Compliant mechanisms for pianos and similar instruments

Abstract

Systems, methods, and devices for improving the mechanisms of musical instruments, including piano and similar instruments, through the integration of compliant mechanisms, improved or better selected materials, and improved or better selected manufacturing processes. A device may include a damper underlever. The damper underlever may include a plurality of rigid links. The rigid links may include a damper flange, a damper lever connected to the damper flange by a first rotational connection, and a damper block connected to the damper lever by a second rotational connection. The damper underlever may also include a first compliant feature providing rotational motion between at least two rigid links.

Description

Compliant Mechanisms for Pianos and Similar InstrumentsTECHNICAL FIELD[1] The present disclosure relates to mechanisms for musical instruments generally, and more particularly to compliant mechanisms for pianos and similar instruments.BACKGROUND ART[2] Estimates for the value of the annual global musical instrument market approach $50 billion (USD), with new acoustic pianos around $1.2 billion and new electronic (hereafter also referred to as “digital” or “analog” without regard to the unique meanings of those words) pianos around $1.5 billion. Organizations invest significant dollars in acquiring and maintaining high quality instruments. The various instrument markets are competitive and require manufacturers to innovate to reduce prices, improve the quality, and / or reduce maintenance.[3] Instruments with keys are some of the most mechanically complex musical instruments, particularly the mechanisms of pianos and similar instruments. The more complex ones are finely regulated and complex combinations of linkages, pin and other joints, stops and adjustment screws, springs, and various other components that transform input to the key to play one or more notes. They can have hundreds of parts and are generally made from wood, metal, felt, leather, and various other materials. The materials and geometries tend to expand, shrink, and wear over time from use and environmental changes. This can quickly deregulate the mechanisms (by changing distances between joints, joint stiffnesses, and the integrity of the various connections), which negatively affects the way the instrument feels to musicians. Furthermore, if the joints, linkages, or materials degrade enough-such as felt or leather compressing or a pin coming out of a joint-the mechanisms can get damaged by moving in ways it is not designed for or interference with nearby mechanisms. Together, all of this leads to the need for frequent maintenance and regulation so the mechanisms make the instrument play with the desired feel. Unfortunately, the owner often has to make the undesirable choice of either (i) neglecting the instrument and letting it fall into unreasonable disrepair or (ii) invest in the labor, material and downtime to maintain it while generally getting an imperfect result. This discouraging prospect is a burden for people that prevents them from becoming musicians or leads them to abandon being musicians, reducing opportunities for the general public to benefit from the complex and inspiring music that can be played on these instruments.[4] A limited number of designs have used compliant features with narrow to no success. For example, patent US 3,545,329 teaches a mechanism made from Delrin, a U-shaped resiliency flexible hinge interconnecting an upright whip to a jack, and a U-shaped resiliently flexible hinge interconnecting an upright damper lever to its supporting flange. It does not disclose a resiliently flexible hinge other places, such as between the pin joint of the pictured whip flange and whip, between the pin joint of the pictured hammer flange and hammer butt, or between any contact surfaces. The full shortcomings are not known, but the patent was granted in 1970 and resulted in no substantial market presence for any embodiments of the patent. The ‘329 embodiments likely failed to replicate the feel of contemporary dampers and wippen / jack mechanism.[5] Similarly, US 3,651,732 is a patent granted in 1972 that resulted in no substantial market presence for embodiments of the patent. It teaches the use of one or more flexible bands made from thin sheet metal, glassfibers infused with resin, plastic tapes, or cloth tapes in tension. The bands loop back to self-intersect and appear to require inserts that fit inside the loops to provide stiffness and other structural characteristics for the mechanism. They include surface-to-surface mates between the band(s) and other components. The band(s) incorporate leaf springs as separate spring elements.[6] US 4,995,291 (granted 1991, expired 1995) depicts a grand-styled, table-top type piano consistent with the less demanding needs of a low-end digital keyboard. In it, a rod-like jack and a hammer each have a flexible piece that allows them to rotate when the key is pressed. While the ‘291 claims to preserve the particular feel of let off, it would not preserve the general feel of an acoustic piano action. Notable, this and other digital keyboards appear to forgo a hammer head at the end of the shank in lieu of a weight. Additionally, the whole mechanism is likely to wear quickly.[7] JP 6,413,395 (granted 2018) also depicts a grand-styled, electronic keyboard attempting, but failing, to feel the same as acoustic pianos through the use of bendable portions-here, for an integrated hammer flange, joint, shank, and weight as well as for an integrated wippen flange, joint, and portion that replaces what a would the wippen, jack, and repetition lever in a grand-styled mechanism. This failure highlights a failure of that disclosure to implement compliant mechanisms in a way that feels sufficiently close to a traditional piano action. This likely resulted from a general understanding of bending, but a lack of understanding compliant mechanisms (including inertial and stiffness properties of the mechanism).[8] EP 3,073,485 (granted 2021; see also JP 6,515,622 granted 2019), JP 6,511,903 (granted 2019), and JP 6,561,677 (granted 2019), filed by Yamaha Corp for grand-styled actions, teach any suitable types of hinge that allows rotation around a rotation axis as a repetition lever hinge (or the similar hinge connecting the support or wippen to the rail), including a barrel hinge, folding hinge, or an integrated blade or film. It notes that an integrally formed hinge allows for a reduction in part count. However, the use of traditional joints for the hammer, wippen, and / or other portions of the action indicate difficulty in integrating integral hinges into the action. Furthermore, the non-flexible hinge options and presence of separate springs to bias the angle of the hinge toward a starting position indicate integral hinges are not being used to significantly bias the repetition lever or wippen as well as a failure to minimize part count by integrating compliant features. Additionally, it includes a sound emission mechanism consistent with an electronic or digital piano, instruments which generally fail to replicate the feel of their non-digital grand piano counterparts-the ‘485 (and ‘622) patent specifically negates using the mechanism in acoustic pianos because this mechanism changes the feel of the playing the keys.[9] Other examples with limited use of bending or flexible portions that failed to gain a noticeable market presence include expired or abandoned US 269,405; US 1,900,488; US 3,198,053; and US 2009 / 0173206. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For a more complete understanding of the disclosure and the advantages thereof, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

[0011] Fig. 1 is a diagram of steps that can be used to design a mechanism according to various embodiments of the disclosure.

[0012] Fig. 2 is a side view of an upright piano action based on the prior art.

[0013] Fig. 3 is a side view of a grand piano action based on the prior art.

[0014] Fig. 4A is a front view of an upright piano with portions of the trapworks depicted.

[0015] Fig. 4B is a side view of a portion of a grand piano with portions of the trapworks depicted.

[0016] Figs. 5 A-F are side views of compliant damper underlever.

[0017] Fig. 6 shows a side view of a black box compliant damper underlever.

[0018] Figs. 7 A-F are side views of compliant sostenuto.

[0019] Figs. 8 A-E are side views of compliant hammers.

[0020] Figs. 9 A-D are side views of complaint wippen, jack, and / or repetition lever.

[0021] Fig. 10 shows a side view of a compliant grand piano action.

[0022] Figs. 11 A-C show various side views of compliant upright action piano.

[0023] Figs. 12 A-C show various isometric views of compliant trapwork.

[0024] Figs. 13 A-G show various side views of variable stiffness mechanisms.

[0025] Figs. 14 A-G show various side views of adjustable stops.

[0026] Figs. 15 A-B depict various views of non-integral compliant features.SUMMARY

[0027] This Disclosure is included so as to introduce, in an abbreviated form, various topics to be elaborated upon below in the Best Mode. This Summary is not intended to identify key or essential aspects of the claimed invention. This Summary is similarly not intended for use as an aid in determining the scope of the claims.

[0028] The present disclosure relates to improving the mechanisms of musical instruments, including piano and similar instruments, through the integration of compliant mechanisms, improved or better selected materials, and improved or better selected manufacturing processes. Such improvements help remove the problems described above as the joints can be integral with the linkages and can be made of high strength, flexible materials not susceptible to humidity, fatigue, unwanted motion, and wear. Joints can now be designed with tailored or customizable stiffnesses. The benefits include more robust and reliable instruments through enhancements to designs (supported by modern analysis) and manufacturing. The enhancements reduce or eliminate the need for costly mechanism regulation and maintenance. They also improve, among other things, the overall performance, part count, complexity, cost, difficulty, and time requirements of manufacturing, building, and maintaining these instruments, which all benefit the manufacturers, consumers, musicians, and those who maintain the instruments. This in turn makes the instruments more available and less burdensome for musicians, and ultimately means humanity benefits from having more music in the world.

[0029] In an embodiment, at least a portion of a mechanism in an instrument becomes the subject of interest. One or more use cases and characteristics for that portion are defined, including pertinent input links, forces, and motion; reaction forces, motion, and perceived stiffness related to that portion; output links, forces, and motion; ground points; adjustments used to regulate the instrument; and the physical space that portion of the mechanism operates in - notably, forces, motion, and perceived stiffness can contribute to the feel or other characteristics of the instrument when a musician plays it. The portion of the mechanism is redesigned toinclude a compliant mechanism while maintaining a desired characteristic of the instrument (like the feel). Material selection and manufacturing process can be significant elements of the new design.

[0030] For example, a compliant feature can provide transfer of motion and force by its own bending or elasticity. The displacement of the compliant feature and the force required to deflect it generally depend on the length and cross sectional geometry of the feature, the material properties of the feature, and conditions that affect the feature (such as gravity, energy stored in the feature that bias the bend back to a rest position, temperature, and humidity). Selection of material determines material properties, which influences the design geometry (for example changing the Young’s modulus of a material directly changes the force required to deflect a compliant feature). It is worth highlighting that the selected material determines how the material properties are affected by variations such as temperature and humidity changes. Selection of the manufacturing process affects the material properties, tolerances, and other elements of the feature.

[0031] With examples of instrument mechanisms where traditional pin joints are replaced by compliant joints, and possible linkages replaced by compliant mechanisms, the compliant joints may take the physical form of one of many different geometries and forms of compliant mechanisms ranging from simple blade flexure or small length flexural pivot to complex compliant mechanisms as determined by the needed functionality and behavior of the joints or linkages being designed to.

[0032] Take, for example, a possible application of the disclosure with a grand piano damper assembly. The damper underlever transfers motion of the key to lift the damper head off of the string(s) associated with a note. Current damper underlever designs in the prior art require approximately 17 to 24 individual parts that need to be manufactured and assembled with finish processing. One benefit of the present disclosure is that its implementation could reduce the part count to 4 to 7 parts (depending on the inherent bias required to silence the string). This helps eliminate significant burdens throughout the entire lifecycle from design to maintenance. Additionally, if the manufacturer required a certain amount of stiffness or inertial properties from the underlever, the flexures and their stiffnesses can be adjusted to accommodate that, rather than the less reliable method of adding weights to the underlever. This feature allows there to be a reduction from 4 to 7 parts to simply 4 parts. Lowering part count and manufacturing time directly leads to savings in costs and improved consistency.

[0033] In an example, a damper underlever has a ground location, a lift location, and a compliant feature that allows motion between the ground location and the lift location.

[0034] In an example, a damper underlever has a damper flange rotationally connected to a damper lever rotationally connected to a damper block and at least one of the rotational connections uses a compliant feature to allow the rotation.

[0035] These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following description and appended claims.DETAILED DISCLOSURE

[0036] This detailed description presents exemplary aspects and embodiments of the disclosure disclosed herein. No individual embodiment is meant to define the scope of the disclosure. The embodiments disclosedprovide non-limiting examples of various aspects within the scope of the claimed invention. Information that is well known to one of ordinary skill is assumed to be known and not necessarily included.

