance D9is a factor that determines the minimum length LB1for a conventional bridle strap.

The length LB1corresponds to a length with which the bridle strap has no slack in the state b. The length LB1also corresponds to a length with which the bridle strap does not pull the hammer butt forward in the state b. When the length of the bridle strap is less than LB1, the following problems arise. In the state a, when the piano player depresses the shift pedal, the hammer and the hammer butt rotate backward. During this, the hammer butt pulls the bridle strap backward. The bridle strap pulls the whippen upward, and the whippen rotates upward. As a result, the tail of the key is lifted and the front of the key falls, both without the piano player's intent. In order to avoid this, the bridle strap has a length of at least LB1.

CITED TECHNICAL DOCUMENTS

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

The aforementioned upright piano has following problems. Whether the piano player uses the shift pedal is independent of the number of piano wires hit by the hammer. The hammer hits the same number of piano wires at all times. The only advantage of using the shift pedal lies in that the piano player can change the degrees of loudness or softness of a note. This does not change the sound itself, only producing a monotonic sound. On the contrary, when the piano player depresses a shift pedal in a grand piano, different sounds are produced. Upright pianos are inferior to grand pianos in terms of the capacity of producing expressive sounds.

The hammer is made up of a hammer head and a hammer shank. The hammer head hits the string. In upright pianos, a certain predetermined portion of the hammer head is always used to hit the string. This fact is another reason why the upright pianos are inferior to the grand ones in terms of the capacity of producing expressive sounds. As described above, after the hammer hits the string, the back check catches the back stop. Then, the bridle strap pulls the hammer forward to its original position.

When the back check catches the back stop, a distance between the back stop and the bridle wire is smaller than the distance D9. Thus, the bridle strap has a slack. When the bridle strap pulls the hammer butt, the slack of the bridle strap affects badly. Downward rotation of the whippen increases the distance between the back stop and the bridle wire. This removes the slack of the bridle strap and the bridle strap can pull the hammer butt.

In order to remove the slack of the bridle strap, the whippen is required to rotate downward. This rotation takes a time. A time interval from the point when the back check releases the back stop and the point when the bridle strap begins to pull the hammer butt is denoted by T2. The presence of the time T2results in a shorter time T1. The time T2is a cause of worse playing of repeated notes on the single key in the upright piano.

According to a certain experiment that the present inventor knows, the piano player can play 7 repeated notes per second on the same key of an upright piano. On the contrary, the piano player can play 14 repeated notes per second on the same key of a grand piano. The present invention is directed to solve the aforementioned problems and an object thereof is to provide an action of an upright piano with which it is possible to provide more expressive change in different sounds and better playing of repeated notes on a single key.

Means to Solve the Problems

In order to solve the problem, the present invention has a following configuration. An action of an upright piano according to an invention of claim1comprises a key, an action rail extending horizontally in the right-and-left direction from the perspective of a piano player's side, a whippen rotatably supported by the action rail and located on a rear end of the key, a jack rotatably supported by the whippen, a hammer butt to be pushed up by the jack, a hammer supported by the hammer butt, and a string to be hit by the hammer, wherein a guiding member extending longitudinally along said action rail is secured to said action rail, said guiding member has a guided member that is slidable along said guiding member, said hammer butt being rotatably supported by a hammer-butt flange, the hammer-butt flange being secured to the guided member, said guided member is connected to a pedal rod via a joint member, the pedal rod being connected to a pedal, an elastic member biases said guided member in a right or left direction from the perspective of the piano player's side, and a force applied by a piano player to said pedal acts on said guided member through said pedal rod and said joint member, the force acting on said guided member having a direction that is opposite to the direction of a bias force applied by said elastic member.

When the piano player applies a force to the pedal, this force acts on the guided member through the pedal rod and the joint member. The force acting on the guided member is a force in a longitudinal direction of the guiding member and a horizontal (right to left) force. This force causes the guided member to slide along the guiding member. As in conventional upright pianos, a trap lever may be provided between the pedal and the pedal rod. The joint member connects the guided member and the pedal rod. The joint member converts a vertical force transmitted from the pedal rod into a horizontal (right-and-left) force. This horizontal force is transmitted from the joint member to the guided member.

The joint member may be, for example, a wire or a chain. The wire or the chain may be on a pulley. The joint member may be, for example, a member such as a pounder. In this case, the guided member may be rotatably connected to the member such as a pounder at any position thereon. The pedal rod is also rotatably connected the member such as a pounder at a different position thereon. The member such as a pounder may have one or more joint (s) that can be bent in the middle portion of the member.

The joint member may be, for example, a rotary member that can rotate. In this case, for example, the guided member is rotatably connected at to the rotary member a position other than the rotation center of the rotary member. The pedal rod is rotatably connected to the rotary member at a position other than the rotation center of the rotary member. The position where the guided member is connected to the rotary member is different from the position where the pedal rod is connected to the rotary member. It is preferable that a line segment connecting the rotation center of the rotary member and the joint position of the guided member is perpendicular to a line segment connecting the rotary center of the rotary member and the joint position of the pedal rod. When these two line segments cross at a right angle, the vertical force applied from the pedal rod to the rotary member is effectively converted into a horizontal (right-and-left) force. This horizontal force is applied from the rotary member to the guided member. In addition, it is preferable that the rotation center of the rotary member, the joint position of the guided member, and the joint position of the pedal rod are not on the same straight line.

