AU643398B2 - Improved upright piano - Google Patents

Description

64 398

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT P/00/011 Regulation 3.2 Invention Title: "Improved Upright Piano" a. oo* ao a a 0 The following statement is a full description of this invention, including the best method of performing it known to me: o o GH&CO REF: P20817J/TJS:em 1 1) A 2 This invention relates to pianos and in particular to an upright piano. However, it w 4 ll be appreciated that the invention is not limited to this particular field of use.

Generally, upright pianos incorporate a series of piano action assemblies each corresponding to a key.

Each action assembly is arranged such that the depression of a key causes a hammer associated with the piano action assembly to strike a corresponding string of the piano.

In conventional upright piano actions this is achieved by having the hammer assembly arranged in a relatively upright orientation with a butt at its lower end which is rotatably mounted on the main action rail.

The hammer assembly also incorporates a hammer head remote from the butt and is arranged to rotate from a rest position to a string striking position wherein the hammer head strikes the string.

The hammer assembly is caused to rotate on depression of the key by an assembly incorporE.ting a 20 wippen and a jack. The jack interconnects the wippen and the hammer butt and is arranged to engage the hammer butt at its lower end at a position off set from the point of pivot of the hammer butt. The jack is caused to apply an upward pressure on the hammer butt when in the rest 25 position which causes the hammer butt to rotate from the rest position to the string striking position. The jack is caused to apply this upward pressure by depression of the key which imparts a force through the wippen to the jack.

i 30 Furthermore, the jack is caused to disengage from the hammer butt as it rotates from the rest to the string striking position. The point at which this occurs is the "set off" point and the pressure that is required on the key to cause the jack to disengage is called the "set off" pressure.

Biasing means act on the hammer butt to return the hammer from the string striking position to the rest position. In addition, a jack spring acts on the jack to S:20817J 3 cause it to re-engage the hammer butt once it has disengaged the hammer butt.

A player of the piano is able to sense the "set off" point because as the hammer rotates under the influence of the jack, a resisting force is applied to the hammer butt by the biasing means. This resisting force is transmitted through the jack and wippen to the key.

However, on release of the jack from the hammer butt, this resisting forc is no longer transmitted to the key.

Therefore, as the jack is released from the hammer butt, the player senses a changing of pressure on the key.

To enable the jack to re-engage the hammer butt it is necessary to either completely release the key or the jack spring has to be highly tensioned such that it overcomes the biasing forcL acting on the hammer butt.

If the jack spring does impart a force which is greater than the biasing force, then the key does not have to be fully released, as the jack acting on the hammer butt :..-under the influence of the jack spring is able to rotate the hammer butt towards the string striking position to a position wherein the jack is able to re-engage the hammer butt.

In the repetitive playing of a piano, the keys are not fully released. Consequently, if a piano is to have 25 good repetitive playing characteristics, the piano should be arranged such that the jack spring is tensioned to a level that is greater than the biasing means when the hammer butt is near the rest position to enable the jack to re-engage the hammer butt without the key being fully 30 released.

In conventional uprighc pianos, to enable good repetitive characteristics, the biasing means has been arranged to apply a relatively low force on the hammer.

In this way the jack spring is able to overcome this force to enable the jack to re-engage the hammer butt when the key is not fully released.

However, by having the biasing means only apply a relatively low force on the hammer butt, the pressure S:20817J 4 transmitted to the key by the resisting force of the biasing means as the hammer rotates from the rest to the string position is low. Consequently, the "set off" pressure is low and the "set off" point is not clearly distinguished. This is in contrast to a grand piano key action wherein the "set off" pressure is much greater and the "set off" point is more clearly distinguished.

Because of this the key action of a grand piano has an improved "touch" which enables the player to control the iC strength and sound much more accurately.

It is an aim of a first aspect of the present invention to provide an upright piano action which more clearly distingishes the "set off" point.

It is a further aim of a first aspect of the present invention to provide a piano action which has improved repetitive playing characteristics.