[0037] The disclosure relates to improved mechanisms for musical instruments, such as pianos, spinets, organs, and instruments that have similar mechanisms. The disclosure generally includes the integration of one or more compliant mechanisms or features within the improved mechanism. Additionally, the discerning selection of materials used in the mechanism or of manufacturing processes to produce the mechanism can significantly contribute to these improved mechanisms.

[0038] An implementation that replaces one or more portions of a musical instrument mechanism using a mechanism with a compliant feature and (a) made from a modern material with high strength, low moisture absorption, and other desirable material properties, (b) designed and analyzed to have desired stiffness and stress level (with a long fatigue life) to replicate the motion and feel of the mechanism, and (c) with a modern manufacturing method (for example injection molding) can result in benefits including: improved mechanism function, improved mechanism life, improved mechanism cost, improved manufacturing processes (less time, labor, and cost), improved maintenance requirements (less need combined with less time, labor, and cost). These improvements will positively affect instrument mechanism design, manufacture, feel during playing, maintenance, and life expectancy.

[0039] There are many challenges often associated with musical instruments and their mechanisms. For example, pianos and many other instruments often include mechanisms with wooden components, which is susceptible to humidity, temperature, and changes to both conditions. These conditions can cause physical changes in the mechanism such as thermal expansion and moisture absorption. This can affect the distances between joints, the tightness of joints (affecting joint looseness, stickiness, or stiffness), the paths links travel, and speed links travel. In many cases, this affects the feel associated with playing the instrument (like the reaction forces the player experiences playing the instrument) and requires regulation to get the instrument to have a more desired feel. In more extreme cases, this can result in additional problems such as pins walking out of joints, unwanted noise being generated within the mechanism, misalignment and twisting of or within the mechanism, failure of the mechanism to play a note properly, and even irreparable damage to the mechanism or instrument.

[0040] Additionally, wood is a relatively difficult material to design with. It is non-homogeneous with material properties that are anisotropic depending on grain direction, vary from location to location within the material, and inconsistent from tree to tree even if the trees are the same species. On the spectrum of materials, wood is soft, brittle, and relatively poor in fatigue. Instruments, by their very nature, produce sound by vibrating (which can transfer to mechanism components) and many instrument mechanisms are actuated in conjunction with producing and / or controlling the sound. Subject to such excitations, a wooden component in a mechanism can easily crack, warp, twist, wear, and break because of the energies associated with use of the instrument-results which are aggravated by environmental conditions like changes in temperature and humidity. The end result is an instrument mechanism that can quickly misalign, come out of regulation, develop a poor feel, and require expensive repairs.

[0041] Wood is a beautiful material that is in high demand, but it is a finite resource. It continues to increase in cost and becomes harder to obtain, especially for the fine quality grades used in instrument mechanisms like piano and similar actions. Additionally, because wood degrades over time and because it cannot be reconstituted once it has had portions removed, it is generally not reused or recycled in the mechanisms of pianos and similar instruments.

[0042] Some designs seek to mitigate the issues with wood through using other materials. For example, companies like Wessell, Nickel & Gross (WNG) and Kawai produce piano action mechanism parts where traditionally wooden elements are replaced with alternative materials like epoxy carbon fiber, “advanced composite material [that] is much stronger and [more] durable than wood,” ABS Styran, and ABS-Carbon (see https: / / wessellnickelandgross.com / our-action-parts / materials / and https: / / kawaius.com / technology / carbon-fiber-technology / ). These relatively modern, engineered materials tend to be less finite and may be recyclable. However, these implementations of alternative materials in lieu of wood still use felt as a liner, traditional rigid- link joints and contact surfaces-like revolute joints, passive joints, and prismatic joints-and continue to suffer from many of the problems described here.

[0043] Rigid-link joints and contact surfaces bring their own set of problems separate from the material used for the components. Many mechanisms employ revolute joints with a metal pin around which components can rotate relative to each other. Mechanisms occasionally employ passive joints and prismatic joints where a surface of one component slides or rotates against a surface of another component. Essentially all rigid-link joints in instruments inherently require space between components and create friction and other forces where rotating or sliding motion takes place between component surfaces. Such mechanisms inherently have slop and cause wear that can degrade the function of the mechanism. Similar to degradation of wooden materials, slop and ware in joints can lead to imprecise mechanism, pins walking out of joints, unwanted noise being generated within the mechanism, misalignment of or within the mechanism, failure of the mechanism to play a note properly, and even irreparable damage to the mechanism or instrument. This still results in an instrument mechanism that can quickly misalign, come out of regulation, develop a poor feel, and require expensive repairs. Additionally, contact joints often rely on friction and precise relative motion between two or more surfaces in contact with each other. The friction causes increased wear which undermines the ability of the mechanism to get the desired motion.

[0044] Felt, leather, and other materials are often used in conjunction with rigid-link joints and contact surfaces in many instrument mechanisms to limit unwanted noise and wear and to facilitate assembly. In general, these materials are less robust than wood, alternatives to wood, and other materials (pins in pin joints are generally metal), resulting in mechanism components that wear out and cause issues more quickly.

[0045] Additionally, instrument mechanisms with rigid link joints (particularly those with wooden components) are typically complex, costly and time consuming to manufacture, costly and time consuming to assemble, and costly and time consuming to maintain. This is particularly true in instruments with large numbers of such mechanisms like in the actions of pianos, organs, and similar instruments. For example, piano actions can quickly become out of regulation and feel undesirable, requiring a technician or other expert to spend hours with the piano adjusting the action to improve the feel. This creates a challenge for manyconsumers of instruments, like musicians and institutions, who either dislike or are unprepared for the upfront cost and / or intensive maintenance requirements of these instruments. If an instrument remains un-maintained, a musician may enjoy playing less and the instrument tends to get worse, compounding the problem. This in turn creates a burden that prevents potential musicians from beginning to play an instrument or musicians to abandon playing one once they have started.

[0046] In an embodiment of an instrument mechanism of the disclosure where a pin joint has been removed or replaced with a compliant feature, preferably one made from alternative materials such as high strength and flexible polymers with a low rate of moisture absorption, many of the issues facing current instruments lessen or disappear all together, thereby improving the instrument’s mechanism. In addition to removing wood, the embodiment likely removes some felt, further improving the mechanism. Furthermore, implementation of a compliant feature in lieu of a rigid joint or contact surface reduces the part count (by integrating multiple parts into one), manufacturing cost and time, and assembly cost and time. Implementation of engineered polymers further reduces the manufacturing cost because it is less expensive to make these mechanism parts out of polymers than wood. Because a redesigned, compliant version of an instrument mechanism is more robust and reliable than its current counterpart, there is less need for regular maintenance and regulation of instrument mechanisms such as actions, pedals, and similar mechanisms. Additionally, the inclusion of an adjustment in some implementations allows further control of the compliant mechanism, improving the ability of the mechanism to replicate the feel of the current non-compliant counterpart.

[0047] Implementations of the disclosure include a mechanism of a musical instrument where the desired motion and force transfer are achieved through the integration of a compliant feature. This may come in the form of redesigning an existing mechanism of a musical instrument to include one or more compliant features. It may also come in the form of replacing an existing mechanism with a compliant mechanism that transfers motion or force in an unconventional way.

[0048] Implementation of the disclosure benefits from understanding the function and / or workings of a selected instrument mechanism; the compliant features or linkages which could be incorporated to perform, augment, or improve the function of the mechanism; and the possible manufacturing processes and materials that could be used to make the improved mechanism.

[0049] FIG. 1 comprises steps that can be followed in to create a compliant mechanism for a musical instrument 100 such as those found in the action, trapworks and pedals, or other portions of a piano and similar instruments. The steps consist generally of identifying a mechanism 110, determining a characteristic of the mechanism 130, designing a compliant mechanism 150 (including analyzing), and integrating the compliant mechanism 170. Each step includes substeps associated with the step and FIG. 1 lists exemplary substeps that may or may not be required for an embodiment of the disclosure.

[0050] Identifying a mechanism 110 refers generally to determining the part of the instrument that will be redesigned. Exemplary substeps associated with identifying a mechanism 110 include identifying or selecting: a portion of a mechanism of a musical instrument 112 to be redesigned (use of the word “portion” is not meant to prevent a whole mechanism from being selected or identified, just to point out that a subset of the mechanism can be the subject of redesign), a use case 114 for the portion of the mechanism which will serveas a benchmark for designing the compliant mechanism, a physical operating space 116 in which the portion of the mechanism operates, an input link 118 for the portion of the mechanism, and an output link 120 for the portion of the mechanism.

[0051] Determining a characteristic of the mechanism 130 refers generally to creating a baseline for a portion of the mechanism 112 during use case 114 against which the compliant mechanism will be compared. Exemplary substeps associated with determining a characteristic of the mechanism 130 include determining at least one of the following for use case 114: input energy 132 applied to the input link, “feel” or haptic response 134, reaction energy 136 from input energy 132, output energy 138 at output link 120, motion of input link 140, motion of output link 142, and an adjustment 144 to modify the operation of the portion of the mechanism 112. Often, multiple characteristics will serve as a baseline for a given use case.

[0052] Referring to “feel” or haptic response 134, this is meant to refer to any response of the mechanism that is detectable outside the system of the mechanism. While not meant to be exhaustive, examples of this include a response sensed by a person playing the instrument, a response acting where the input energy is applied, and a response detected by a sensor used by a system to help control an input. Playing an instrument results in reactionary forces that are experienced by who or whatever is providing the input to the instrument, which a person or input device could experience as a resistance to the input. Additionally, any and all of a person’s senses can contribute to the experience that person has when they play a the instrument, which can include feeling reaction forces in keys and / or pedals, hearing sounds based on how they’re playing the instrument, seeing the motion of the instrument as a whole or portions of the piano. Similarly, a system could monitor the instrument’s response to an input using any number and variety of sensors which could detect countless types of responses. Furthermore, the detected responses could be used to determine additional or future inputs to the instrument. Senses and sensors can detect, for example, sound, reaction forces, output forces, motion, and temperature. These can represent individual moments or data points: they can also be viewed over time.

[0053] As used herein, “energy” can manifest in many forms, including work, power, force, torque, moment, pressure, stress, and heat; one common measurement for “energy” in the piano industry is “grams friction.” Energy can be measured instantaneously or over a period of time. It is usually broken into 2 subsets: Kinetic and Potential. Energy can go into the mechanism, be stored in the mechanism, and exit the mechanism. Its use is meant to convey that a characteristic with “energy” can be sensed or measured.

[0054] Designing a compliant mechanism 150 refers generally to using a compliant element in a replacement for portion 112 to replicate the characteristic determined in step 130. Exemplary substeps associated with designing a compliant mechanism 150 include making the design so it: operates in the physical operating space 152, replicates the reaction energy 154, replicates the “feel” or haptic response 156 (while not the only factors affecting the feel or haptic response, the stiffness of the joint and various other moments affecting the mechanism contribute to the feel or haptic response), replicates the output energy at output link 158, replicates the input link motion 160, replicates the output link motion 162, includes a compliant element 164, includes the adjustment 166, and validates the compliant design 168 against the baseline. Validating against thebaseline can be done multiple ways, including hand calculations modeling implementations, computer simulations of electronic implementations, and tests of physical implementations.

[0055] Integrating the compliant mechanism 170 refers generally to implementation of a design into a musical instrument. The exemplary substeps of integrating the compliant mechanism into musical instrument 172 should be done in a way that preserves the characteristic determined in step 130.