The joint member may be, for example, a rack and a pinion. In this case, for example, a rack that extends horizontally in the right-and-left direction is formed on the guided member. The pinion that engages with the rack is rotatably mounted to a static member such as the action rail. In addition, an arm is provided on the pinion that is integrally operated with the pinion. One end of this arm is rotatably connected to one end of the pedal rod. When the pedal rod moves up and down, the arm of the pinion rotates, and thus the pinion rotates. The pinion is only rotated and the rotation center of the pinion is not displaced. When the pinion rotates, the rack moves from right to left or vise versa in response to a force applied by the pinion. Then, the guided member moves from right to left or vise versa along with the rack.

The elastic member biases the guided member in the right or left direction. The force applied by the elastic member may act on the guided member directly or indirectly through another member. When the piano player applies no force to the pedal, the elastic member pulls the guided member towards one end of the guiding member. When the piano player applies a three to the pedal, the guided member receives, from the joint member, a force in the direction opposite to the bias force applied by the elastic member. The guided member slides along the guiding member against the bias force applied by the elastic member. When the piano player releases the pedal and no force is applied thereto, the bias force applied by the elastic member returns the guided member to its original position before it slides.

The hammer-butt flange is secured to the guided member. Accordingly, the hammer-butt flange, the hammer butt, and the hammer slide along with the guided member. The distance along which the guided member slides is equal to the distance along which the hammer-butt flange, the hammer butt, and the hammer slide. The distance along which the guided member slides varies depending on the depth that the piano player presses the pedal. When the piano player presses the pedal to the lowest point of its travel, the distance along which the guided member slides becomes the maximum. The depth that the piano player presses the pedal depends on the magnitude of the force that the piano player applies to the pedal. When the depth that the piano player presses the pedal is equal to zero, no force is applied by the piano player to the pedal. When the piano player presses the pedal to the lowest point of its travel, the force applied by the piano player to the pedal is the maximum.

When the piano player applies a force to the pedal, the hammer slides horizontally in the right-and-left direction. This alters the position of the hammer head relative to the string. Depending on the distance along which the hammer slides, the number of piano wires hit by the hammer varies. In addition, the area on the hammer head that hits the piano wire also varies. The area on the hammer head that hits the piano wire is an area on the hammer felt that is a part of the hammer head.

Changing the number of the piano wires hit by the hammer produces different sounds when the hammer hits the string. In addition, changing the area on the hammer head that hits the piano wire produces different sounds when the hammer hits the string. When a certain portion of the hammer head often hits the piano wire, this portion is hardened. The remaining portion of the hammer head is still soft. When the hammer slides, the hardness of the area on the hammer head that hits the piano wire is changed.

The piano player can change degrees of loudness or softness of a note by means of changing the magnitude of the force to depress the key. This can eliminate a shift pedal provided in a conventional upright piano. In addition, the half-blow rail is not required to rotate backward. Accordingly, for example, the half-blow rail may be secured to the hammer-rest rail. The half-blow rail and the hammer-rest rail may be integrally formed as a single member.

Since the half-blow rail is not required to rotate backward, the back stop does not rotate backward in the action in the rest state. Thus, the minimum length LB2of the bridle strap is shorter than the aforementioned length L. This reduces the amount of the slack to be removed from the bridle strap when the bridle strap pulls forward the hammer after it hits the string. The time T2is reduced and the time T1is also reduced. Accordingly, the upright piano permits better playing of repeated notes on the single key.

The distance along which the guided member slides has an upper limit. This is because the hammer felt should hit its associated piano wire(s). If the guided member slides horizontally to the left when the piano player presses the pedal, the upper limit of the distance along which the guided member slides is a “horizontal distance in the right-and-left direction between the right edge of the hammer felt when the pedal is in the released state and the leftmost piano wire associated with the hammer felt in question”. In addition, if the guided member slides horizontally to the right when the piano player depresses the pedal, the upper limit of the distance along which the guided member slides is a horizontal distance in the right-and-left direction between the left edge of the hammer head when the pedal is in the release state and the rightmost piano wire associated with the hammer felt in question”.

In addition, the distance along which the guided member slides may affect the length LB2. Because of this, the length LB2may be increased. However, the increased amount of the length LB2is significantly smaller than the difference between the length LB2and the length LB1. Accordingly, even in such a case, the time T2is reduced and the upright piano permits better playing of repeated notes on the single key.

The action of the upright piano according to an invention of Claim2is the action of the upright piano of Claim1, wherein said jack has a pushing-up portion that pushes up said hammer butt, said hammer butt has a pushed-up portion to be pushed up by said pushing-up portion, a right edge of a protruding end of said pushing-up portion is located immediately beneath a right edge of said pushed-up portion or is away to the right from the right edge of said pushed-up portion from the perspective of the piano player's side, when the piano player applies no force to said key and said pedal, and a left edge of the protruding end of said pushing-up portion is located immediately beneath a left edge of said pushed-up portion or is away to the left from the left edge of said pushed-up portion from the perspective of the piano player's side, when the piano player applies no force to said key and said pedal.

The action having such a structure is preferable for the upright piano in which pedal is not used so frequently. The jack is rotatably supported by the whippen. The whippen is rotatably supported by the action rail. When the guided member slides, the jack does not slide. When the action is in the ready state, the pushed-up portion of the hammer butt is rest on the protruding end of the pushing-up portion of the jack. When the guided member slides in the right-and-left direction, the pushed-up portion of the hammer butt slides on the protruding end of the pushing-up portion of the jack.

If the area on the pushed-up portion of the hammer butt that contacts with the protruding end of the pushing-up portion of the jack has an uneven portion, the following problem will arise. When the protruding end of the pushing-up portion of the jack slips under the uneven portion or slips out of the uneven portion, an upward force is applied from the jack to the hammer butt. This force causes the hammer butt to bounce upward, and the hammer thus rotates backward. A larger uneven portion may result in an unexpected hit of the hammer to the string without the piano player's intent.