:According to the first aspect of the present invention there is provided an upright piano action for a piano incorporating a piano frame, the action comprising 20 a hammer butt rotatably secured relative to the frame, a S: shank mounted to the hammer butt and supporting a hammer head thereon remote from the hammer butt, the hammer butt being rotatable between a rest position wherein the hammer head is remote from a string of the piano and a 25 string striking position wherein the hammer head strikes the string, a jack engaging the hammer butt when in the rest position and being arranged to cause the hammer butt to rotate from its rest position to the string striking position by depression of a respective key of the piano, 30 biasing means acting on the hammer butt to bias the hammer butt from the string striking position to the rest position, the biasing means being arranged to apply a first force at a first location on the hammer butt when the hammer butt is in or adjacent its rest position and to apply a second force at a second location cn the hammer butt when the hammer butt rotates from the rest position to an intermediate position between the rest and string striking positions, the first location on the S:20817J

I.

hammer butt being remote from the second location and wherein the moment of force generated by the biasing means to bias the hammer butt from the string striking position to the rest position is greater when the biasing means applies the second force on the second location of the hammer butt, than when the biasing means applies the first force on the first location of the hammer butt.

By providing a biasing means which causes a different moment of force on the hammer butt depending on the position of the hammer butt as it rotates from the rest position to the string striking position, the piano action of the present invention can be arranged to have good repetitive playing characteristics as the biasing means imparts only a low moment of force at or adjacent the rest position, yet also provides a much greater resisting force to enable a high "set off" pressure to be attained which gives rise to a clearly distinguished "set S* off" point.

gee. Notwithstanding any other forms that may fall within 20 its scope, the preferred forms of the invention will now described by way of example only with reference to the accompanying drawings in which: Figure 1 shows a first embodiment of a piano action embodying the present invention; 25 Figure 2 shows a second embodiment of a piano action embodying the present invention; Figure 3 shows the damper assembly in conjunction with the piano action of figure 1; and Figure 4 shows a diagrammatic end section of the S 30 piano; Figure 1 shows a piano action 10 in a state of rest.

As can be seen, a main action rail 11 is provided which is fixed relative to the piano frame (not shown). A wippen 12 is pivotally mounted to a lower end of the main action rail 11 and is also connected through linkage assembly 13 to the key 14. With this arrangement, depression of the key 14 activates the piano action from a state of rest and induces an upward movement of the S:20817J '4' r 6 wippen 12 causing the wippen to pivot around the main action rail 11.

A hammer assembly 15, comprising a hammer" head 16, shank 17 and hammer butt 18 is pivotally mounted about a pivot axis 19 of the hammer butt 18 to a hammer flange which is rigidly connected to an upper end of the main action rail 11.

A jack 21 interconnects the hammer butt 18 and wippen 12. The jack 21 is pivotally mounted at its lower end to the wippen 12 and is engaged at its upper end 22 to a lower arcuate surface 23 of the hammer butt 18. The jack 21 is arranged such that upward movement of the wippen 12 induced by the depression of the key 14 causes the jack 21 to apply an upward force to the arcuate surface 23 of the hammer butt 18. As the arcuate surface 23 is offset from the pivot axis 19, the hammer is caused to rotate about pivot axis 19 by the upward movement of **the jack 21 and is able to rotate the hammer butt 18 from the rest position to a string striking position (not 20 shown) wherein the hammer head strikes the strings 24 (figure 3).

The rotation of the hanmmer butt to the string striking position is resisted by biasing means attached to a return spring rail 26 and arranged to bias 25 the hammer to return to its rest position.

A back check block 27 is mounted by wire 28 to an end of the wippen 12 remote from the pivot connection of the wippen 12 to the main action rail 11. On movement of the wippen 12, due to depression of the key 14, the back 30 check 27 moves towards the hammer butt 18. A back stop 29 extends from the rear of the hammer butt 18 and is arranged such that when the key 14 is fully depressed, the back check 27 is adjacent the back stop 29.