[0056] Understanding the Mechanism

[0057] The amount of understanding about a current musical instrument mechanism that is required to implement a compliant mechanism version depends on the type of implementation being done. At the broadest level, the most important aspects are to provide the feel a musician expects in playing the instrument and to control the sound output as expected in conjunction with the feel. For example, playing a key or pressing a pedal should feel a certain way and produce expected note(s) (including dynamics and length of note). This broad level is consistent with a black-box type of approach that allows complete freedom regarding the mechanism itself so long as the feel or other desired characteristic is reproduced by the mechanism.

[0058] At the opposite end of the spectrum in reproducing the feel is understanding every element of the mechanism and being able to fully reproduce each element. This approach is the kind that enables implementation of compliant mechanism and other technologies to sub-parts of the mechanism without having to make changes to the rest of the mechanism. Some factors that are often critical are the link lengths, distances between joints and contact surfaces, friction or resistance at the joints and contact surfaces, compression of the materials, and spring forces. For example, as felt lining pin joints or other contact surfaces wears out, it often compresses with less springing back to its as-installed shape, undermining proper regulation. Leather can face the same issue.

[0059] Since the disclosure includes both approaches, some example actions are discussed below. In general, the design (and deviation from design through adjustments, wear, and other factors) results in various reaction forces felt in the key (or other input lever, knob, or other input link) by the musician or other driver as the key actuates. Additionally, a musician or system can detect other reactions from the instrument through other senses. The experience of the user or system during play comprises the feel (or haptic response) of the instrument. The feel can be measured through various techniques. For example, piano mechanisms (including action parts such as the wippen, jack, hammer, and, when present and engaged, the repetition lever and damper) contribute to and are typically regulated and adjusted based on an acceptable range for touchweight. Touchweight refers to the amount of weight required to be applied to the front end of a key for the key to start rotating “downweight” or still lift “upweight.” Downweight is often around 40-60 grams, may target 47-56 grams or even 48-52 grams, but may be below 28 grams or higher than 87 grams. Upweight is often between 10-32 grams, may target 20 grams within + / - 4 grams. The mechanism parts and joints have weight, stiffness or resistance to motion, spring force which biases the parts, and other factors that contribute to the touchweight and overall response.

[0060] Additionally, there are published materials that describe characteristics that contribute to the feel in significant detail-included herein by reference are examples “Piano Servicing, Tuning, and Rebuilding” byArthur A. Reblitz (The Vestal Press, LTD, 1992) and “Pianos Inside Out” by Mario Igrec (In Tune Press, Inc. 2014). There are additional descriptions for pianos and other instruments with similar mechanisms. Once the feel is understood, it can be reproduced in the implementation of the disclosure (if desired).

[0061] Examples of relevant instruments include upright pianos, grand pianos, ravenchords, historical pianos, digital pianos, organs, electric keyboards (such as synthesizers and stage keyboards), clavichords, harpsichords, keytars, accordions, and the numerous variations on them. The following parts and mechanisms, their motions, and their interactions with other components are known within the musical instrument industries and are provided to establish the names and features by which they are called herein. However, a specific characteristic used in designing a compliant mechanism may still require measurement or other examination.

[0062] Fig. 2 depicts an example of an upright piano action model. It includes key 201; stop 202; weight 203; key front 204; balance rail 205; rest 206; capstan 207; wippen or whippen 213; jack flange 214; jack spring 215; jack knuckle 216; jack 217; bridle wire 218; back check 219; bridle strap 220; ground 221; letoff regulation button 222; butt felt 223; back stop 224; hammer butt 225; hammer shank 226; hammer head 227; hammer felt 228; wippen flange 230; damper spoon 231; ground 232; hammer flange 233; damper lever 234; damper flange 235; damper stop 237; damper wire 238; damper head 240; damper felt 421; string 242; hammer rail 243. Other implementations also include an abstract or sticker with a flange that mounts to ground rail.

[0063] Some common properties of the upright action parts and their joints include grams friction (g), torque (mm-g), and range of motion (arc degrees). For example, there are pin joints associated with the wippen (wippen flange 230 to the rest of wippen 213), jack (jack flange 214 on the wippen to the rest of jack 217), damper (damper flange 235 to damper lever 234), and hammer (hammer flange 233 to hammer butt 225). While the values associated with these parts depends upon the action design, common values are as follows. The wippen often has values in the range of 1.4-4.0 g, 37-100 mm-g, and 2-4 arc degrees. The jack often has values in the range of 0.5-4.0 g, 12-100 mm-g, and 5-8 arc degrees. The damper often has values in the range of 1-8 g, 50-400 mm-g, and 2-4 arc degrees. The hammer often has values in the range of 1.5-4.0 g, 37-100 mm-g, and 10-12 arc degrees.

[0064] Fig. 3 depicts an example of a grand piano action model. It includes key 301; stop 302; weights 303; key front 304; balance rail 305; rest 306; capstan 307; wippen or whippen 313; wippen spoon 314; combination spring 315; jack knuckle 316; jack 317; repetition flange 318; repetition lever 319; repetition button 320; ground 321; letoff button 322; drop screw 323; hammer pin 324; hammer knuckle 325; hammer shank 326; hammer head 327; hammer felt 328; hammer shank base 329; wippen flange 330; damper spoon 331; ground 332; hammer flange 333; damper lever 334; damper flange 335; damper sostenuto 336; ground 337; damper wire 338; damper block 339; damper head 340; damper felt 341; string 342.

[0065] Some common properties of the upright action parts and their joints include grams friction (g), torque (mm-g), and range of motion (arc degrees). For example, there are pin joints associated with the wippen (wippen flange 330 to the rest of wippen 313), jack (wippen 313 on to jack 317), repetition lever (repetition flange 318 to repetition lever 319), damper (damper flange 335 to damper lever 334), and hammer (hammerflange 330 to hammer shank base 329). While the values associated with these parts depends upon the action design, common values are as follows. The wippen often has values in the range of 1.4-4.0 g, 37-100 mm-g, and 2-4 arc degrees. The jack often has values in the range of 0.5-4.0 g, 12-100 mm-g, and 5-8 arc degrees. The repetition lever often has values in the range of 1.4-4.0 g, 37-100 mm-g, and 2-4 arc degrees. The damper often has values in the range of 2-4 g, 40-100 mm-g, and 4-7 arc degrees. The hammer often has values in the range of 1.5-4.0 g, 37-100 mm-g, and 10-12 arc degrees.

[0066] Figs. 4 A-B depict examples of trapworks in various pianos with some internal components shown (as dashed lines); 4 A is an upright piano seen from the front and 4B is a portion of a grand piano seen from the side. The right pedal is generally the “sustain” or “damper” pedal which moves the dampers off the string (such as with rail 422B); the left pedal is generally the “soft” or “una corda” pedal which brings the hammers closer to the string (such as with rail 425 A) or shifts the action sideways so the hammers don’t play as effectively; and the center pedal can serve one of many functions, including “sostenuto” (which rotates sostenuto bar 426B to sustain individual notes) and “silent” (which drops cloth curtain 430A between the hammer and strings). Trapworks generally also include pedals 410, levers and rods 415, pins 416, fulcrums 418, springs 419, hinges 420, felt, and miscellaneous hardware (like screws, washers, and nuts) which create a system that engages with the action to control the notes. The grand piano trapworks has many similar elements arranged in configurations more suited to the grand piano. A trapwork may also include springs. The feel of the trapworks varies greatly depending on the design of the specific mechanism, including the purpose, level lengths, pivot locations, weights of the various parts in the mechanism, any springs in the design, and friction in the joints.

[0067] The other relevant instruments have actions and other mechanisms which are well known. Organs, for example, have tracker actions which use mechanical linkages, direct electric actions which use electrical connections, electro-pneumatic actions which use an electrically assisted pneumatic system, and tubularpneumatic actions which use pressure changes to actuate pneumatic valves. Clavichords employ a class 1 lever, where the key is pressed on one side, forcing a brass tangent placed on the distal end of the key lever to directly strike the string. A harpsichord takes this lever and adds an extension on the distal end of the key lever to allow the string to be plucked rather than struck. The fortepiano was invented to introduce two new features, musical dynamic ranges (forte = loud, piano = soft), and rapid playing (double repetition). This was accomplished by compounding the mechanical advantage of several levers on top of each other.

[0068] Compliant Mechanisms and Features

[0069] A compliant mechanism is a mechanism designed with at least one relatively flexible portion that allows the mechanism to bend or deform relative to itself to transfer and / or transform motion, force, or other energy (aka flexure or compliant feature). This is done by ensuring that at least part of the mechanism (a compliant feature) is made using a design and material that will deform and / or deflect in a desired way to store energy (like a spring) and / or provide a desired output based on an input motion, force, or other energy. Careful design of the compliant feature can allow the energy storage and output to have very specific behaviors and / or characteristics. Compliant features are generally designed to deform elastically, meaning they will not permanently deform and will perform consistently through numerous cycles of use. Compliantmechanisms can be contrasted with traditional mechanisms, which are made from rigid links connected by movable joints and often have separate springs to store energy and / or bias the mechanism toward a preferred state. The flexibility and energy storage of compliant features naturally bias a compliant mechanism toward a preferred state, such as a one or more rest positions (stops or other elements of the mechanism may prevent a flexure from reaching a natural rest position in lieu of an overall rest position for the mechanism). Since compliant mechanisms depend on their own relative flexibility, mechanisms made with compliant features can often be made with fewer parts than their traditional mechanism counterparts.

[0070] As mentioned previously, there is a spectrum upon which compliant mechanisms can be implemented within musical instruments, such as in the mechanisms of keyed instruments. Again, black-box replacement is on one side and one-to-one joint replacement is on another. Included between those two are various alternatives, such as replacing sub-portions of mechanisms with compliant mechanisms in the black-box style. There will be a multitude of possible implementations for any given mechanism and the selection of the specific implementation includes factors outside the scope of the disclosure such as the degree to which the feel and other aspects of preceding mechanisms will be replicated in the implementation, material selection, design and manufacturing costs, manufacturability, expected life of the instrument, the external environment the mechanism will experience, to name a few.

[0071] As such, it will be helpful to understand compliant joints and mechanisms generally and the types which are possible. Incorporated herein by reference are the books “Compliant Mechanisms” by Larry L. Howell (John Wiley & Sons, Inc., 2001) and “Handbook of Compliant Mechanisms” edited by Larry L. Howell, et. al (John Wiley & Sons Ltd., 2013). Both include descriptions of compliant mechanisms; various ways of modeling and predicting the motion, stresses, and other properties of compliant joints, features, and mechanisms; and other helpful information related to mechanisms that implement compliance to transfer motion and energy. “Handbook of Compliant Mechanisms” section 2.2 highlights “as with any engineered system there are trade-offs to be made as concepts are selected and design parameters are chosen. .. . three interrelated areas where designers commonly need to carefully consider trade-offs for compliant mechanisms [are] fatigue failure, achieving large deflections and maintaining off-axis stiffness.” For example, fatigue failure is often reduced by using thinner compliant sections and minimizing the size of the deflection, but thinner compliant sections often result in less off-axis stiffness. Section 2.2 additionally points out that designers creating rigid-body designs can often design the motions of the mechanism (its kinematics) from the transmission of forces (kinetics), but it is hard to do when designing compliant mechanisms because the motion is a result of forces causing deflection. Table 10.1 “Elements of Mechanisms’ subcategories and classes” lists flexible elements and rigid-link joints that can provide motion within a mechanism. Table 10.2 “Mechanisms' subcategories and classes” includes lists of kinematic motion and kinetic forces.