The following description is for the case where the pedal is in the released state and the key is in the rest state. In this case, when seen from the perspective of the piano player's side, the entire length of the pushed-up portion of the hammer butt from the right edge to the left edge is in contact with the protruding end of the pushing-up portion of the jack from above. Accordingly, when seen from the perspective of the piano player's side, the entire length of the pushed-up portion of the hammer butt from the right edge to the left edge is abutted against the pushing-up portion of the jack, and equally compressed to be thinner. Thus, when seen from the piano player's side, the pushed-up portion of the hammer butt has no level difference or uneven portion(s) between the right edge and the left edge of it.

Accordingly, when the guided member slides in the right-and-left direction, the pushed-up portion of the hammer butt smoothly slides on the protruding end of the pushing-up portion of the jack. The protruding end of the pushing-up portion of the jack never slips under any uneven portion. The protruding end of the pushing-up portion of the jack never slips out of any uneven portion. The hammer butt never bounds upward without the piano player's intent when the guided member slides. In addition, the hammer never rotates backward without the piano player's intent.

The action of the upright piano according to an invention of Claim3is the action of the upright piano of Claim1, wherein said jack has a pushing-up portion that pushes up said hammer butt, said hammer butt has a pushed-up portion to be pushed up by said pushing-up portion, a right edge of a protruding end of said pushing-up portion is always located immediately beneath a right edge of said pushed-up portion or is always away to the right from the right edge of said pushed-up portion from the perspective of the piano player's side, when the piano player applies no force to said key, and a left edge of the protruding end of said pushing-up portion is always located immediately beneath a left edge of said pushed-up portion or is always away to the left from the left edge of said pushed-up portion from the perspective of the piano player's side, when the piano player applies no force to said key.

The action having such a structure is preferable for the upright piano in which pedal is used so frequently. The following description is for the case where the key is in the rest state. It is not considered whether the pedal is in the released state or in the activated state. In this case, when seen from the perspective of the piano player's side, the entire length of the pushed-up portion of the hammer butt from the right edge to the left edge is in contact with the protruding end of the pushing-up portion of the jack from above. When seen from the perspective of the piano player's side, the entire length of the pushed-up portion of the hammer butt from the right edge to the left edge is abutted against the pushing-up portion of the jack, and equally compressed to be thinner. Thus, when seen from the piano player's side, the pushed-up portion of the hammer butt has no level difference or uneven portion (s) between the right edge and the left edge of it.

Accordingly, when the guided member slides in the right-and-left direction, the pushed-up portion of the hammer butt smoothly slides on the protruding end of the pushing-up portion of the jack. The protruding end of the pushing-up portion of the jack never slips under any uneven portion. The protruding end of the pushing-up portion of the jack never slips out of any uneven portion. The hammer butt never bounds upward without the piano player's intent when the guided member slides. In addition, the hammer never rotates backward without the piano player's intent.

The action of the upright piano according to an invention of Claim3is the action of the upright piano of any one of Claims1to3, wherein said hammer butt, a back stop shank extending from said hammer butt towards a piano player's side, and a back stop secured to an end of the back stop shank form a first assembly, a bridle wire is projected from said whippen, a bridle strap connects said first assembly and said bridle wire, a position on said bridle wire at which said bridle strap is connected thereto is defined as a first joint position, a position, on a length of said bridle strap contacting with said first assembly, that is closest to said first, joint position when said bridle strap has no slack between said first assembly and said bridle wire is defined as a first contact position, and a position in said first assembly contacting the first contact position is defined as a second contact position, a length of said bridle strap between said first joint position and said first contact position is defined as a first length, a distance between said first joint position and said second contact position when no force is applied by the piano player to said key and said pedal is defined as a first distance, provided that it is assumed that said bridle strap is not present, a distance between said first joint position and said second contact position when a distance along which said guided member slides in response to the application of force by the piano player to said pedal is the maximum and no force is applied by the piano player to said key is defined as a second distance, provided that it is assumed that said bridle strap is not present, a distance between said first joint position and said second contact position at a moment when said hammer hits said string and when no force is applied by the piano player to said pedal is defined as a third distance, provided that it is assumed that said bridle strap is not present, a distance between said first joint position and said second contact position at a moment when said hammer hits said string and when a distance along which said guided member slides in response to the application of force by the piano player to said pedal is the maximum is defined as a fourth distance, provided that it is assumed that said bridle strap is not present, and said first length is a length obtained by multiplying the longest distance of said first distance, said second distance, said third distance, and said fourth distance by a value of from 1 to 1.03.

In the following description, a “state c” means a “state in which the pedal is in the released state and the action is in the ready state”. A “state d” means a “state in which the pedal is in the activated state and the pedal is pressed to its lowest point of its travel as well as the action is in the ready state”. A “state e” means a “moment at which the hammer hits the string and the pedal is in the released state”. A “state f” means a “moment at which the hammer hits the string and the pedal is in the activated state, as well as the pedal is pressed to the lowest point of its travel”.

First, in the state c, it is assumed that the bridle strap is not present. In this case, a distance between the first joint position and the second contact position corresponds to a first distance. In the state d, it is assumed that the bridle strap is not present. In this case, a distance between the first joint position and the second contact position corresponds to a second distance. In the state e, it is assumed that the bridle strap is not present. In this case, a distance between the first joint position and the second contact position corresponds to a third distance. In the state f, it is assumed that the bridle strap is, not present. In this case, a distance between the first joint position and the second contact position corresponds to a fourth distance.