An adjustable setoff button 30 extends from the main action rail 11 and is arranged to engage an arm 31 of the jack 21 as the jack rises due to movement of the wippen 12. The setoff button 30 is adjusted such that it will S:20817J t t I, r 7 engage the arm 31 of the jack when the key 14 is depressed a predetermined distance.

As the setoff button 30 contacts the arm 31 of the jack 21, further upward movement of the wippen 12 causes the jack 21 to rotate around its pivot connection to the wippen 12. This pivotal movement of the jack causes the upper end 22 of the jack 21 to move away from the arcuate surface 23 of the hammer butt 18, thereby releasing the jack from hammer butt and consequently, removing pressure from the jack on the hammer butt 18. The piano action is arranged such that under inertia the hammer butt continues to move to the string striking position.

The pressure applied to the key 14 which is required to disengage the jack 21 from the hammer butt 18 is called the setoff pressure and the point at which the jack disengages the hammer butt 18 is called the setoff point.

A spring 32 for the jack 21 is located beneath the arm 31 of the jack 21 and is connected to the wippen 12.

An adjustment screw 33 is located within the wippen 12 to adjust the tension of the spring 32. The jack spring 32 resists the pivoting of the jack away from the hammer butt 18 which occurs once the jack 21 contacts the setoff button 25 After the key has been depressed passed the setoff point the hammer moves to the string striking position and then returns to its rest position under the influence of the biasing means 25. Furthermore, on release of the key 14 the wippen 12 moves downwardly relative to the 30 main action rail 11, causing the jack arm 31 to disengage the setoff button 30 and also enabling the top 22 of the jack 21 to slide down the lower surface of the hammer butt 18 under the influence of the jack spring 32 to its operative position where it re-engages the arcuate surface 23 of the hammer butt 18.

In the embodiment as illustrated in figure 1, the biasing means 25 comprise a wire spring 34 which is connected at a first end to the spring return rail 26.

S:20817J 8 The wire spring 34 extends outwardly from the return rail 26 and is arranged to engage the hammer butt at a first location 35 when the hammer butt is in its rest position.

The wire spring 34 applies a force to the hammer butt 18 at the first location 35 and this causes a moment of force to be generated on the hammer butt 18 around the pivotal axis 19. With this moment of force the hammer butt is biased into its rest position.

A bearing 36 is secured to the hammer butt 18 and is arranged in a second location 37 remote from the pivot axis 19 of the hammer butt 18. The bearing 36 is arranged such that as the hammer moves from its rest position to a string stiking position the bearing engages the wire spring 34.

As the bearing 36 contacts the wire spring 34, a force is imparted onto the hammer butt at the second location 37. This force imparted at the second location .ooooi creates a larger moment of force to act on the hammer butt about the pivot axis 19 than was generated by the S* 20 force applied at the first location 35. This is primarily due to the greater distance from the second location 37 to the pivot axis 19, but another contributing factor is that the bearing 36 contacts the wire spring 34 at a point which is closer to the spring S 25 return rail 26 than the point the hammer butt contacts the wire spring at the first location, and therefore, the spring is stiffer and imparts a greater force at the second location 37 than the force imparted at the first location 30 By generating this larger moment of force acting on the hammer butt due to the bearing 36 contacting the wire 34, a greater resistance to the rotation of the hammer butt .to the string stiking position under the action of the jack occurs. This greater resistance causes a corresponding force to be imparted through the jack 21 to the key 14 which results in a greater pressure being required to depress the key which is felt by a player of the key.

S:20817J 9 The size of the moment of force caused by the bearing 36 contacting the wire 34 as well as the position at which the hammer butt, as it rotates from the rest position to the string striking position, contacts the wire 34 can be easily varied by merely adjusting the location of the bearing 36 on the hammer butt 18 to therefore move the second location 37 and/or move the point at which the bearing 36 contacts the wire 34.