[0072] In general, “Compliant Mechanisms” includes helpful information in designing compliant features and compliant mechanisms. This includes a number of equations that express helpful relationships between motion, forces, geometry, and material properties. For example, Appendix E “Pseudo-Rigid-Body Models” provides numerous examples of compliant features that could be used in a compliant mechanism with equations that do a good job describing the path of the end of a feature (‘a’ and ‘b’), the angle of a pseudo-beam (0), the expected spring constant of the feature (K), and the maximum stress the features experiences (o). These equations are written in terms of the feature’s geometry (feature length (lowercase ‘1’), moment of inertia relative to bending (uppercase ‘I’), etc), material properties (Young’s modulus (E)), and input force (force (F), moment (M), etc).

[0073] Of particular note, “Handbook of Compliant Mechanisms” includes a “Library of Compliant Mechanisms” and examples describing hundreds of examples of compliant features and mechanisms, as well as other helpful information related to mechanisms with compliant features. Some examples from “Handbook of Compliant Mechanism” include various beams, EM-1 to EM-5, EM-6 (small-length flexural pivot), EM-9 (multiple -curve -beam flexural pivot), EM-10 (core), EM-11 (small-length flexure), EM-12 (living hinges), EM-13 (cross-axis flexural pivot), EM-14 (statically balanced cross-axis flexural pivot), EM-15 (constant stiffness cross-axis flexural pivot), EM-16 double blade rotary pivot, EM-17, EM-18 (large deformation hinge), EM-19 (split-tube flexures), EM-20, EM-21 (isolation-based HCCM), EM-22 (isolation-based HCCM), EM-23 (High Compression Compliant Mechanism), EM-25 (anti-symmetric double leaf-type isosceles-trapezoidal, large-displacement beam-based flexure joint), EM-29 (split-tube flexure), EM-31 (torsion translator), EM-32 (tubular cross-axis flexural pivot), EM-35, EM-36, EM-37 (notch joint), ME-38, EM-39 (leaf spring translational joint), EM-40, EM-41, M-l (compliant mechanism type synthesis), M-3 (Watt inversion), M-4 (Stephenson inversion), M-7 to M-12, M15 to M21, M-23, M-25 (CORE bearing), M- 26 (long-stroke flexure pivot), M-29 (precision cross-bladed translator), M-32 (octa constraint rotary), M-33 to M-36, M-37 (press), M-38 to M43, M-45, M-50, M-51 (fully compliant five bar mechanism design and control for trajectory following), M-52 (slaving mechanism for compound flexure pivots), M-55 (displacement-amplifying compliant mechanism), M-58, M59 (HexFlex (TM)), M-61 to M-65, M-75 to M-80, M-90 to M-94, M-95 (bistable cylinder), M-96, M-97, M-98 (partially compliant bistable six-bar mechanism), M-99 - M103, M-107, M-l 10, M-l 11 (multistage compliant force amplifier mechanism design), M-l 12. Also worth noting are descriptions of rigid-link joints, including EM-47 (revolute joint), EM-48 (passive joint), EM-49 (prismatic joint), EM-50 (universal joint), EM-51 (half joint), EM-52 (spherical joint), EM-53 (planar joint), EM-54 (helical joint), and EM-55 (cylindric joint).

[0074] In the one-to-one replacement approach, each joint and contact surface can be a rigid-link joint (or contact surface), a compliant joint, or a fixed connection (3 categories of joints). Additionally, each segment between joints can be rigid or compliant (2 categories of segments). When each joint and segment of a mechanism is evaluated this way relative to the rest of a mechanism, the possible combinations multiply quickly. For example, a simple 4-bar mechanism (with one bar replaced by ground) has 4 joints and 3 segments, resulting in 3A4 * 2A3 = 648 combinations of joint and segment types. On top of that, each rigid- link joint, compliant joint, fixed connection, rigid segment, and compliant segment has a vast variety of potential implementations. Furthermore, a compliant feature (a) can be made as a single, integral piece with the links and / or ground points (b) it can be made separately and integrated into the links or ground points after the links or ground points have been made, or (c) a combination of both cases can be done where the compliant feature is made as one piece with one of the links or ground points and then integrated into another link or ground point after the other link or ground point has been made.

[0075] When implemented in a piano or similar instrument, virtually any joint or contact surface can be replaced with a compliant feature. One approach includes trying to keep the center of rotation in about the same location(s) as the traditional joint or contact surface while another approach allows the design to focus on a different characteristic of the mechanism to replicate. Similarly, any spring acting to bias two links away from or toward each other could be integrated into a compliant feature. Candidates for which one or more individual joints, contact surfaces, and / or springs could be replaced include full or sub-portions of actions (including the interfaces between or within rails, keys, dampers, wippens, jacks, repetition levers, hammer); and trapworks (including pedals, linkages, levers, and rails).

[0076] Figs. 5 A-F shows various implementations that could replace the damper underlever-the portion of the damper mechanism comprising damper flange 335, damper block 339, damper lever 334, damper sostenuto 336 (when present), and the joints that allow motion between those parts. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. Compliant damper flange 535 generally mounts to ground and often has guide notch 570 to help align the damper mechanism in the action. Compliant damper block 539 attaches to one end of a damper wire; typical methods of attaching a damper wire to a damper block can be used. For example in one implementation, a bushing is inserted into the front or rear of damper block 539, a damper wire feeds through the top of damper block 539 into a hole in the bushing, and a screw threaded into the bushing secures the wire to damper block 539. Compliant damper lever 534 receives an upward input (generally from below by a key or a damper pedal portion of the trapworks) to push the damper wire upward and lift a damper head. Options for how the upward input may be applied include to compliant damper lever 534, felt on compliant damper lever 534, a damper spoon, an adjustable screw (the screw could be attached via a feature like hole 531 F), or, when present, compliant damper sostenuto 536 (which is integrated into the compliant damper underlever to interact with a sostenuto portion of the trapworks). The compliant damper underlever generally includes one or more rigid portions 580, one or more flexible portions 590, ground hole 572, damper wire hole 574, and insert hole 576. The holes for connecting to ground and the damper wire can be made during manufacture; however, one or more of the holes can be added, modified, or otherwise finished later by a person preparing the damper mechanism for installation.

[0077] Fig. 6 depicts a side view of an implementation with a black box replacement of a damper underlever. It includes portion 600 of a compliant damper assembly. Portion 600 includes grounded structure 610, movable body 620, and multiple compliant features 630. It also has key lift location 642, damper rail lift location 644, and sostenuto tab 650. At these locations, the corresponding portions of a grand piano can lift or hold the damper head and felt off of the string. Grounded structure 610 includes screw hole 612 to facilitate attaching grounded structure 610 to a piano. Movable body 620 includes damper block portion 622 with damper wire hole 624 and wire screw hole 626. Damper wire hole 624 is designed to receive a damper wire and is deep enough to allow varying lengths of the damper wire within damper block portion 622. One purpose of wire screw hole 626 is to provide threads for a screw to engage with so the screw can press into the damper wire, holding the damper wire in place within damper block portion 622. The threads can be formed directly in damper block portion 622 or can be provided by an insert such as a damper bushing which fits intowire screw hole 626. Like with other implementations, not every model of grand piano has a sostenuto feature and sostenuto tab 650 can be omitted.

[0078] Figs. 7 A-F shows various implementations that could replace a sostenuto in a damper block-the portion comprising damper sostenuto 336 and the rotational joint that connects damper sostenuto 336 to damper block 339. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. The integration of compliant sostenuto 736 into compliant damper block 739 generally includes one or more rigid portions 780 and one or more flexible portions 790 that combine to allow compliant sostenuto 736 to rotate relative to compliant damper 739 when sostenuto 736 is pushed upward or downward. Of particular note, 790B is mirrored by a second flexure on the opposite side of damper block 739B. Similarly, 791C is mirrored by a third flexure on the opposite side of damper block 739C.

[0079] Figs. 8 A-E shows various implementations of a compliant hammer which could replace the portion of the hammer that includes and is on either side of the revolute joint of hammer pin 324, including hammer flange 333 and hammer shank base 329 (the part that transitions from the pin joint to the general hammer shank 326). The reference numbers in the figures have the letter of the figure appended to the end for differentiation. Compliant hammer flange 833 generally mounts to ground. Compliant hammer shank 826 and compliant hammer shank base 829 are where the knuckle mounts and the hammer receives the upward motion from the key or pedal. They may be a single piece of material (similar to wooden shanks) or constructed separately and joined together (like Wessell Nickel & Gross). For example, a shank can be secured to compliant shank base 829 via shank cavity 850. Alternatively, compliant shank base 829 could have a protrusion that goes into a shank cavity. Compliant hammer flexure 824 rotationally connects compliant hammer flange 833 with compliant hammer shank base 829. The compliant hammer generally includes one or more rigid portions 880, one or more flexible portions 890, ground hole 872, knuckle cavity 878. The holes for connecting to ground and cavities for attaching knuckles can be made during manufacture; however, one or more of the holes or cavities can be added, modified, or otherwise finished later by a person preparing the compliant hammer for installation. As with non-compliant counterpart hammers, input to the compliant hammer is generally applied to hammer shank 826 or hammer shank base 829 and rotates the free end of hammer shank 826.

[0080] Figs. 9 A-D shows various implementations of compliant wippen, compliant jack, and / or compliant repetition lever that could replace portions of the same in a piano action. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. Compliant wippen 913, compliant jack 917, and compliant repetition lever 919 function similarly to traditional versions in that they transfer an input force or motion from input location 907 to output location 925. To facilitate this, compliant wippen 913 is rotationally connected to ground flange 930 by a compliant joint; compliant jack 917 is rotationally connected to compliant wippen 913 by a compliant joint; and compliant repetition lever 919 is rotationally connected to compliant wippen 913 or ground 930 by a compliant joint. The various combinations of compliant wippen 913, compliant jack 917, and compliant repetition lever 919 may include one or more rigid portions 980, one or more flexible portions 990, jack knuckle 916, repetition button location 920, drop screw contact 923, and weight location 903. Alternatively, contact points like input location 907, output location 925, jack knuckle916, drop screw contact 923, repetition button location 920, and drop screw contact 923 could be replaced by a compliant joint and connected to a ground or another part of the action.

[0081] Fig. 10 shows multiple implementations in a portion of a grand piano action model similar to that depicted in Fig 3. The multiple implementations can be used in combination with each other as shown or they can be used separately with rigid-link or other compliant mechanisms. Fig. 3 has compliant damper underlever 1030, compliant hammer 1020, and the combination of compliant wippen 1013, compliant jack 1017, and compliant repetition lever 1019. The compliant portions can be configured so inputs into the action result in the same outputs the action would have with traditional parts, such as the same motions, forces, sounds, and other haptic responses.

[0082] Figs. 11 A-C shows various implementations of black-box mechanisms (non-one-to-one) oriented as if used in an upright type piano action. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. They generally include one or more rigid portions 1180 and one or more flexible portions 1190. When an input at input location 1107 is received, the input is transferred through the mechanism to rotate hammer butt 1125, a hammer shank, and / or hammer head 1127 toward a string (which would be positioned on the left hand side of each Fig.

[0083] Fig. 11 A depicts a compliant mechanism that could be used instead of wippen 213, jack 217, and hammer butt 225. Compliant wippen 1113 A is rotationally connected to wippen flange 1130 A by a compliant joint. Compliant jack 1117A is rotationally connected to compliant wippen 1113A by a compliant joint. Compliant hammer butt 1125A is rotationally connected to jack 1117A and to hammer flange 1133A by a compliant joint. A hammer shank can be attached to hammer butt 1125A at shank base 1129A. Alternatively, a hammer shank can be integrally manufactured with hammer butt 1125 A. When an input pushes up on input location 1107 A, the input transfers through compliant jack 1117A and into compliant hammer butt 1125 A, causing compliant hammer butt 1125A to rotate. Since a hammer shank would be fixed to compliant hammer butt 1125 A, the hammer shank would rotate with compliant hammer butt 1125A.

