EP0259060A2

EP0259060A2 - Action for upright piano

Info

Publication number: EP0259060A2
Application number: EP87307330A
Authority: EP
Inventors: Paul Gerhard Wall
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-09-04
Filing date: 1987-08-19
Publication date: 1988-03-09
Also published as: EP0259060A3; KR880004419A; CA1224950A; JPS6388599A

Abstract

An action for an upright piano which emulates or simulates the action of a grand piano is provided. In the action, a back check lever (3) is positioned above the back of the key, and a grand piano whippen is positioned above the back check lever (3). The grand whippen acts on a knuckle (20) provided on a catcher arm (23) integrally connected with the hammer shank (24) at a substantial angle. Depression of the key produces upward movement of the back (1) of the key, the back check lever (3), and the grand whippen, in turn producing rotation of the catcher arm (23) which drives the hammer (27) towards the string (30). The catcher arm (23) has a catcher (45) at its forward end and the back check lever (3) has a back check (46) for catching the catcher after the hammer has rebounded from the string. A damping action is mounted independently from the hammer action.

Description

This invention relates to an action for an upright piano, the action being the mechanism which transmits the impetus given by the player's touch to the piano strings.
An ideal piano action would have the following characteristics: Firstly, the piano player should have good control over the hammer blow, in order to be able to vary the character of the notes played. Secondly, there must be escapement so that the hammer can rebound freely after striking the string, even if the key is still being depressed by the player. Thirdly, the motion of the hammer should be checked after it has rebounded from the string. Fourthly, the player should be able to repeat the note immediately and continuously if desired, even if the key is not fully released. Fifthly, the damping action should be instantaneous and silent.
Different piano actions approach these ideals to varying degrees. The action of a grand piano is generally considered to much more closely approach these ideals than the action of an upright piano. For example, the grand piano action allows for immediate and continued repetition of a note, even if the key has not fully returned to its normal (undepressed) position, while the upright action requires that the key return to or almost to its normal position before the note can be repeated. This difference is due to the superior design of the grand piano whippen assembly.
The conventional upright piano action has a single simple escapement, that of the hammer from the jack of the whippen assembly. The head of the jack is ordinarily in contact with the butt of the hammer. When the key is depressed the jack is moved upwardly, forcing the butt of the hammer to rotate upwardly about the pivot point on its flange. At a certain point before the hammer contacts the string, escapement takes place. The jack rotates out from under the butt of the hammer, freeing the hammer to continue under its own inertia towards the string and to rebound freely after impact. After rebounding from the string, the catcher is caught by the backcheck and held in this position as long as the key is depressed. In order for the note to be repeated, the key must be fully released or very nearly so, so that the jack can drop back into position under the hammer butt.
By contrast, in the grand piano action the jack can drop back under the knuckle before the key is fully released. In a grand piano action, there is a compound escapement, involving the jack coming into contact with a regulating button and being forced to rotate out from under the knuckle of the hammer, and also the repetition lever coming into contact with a drop screw. As the key is depressed, the escapement takes place and the hammer flies freely towards the string under its own inertia. After rebounding from the string, the catcher is caught by the backcheck and held in this position as long as the key is depressed. Then, when the key is released slightly, the repetition lever supports the knuckle, allowing the jack to drop back into position. Consequently, if the key is depressed again, the jack can immediately move upwards and attack the knuckle. Repeating a note immediately and continuously is thus far easier than on an upright piano.
Checking in a grand piano action must generally be more secure than in an uupright action, due to the force in the direction of the string exerted by the repetition lever on the knuckle on the hammer shank.
With respect to damping in a grand piano, the damper is held onto the string by gravity. As soon as the key is released, the damper starts to drop back onto the string. The damper is also under the direct control of the key. When the key is depressed the effect produced by gravity on the damper must be overcome. The fact that the damper is under direct control of the key and that the damper is held on the string only by gravity gives the grand piano a precise touch which is appreciated by many players.