When it is assumed that the bridle strap is not present, the first joint position means the “first joint position when the bridle strap is present” while the second contact position means the “second contact position when the bridle strap is present”. Depending on the size and shape of the parts forming the action, the lengths of the first distance, the second distance, the third distance and the fourth distance also vary. The longest distance of the first through fourth distances is the minimum length for the first length.

if the first length has a length that is equal to or longer than the first distance, the front of the key does not fall without the piano player's intent in the state c. If the first length has a length that is equal to or longer than the second distance, the front of the key does not fall without the piano player's intent in the state d. If the first length has a length that is equal to or longer than the third distance, the bridle strap does not pull the hammer butt forward in the state e. In addition, the rotation speed of the hammer when it hits the string is not decreased.

If first length has a length equal to or longer than the fourth distance, the bridle strap does not pull the hammer butt forward in the state f. In addition, the rotation speed of the hammer when it hits the string is not decreased. Accordingly, when the first length is equal to or longer than the longest distance of the first through fourth distances, the front of the key does not fall without the piano player's intent. In addition, the rotation speed of the hammer when it hits the string is not decreased. The minimum length for the first length is the longest distance of the first through fourth distances.

The minimum length LB2of the bridle strap is a length as follows. First, the “position where the first assembly is connected to the bridle strap” is the “second joint position”. The “length of the bridle strap between the second joint position and the first contact position” is the “second length”. The length LB2is a total of the minimum length for the first length and the second length.

The following description is for the case where the length of the bridle strap is a “total of the length obtained by multiplying the minimum length for the first length by a value of 1 to 1.03 and the second length”. In this case, in the state e f, a slack of the bridle strap is denoted by S1. A slack S2represents a “slack of a bridle strap at the moment when a hammer hits a string in a conventional action in which a half-blow rail rotates”. The slack S1is smaller than the slack S2. Thus, the time T2is shorter than in the case of conventional actions. As a result, the upright piano permits better playing of repeated notes on the single key.

In addition, the present inventor examined how the bridle straps of different lengths affect the feeling of the piano player from the viewpoint of playing repeated notes on the single key. A “first case” means “the case where the first length is equal to the longest distance of the first through fourth distances”. A “second case” means “the case where the first length is a length obtained by multiplying the longest distance of the first through fourth distances by a value of 1.03”. A “third case” means the case where the first length is a length obtained by multiplying the longest distance of the first through fourth distances by a value larger than 1.03”. When comparing the first case and the second case, the piano player felt no difference in terms of the playing of repeated notes on the single key. However, when comparing the first case and the third case, the piano player felt that the third case is inferior to the first case in terms of the playing of repeated notes on the single key.

Accordingly, it is preferable that the first length is a “length obtained by multiplying the longest distance of the first through fourth distances by a value ranging from 1 to 1.03” from the viewpoint of the feeling that the piano player has when he or she plays repeated notes on the single key. With the first length having such a range of lengths, the action can be adjusted more easily. In addition, with the first length having such a range of lengths, it becomes easier to address the expansion and compression of the bridle strap due to temperature or humidity. It should be noted that the first contact position may vary depending on the shape end the size of the first assembly and that the second joint position also may vary. It is needless to say that the second joint position may be completely overlapped with the first contact position.

Effect of the Invention

The action of the upright piano as described above can help the piano player to play notes more expressively and can provide better playing of repeated notes on a single key.

MODES FOR CARRYING OUT THE INVENTION

Modes for carrying out the present invention are described with reference toFIGS. 1 to 8. The right side ofFIG. 1corresponds to the side where a piano player sits. The lower right ofFIG. 2corresponds to the side where a piano player sits. The bottom ofFIG. 5corresponds to the side where a piano player sits. As shown inFIG. 1, an upright piano comprises a number of actions1(only one of which is illustrated). The action1has a key12, an action rail14, a hammer-rest rail18, a whippen21, a jack30, a hammer butt36, a hammer44, and a string51.

Balance rail pins (not shown) are provided on a key frame10. The key12is supported rotatably on a balance rail pin at the center of the key12. Action brackets (not shown) are provided on each end of the key frame10. The action brackets hold the main action rail14and the hammer-rest rail18between them. A half-blow rail19is secured to the back surface of the hammer-rest rail18, and the half-blow rail19is thus static. Each of the action rail14, the hammer-rest rail18, and the half-blow rail19extends horizontally in the right-and-left direction.

The wippen21extends back and upward from the key12. The rear end of the whippen21is hinged with a whippen flange22that is connected to the lower end of the action rail14. The whippen21is rest on the tail of the key12through a heel23. The jack30is provided above the whippen21in such a manner that the jack30can pivot on a fulcrum. A back-check wire26and a bridle wire24extend upward from the front end of the wippen21. The jack30, the back-check wire26and the bridle wire24are aligned in this order from back to front.

As shown inFIGS. 1,7, and8, the front end of a bridle strap25is connected to the free end of the bridle wire24. The bridle strap25is a cloth strap. A point on the bridle strap25where it is connected with the free end of the bridle wire24is denoted as a first joint position P1. A back check27is connected to the free end of the back-check wire26.

The jack30has a jack tail31and a pushing-up portion32. The jack tail31projects upward and the pushing-up portion32extends vertically. The rear end of the jack tail31is connected to the lower end of the pushing-up portion32. The jack30has an “L” shape. At the corner of the “L” shape, the jack30is hinged with the whippen21. A protruding end of the pushing-up portion32has a horizontal (right-and-left) width of WJ(seeFIG. 6). The action rail14has a stepped portion15in the upper surface at the front end of it. The stepped portion15extends horizontally in the right-and-left direction along the longitudinal direction of the action rail14.