[0084] Fig. 1 1 B depicts a compliant mechanism that could be used instead of wippen 213, jack 217, hammer butt 225, and damper lever 234. It includes rigid portions 1180, flexible portions 1190, and tri-segments1170B. Each tri-segment 1170B is connected to ground 1185B, sticker 1160B, and either hammer butt 1129B or damper lever 1134B. Sticker 1160B can move up and down vertically. As it does, it pulls on tri-segments 1170B, causing hammer butt 1129B and damper lever 1134B to rotate toward sticker 1160B. This pulls damper head 1 MOB away from string 1142B and brings hammer head 1127B toward string 1142B.

[0085] Fig. 11 C depicts a compliant mechanism that could be used to rotate hammer head 1127C. It includes rigid portions 1180C, flexible portions 1190C, and fulcrums 1183C. Sticker 1160C can move up and down vertically. As it does, rigid portions 1180C rotate around fulcrums 1183C, rotating hammer head 1127C toward the string. Arrows generally depict the motion from an input causing sticker 1160C to go up.

[0086] Figs. 12 A-C shows various isometric views of implementations that could be used in the trapworks of a piano to provide rotary motion. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. They generally include one or more rigid portions 1280, one or more flexible portions 1290, base holes 1242 in base 1240 (not all holes are depicted), and upper holes 1230 in upperportion 1232 (not all holes are depicted). Generally, flexible portions 1290 allow rotation between base 1240 and upper portion 1230. In this configuration, base 1240 is configured to surface mount to a component and upper portion 1230 is configured to attach to another component (e.g. fit into or receive a portion of the other component). However, there are other acceptable configurations. For example, the component base 1240 mounts to could be a piano (such as the frame or case) and the other component upper portion 1230 mounts to could be a pedal, lever, or rod of the trap works.

[0087] Figs. 13 A-G shows various implementations that integrate a way to provide adjustment or variable stiffness in the mechanism. Such adjustment or variable stiffness allow an installer or maintainer to better replicate the characteristics of traditional mechanisms in piano and similar instruments. Additionally, it allows an installer or maintainer to vary the mechanism for different use cases, such as with adjusting the stored energy in the mechanism from one end of a piano keyboard to the other (the bass notes on a piano require more force from the damper to quiet the strings than the baritone or treble notes, which is generally accomplished with more weight or spring applied to the damper lever).

[0088] The implementations in Figs. 13 A-G could be dampers, though many features can be applied generally. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. They generally include one or more rigid portions 1380, one or more flexible portions 1390, primary flexure 1392 that allows rotation between two of the rigid portions, one or more adjustment flexure 1395, adjustment point 1374, and counterpoint 1376. When adjustment point 1374 and counterpoint 1376 are pushed apart or pulled together, adjustment point 1374 acts upon one or more adjustment flexures 1395 to increase or decrease the stored energy in primary flexure 1392 (the increase or decrease is based on geometry, not directly to whether the adjustment point 1374 and counterpoint 1376 are being pushed or pulled). These figures, flange 1335 is rotationally connected to lever 1334 by primary flexure 1392, ground hole 1372 can be used to mount flange 1335 to ground, and arrow (with ground symbol) 1378 indicates that lever 1334 starts against a ground or stop and rotates counterclockwise away from ground. One way to push apart or pull together adjustment point 1374 and counterpoint 1376 is through the use of a screw or threaded rod. The screw or threaded rod may be accompanied by bushings or other hardware to attach or otherwise connect it to adjustment point 1374 and counterpoint 1376.

[0089] Figs. 14 A-G shows additional implementations that integrate a way to provide adjustment or variable stiffness in the mechanism. The reference numbers in the figures have the letter of the figure appended to the end for differentiation. The figures generally depict stops, rests, or other contact surfaces upon which other components abut to when in a stable or semi-stable position. They generally include one or more rigid portions 1480, one or more flexible portions 1490, ground location or mounting hole 1472, and adjuster 1460 which modifies the rest position of the geometry of a flexible portion 1490 and changes its potential energy, and at least one contact location 1470. The position or energy with which the position of a contact location 1470 is held is modified as a related adjuster 1460 is tuned (adjusted to modify the geometry of a related flexible portion 1490). Adjuster 1460 may be installed or integral to the compliant mechanism or may contact the compliant mechanism (at adjuster contact location 1462) and be installed or integral to a part near the compliant mechanism. Examples of contact surfaces include those contacted by a hammer knuckle, a hammerset screw, a jack button, capstan locations, hammer stops and backchecks, repetition lever stops, damper stops, and trapwork to action engagement. They may control adjustments within a mechanism such as key weight, motion timing (like damper, wippen, jack, repetition lever, or hammer engagement or reset), damper weight or spring strength, repetition lever height, repetition lever spring strength, drop, let off, and stiffness of rotational joints.

[0090] Fig. 14 G shows an implementation with adjustable or variable stiffness elements paired with a portion of a mechanism with a rotational joint. In this instance, the portion of the implementation shown hammer knuckle 1425G resting on contact location 1470G with the adjustable or variable stiffness elements integral with hammer flange 1433G. Hammer knuckle 1425G is connected to hammer shank base 1429G, which is rotationally connected to hammer flange 1433G by a flexure.

[0091] Figs. 15 A-B shows an implementation where the flexible segment is an insert into the rigid portions rather than integral (made at the same time from the same material). Fig. 15 A shows a cross section of a flexure connecting 2 rigid portions. Fig. 15 B shows a cross section oriented perpendicular to 15 A of the flexure and one of the rigid portions. It generally includes one or more rigid portions 1580 and one or more flexible portions 1590. Additionally, the flexible portion may comprise one or more securing features 1592 which helps keep flexure 1590 inserted into rigid portion 1580. A variety of shapes (including cavities in 1590), surface finishes, and other characteristics would work to provide securing features 1592. Additionally, rigid portion 1580 may have reciprocal or complementary features that aid in securing 1-92. Alternatively, one portion of the flexible portion could be integral with a first rigid portion while another portion is an insert into a second rigid portion. The insert could be accomplished by press-fitting the flexible segment into a rigid portion(s), molding the rigid portion(s) around the flexible portion, or any other reasonable way of manufacturing. One benefit to doing it this way is being able to gain benefits of compliant mechanisms while still allowing portions of the mechanism to be separable for manufacturer, installation, and maintenance & repair.

[0092] Material Selection & Manufacturing

[0093] There are many materials which can be used with the disclosure and the selection of any specific material includes factors outside the scope of the disclosure. The selection of any specific material for use with the disclosure brings material properties which affect the implementation of the disclosure. For example, many materials have known or estimated strengths, flexibilities, endurance limits, amounts of thermal or temperature -based expansion, melting point, moisture absorption rates, densities, acoustic / vibration transfers and damping, hardness, manufacturabilities, and colors and other optical properties. If, for instance, a compliant feature in the mechanism is designed so the peak stress is less than the endurance limit, then the compliant feature has a theoretically infinite fatigue life (meaning it theoretically won’t break from the stress associated with the cyclical loading of the mechanism).

[0094] In some cases, a given material property may drive the selection of the material, likely in combination with other material properties. In other cases, any given material property is secondary to the decision. In either type of case, such properties can impact an implementation’s function, reliability, length of life, safety, installation and maintenance, and other important factors that influence design, business, and other decisionsrelated to the implementation. Additionally, a material can be treated in a way that changes material properties, such as with an agent or layer. For example, a flexure can be treated with heat, graphene, other materials, or vapor smoothing to extend the life and improve the strength of the flexure.

[0095] As an example, visual characteristics of a material selected for an implementation may not affect the ability of the disclosure as implemented to play a note based on motion of a key, but could have significant impact on the ability of a technician to install or maintain an instrument mechanism. Additionally, a material may have a relatively negative reputation in the market which may not affect an implementation of the disclosure using that material to perform its function, but which may limit the marketability of that implementation. Furthermore, some materials could be hazardous or otherwise unsafe in one environment or use case, but not in others. Such properties may have little bearing on the ability of an implementation to perform its function, yet may contribute to the material selection process for non-inventive reasons.

[0096] Many factors significantly impact the implementation of the disclosure in various instruments, including temperature-base expansion, moisture absorption, durability, density, and structural properties. Of particular importance are factors that affect flexibility like yield strength and modulus of elasticity. In one implementation, the factors that drive the material selection include: ratio of yield strength / modulus; long fatigue life, potential for infinite life; ductile and capacity for large strain in elastic deformation without entering plastic deformation; high tensile yield and ultimate strengths; water resistant with low moisture absorption (to maintain consistent function and limit expansion from water absorption) (preferably one with very low moisture absorption); lightweight; high heat deflection temperature; strong memory retention; ease of manufacturing both limited and mass production runs. For example, a higher the ratio of yield strength to Young’ s modulus, increases the likelihood of having long or infinite life-and while not a requirement, a ratio >= 20 may be preferred in some cases. In other implementations, various combinations of these factors will take priority and may be balanced with other factors.

[0097] Wood is a common material for many of the rigid links in piano and similar instruments. However, other materials are more likely to be selected for compliant features, such as polymers or metals, because these alternative materials can more easily provide the desired feel with a long life expectancy and better lend themselves to manufacturing compliant mechanisms. For example, a compliant portion of a piano action, such as a compliant damper underlever implementation, will likely have a generally consistent 2-dimensional (2D) cross section. Injection molding such a part would be fairly straightforward and provide a savings in cost, time, and labor over current methods used for producing parts from wood or blocks of other material. Similarly, 3D printing can be used to produce parts with a generally consistent 2D cross section as well as parts with more complex geometries that are more difficult or unfeasible to injection mold. These processes are just two of the many processes that can be used to produce implementations of the disclosure.

[0098] The following pertain to further implementations of the disclosure.

[0099] Example 1 is a method of designing a compliant mechanism for a musical instrument. The method includes determining a characteristic of a portion of a mechanism of a musical instrument for use as a baseline in determining whether a compliant mechanism operates like the portion of the mechanism. The method also includes creating the compliant mechanism which reproduces the characteristic.

[0100] Example 2 is a method as in Example 1 , and further includes determining a second characteristic of the portion of the mechanism for use as a second baseline in determining whether the compliant mechanism operates like the portion of the mechanism and wherein the compliant mechanism which is created also reproduces the second characteristic.

[0101] Example 3 is a method as in any of Examples 1-2, and further includes determining additional characteristics of the portion of the mechanism for use as additional baselines in determining whether the compliant mechanism operates like the portion of the mechanism and wherein the compliant mechanism which is created also reproduces the additional characteristics.

[0102] Example 4 is a method as in any of Examples 1-3, wherein the characteristic results from energy being input into the portion of the mechanism and is selected from the group consisting of a reaction energy, a feel or haptic response, an output energy, an input motion, and an output motion.

[0103] Example 5 is a method as in any of Examples 1-4, wherein the characteristic is an adjustment that modifies the motion of the mechanism.

[0104] Example 6 is a method as in any of Examples 1-5, wherein the characteristic is an adjustment that modifies the energy transfer of the mechanism.

[0105] Example 7 is a method as in any of Examples 1-6, wherein the characteristic is a physical space the mechanism operates within.

[0106] Example 8 is a method as in any of Examples 1-7, wherein creating the compliant mechanism is performed by designing the compliant mechanism.

[0107] Example 9 is a method as in any of Examples 1-8, wherein creating the compliant mechanism is performed by producing the compliant mechanism.