By contrast, the damper in the upright piano is held onto the string by means of a small damper spring. When the key is depressed the force exerted by the spring on the damper must be overcome. Overcoming this force is a gradual process and the touch of the upright piano keys is consequently somewhat different from that of the grand piano. The spring may also deteriorate with time and thereby produce an inconsistent touch. If sufficient deterioration occurs, the damper may be left in imperfect contact with the string, thereby reducing its ability to dampen string vibration. Also, the damper is not under the direct control of the key but rather is activated via an intermediate lever. These factors result in a damper action which has a less controlled and consistent touch and which is more prone to mechanical problems than the damper action in a grand piano.
In addition to superior note repetition, the grand piano action has an advantage over the upright piano action in relation to the operation of the left or soft pedal, largely due to the fact that the hammer and damper actions are structurally independent of each other.
In the grand piano, when the left pedal is depressed, the keyframe slides laterally on the keybed. The hammer action is attached to the keyframe, and consequently it also slides laterally when the soft pedal is depressed. If a key in the treble section is played, the hammer ordinarily strikes three strings. However, if the key is played while the soft pedal is being depressed, the hammer will move laterally with the keyframe and strike only two strings. A softer sound will consequently be produced.
In a conventional upright piano, movement of the keyframe is not possible, because the dampers are attached to the main action rail, as are the hammer flanges. Since the dampers must not move in relation to the strings (because they must be seated properly on the strings in order to dampen string vibration), this means that the hammer action, being supported on the same main action rail, cannot move with respect to the strings. By contrast, in the grand piano, the dampers are attached to a damper flange rail which is independent from the main action rail. The keyframe can therefore be made free to move laterally when the soft pedal is used, without having the dampers shift.
In a conventional upright piano, softening is achieved by having the hammer rail move the hammers closer to the strings when the soft pedal is depressed. If a key is played with the soft pedal depressed, some of the motion normally imparted to the hammer is lost because of the shorter distance between the hammers and the strings and because of the shorter period of contact between the jack and the hammer butt resulting from the shifting of the hammer rail, so the hammer strikes the strings with less force than normal. A hammer in the treble section of the piano will normally strike three strings, but will strike them with less force than usual when the soft pedal is used, and will therefore produce a softer sound.
It is an object of the present invention to provide an action for an upright piano which emulates or simulates the grand piano action. The action allows notes to be repeated even when the key has not fully returned to its normal position, and because the hammer action and the damper action are independent, allows the keyframe to move laterally when the soft pedal is depressed.
In the action of the present invention, the conventional upright piano whippen and hammer butt have been replaced with ones such as those in the grand piano. This allows for immediate and continued repetition of notes. The damper and hammer of the present action are not located on the same action rail, but rather are set up independently on their own action rails. This independent structure allows for several advantages. Firstly, the dampers may be arranged in such a manner as to be activated by gravity, as is the case in a grand piano, and not by means of a spring, as is the case in an upright piano. Secondly, the keyframe and hammer action can be allowed to slide laterally on the keybed when the soft pedal is depressed, without moving the dampers, thereby allowing for the action of a true soft pedal.
The action allows the upright piano to play very much as if it were a grand piano, having a touch similar or identical to that of a grand piano. The action is arranged in such a manner as to fit easily into the compact size and shape of the upright piano.
Features of the invention will be described or will become apparent in the course of the following detailed description of the preferred embodiment of the invention.
The preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a side view of one note element of the action, showing it in the unactuated position; and
Fig. 2 is a view corresponding to Fig. 1, exploded to show the independence of the hammer action and the damper action.