It is preferred that the bearing is timed to contact the wire spring 34 immediately prior to the jack 21 being released from the hammer butt. With this arrangement, there is a sudden increase in the pressure felt by the player when the bearing 36 contacts the wire 34 followed by a sudden decrease of pressure felt by the player on release of the jack 21 from the hammer butt 18. This occurs as the pressure on the key induced as a result of the larger moment acting on the hammer butt due to the contact of the wire spring 34 with the bearing 36, is gg suddenly removed. The removal of this pressure is again 20 felt by the player of the piano. Consequently, there is an increase in setoff pressure and the player is far more easily able to distinguish the setoff point. In thit way, upright piano action 10 is more akin to a grand piano.

25 Furthermore, the biasing means 25 has benefits in improving repetition characteristics of the piano action.

In the repetitive playing of the key 14, the key is not fully released, and although the hammer is able to return to its rest position under the influence of the 30 biasing means 25, the wipen has not moved sufficiently in a downward direction to enable the jack 21 to contact the arcuate surface 23. Therefore, to enable repetition of playing when the key is not fully released it is necessary for the jack spring 32 to urge the jack 21 against the hammer butt 18 to cause the hammer butt to rotate sufficiently towards the stiking string position to enable the jack to contact the arcuate surface 23.

S:20817J 10 To enable rotation of the hammer butt towards the striking string position to occur, the force of the jack 21 must be greater than the biasing means 25 when in the rest position. To facilatate this, the biasing means is arranged such that when in the rest position, only a relatively small moment of force is imparted on the hammer butt urging it towards the rest position. This is achieved by ensuring that the first location 35 wherein the wire spring 34 contacts the hammer butt is adjacent the pivot axis 19.

In figure 1, repetition spring means 38 in the form of repetitive spring 39 and repetition cord 40 act between the main action rail 11 and the jack 21. The repetition spring means is arranged to assist the jack in returning the jack 21 to its operative position such that the combined effect of the repetition spring means 38 and jack spring 32 is greater in tension when the jack is not in its operative position then the biasing means 25 when V. in the rest position. In this way, the top 22 of the eS 20 jack 21 is able to supply sufficient force on the hammer butt 18 to counteract the biasing force of the biasing means 25 and thereby enables the hammer not to return to its rest position but to be pivoted around the pivot axis 19 sufficiently to enable the top 22 of the jack to 25 re-engage with the arcuate surface 23 in an operative position to thereby enable repetitive playing of the key without the key needing to be inully released.

Furthermore, as the jack 21 is caused to pivot when contacting the setoff button 30, the jack 21 moves away 30 from the hammer butt 18 and consequently, there is an increase in tension in the repetition spring 39. As the

S

key 14 is released the extra tension of the repetition spring 39 pulls the jack 21 back into its engaged position for faster repetition.

Even though the jack spring 32 and repetition spring 39 in combination when the jack 21 is not in its operative position is greater than the biasing means when in the rest position there is no danger that the S:20817J 11 jack spring and repetition spring alone would cause the hammer to rotate to the string striking position. This is so because as the hammer butt 18 begins to rotate under the force of the jack spring and repetition spring, the bearing 36 on the hammer butt 18 is caused to contact the wire spring 34. Once this occurs, further rotation of the hammer butt 18 solely under the influence of the jack spring 32 or repetition spring 39 would be prevented. In this way the biasing means 25 enables a greater force to act on the jack to improve the repetitive playing characteristics of the piano action Figure 2 shows a second embodiment of the piano action. The second embodiment differs from the first 15 embodiment in the arrangement of the biasing means 25 and oooo the jack spring 32.

":As illustrated in figure 2, the biasing means comprises a specifically modified wire spring 41 which S"incorporates two bearing surfaces (42 and 43). The first bearing 42 is arranged to engage the hammer butt 18 at the first location 35 when the hammer butt is in a rest ""position. The second bearing 43 is arranged to engage the hammer but. 18 at the second location 37 as the hammer butt 18 rotates to an intermediate position 0 25 between the rest position and the string striking position. With the specially modified wire spring 41 it is no longer necessary to provide the bearing 36 on the :oe•I hammer butt as illustrated in the first embodiment.