[0108] Example 10 is a method as in any of Examples 1-9, wherein creating the compliant mechanism is performed by modeling the compliant mechanism.

[0109] Example 11 is a method as in any of Examples 1-10, wherein the portion of the mechanism includes a pin joint connecting a hammer flange to a hammer.

[0110] Example 12 is a method as in any of Examples 1-11, wherein the portion of the mechanism includes a pin joint connecting a jack to a wippen.

[0111] Example 13 is a method as in any of Examples 1-12, wherein the portion of the mechanism includes a pin joint connecting a repetition lever to a wippen.

[0112] Example 14 is a method as in any of Examples 1-13, wherein the portion of the mechanism includes a pin joint connecting a damper flange to a damper.

[0113] Example 15 is a method as in any of Examples 1-14, wherein the portion of the mechanism includes surfaces at which a hammer and a jack contact each other.

[0114] Example 16 is a method as in any of Examples 1-15, wherein the portion of the mechanism includes surfaces at which a letoff button and a jack contact each other.

[0115] Example 17 is a method as in any of Examples 1-16, wherein the portion of the mechanism includes surfaces at which a repetition lever and a letoff screw contact each other.

[0116] Example 18 is a method as in any of Examples 1-17, wherein the portion of the mechanism includes surfaces at which a sticker and a wippen contact each other.

[0117] Example 19 is a method as in any of Examples 1-18, wherein the portion of the mechanism includes surfaces at which a back stop and a back check contact each other.

[0118] Example 20 is a method as in any of Examples 1-19, wherein the portion of the mechanism includes at least 2 pin joints in a piano action.

[0119] Example 21 is a method as in any of Examples 1-20, wherein the portion of the mechanism includes at least 3 pin joints in a piano action.

[0120] Example 22 is a method of designing a compliant mechanism for a musical instrument. The method includes determining a characteristic of a portion of a mechanism of a musical instrument for use as a baseline in determining whether a compliant mechanism operates like the portion of the mechanism. The method also includes creating the compliant mechanism which reproduces the characteristic. The method includes identifying a portion of a mechanism of a musical instrument to be redesigned. The method also includes identifying a use case for the portion. The method also includes identifying a physical space the portion operates in during the use case. The method also includes identifying an input link for the portion. The method also includes identifying an output link for the portion. The method also includes determining an input force applied to the input link during the use case. The method also includes determining a reaction force for the input force. The method also includes determining an output force of the output link during the use case. The method also includes determining the motion of the input link in response to the input force (during the use case). The method also includes determining the motion of the output link in response to the input force (during the use case). The method also includes designing a compliant mechanism that can replicate the reaction force for the input force on the input link. The method also includes designing the compliant mechanism to replicate the output force on the output link for the input force on the input link. The method also includes designing the compliant mechanism to replicate the stiffness associated with the motion associated with the portion during the use case. The method also includes designing the compliant mechanism to replicate the motion of the portion during the use case. The method also includes designing the compliant mechanism so the compliant portion of the compliant mechanism can sustain the fatigue stresses associated with the motion of the compliant mechanism when used in place of the mechanism portion during the use case.

[0121] Example 23 is a musical instrument mechanism. The musical instrument includes a flange portion that connects to a musical instrument. The musical also instrument includes a body portion that receives an input force. The musical also instrument includes a compliant feature connecting the flange portion and the body portion in such a way that the body portion can rotate relative to the flange portion about an axis generally located near the compliant feature.

[0122] Example 24 is a method as in any of Example 23, wherein the axis generally mimics the axis of rotation of a rigid-link pin joint of a preexisting musical instrument mechanism

[0123] Example 25 is a method as in any of Examples 23-24, wherein the compliant feature provides a spring constant that resists motion of the body portion in a way that mimics the stiffness of a rigid-link pin joint of a preexisting musical instrument mechanism.

[0124] Example 26 is a method as in any of Examples 23-25, wherein the musical instrument mechanism is selected from a group consisting of a hammer, a damper, a wippen and jack pair, a wippen and repetition lever pair, a key of a keyboard, and a pedal.

[0125] Example 27 is a musical instrument mechanism. The mechanism includes a compliant feature which transfers input energy into output energy and wherein the output energy is used to affect the play of a note of the musical instrument.

[0126] Example 28 is a method as in any of Examples 27, wherein the compliant feature movably connects a hammer to the musical instrument.

[0127] Example 29 is a method as in any of Examples 27-28, wherein the compliant feature movably connects a back stop to a back check.

[0128] Example 30 is a method as in any of Examples 27-29, wherein the compliant feature movably connects a back stop to a wippen.

[0129] Example 31 is a method as in any of Examples 27-30, wherein the compliant feature movably connects a back stop to a key.

[0130] Example 32 is a method as in any of Examples 27-31, wherein the compliant feature movably connects a hammer to a jack.

[0131] Example 33 is a method as in any of Examples 27-32, wherein the compliant feature movably connects a jack to a letoff button.

[0132] Example 34 is a method as in any of Examples 27-33, wherein the compliant feature movably connects a jack to a wippen.

[0133] Example 35 is a method as in any of Examples 27-34, wherein the compliant feature movably connects a repetition lever to a wippen.

[0134] Example 36 is a method as in any of Examples 27-35, wherein the compliant feature movably connects a wippen to the musical instrument.

[0135] Example 37 is a method as in any of Examples 27-36, wherein the compliant feature movably connects a wippen to a sticker.

[0136] Example 38 is a method as in any of Examples l- 1 , wherein the compliant feature movably connects a damper to the musical instrument.

[0137] Example 39 is a method as in any of Examples 27-38, wherein the compliant feature movably connects a damper to a damper stop.

[0138] Example 40 is a method as in any of Examples 27-39, wherein the compliant feature movably connects a damper to a key.

[0139] Example 41 is a method as in any of Examples 27-40, wherein the compliant feature movably connects a key to the musical instrument.

[0140] Example 42 is a method as in any of Examples 27-41, wherein the compliant feature movably connects a pedal to the musical instrument.

[0141] Example 43 is a method as in any of Examples 27-42, wherein the compliant feature movably connects a link in a trapworks of the musical instrument associated with a pedal to the musical instrument.

[0142] Example 44 is a method as in any of Examples 27-43, wherein the compliant feature biases the mechanism toward a rest position.

[0143] Example 45 is a method as in any of Examples 27-44, and further including a baseline characteristic of a contemporary version of the mechanism without the compliant feature; and wherein the compliant feature replicates the baseline characteristic.

[0144] Example 46 is a method as in any of Examples 27-45, and further including a baseline characteristic of a contemporary version of the mechanism without the compliant feature; and wherein the compliant feature improves upon the baseline characteristic.

[0145] Example 47 is a method as in any of Examples 27-46, further including an additional compliant feature which cooperates with the compliant feature to transfer input energy into output energy.

[0146] Example 48 is a method as in any of Examples 27-47, wherein the compliant feature is a first compliant segment and the additional compliant feature is a second compliant segment.

[0147] Example 49 is a method as in any of Examples 27-48, wherein the input energy is a force pushing down on a front portion of a key of a piano keyboard.

[0148] Example 50 is a method as in any of Examples 27-49, wherein the input energy is a force pushing up on a rear portion of a key of a piano keyboard.

[0149] Example 51 is a method as in any of Examples 27-50, wherein the input energy comes from an electro-mechanical system.

[0150] Example 52 is a method as in any of Examples 27-51, wherein the input energy comes from a pneumatic system.

[0151] Example 53 is a method as in any of Examples 27-52, wherein the output energy leaves the mechanism through a hammer of the mechanism hitting a string which vibrates to play the note.

[0152] Example 54 is a method as in any of Examples 27-53, wherein the output energy leaves the mechanism through a hammer of the mechanism hitting a sensor of the piano to play the note.

[0153] Example 55 is a method as in any of Examples 27-54, wherein affecting the play of a note is selected from a group consisting of initiating or altering how a string is vibrated, a sensor registers the note, and a valve is actuated.

[0154] Example 56 is a method of designing a compliant action for a piano or similar instrument. The method includes determining a portion of an existing action to replace. The method also includes determining a characteristic of the portion to replicate in a compliant action. The method also includes creating the compliant action replicating the characteristic. The compliant action includes a compliant feature.

[0155] Example 57 is a method as in any of Examples 56, wherein the compliant feature allows a hammer of the action to rotate relative to itself.

[0156] Example 58 is a method as in any of Examples 56-57, wherein the compliant feature allows a wippen of the action to rotate relative to itself.

[0157] Example 59 is a method as in any of Examples 56-58, wherein the compliant feature allows a repetition lever of the action to rotate relative to itself.

[0158] Example 60 is a method as in any of Examples 56-59, wherein the compliant feature allows a grand piano damper of the action to rotate relative to itself.

[0159] Example 61 is a method as in any of Examples 56-60, wherein the compliant feature allows a grand piano jack of the action to rotate relative to itself.

[0160] Example 62 is a method for playing notes of a piano. The method includes a piano action including a compliant part which transfers input energy into output energy and wherein the output energy is used to play the note.

[0161] Example 63 is a method as in any of Example 62, wherein the compliant part includes a hammer and a hammer flange rotatably connected by a compliant segment.

[0162] Example 64 is a method as in any of Examples 62-63, wherein the compliant part includes a wippen and a wippen flange rotatably connected by a compliant segment.

[0163] Example 65 is a method as in any of Examples 62-64, wherein the compliant part includes a wippen and a repetition lever rotatably connected by a compliant member.

[0164] Example 66 is a hammer for a musical instrument. The hammer includes a plurality of portions coupled end-to-end to form a continuous chain of segments. The hammer also includes a first rigid portion providing a ground link to a musical instrument, a second rigid portion, and at least one flexible portion. It also provides that the at least one flexible position allows relative motion between the first rigid position and the second rigid portion.

[0165] Example 67 is a hammer as in any of Example 66, where in the second rigid portion includes a hammer shank.

[0166] Example 68 is a hammer as in any of Examples 66-67, where in the second rigid portion includes a hammer head.

[0167] Example 69 is a method of designing musical instrument mechanisms. The method includes creating a representation of an existing portion of a musical instrument mechanism with two or more rigid portions connected by a joint that allows relative motion between the two or more rigid portions. The method also includes recreating the representation with an alternate, compliant feature.

[0168] Example 70 is a method as in any of Example 69, and further including repeating the recreating step multiple times, each time using a different alternate, compliant feature.

[0169] Example 71 is a method as in any of Examples 69-70, wherein the representation further includes a second joint that allows relative motion between at least one of the two or more rigid portions and another rigid portion. The method also further includes varying the second joint to increase the number of possible representations by the number of times the second joint is varied.

[0170] Example 72 is a damper underlever. The damper underlever includes a lift location, a damper block connected to the lift location, a ground location, and a compliant feature connecting the lift location to the ground location. The compliant feature allows for motion between the lift location and the ground location.

[0171] Example 73 is a damper underlever as in any of Example 72, wherein the compliant feature is designed and manufactured with a targeted stiffness.

[0172] Example 74 is a damper underlever as in any of Examples 72-73, wherein the compliant feature is designed and manufactured with a targeted stress level.

[0173] Example 75 is a damper underlever as in any of Examples 72-74, wherein the compliant feature is designed and manufactured with a targeted fatigue life.

[0174] Example 76 is a damper underlever as in any of Examples 72-75, wherein the fatigue life is evaluated by comparing a peak stress of the compliant feature to an endurance limit associated with whatever material the compliant feature is made from.

[0175] Example 77 is a damper underlever as in any of Examples 72-76, wherein the damper underlever is designed and manufactured to have a targeted stiffness.