The structure and operation of the action are as follows, described with reference to Fig. 1.
The player depresses the front of the key (not shown), which raises the back of the key 1, the key being installed in the usual lever fashion on the keyframe 2. The upward movement of the back of the key 1 raises the back check lever 3 via capstan screw 4 causing it to rotate about its flange 5, installed on a backcheck lever rail 6. The upward movement of the back check lever 3 lifts capstan screw 7, causing whippen assembly to move upwardly, rotating in about its flange 8 which is attached to the whippen rail 9.
The whippen assembly is essentially that of a grand piano, comprising a whippen arm 10 pivotally connected near its front end to a flange 8 on whippen rail 9, a repetition lever 11 pivotally connected to a repetition lever flange 12 protruding upwardly from an intermediate point of the whippen arm 10; a jack 13 pivotally connected to the whippen arm 10 near the rear end of the whippen arm, the jack comprising an upwardly-directed attack arm 14 passing through a slot 15 provided in the repetition lever 11 and a rearwardly-directed bell-crank arm 16 integral with the attack arm 14. A repetition lever spring 17 biases a jack regulating button 18 on the attack arm 14 forwardly against a stop 19 for positioning the end of the attack arm 14 directly under the knuckle 20, and at the same time biases the repetition lever 11 upwardly against a felt pad on repetition lever screw 21 such that the repetition lever 11 is prevented from ordinarily lying below the end of the attack arm 14 in the area of the knuckle 20. The stop 19 and the repetition lever screw 21 are both carried on a stop support arm 22.
The upward movement of the whippen assembly produced by depressing the key 1 causes the jack 13 to move upwards so that its attack arm 14 "attacks" the knuckle 20 on the catcher arm 23. The attack on the knuckle 20 causes the catcher arm 23 and integral hammer shank 24 to rotate about the hammer flange 25 installed on main action rail 26, thereby urging the hammer 27 away from its resting position near the hammer rail 28, towards the string 30. The hammer 27 is ordinarily assisted to its resting position by a hammer butt spring 31 between the hammer shank 24 and spring rail 29.
Just before the hammer 27 hits the string 30, the bell-crank arm 16 of the jack 13 comes into contact with the regulating button 32 attached underneath main action rail 26. The regulating button 32 causes the jack 13 to rotate counter-clockwise (with respect to the viewpoint used in the drawings), i.e. so that the attack arm 14 moves rearwardly (i.e. generally away from the front of the piano and towards the string 30) and away from underneath the knuckle 20. At essentially the same time, the rearward end of repetition lever 11 comes into contact with the drop screw 33 installed in hammer flange 25. The drop screw 33 prevents any further upward movement of the repetition lever 11. Thus the drop screw 33 and the regulating button 32 control the compound escapement of the hammer assembly from the repetition lever 11 and attack arm 14 respectively. When this escapement occurs, the hammer 27 flies towards the string 30.
The damping action will now be described. As can be seen clearly from Fig. 2, the damping action is independent of the hammer action, and is under direct control of the back of the key 1. As the key 1 is depressed, the rising back end of the key 1 come into contact with the damper lever 34, which is pivotally installed on flange 35 mounted on lower damper lever rail 36. The resulting upward rotation of the damper lever 34 lifts the damper wire 37 connected to the damper lifter flange 38, ultimately causing the upper damper lever 39 to rotate about its flange 40 installed on the upper damper lever rail 41. This rotation causes the damper 42 to be lifted off the string 30. Lead weights 43 in the damper lever 34 cause the damper 42 to return to the string 30 as the key 1 starts returning to its resting position. The right pedal lifts all of the dampers 42 from the strings 30 by acting to lift the damper lift rail 44 which raises the damper lever 34.
When the hammer 27 strikes the string 30 and rebounds, being free to do so by virtue of the escapement, the rebounding knuckle 20 lands on the repetition lever 11. Since the downward force of the rebounding hammer is greater than the force of the repetition lever spring 17, the knuckle 20 pushes the repetition lever 11 down, causing it to pivot about its flange 12. The downward motion continues until the motion of the hammer 27 is checked when the catcher 45 falls into the back check 46, which is moved into position by virtue of the raising of the back check lever 3. As in a grand action, the checking is quite secure, which is necessary because of the presence of the repetition lever. The hammer remains in the checked position as long as the key 1 is depressed.
At this point the key 1 is fully depressed, the repetition lever 11 is slightly depressed away from repetition lever screw 21 and is exerting upward pressure on the knuckle 20 by virtue of the upward force which the spring 17 exerts on the repetition lever 11. As long as the key remains depressed, the upward force of the repetition lever spring tries to push the knuckle 20 up, but cannot because the hammer is held in check. However, as soon as the key 1 is slightly released and starts to come up, the back check 46 releases the catcher 45, and the upward force exerted by the repetition lever 11 on the knuckle 20 acts to support the knuckle 20 briefly, allowing the attack arm 14 of the jack 13 to return to its starting position under the knuckle 20 as soon as it is clear of the regulating button 32. This immediate repositioning of the attack arm 14 of the jack 13 allows for immediate and continued repetition of the note if desired, without need for the key 1 to be fully released.
Whe the soft pedal (not shown) is depressed, the keyframe 2 and hammer action, including the backcheck lever rail 6, the whippen rail 9, main action rail 26, and spring rail 29, slide laterally on the keybed (not shown). If the key 1 is depressed while the soft pedal is depressed, the hammer 27 thus strikes fewer strings than usual, thereby producing a softer sound.
This is possible because as in a grand piano, the damper action is completely independent of the hammer action (as shown clearly in Fig.2), so that the keyframe and the hammer action can be move laterally without affecting the damping mechanism.