Furthermore, in the second embodiment the jack spring 44 comprises a highly tensioned coil spring With this arrangement it is no longer necessary tj incorporate the repetition spring means 39 as the coispring 45 provides sufficient force to overcome the force imparted by the biasing means 25 at the first location.

Although not shown, an adjustable wire spring similar to adjustable jack spring 32 in figure 1 may be incorporated to assist the coil spring 45 for finer control of the jack springs tension.

S:20817J 12 In an upright piano, the action and keyboard is in a fixed position. When the soft pedal is activated, the hammers move closer to the strings. In a grand piano, the action and keyboard are fix-d together and when the soft pedal is activated, the action and keyboard move sideways and the hammers strike a lesser amount of strings.

The touch changes in an upright piano when the soft pedal is activated; in a grand piano, the touch does not change when the soft pedal is activated In the embodiment shown in figure 3, the keyboard and action move sideways to be more similar to a grand piano, this is done by separating the dampers from the main rail of the upright action.

15 Figure 3 shows the piano action of figure 1 with an improved damper assembly. The damper 47 is locked on the damper main rail 48 which is attached to the piano plate *"(attachment not shown). The damper is activated when the S"key 14 rises at the string end of the piano, as the actuator 49 is caused to pivot around the damper main rail 48. This imparts a movement to the damper 44 o ""towards the string 24.

An important distinction between the prior art damper arrangement and the damper arrangement of Figure 3 .:o.oi S 25 should be noted. Previously, the damper had been operated by movement of the wippen 12. In this embodiment, as the dampers are fitted to a separate '-il (damper rail 48), it is possible for the damper to i, operated directly by the respective key 14. In this way, the operation of the dampers can be adjusted to reduce the key pressure required to operate the dampers so that the damper resistance does not adversely affect the feel of the action. Also, as the damper arrangement is fitted to a separate rail from the action and operated by direct contact with the keys, the damper arrangement can be fitted separately and prior to the fitting of the action so that the individual dampers can be separately adjusted and separately regulated to ensure that each damper S:20817J I 13 operates at the desired key position and key pressure before the action -s fitted. Usually, it is desirable for the damper to start to lift when its key has reached half of its travel.

In the embodiment as illustratud in figure 4, the strings 24 at the strike point are angled as is the action, only the keybed 50 remains the same, horizontal.

With the strings 24 and the action at this or a similar degree from the vertical, gravity is able to influence the return movement to a greater extent than in a normal upright piano. This then increases the setoff pressure and decreases the hammer return time. Having the strings at this angle allows the keys to be longer when fitted in the same size cabinet.

15 Although the invention has been described with particular reference to upright pianos, the invention may also result in an improvement of playing quality in other types of pianos and may be applied in any type of pianos.

Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be ""embodied in many other forms.

.ooooi S:20817J

Claims (13)

1. A piano action for a piano incorporating a piano frame, the action comprising a hammer butt rotatably secured relative to the frame, a shank mounted to the hammer butt and supporting a hammer head thereon remote from the hammer butt, the hammer butt being rotatable between a rest position wherein the hammer head is remote from a string of the piano and a string striking position wherein the hammer head strikes the string, a jack engaging the hammer butt when in the rest position and being arranged to cause the hammer butt to rotate from its rest position to the string striking position by depression of a respective key of the piano, biasing means acting on the hammer butt to bias the hammer butt 15 from the string striking position to the rest position, the biasing means being arranged to apply a first force io at a first location on the hammer butt when the hammer butt is in or adjacent its rest position and to apply a second force at a second location on the hammer butt when the hammer butt rotates from the rest position to an intermediate position between the rest and string striking positions, the first location on the hammer butt "'0being remote from the second location and wherein the moment of force generated by the biasing means to bias 25 the hammer butt from the string striking position to the rest position is greater when the biasing means applies the second force on the second location of the hammer butt, than when the biasing means applies the first force on the first location of the hammer butt.