[0176] Example 78 is a damper underlever as in any of Examples 72-77, further including a movable portion of the damper underlever. The movable portion includes the lift location and the compliant feature. The movable portion is designed and manufactured with a targeted mass property.

[0177] Example 79 is a damper underlever as in any of Examples 72-78, and further including a movable portion of the damper underlever. The movable portion includes the lift location and the compliant feature. The movable portion is designed and manufactured with a targeted inertial property.

[0178] Example 80 is a damper underlever as in any of Examples 72-79, wherein the damper block is configured to remove a damper head from a musical string when an input rotates the lift location relative to the ground location.

[0179] Example 81 is a damper underlever. The damper underlever includes a plurality of rigid links including a damper flange, a damper lever, and a damper block. The damper lever is connected to the damper flange by a first rotational connection. The damper block is connected to the damper lever by a second rotational connection. The damper lever includes a first compliant feature which provides rotational motion between at least two of the plurality of rigid links.

[0180] Example 82 is a damper underlever as in any of Example 81, wherein the first rotational connection is the first compliant feature.

[0181] Example 83 is a damper underlever as in any of Examples 81-82, and further including a second compliant feature and wherein the second rotational connection is the second compliant feature.

[0182] Example 84 is a damper underlever as in any of Examples 81-83, wherein the second rotational connection is the first compliant feature.

[0183] Example 85 is a damper underlever as in any of Examples 81-84, wherein the plurality of rigid links further includes a sostenuto lever connected to the damper block by a third rotational connection.

[0184] Example 86 is a damper underlever as in any of Examples 81-85, wherein the third rotational connection is the first compliant feature.

[0185] Example 87 is a damper underlever as in any of Examples 81-86, and further including a second compliant feature and wherein the first rotational connection is the second compliant feature.

[0186] Example 88 is a damper underlever as in any of Examples 81-87, and further including a third compliant feature and wherein the second rotational connection is the third compliant feature.

[0187] Example 89 is a damper underlever as in any of Examples 81-88, and further including a second compliant feature and wherein the second rotational connection is the second compliant feature.

[0188] Example 90 is a damper underlever as in any of Examples 81-89, wherein the first compliant feature is designed and manufactured with a targeted stiffness.

[0189] Example 91 is a damper underlever as in any of Examples 81-90, wherein the first compliant feature is designed and manufactured with a targeted stress level.

[0190] Example 92 is a damper underlever as in any of Examples 81-91, wherein the damper underlever is designed and manufactured to have a targeted stiffness.

[0191] Example 93 is a damper underlever as in any of Examples 81-92, and further including a movable portion of the damper underlever. The movable portion includes the damper lever, the damper block, and the first rotational connection; and wherein the movable portion is designed and manufactured with a targeted mass property.

[0192] Example 94 is a damper underlever as in any of Examples 81-93, and further including a movable portion of the damper underlever. The movable portion includes the damper lever, the damper block, and the first rotational connection; and wherein the movable portion is designed and manufactured with a targeted inertial property.

[0193] Example 95 is a damper underlever as in any of Examples 81-94, wherein the first compliant feature has a rest position, it stores energy as it rotates away from the rest position, and the stored energy biases the first compliant feature toward the rest position.

[0194] Example 96 is a damper underlever as in any of Examples 81-95, and further including an adjustment that contacts a portion of the first compliant feature and wherein changing the way the adjustment contacts the portion of the first compliant feature modifies the bias of the first compliant feature toward the rest position.

[0195] Example 97 is a damper underlever as in any of Examples 81-96, and further including a second compliant feature; an adjustment point on the second compliant feature; and a counterpoint. Adjustments between the adjustment point and counterpoint cause the second compliant feature to modify the bias of the first compliant feature toward the rest position.

[0196] Example 98 is a damper underlever as in any of Examples 81-97, wherein the first rotational connection is a pin joint.

[0197] Example 99 is a damper underlever as in any of Examples 81-98, wherein the second rotational connection is a pin joint.

[0198] Example 100 is a damper underlever as in any of Examples 81-99, wherein the third rotational connection is a pin joint.

[0199] Example 101 is a damper underlever including a damper flange and a damper lever rotatably connected to the damper flange by a compliant feature.

[0200] Example 102 is a damper underlever including a damper link and a damper block rotatably connected to the damper lever by a compliant feature.

[0201] Example 103 is a damper underlever including a damper block and a sostenuto link rotatably connected to the damper block by a compliant feature.

[0202] Example 104 is a method of designing a damper. The method includes designing a damper underlever with at least one compliant feature to provide rotational motion between 2 rigid links of the damper underlever.

[0203] Example 105 is a method of manufacturing a damper. The method includes integrating at least one compliant feature to rotationally connect at least 2 rigid links of a damper underlever.

[0204] Example 106 is a musical instrument mechanism. The mechanism includes a first rigid link, a second rigid link, and a characteristic relating the first rigid link and the second rigid link influenced by a revolute or contact joint. The method also includes a compliant feature influencing the characteristic instead of the revolute or contact joint.

[0205] Example 107 is a musical instrument mechanism. The mechanism includes a first link and a second link connected to the first link by a primary flexure. The mechanism also includes an adjustment that changes the energy in the primary flexure to change the amount of bias of the first link relative to the second link.

[0206] Example 108 is a mechanism as in any of Example 107, wherein the adjustment directly contacts one or more portions of the primary flexure to change the geometry of the primary flexure relative to itself.

[0207] Example 109 is a mechanism as in any of Examples 107-108, and further including an adjustment flexure acting on the first link and second link, an adjustment point on the adjustment flexure, and a counterpoint. The adjustment is caused by changing the distance between the adjustment point and the counterpoint.

[0208] Example 110 is a mechanism as in any of Examples 1-109, and further including an adjustment flexure acting on the first link and second link, an adjustment point on the adjustment flexure, and a counterpoint. The adjustment is caused by changing the orientation between the adjustment point and the counterpoint.

[0209] Example 111 is a piano action. The action includes a wippen with a compliant feature allowing the wippen to rotate relative to a piano when a wippen flange of the wippen is mounted to the piano and a jack with a compliant feature allowing the jack to rotate relative to the wippen.

[0210] Example 112 is a piano action as in any of Exampel 111, and further comprising a repetition lever with a compliant feature allowing the repetition lever to rotate relative to the wippen.

[0211] Example 113 is a grand piano action as in any of Examples 111-112, further comprising a hammer with a compliant feature allowing the hammer to rotate relative to the grand piano when a hammer flange of the hammer is mounted to the grand piano.

[0212] Example 114 is a grand piano action as in any of Examples 111-113, further comprising a damper with a compliant feature allowing the damper to rotate relative to the grand piano when a damper flange of the dammer is mounted to the grand piano.

[0213] Example 115 is a grand piano action as in any of Examples 111-114, wherein the piano is a grand piano.

[0214] Example 116 is a grand piano action as in any of Examples 111-115, wherein the piano is an upright piano.

[0215] Example 117 is a grand piano action as in any of Examples 111-116, wherein each compliant feature includes a spring force that acts to bias the rotation toward a rest position.

[0216] Example 118 is any of the examples 1-117 and can include various features and combinations provided therein.

[0217] There are many Examples that include various combinations of the features in the Examples above.

[0218] It will be understood that while the disclosure has been described in conjunction with specific embodiments thereof, the foregoing description and examples are intended to illustrate, but not limit the scope of the invention claimed. Other aspects, advantages, and modifications will be apparent to those skilled in the art to which the disclosure pertains, and these aspects and modifications are within the scope of the claimed invention, which is limited only by the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A damper underlever comprising: a plurality of rigid links comprising: a damper flange; a damper lever; and a damper block; wherein the damper lever is connected to the damper flange by a first rotational connection; wherein the damper block is connected to the damper lever by a second rotational connection; and wherein a first compliant feature provides rotational motion between at least two of the plurality of rigid links.

2. The damper underlever of claim 1, wherein the first rotational connection is the first compliant feature.

3. The damper underlever of claim 2, further comprising a second compliant feature and wherein the second rotational connection is the second compliant feature.

4. The damper underlever of claim 1, wherein the second rotational connection is the first compliant feature.

5. The damper underlever of claim 1, wherein the plurality of rigid links further comprise a sostenuto lever connected to the damper block by a third rotational connection.

6. The damper underlever of claim 5, wherein the third rotational connection is the first compliant feature.

7. The damper underlever of claim 6, further comprising a second compliant feature and wherein the first rotationai connection is the second compliant feature.

8. The damper underlever of claim 7, further comprising a third compliant feature and wherein the second rotational connection is the third compliant feature.

9. The damper underlever of claim 5, further comprising a second compliant feature and wherein the second rotational connection is the second compliant feature.

10. The damper underlever of claim 1, wherein the first compliant feature is designed and manufactured with a targeted stiffness.

11. The damper underlever of claim 1, wherein the first compliant feature is designed and manufactured with a targeted stress level.

12. The damper underlever of claim 1, wherein the damper underlever is designed and manufactured to have a targeted stiffness.

13. The damper underlever of claim 1, further comprising a movable portion of the damper underlever comprising the damper lever, the damper block, and the first rotational connection; and wherein the movable portion is designed and manufactured with a targeted mass property.

14. The damper underlever of claim 1, further comprising a movable portion of the damper underlever comprising the damper lever, the damper block, and the first rotational connection; and wherein the movable portion is designed and manufactured with a targeted inertial property.

15. The damper underlever of claim 1, wherein the first compliant feature has a rest position, it stores energy as it rotates away from the rest position, and the stored energy biases the first compliant feature toward the rest position.

16. The damper underlever of claim 15, further comprising an adjustment that contacts a portion of the first compliant feature and wherein changing the way the adjustment contacts the portion of the first compliant feature modifies the bias of the first compliant feature toward the rest position.

17. The damper underlever of claim 15, further comprising a second compliant feature; an adjustment point on the second compliant feature; and a counterpoint; and wherein adjustments between the adjustment point and counterpoint cause the second compliant feature to modify the bias of the first compliant feature toward the rest position.

18. The damper underlever of claim 1, wherein the first rotational connection is a pin joint.

19. The damper underlever of claim 1, wherein the second rotational connection is a pin joint.

20. The damper underlever of claim 5, wherein the third rotational connection is a pin joint.

21. A damper underlever comprising: a lift location; a damper block connected to the lift location; a ground location; and a compliant feature connecting the lift location to the ground location which allows for motion between the lift location and the ground location.

22. The damper underlever of claim 21, wherein the compliant feature is designed and manufactured with a targeted stiffness.

23. The damper underlever of claim 21, wherein the compliant feature is designed and manufactured with a targeted stress level.

24. The damper underlever of claim 21, wherein the compliant feature is designed and manufactured with a targeted fatigue life.

25. The damper underlever of claim 24, wherein the fatigue life is evaluated by comparing a peak stress of the compliant feature to an endurance limit associated with whatever material the compliant feature is made from.

26. The damper underlever of claim 21, wherein the damper underlever is designed and manufactured to have a targeted stiffness.

27. The damper underlever of claim 21, further comprising a movable portion of the damper underlever comprising the lift location and the compliant feature; and wherein the movable portion is designed and manufactured with a targeted mass property.

28. The damper underlever of claim 21, further comprising a movable portion of the damper underlever comprising the lift location and the compliant feature; and wherein the movable portion is designed and manufactured with a targeted inertial property.

29. The damper underlever of claim 21, wherein the damper block is configured to remove a damper head from a musical string when an input rotates the lift location relative to the ground location.