Claims

1. In an upright piano action in which each note element of the action comprises a substantially horizontal key (1) in the form of a lever pivotally connected to a frame member (2) of the piano such that the back of the key is raised when the front playing portion of the key is depressed, a back check lever (3) pivotally connected to a frame member (6) and positioned above the back of said key to be raised by upward movement of the back of the key, at least one substantially vertically-oriented piano string (30) installed on a frame member, a hammer-carrying shank (24) pivotally installed on a main action rail (26) about a horizontal axis for moving said hammer (27) towards and away from said at least one piano string, and actuating means arranged between said back check lever and said hammer shank for actuating said hammer in response to the upward movement of said back check lever, the improvement in which said actuating means for each note element comprises:
a catcher arm (23) integrally connected with said hammer shank at a substantial angle such that substantially upward movement of said catcher arm produces essentially rearward movement of said hammer towards said piano string, said catcher arm including a knuckle (20) on its lower surface and further including a catcher (45) at its forward end for engagement with a back check (46) provided on said back check lever when said key has been fully depressed and said hammer has rebounded from said piano string;
a grand whippen disposed above said back check lever, said grand whippen comprising: a whippen arm (10) pivotally connected near its front end to a whippen rail (9); a repetition lever (11) above and pivotally connected with respect to said whippen arm; a jack (13) pivotally connected to said whippen arm near the rear end of said whippen arm, said jack comprising an upwardly-directed attack arm (14) passing through a slot (15) provided in said repetition lever and a rearwardly-directed bell-crank arm (16) integral with said attack arm; and spring means (17) for biasing said attack arm of said jack forwardly against a stop (19) for positioning directly under said knuckle and for biasing said repetition lever upwardly and against a stop (21) such that said repetition lever does not ordinarily lie below the end of said attack arm in the area of the knuckle, said stops being attached above said whippen arm;
regulating means (32) positioned below said main action rail and positioned above said bell-crank arm of said jack for engaging said bell-crank arm just prior to said hammer contacting said piano string; and
means (33) fixed with respect to said main action rail and positioned for engaging said repetition lever just prior to said hammer contacting said piano string.

2. An upright piano action improvement as recited in claim 1, in which said actuating means for each note element is installed on a keyframe (2) of the piano capable of lateral movement with respect to said piano strings.

3. An upright piano action improvement as recited in claim 2, further comprising damping means including a damper lever (34) pivotally connected to a damper lever rail (36) and positioned above the back of said key to be contacted by the rising back of said key when said key is depressed, a damper wire (37) connected to said damper lever to be raised when said damper lever is raised, a damper (42) ordinarily resting on said piano strings, an upper damper lever (39) pivotally installed on an upper damper lever rail (41) connecting said damper wire and said damper for converting said upward movement of said damper wire into movement of said damper forward and away from said strings, said damping means being structurally independent from said actuating means whereby said actuating means may move laterally without said damping means being moved laterally.

4. In an upright piano action in which each note element of the action comprises a substantially horizontal key (1) in the form of a lever pivotally connected to a frame member (2) of the piano such that the back of the key is raised when the front playing portion of the key is depressed, a back check lever (3) pivotally connected to a frame member (6) and positioned above the back of said key to be raised by upward movement of the back of the key, at least one substantially vertically-oriented piano string (30) installed on a frame member, a hammer-carrying shank (24) pivotally installed on a main action rail (26) about a horizontal axis for moving said hammer (27) towards and away from said at least one piano string, and actuating means arranged between said back check lever and said hammer shank for actuating said hammer in response to the upward movement of said back check lever, the upright piano also having a damping mechanism for damping string vibrations except when a key or a foot pedal is depressed, the improvement in which said action is supported on a keyframe (2) of the piano not connected to said damper mechanism and therefore capable of lateral movement with respect to said damper mechanism and said piano strings, and in which said actuating means for each note element comprises:
a catcher arm (23) integrally connected with said hammer shank at a substantial angle such that substantially upward movement of said catcher arm produces essentially rearward movement of said hammer towards said piano string, said catcher arm including a knuckle (20) on its lower surface and further including a catcher (45) at its forward end for engagement with a back check (46) provided on said back check lever when said key has been fully depressed and said hammer has rebounded from said piano string;
a grand whippen disposed above said back check lever, said grand whippen comprising: a whippen arm (10) pivotally connected near its front end to a whippen rail (9); a repetition lever (11) above and pivotally connected with respect to said whippen arm; a jack (13) pivotally connected to said whippen arm near the rear end of said whippen arm, said jack comprising an upwardly-directed attack arm (14) pasing through a slot (15) provided in said repetition lever and a rearwardly-directed bell-crank arm (16) integral with said attack arm; and spring means (17) for biasing said attack arm of said jack forwardly against a stop (19) for positioning directly under said knuckle and for biasing said repetition lever upwardly and against a stop (21) such that said repetition lever does not ordinarily lie below the end of said attack arm in the area of the knuckle, said stops being attached above said whippen arm;
regulating means (32) positioned below said main action rail and positioned above said bell-crank arm of said jack for engaging said bell-crank arm just prior to said hammer contacting said piano string; and
means (33) fixed with respect to said main action rail and positioned for engaging said repetition lever just prior to said hammer contacting said piano string.

5. An upright piano action improvement as recited in claim 4, in which said damping mechanism includes a damper lever (34) pivotally connected to a damper lever rail (36) and positioned above the back of said key to be contacted by the rising back of said key when said key is depressed, a damper wire (37) connected to said damper lever to be raised when said damper lever is raised, a damper (42) ordinarily resting on said piano strings, an upper damper lever (39) pivotally installed on an upper damper lever rail (41) connecting said damper wire and said damper for converting said upward movement of said damper wire into movement of said damper forward and away from said strings.