As shown inFIG. 2, a support member56is attached to the back of the action rail14at the left end of it. The support member56has an arm57A and an arm57B. One end of the arm57A is connected to one end of the arm57B. Thus, the support member56has an “L” shape. The lower end of the arm57A is secured to the back of the action rail14at the left end of it. The arm57A extends upward from the action rail14. The arm57B extends diagonally forward left from the upper end of the arm57A.

A joint member60is attached to the end of the arm57B. The joint member60has an arm61A and an arm61B. One end of the arm61A is connected to one end of the arm61B. The arm61A forms a right angle with the arm61B. Thus, the joint member60has an “L” shape. At the corner of the “L” shape, the joint member60is supported rotatably on the end of the arm57B so that it can pivot in a hypothetica surface. This hypothetica surface is in parallel to the action rail14and spans in a vertical direction. The joint member60serves as a rotary member. An oblong hole62is formed in the arm61A at the end of it along the longitudinal direction of the arm61A.

As shown inFIGS. 1 and 2, a guiding member67is fixed to the front surface of the stepped portion15. The guiding member67extends horizontally in the right-and-left direction along the action rail14. A groove68is formed in the front surface of the guiding member67(seeFIG. 3). The groove68extends horizontally in the right-and-left direction along the guiding member67. A closure portion69is provided at the right end of the groove68. The closure portion69closes or blocks the right end of the groove68. Upper and lower inner walls68U and68L, which are opposed to each other, are provided in the groove68. The front edges of the inner walls68U and68L form edge portions70, respectively (see,FIG. 3). Each edge portion70extends horizontally in the right-and-left direction along the guiding member67. The edge portions70project inward in the groove68. The guiding member67extends horizontally in the right-and-left direction and has a generally “C” shape in cross section (see,FIG. 3).

The groove68is covered with a guided member73. The guided member73extends horizontally in the right-and-left direction and has an “H” shape in cross section. The recess of the “H” shape engages with the edge portions70of the groove68. The guided member73is slidable in the right-and-left direction along the guiding member67. One end of a tension spring75is connected to the left end of the action rail14. The other end of the tension spring75is connected to the end of the arm61A. The tension spring75serves as an elastic member.

The guided member73has a protrusion74at its left end on the front surface. The protrusion74covers a hole62in the arm61A from the backside. The protrusion74is movable in the hole62along the longitudinal direction of the arm61A. The arm61A stands almost vertical when the right end of the guided member73is in contact with the closure portion69. In this state, the protrusion74in the hole62is closest to the rotation center of the joint member60. In addition, in this state, the arm61B extends leftward almost horizontally.

The tension spring75continuously pulls the end of the arm61A in the rightward direction. The traction force of the tension spring75is transmitted through the hole62to the protrusion74. In other words, the tension spring75continuously biases the guided member73rightward. A number of hammer-butt flanges41are secured on the front surface of the guided member73. A single hammer-butt flange41is associated with one key12, one hammer butt36and one hammer44. As shown inFIG. 1, the lower end of the hammer butt36is supported rotatably at the upper end of the hammer-butt flange41.

A pushed-up portion37is formed over the lower front portion to the lower portion of the front surface of the hammer butt36. A non-woven fabric is adhered to the pushed-up portion37. The pushed-up portion37has a horizontal (right-and-left) width of WB(see,FIG. 6). A back stop shank38is projected from an upper portion of the front surface of the hammer butt36. The back stop shank38extends forward from the hammer butt36. A back stop39is secured to the end of the back stop shank38. A combination of the hammer butt36, the back stop shank38, and the back stop39serves as a first assembly35.

As shown inFIGS. 1 and 7, a rear end of the bridle strap25is connected at a junction between the back stop shank38and the back stop39. A point on the bridle strap25where it is connected to the first assembly35is denoted as a second joint position P2(see,FIGS. 7 and 8). The hammer butt36supports the hammer44. The hammer44has a hammer shank45and a hammer head46. The hammer shank45is projected from the top surface of the hammer butt36. The hammer head46is fixed to the end of the hammer shank45. The hammer head46has a hammer moulding47and a hammer felt48. The hammer felt48is opposed to the string51. The hammer felt48has a horizontal (right-and-left) width of WH(see,FIG. 5(i)).

The half-blow rail19is positioned in front of the hammer shank45. As shown inFIG. 1, the string51is stretched behind the hammer44. As shown inFIG. 5, the string51is comprised of three piano wires52A,52B, and52C. The piano wires52A,52B, and520are aligned in this order from right to left. A horizontal (right-and-left) distance between the central axis of the piano wire52A and the central axis of the piano wire52B is denoted as DAB. A horizontal (right-and-left) distance between the central axis of the piano wire52B and the central axis of the piano wire520is denoted as DBC.

With the right end of the guided member73being in contact with the closure portion69, a piano player depresses the key12. As a result, the hammer felt48hits the piano wires52A,52B, and520at positions PA1, PB1and PC1, respectively (see,FIG. 5(i)).