2. A piano action as claimed in claim 1, wherein as the hammer butt moves from the rest position to the string striking position, the jack is caused to disengage the hammer butt, the biasing means being further arranged to apply the second force on the second location on the hammer butt immediately before the jack disengages the hammer butt.

3. A piano action for a piano incorporating a piano frame, the action comprising a hammer butt rotatably S:20817J 15 secured relative to the frame, a shank mounted to the hammer butt and supporting a hammer head thereon rpmote from the hammer butt, the hammer butt being rotatable about a pivot axis between a rest position wherein the har~xyer head is remote from a string of the piano and a string striking position wherein the hammer head strikes the string, a jack engaging the hammer butt when in the rest position and being arranged to cause the hammer butt to rotate from its rest position to the string striking position by depression of a respective key of the piano, biasing means acting on the hammer butt to bias the hammer butt from the string striking position to the rest position, the biasing means being arranged to apply a first force at a first location on the hammer butt when 15 the hammer butt is in or adjacent its rest position and og to apply a second force at a second location on the 0* *"*hammer butt when the hammer butt rotates from the rest position to an intermediate position between the rest and So*. string striking positions, the first location on the hammer butt being adjacent said pivot axis and the second location being remote from said pivot axis in a direction ""perpendicular to the pivot axis such that the moment of force generated by the biasing means to bias the hammer butt from the string striking position to the rest oeeoo S 25 position is greater when the biasing means applies the S"second force on the second location of the hammer butt, than when the biasing means applies the first force on the first location of the hammer butt.

4. A piano action as claimed in claim 3, wherein as the hammer butt moves from the rest position to the string striking position, the jack is caused to disengage the hammer butt, the biasing means being further arranged to apply the second force on the second location on the hammer butt immediately before the jack disengages the hammer butt.

A piano action as claimed in claim 4, wherein the biasing means comprises a wire spring which is arranged to contact the hammer butt at the first location S:20817J I I 16 when the hammer butt is in the rest position and to contact a bearing mounted to the hammer butt at the second location when the hammer butt moves to the intermediate position.

6. A piano action as claimed in claim 5, wherein the position of the bearing on the hammer butt is adjustable.

7. A piano action as claimed in claim 4, wherein the biasing means comprise a wire spring having first and second bearings located thereon, the first bearing being arranged to contact the hammer butt at the first location when the hammer butt is in the rest position and the second bearing being arranged to contact the hammer butt at the second location when the hammer butt moves to the 15 intermediate position. oo

8. A piano action as claimed in claim 7, wherein the position of second bearing on the wire spring is *"capable of being adjusted.

9. A piano action as claimed in claim 2 or any one of claims 4 to 8, further comprising a jack spring acting between said jack and said frame, wherein said jack is "able to re-engage said hammer butt under the influence of said spring without the key being full returned to its rest position, 25

10. A piano action as claimed in claim 9 wherein the S" jack spring only has to operate against the first force of the biasing means to enable the jack to re-engage the .ee.Oi S" hammer butt without the key being fully returned to the rest position.

11. A piano action as claimed in claim 9 or further comprising a repetition spring means acting between said jack and said frame and being arranged to assist said jack spring to re-engage said jack with the hammer butt.

12. A piano incorporating a piano action as claimed in any one of claims 1 to 11. S:20817J 'S 17

13. A piano action substantially as herein described with reference to the accompanying drawings. DATED this 10th day of November 1992 ANTHONY GERALD CAUGHT By his Patent Attorneys GRIFFITH HACK CO S:20817J 18 ABSTRACT "IMPROVED UPRIGHT PIANO" The present invention relates to an improved piano action. The piano action comprises a hammer butt rotatably secured to a frame and supporting the hammer head. The hammer butt is rotatable between a rest position and a string striking position where the hammer head strikes the string. Biasing means are provided to bias the hammer butt from the string striking position to the rest position. The moment of the force on the hammer butt provided by the biasing means depends on the position of the hammer butt as it rotates from the rest position to the string striking position. This enables the piano to C. *c S 15 have good repetitive playing characteristics. 4 O S:20817J