30. A method of designing a compliant mechanism for a musical instrument comprising: determining a characteristic of a portion of a mechanism of a musical instrument for use as a baseline in determining whether a compliant mechanism operates like the portion of the mechanism; andcreating the compliant mechanism which reproduces the characteristic.

31. The method of claim 30, further comprising determining a second characteristic of the portion of the mechanism for use as a second baseline in determining whether the compliant mechanism operates like the portion of the mechanism and wherein the compliant mechanism which is created also reproduces the second characteristic.

32. The method of claim 30, further comprising determining additional characteristics of the portion of the mechanism for use as additional baselines in determining whether the compliant mechanism operates like the portion of the mechanism and wherein the compliant mechanism which is created also reproduces the additional characteristics.

33. The method of claim 30, wherein the characteristic results from energy being input into the portion of the mechanism and is selected from the group consisting of a reaction energy, a feel or haptic response, an output energy, an input motion, and an output motion.

34. The method of claim 30, wherein the characteristic is an adjustment that modifies the motion of the mechanism.

35. The method of claim 30, wherein the characteristic is an adjustment that modifies the energy transfer of the mechanism.

36. The method of claim 30, wherein the characteristic is a physical space the mechanism operates within.

37. The method of claim 30, wherein creating the compliant mechanism is performed by designing the compliant mechanism.

38. The method of claim 30, wherein creating the compliant mechanism is performed by producing the compliant mechanism.

39. The method of claim 30, wherein creating the compliant mechanism is performed by modeling the compliant mechanism.

40. The method of claim 30, wherein the portion of the mechanism comprises a pin joint connecting a hammer flange to a hammer.

41. The method of claim 30, wherein the portion of the mechanism comprises a pin joint connecting a jack to a wippen.

42. The method of claim 30, wherein the portion of the mechanism comprises a pin joint connecting a repetition lever to a wippen.

43. The method of claim 30, wherein the portion of the mechanism comprises a pin joint connecting a damper flange to a damper.

44. The method of claim 30, wherein the portion of the mechanism comprises surfaces at which a hammer and a jack contact each other.

45. The method of claim 30, wherein the portion of the mechanism comprises surfaces at which a letoff button and a jack contact each other.

46. The method of claim 30, wherein the portion of the mechanism comprises surfaces at which a repetition lever and a letoff screw contact each other.

47. The method of claim 30, wherein the portion of the mechanism comprises surfaces at which a sticker and a wippen contact each other.

48. The method of claim 30, wherein the portion of the mechanism comprises surfaces at which a back stop and a back check contact each other.

49. The method of claim 30, wherein the portion of the mechanism comprises at least 2 pin joints in a piano action.

50. The method of claim 30, wherein the portion of the mechanism comprises at least 3 pin joints in a piano action.

51. A method of designing a compliant mechanism for a musical instrument comprising: identifying a portion of a mechanism of a musical instrument to be redesigned; identifying a use case for the portion; identifying a physical space the portion operates in during the use case; identifying an input link for the portion; identifying an output link for the portion; determining an input force applied to the input link during the use case; determining a reaction force for the input force; determining an output force of the output link during the use case; determining the motion of the input link in response to the input force (during the use case); determining the motion of the output link in response to the input force (during the use case); designing a compliant mechanism that can replicate the reaction force for the input force on the input link; designing the compliant mechanism to replicate the output force on the output link for the input force on the input link; designing the compliant mechanism to replicate the stiffness associated with the motion associated with the portion during the use case; designing the compliant mechanism to replicate the motion of the portion during the use case; and designing the compliant mechanism so the compliant portion of the compliant mechanism can sustain the fatigue stresses associated with the motion of the compliant mechanism when used in place of the mechanism portion during the use case.

52. A musical instrument mechanism comprising: a flange portion that connects to a musical instrument, a body portion that receives an input force; and a compliant feature connecting the flange portion and the body portion in such a way that the body portion can rotate relative to the flange portion about an axis generally located near the compliant feature.

53. The musical instrument mechanism of claim 52, wherein the axis generally mimics the axis of rotation of a rigid-link pin joint of a preexisting musical instrument mechanism.

54. The musical instrument mechanism of claim 52, wherein the compliant feature provides a spring constant that resists motion of the body portion in a way that mimics the stiffness of a rigid-link pin joint of a preexisting musical instrument mechanism.

55. The musical instrument mechanism of claim 52, wherein the musical instrument mechanism is selected from a group consisting of a hammer, a damper, a wippen and jack pair, a wippen and repetition lever pair, a key of a keyboard, and a pedal.

56. A musical instrument mechanism comprising: a mechanism comprising a compliant feature which transfers input energy into output energy and wherein the output energy is used to affect the play of a note of the musical instrument.

57. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a hammer to the musical instrument.

58. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a back stop to a back check.

59. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a back stop to a wippen.

60. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a back stop to a key.

61. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a hammer to a jack.

62. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a jack to a letoff button.

63. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a jack to a wippen.

64. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a repetition lever to a wippen.

65. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a wippen to the musical instrument.

66. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a wippen to a sticker.

67. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a damper to the musical instrument.

68. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a damper to a damper stop.

69. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a damper to a key.

70. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a key to the musical instrument.

71. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a pedal to the musical instrument.

72. The musical instrument mechanism of claim 56, wherein the compliant feature movably connects a link in a trapworks of the musical instrument associated with a pedal to the musical instrument.

73. The musical instrument mechanism of claim 56, wherein the compliant feature biases the mechanism toward a rest position.

74. The musical instrument mechanism of claim 56, further comprising a baseline characteristic of a contemporary version of the mechanism without the compliant feature; and wherein the compliant feature replicates the baseline characteristic.

75. The musical instrument mechanism of claim 56, further comprising a baseline characteristic of a contemporary version of the mechanism without the compliant feature; and wherein the compliant feature improves upon the baseline characteristic.

76. The musical instrument mechanism of claim 56, further comprising an additional compliant feature which cooperates with the compliant feature to transfer input energy into output energy.

77. The musical instrument mechanism of claim 76, wherein the compliant feature is a first compliant segment and the additional compliant feature is a second compliant segment.

78. The musical instrument mechanism of claim 56, wherein the input energy is a force pushing down on a front portion of a key of a piano keyboard.

79. The musical instrument mechanism of claim 56, wherein the input energy is a force pushing up on a rear portion of a key of a piano keyboard.

80. The musical instrument mechanism of claim 56, wherein the input energy comes from an electromechanical system.

81. The musical instrument mechanism of claim 56, wherein the input energy comes from a pneumatic system.

82. The musical instrument mechanism of claim 56, wherein the output energy leaves the mechanism through a hammer of the mechanism hitting a string which vibrates to play the note.

83. The musical instrument mechanism of claim 56, wherein the output energy leaves the mechanism through a hammer of the mechanism hitting a sensor of the piano to play the note.

84. The musical instrument mechanism of claim 56, wherein affecting the play of a note is selected from a group consisting of initiating or altering how a string is vibrated, a sensor registers the note, and a valve is actuated.

85. A method of designing a compliant action for a piano or similar instrument comprising: determining a portion of an existing action to replace; determining a characteristic of the portion to replicate in a compliant action; creating the compliant action replicating the characteristic, comprising a compliant feature.

86. The method of claim 85, wherein the compliant feature allows a hammer of the action to rotate relative to itself.

87. The method of claim 85, wherein the compliant feature allows a wippen of the action to rotate relative to itself.

88. The method of claim 85, wherein the compliant feature allows a repetition lever of the action to rotate relative to itself.

89. The method of claim 85, wherein the compliant feature allows a grand piano damper of the action to rotate relative to itself.

90. The method of claim 5856, wherein the compliant feature allows a grand piano jack of the action to rotate relative to itself.

91. A method for playing notes of a piano, comprising: a piano action comprising a compliant part which transfers input energy into output energy and wherein the output energy is used to play the note.

92. The method of claim 91, wherein the compliant part comprises a hammer and a hammer flange rotatably connected by a compliant segment.

93. The method of claim 91, wherein the compliant part comprises a wippen and a wippen flange rotatably connected by a compliant segment.

94. The method of claim 91, wherein the compliant part comprises a wippen and a repetition lever rotatably connected by a compliant member.

95. A hammer for a musical instrument comprising: a plurality of portions coupled end-to-end to form a continuous chain of segments comprising: a first rigid portion providing a ground link to a musical instrument, a second rigid portion, and at least one flexible portion, wherein the at least one flexible position allows relative motion between the first rigid position and the second rigid portion.

96. The hammer of claim 95, where in the second rigid portion comprises a hammer shank.

97. The hammer of claim 95, where in the second rigid portion comprises a hammer head.

98. A method of designing musical instrument mechanisms comprising: creating a representation of an existing portion of a musical instrument mechanism comprising two or more rigid portions connected by a joint that allows relative motion between the two or more rigid portions; and recreating the representation with an alternate, compliant feature.

99. The method of claim 98, further comprising repeating the recreating step multiple times, each time using a different alternate, compliant feature.

100. The method of claim 98, wherein the representation further comprises a second joint that allows relative motion between at least one of the two or more rigid portions and another rigid portion; the method further comprising varying the second joint to increase the number of possible representations by the number of times the second joint is varied.

101. A damper underlever comprising: a damper flange; anda damper lever rotatably connected to the damper flange by a compliant feature.

102. A damper underlever comprising: a damper link; and a damper block rotatably connected to the damper lever by a compliant feature.

103. A damper underlever comprising: a damper block; and a sostenuto link rotatably connected to the damper block by a compliant feature.

104. A method of designing a damper comprising: designing a damper underlever with at least one compliant feature to provide rotational motion between 2 rigid links of the damper underlever.

105. A method of manufacturing a damper comprising: integrating at least one compliant feature to rotationally connect at least 2 rigid links of a damper underlever.

106. A musical instrument mechanism comprising: a first rigid link; a second rigid link; a characteristic relating the first rigid link and the second rigid link influenced by a revolute or contact joint; and a compliant feature influencing the characteristic instead of the revolute or contact joint.

107. A musical instrument mechanism comprising: a first link; a second link connected to the first link by a primary flexure; and an adjustment that changes the energy in the primary flexure to change the amount of bias of the first link relative to the second link.

108. The musical instrument mechanism of claim 107, wherein the adjustment directly contacts one or more portions of the primary flexure to change the geometry of the primary flexure relative to itself.

109. The musical instrument mechanism of claim 107, further comprising an adjustment flexure acting on the first link and second link; an adjustment point on the adjustment flexure; and a counterpoint; and wherein the adjustment is caused by changing the distance between the adjustment point and the counterpoint.

110. The musical instrument mechanism of claim 107, further comprising an adjustment flexure acting on the first link and second link; an adjustment point on the adjustment flexure; and a counterpoint; and wherein the adjustment is caused by changing the orientation between the adjustment point and the counterpoint.

111. A piano action comprising : a wippen with a compliant feature allowing the wippen to rotate relative to an piano when a wippen flange of the wippen is mounted to the piano; and a jack with a compliant feature allowing the jack to rotate relative to the wippen.

112. The piano action of claim 111, further comprising a repetition lever with a compliant feature allowing the repetition lever to rotate relative to the wippen.

113. The piano action of claim 111, further comprising a hammer with a compliant feature allowing the hammer to rotate relative to the piano when a hammer flange of the hammer is mounted to the piano.

114. The piano action of claim 111, further comprising a damper with a compliant feature allowing the damper to rotate relative to the piano when a damper flange of the dammer is mounted to the piano.

115. The piano action of claim 111, wherein the piano is a grand piano.

116. The piano action of claim 111, wherein the piano is an upright piano.

117. The piano action of claim 111, wherein each compliant feature includes a spring force that acts to bias the rotation toward a rest position.

Images