The position PA1is away to the left from the right edge48R of the hammer felt48by a distance DHR. The position PB1is away to the left from the position PA1by a distance DAB. The position PC1is away to the left from the position PB1by a distance DBC. The left edge48L, of the hammer felt48is away to the left from the position PC1by a distance DHL. The horizontal (right-and-left) distance between the right edge48R and the position PC1is equal to or larger than a distance LSMAXwhich will be described later. The following mathematical formulas (1) to (3) are satisfied:
WH=DHR+DAB+DBC+DHL≧LSMAX+DHL(4)
DHR≧0  (2)
DHL≧0  (3)

As shown inFIG. 4, a pedal77is provided at a lower portion of the upright piano. The front end of the pedal77is projected forward from a knee panel (not shown). The rear end of the pedal77is supported rotatably by a base plate78so that it can pivot thereon. The central portion of the pedal77is connected to the right end of a trap lever79from below. The lower end of a pedal rod81is abutted to the left end of the trap lever79from above. The central portion of the trap lever79is supported by a fulcrum80in such a manner that the trap lever can swing thereon. As shown inFIG. 2, the upper end of the pedal rod81is connected to the end of the arm61B of the joint member60so that it can pivot thereon. In other words, the guided member73is connected to the pedal rod81through the joint member60. The pedal rod81is connected to the pedal77through the trap lever79.

When the pedal77is in the released state, the right end of the guided member73is in contact with the closure portion69(see,FIG. 2). The following description is for the case where the pedal77is in the released state and the key12is in the rest state. When seen from the perspective of the piano player, the hammer butt36is positioned relative to the jack30as shown inFIG. 6(i). The entire length from the right edge37R to the left edge37L of the pushed-up portion37is in contact with the protruding end33of the pushing-up portion32from above.

In this state, the right edge37R of the pushed-up portion37is positioned to the left from the right edge33R of the protruding end33. A horizontal (right-and-left) distance between the right edge37R and the right edge33R is denoted as DJBR. In addition, the left edge37L of the pushed-up portion37is positioned to the right of the left edge33L of the protruding end33. A horizontal (right-and-left) distance between the left edge37L and the left edge is denoted as DJBL. The distance DJBLis equal to or longer than the distance LSMAXwhich will be described later. The following mathematical formulas (4) and (5) are satisfied:
WJ=DJBR+WB+DJBL≧WB+LSMAX(4)
DJBR≧0  (5).

Next, an operation is described. The following description is for the case where the action1is in the ready state and the pedal77is in the released state. The piano player depresses the key12in the rest state. The whippen21rotates upward and the protruding end33of the pushing-up portion32of the jack30pushes up the pushed-up portion37of the hammer butt36. As a result, the hammer44rotates backward. Then, the jack30escapes from under the hammer butt36. The hammer44rotates backward due to the inertia force and hits the string51. In this case, the positions PA1, PB1, and PC1of the hammer felt48hit the piano wires52A,52E, and52C, respectively (see,FIG. 5(i)).

After hitting the string51, the hammer44rotates forward. Then, the back check27catches the back stop39and the hammer44is stopped. Next, the piano player releases the key12. The whippen21rotates downward, and the back check27releases the back stop39. The whippen21further rotates downward, and the bridle wire24rotates downward along with the whippen21. The distance between the back stop39and the bridle wire24is increased. Subsequently, the bridle strap25pulls the first assembly35forward. The first assembly35rotates forward along with the hammer44. The rotated hammer44is abutted with the half-blow rail19. In addition, when the whippen21falls, the protruding end33of the pushing-up portion32of the jack30slips under the pushed-up portion37of the hammer butt36. The action1is thus returned to the ready state.

When the bridle strap25is pulling the first assembly35, the bridle strap25has no slack. In this state, the rear end of the bridle strap25contacts with the back surface of the back stop39(see,FIG. 7(ii)). A point on the bridle strap25that is “closest to the first joint position P1on the portion contacting the back stop39” is a first contact position P3. A point on the back stop39that contacts with the first contact position P3is a second contact position P4.

“A length of a segment of the bridle strap25between the first joint position P1and the first contact position P3” is a first length L1(see,FIG. 8). “A length of a segment of the bridle strap25between the second joint position P2and the first contact position P3” is a second length L2. The length LBof the bridle strap25is a total of the first length L1and the second length L2. The bridle strap25has an extra25aahead of the first joint position P1, and an extra25bbehind the second joint position P2. The extras25aand25bare necessary to connect the ends of the bridle strap25to the first assembly35and the bridle wire24, respectively. The extras25aand25bare not included in the length LBof the bridle strap25.

The following description is for the case where the pedal77is in the released state. The piano player presses the pedal77to apply a force to the pedal77. The pedal77is activated. The front end of the pedal77falls, and the middle portion of the pedal77pulls the right end of the trap lever79downward. Then, the left end of the trap lever79rises, and the pedal rod81also rises. When the pedal rod81rises, the arm61B of the joint member60is pushed upward, and the joint member60rotates clockwise. The arm61A of the joint member60also rotates clockwise, which moves the end of the arm61A to the left. The guided member73can move only from right to left or vise versa. Thus, the protrusion74of the guided member73moves within the hole62in the arm61A toward the end of the arm61A. In other words, the protrusion74moves to the left along with the rotation of the arm61A. The arm61A pulls the guided member73to the left via the protrusion74. This means that the joint member60converts a vertical force applied to the arm61B by the pedal rod81into a horizontal force applied to the guided member73.

The guided member73pulled by the arm61A slides to the left along the guiding member67against the bias force by the tension spring75. When the guided member73slides, the first assembly35and the hammer44slide along with the guided member73. A distance that the first assembly35, the hammer44, and the guided member73slide is denoted by LS. The piano player releases the pedal77. No force is applied by the piano player to the pedal77. The pedal77returns to its released state. In this state, no force is transmitted from the pedal77to the guided member73. The guided member73slides to the right because of the bias force applied by the tension spring75and the right end of the guided member73hits the closure portion69.

