key of a musical instrument

Abstract

Key of a musical instrument, in particular a piano, wherein the key (1) is pivotally mounted about a rocking point, so that pivot arms (4, 5) are formed on both sides of the rocking point, and at least one counterweight (9) is provided on at least one of the pivot arms (4, 5), characterized in that the at least one counterweight (9) is at least partially formed from a lead-free bismuth alloy.

Description

[0001] The invention relates to a key of a musical instrument, in particular a piano. The key is pivotally mounted at a cradle point, forming pivot arms on both sides of the cradle point. At least one counterweight is provided on at least one of the pivot arms to adjust the key's restoring force.

[0002] With keyboard instruments in general, and with pianos in particular, it is important that the individual keys are precisely coordinated in terms of their restoring force. It goes without saying that the individual notes of a keyboard instrument will have different volumes when played with exactly the same keystroke. This is due on the one hand to the design and on the other hand to the different auditory perception of different pitches. However, these differences are not problematic because the musician has become accustomed to these characteristics of their musical instrument and is able to correct them. Moreover, these differences are practically identical, at least among musical instruments of the same design. However, it is problematic if the restoring forces of the individual keys are different, since these differences affect each individual key and therefore each individual note differently.Furthermore, such differences depend on the individual musical instrument, meaning that the musician cannot adapt to them. For this reason, it is common practice to adjust the restoring forces of each key on a musical instrument individually using a balancing weight, commonly referred to as a key lead. These balancing weights are usually inserted into holes in the key during manufacture of the musical instrument and thus bring about the desired equalization of the key restoring forces. It has now been discovered that the key restoring forces change over time, so that the original balance of the restoring forces is deteriorated. The cause of this deterioration was previously unknown, which is problematic because repair is very time-consuming and therefore expensive. As a rule, all balancing weights have to be removed and all keys readjusted.It has been discovered that musical instruments of identical design tend to vary the key restoring forces very differently. This makes solving this problem extremely difficult.

[0003] The invention is based on the object of creating a key of the type mentioned at the beginning in which the restoring forces remain constant over a long period of time.

[0004] This object is achieved according to the invention with the following features.

[0005] A key according to the invention for a musical instrument, in particular a piano, is pivotally mounted about a cradle point and is preferably made of wood. This cradle point divides the key into two pivot arms which are rigidly connected to one another. Typically, this cradle point is not located at the center of gravity of the entire key body, but offset therefrom. The entire key body is considered to be the rod-shaped key, the externally visible fingerboard, and in the case of a piano, a hammer which strikes the string. The crucial factor here is that this entire key body, due to its asymmetrical mounting at the cradle point, generates a torque which pushes the externally visible fingerboard outwards. The musician can then press against the fingerboard to operate the key, which automatically returns to its original position due to the aforementioned restoring force.In order to set this restoring force to the same force value for all keys, at least one counterweight is provided in at least one of the pivot arms of the key.

[0006] It has now been discovered that this counterweight is the cause of the lack of long-term stability of the balance of the restoring forces. According to the state of the art, the counterweights are made of lead – as the name "keyboard lead" suggests. Depending on the ambient conditions, the lead can react chemically. In a dry environment, it can react to form lead acetate C4H6O4Pb. At normal air humidity of around 50% relative humidity, however, the lead can react to form lead triacetate C4H 12O7Pb. These chemical reactions each have opposing effects on key balance. For example, the mass of the balance weight increases due to the chemical reaction itself. On the other hand, there is the problem that both lead acetate and lead triacetate have poor solid-state bonding, so that parts of the balance weight can break off when the key is moved, resulting in a reduction in mass. These two effects lead to an increase or decrease in the restoring force, depending on which of the pivot arms the balance weight is attached to and which of the two effects predominates. This lack of reproducibility makes it extremely difficult to find the cause of the problem.

[0007] To solve this problem, it is proposed to construct at least one counterweight from a lead-free bismuth alloy. Bismuth is chemically extremely inert in air, so that no acetates form. Furthermore, bismuth has a sufficiently high density to allow the at least one counterweight to be constructed sufficiently compactly while still achieving adequate compensation for the restoring forces. Extensive series of tests have shown that these counterweights neither significantly change their mass nor become brittle when stored in air, thus ensuring a permanent adjustment of the key's restoring forces.

[0008] For the counterweight, it is advantageous to use a bismuth-tin alloy. This makes the alloy softer and thus easier to handle. A certain degree of malleability is desirable, especially if the counterweight is to be driven into a hole in the key.

[0009] To achieve low reactivity with air, it is advantageous if the bismuth content is higher than the tin content.

[0010] Here and below, it is defined that percentages are to be understood as weight percentages based on the total alloy. It is expressly noted that the alloy may also contain other substances, although these are not specified. However, the presence of other substances is not mandatory. A bismuth content of at least 52% has proven to be effective, resulting in a sufficiently inert alloy.

[0011] Advantageously, the bismuth content is at least 56%, resulting in an alloy that is inert to air.

[0012] A tin content of at least 25% has proven to be effective in ensuring good formability of the alloy.

[0013] Without compromising chemical inertness, the tin content can also be increased to at least 30%, which makes the alloy easier to handle overall.

[0014] An upper limit of 40% for the tin content has proven effective in order to avoid the occurrence of tin pest.

[0015] In order to ensure sufficient chemical stability even under adverse conditions such as polluted air, it is advantageous if the tin content is no more than 34%.

[0016] The subject matter of the invention is explained by way of example with reference to the drawing, without limiting the scope of protection.

[0017] The single figure shows a key 1 pivotally supported on a rocker plate 2. The rocker plate 2 defines a pivot axis 3 about which the key 1 can pivot. Extending on either side of the pivot axis 3 are pivot arms 4, 5, which are rigidly connected to one another and together form a continuous body. A handle 6 is provided on the rocker arm 4. On the rocker arm 5, in contrast, a hammer 7 is provided, which strikes a string. The key 1 also has one or more bores 8 into which a counterweight 9 can be driven. This counterweight 9 is made of a bismuth-tin alloy and serves to adjust the restoring force of the key 1 so that the various keys installed in the musical instrument have the same restoring force. List of reference symbols 1 button 2 weighing point plates 3 swivel axis 4, 5 Swivel arm 6 Handle 7 hammers 8 Hole 9 Balance weight

Claims

[1] Key of a musical instrument, in particular a piano, wherein the key (1) is pivotally mounted about a rocking point, so that pivot arms (4, 5) are formed on both sides of the rocking point, and at least one counterweight (9) is provided on at least one of the pivot arms (4, 5), characterized by that the at least one balancing weight (9) is at least partially formed from a lead-free bismuth alloy. [2] Button according to claim 1, characterized by that the at least one balancing weight (9) is formed from a bismuth-tin alloy. [3] Button according to claim 1 or 2, characterized by that the bismuth content is higher than the tin content. [4] Button according to at least one of claims 1 to 3, characterized by that the bismuth content is at least 52%. [5] Button according to claim 4, characterized by that the bismuth content is at least 56%. [6] Button according to at least one of claims 1 to 5, characterized by that the tin content is at least 25%. [7] Button according to claim 6, characterized by that the tin content is at least 30%. [8] Button according to at least one of claims 1 to 7, characterized by that the tin content is a maximum of 40%. [9] Button according to claim 8, characterized by that the tin content is a maximum of 34%.

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