When the guided member73slides to the right, the protrusion74of the guided member73moves within the hole62in the arm61A of the joint member60towards the rotation center of the joint member60. As a result of the movement of the protrusion74, a force in the right direction is applied from the protrusion74to the arm61A. Thus, the joint member60rotates counter-clockwise. The arm61A returns to its generally vertical posture while the arm61B returns to its generally horizontal posture. The protrusion74returns to the position closest to the rotation center of the joint member60in the hole62.

The distance LSdepends on the depth that the pedal77travels when the piano player presses it. In other words, the distance LSdepends on the magnitude of the force applied by the piano player to the pedal77. When the piano player presses the pedal77to the lowest point of its travel, the distance LSis equal to the longest distance LSMAX. The distance LSMAXsatisfies the following equation (6):
LSMAX≦DHR+DAB+DBC(6)

Because the mathematical formula (6) is satisfied, the hammer felt48always hits the piano wire52C regardless of the amount of the distance LS.

Even when the guided member73slides, the whippen21and the jack30do not slide. The following description is for the case where the guided member73slides horizontally in the right-and-left direction with the action1being in the ready state. In this case, the pushed-up portion37of the hammer butt36slides horizontally in the right-and-left direction while it is in contact with the protruding end33of the pushing-up portion32of the jack30from above.FIG. 6(ii) shows a relative position between the pushed-up portion37and the protruding end33after the guided member73slides to the left by the distance LSMAX.

The following description is for the case where the action1is in the ready state. In this case, regardless of the amount of the distance LS, the entire length of the pushed-up portion37from the right edge37R to the left edge37L seen from the piano player's side is in contact with the protruding end33from above. The entire length of the pushed-up portion37from the right edge37R to the left edge371, seen from the piano player's side is always abutted against the protruding end33, and equally compressed to be thinner. Thus, when seen from the piano player's side, pushed-up portion37has no level difference or uneven portion(s) between the right edge37R and the left edge37L.

Accordingly, when the action1is in the ready state and the guided member73slides, the pushed-up portion37smoothly slides on the protruding end33, in this case, the protruding end33never slips under any uneven portion. The protruding end33never slips out of any uneven portion. The hammer butt36never bounds upward without the piano player's intent. In addition, the hammer44never rotates backward without the piano player's intent.

When the piano player applies a force to the pedal77, the hammer head46slides to the left by the distance LS. Then, the relative position between the hammer felt48and the string51varies. The following relation holds between the positions at which the hammer felt48hits the piano wires52A,52B, and52C and the distance LS.

When the distance LSsatisfies the following mathematical formula (7), the positions PA2, PB2, and PC2of the hammer felt48hit the piano wires52A,52B, and52C, respectively (see,FIG. 5(ii)). The position PA2is away to the right from the position PA1by the distance LS. The position PB2is away to the right from position PB1by the distance LS. The position PC2is away to the right from the position PC1by the distance LS
0<LS≦DHR(7)

When the distance LS satisfies the following mathematical formula (8), the positions PB3and PC3of the hammer felt48hit the piano wires52B and52C, respectively (see,FIG. 5(iii)). The hammer felt48does not hit the piano wire52A. The position PB3is away to the right from the position PB1by the distance LS. The position PC3is away to the right from the position PC1by the distance LS.
DHR<LS≦DHR+DAB(8)

When the distance LSsatisfies the following mathematical formula (9), position PC4of the hammer felt48hits the piano wire52C (see,FIG. 5(iv)). The hammer felt48does not hit the piano wires52A and52B. The position. PC4is away to the right from the position PC1by the distance LS.
DHR+DAB<LS≦LSMAX(9)
Depending on the magnitude of the force applied by the piano player to the pedal77, the number of piano wires hit by the hammer head46varies. The positions on the hammer felt48at which the piano wires52A,52B, and52C are hit also vary. Therefore, the string51makes different sounds when the piano player changes the magnitude of the force applied to the pedal77.

The piano player can change degrees of loudness or softness of a note by means of changing the magnitude of the force to depress the key12. This can eliminate a shift pedal provided in a conventional upright piano. In addition, the half-blow rail19is not required to rotate backward. The following description is for the case where the pedal77is in the released state and the key12is in the rest state. In this case, the hammer butt36and the jack30may be in the following relative relation.

The entire length from the right edge37R to the left edge37L of the pushed-up portion37of the hammer butt36is in contact with the protruding end33of the pushing-up portion32of the jack30from above, seen from the piano player's side. In this state, the right edge33R of the protruding end33is immediately below the right edge37R of the pushed-up portion37. In other words, the distance DJBRis equal to zero. The left edge37L of the pushed-up portion37is away to the right from the left edge33L of the protruding end33by the distance DJBL. The distance DJBLis equal to or larger than the distance LSMAX. In this case, the mathematical formula (4) can be expressed as the following mathematical formula (10):
WJ=WB+DJBL≧WB+LSMAX(10).

Furthermore, with the mathematical formula (10), it is considered that the following mathematical formula (II) holds. In this case, when the guided member73slides to the left by the distance LSMAX, the left edge33L comes immediately beneath the left edge37L.
DJBL=LSMAX(11)

Some actions have strings each made up of two piano wires. In such a case, the string51in this embodiment can be considered to be composed of two piano wires52B and52C. Some actions have strings each made up of a single piano wire. In such a case, the string51in this embodiment can be considered to be a single piano wire52C.

Next, the length LBof the bridle strap25is described. In the following description, a “state C” means a “state in which the pedal77is in the released state and the action1is in the ready state”. A “state D” means a “state in which the pedal77is in the activated state and the pedal77is pressed to its lowest point of its travel as well as the action1is in the ready state”. A “state E” means a “moment at which the hammer44hits the string51and the pedal77is in the released state”. A “state F” means a “moment at which the hammer44hits the string51and the pedal77is in the activated state, as well as the pedal77is pressed to the lowest point of its travel”.

First, in the state C, it is assumed that the bridle strap25is not present. In this case, a distance between the first joint position P1and the second contact position P4corresponds to a first distance D1. In the state D, it is assumed that the bridle strap25is not present. In this case, a distance between the first joint position P1and the second contact position P4corresponds to a second distance D2.

In the state E, is assumed that the bridle strap25is not present. In this case, a distance between the first joint position P1and the second contact position P4corresponds to a third distance D3. In the state F, it is assumed that the bridle strap25is not present. In this case, a distance between the first joint position P1and the second contact position P4corresponds to a fourth distance D4. Depending on the size and shape of the parts forming the action1, the lengths of the first distance D1, the second distance D2, the third distance D3and the fourth distance D4also vary.

The longest distance among the first (D1) through fourth (D4) distances is the distance DMAX. If the first length L1has a length that is equal to or longer than the first distance D1, the front of the key12does not fall without the piano player's intent in the state C. If the first length L1has a length that is equal to or longer than the second distance D2, the front of the key12does not fall without the piano player's intent in the state D. If the first length L1has a length that is equal to or longer than the third distance1)3, the bridle strap25does not pull the first assembly35forward in the state E. In addition, the rotation speed of the hammer44when it hits the string51is not decreased.

If first length L1has a length equal to or longer than the fourth distance D4, the bridle strap25does not pull the first assembly35forward in the state F. In addition, the rotation speed of the hammer44when it hits the string51is not decreased. In other words, the length of the distance DMAXis the minimum length for the first length L1. When the first length L1is equal to or longer than the distance DMAX, the front of the key12does not fall without the piano player's intent and the rotation, speed of the hammer44when it hits the string51is not decreased.

Accordingly, the minimum length LB2for the bridle strap25is a total of the length of the distance DMAXand the second length L2. Next, the following description is for the case where the first length L1is equal to the length obtained by multiplying distance DMAXby a value ranging from 1 to 1.03. In this case, in the state E or F, a slack of the bridle strap25is denoted by S1. A slack S2represents a slack of a bridle strap at the moment when a hammer hits a string in a conventional action in which a half-blow rail rotates. The slack S1is smaller than the slack S2. Thus, the time T2is shorter than in the case of conventional upright pianos. As a result, the upright piano permits better playing of repeated notes on the single key12.

The present inventor compared the following fourth to sixth cases. A “fourth case” means “the case where the first length L1is equal to the distance DMAX”. A “fifth case” means “the case where the first length L1is a length obtained by multiplying the distance DMAXby a value of 1.03”. A “sixth case” means “the case where the first length L1is a length obtained by multiplying the distance DMAXby a value larger than 1.03”.

According to the experiments performed by the present inventor, the piano player felt no difference between the fourth and fifth cases in terms of the playing of repeated notes on the single key12. However, the piano player felt that the sixth case is inferior to the fourth case in terms of the playing of repeated notes on the single key12. Accordingly, it is preferable that the first length L1is a length obtained by multiplying the distance DMAXby a value ranging from 1 to 1.03 from the viewpoint of the feeling that the piano player has when he or she plays repeated notes on the single key12. With the first length L1having such a range of lengths, the action1can be adjusted more easily. In addition, with the first length L1having such a range of lengths, it becomes easier to address the expansion and compression of the bridle strap25due to temperature or humidity.

Some contemporary music compositions require piano players to depress the same key12faster and more frequently. In order to meet such requirements and allow more expressive play, the first length L1is more preferably a length obtained by multiplying the distance DMAXby a value ranging from 1 to 1.025. It is yet more preferable that the first length L1is a length obtained by multiplying the distance DMAXby a value ranging from 1 to 1.02.

The second joint position P2may be any position in the first assembly35. For example, the second joint position P2may be on the back stop shank38. The second joint position P2may be at the boundary between the hammer butt36and the back stop shank38. The second joint position P2may be on the hammer butt36. When the second joint position P2is at a position closer to the rotation center of the hammer butt36, the difference between the first distance D1and the third distance D3, the difference between the first distance D1and the fourth distance D4, the difference between the second distance D2and the third distance D3, and the difference between the second distance D2and the fourth distance D4become smaller.

The following description is for the case where the distance DMAXis equal to the first distance D1or the second distance D2in this case, in the state E or F, the bridle strap25has a slack. This slack is removed from the bridle strap25during the time after the back check27releases the back stop39and before the bridle strap25pulls the first assembly35. This slack becomes smaller as the difference between the first distance D1and the third distance D3, the difference between the first distance D1and the fourth distance D4, the difference between the second distance D2and the third distance D3, and the difference between the second distance D2and the fourth distance D4become smaller. As a result, the time T2becomes shorter.

Thus, it is preferable that the second joint position P2is closer to the rotation center of the hammer butt36from the viewpoint of providing better playing of the repeated notes on the same key12. The guided member73described in this embodiment slides to the left when the piano player presses the pedal77. If the guided member73slides to the right when the piano player presses the pedal77, an action having a structure that is like a mirror image of the action1in this embodiment.

INDUSTRIAL APPLICABILITY

The action of the upright piano according to the present invention is useful as a structure to improve the performance of the upright piano.

DENOTATION OF REFERENCE NUMERALS