Piano mechanics
A lever construction is called a piano mechanism , hammer mechanism or stop mechanism , in which hammers are thrown (“triggered”) against the strings of a piano at the push of a button in order to make them sound. The damping of the strings, which should lead to the controlled fading of the tone, is also part of the mechanics. Almost all individual parts of the mechanics are made of wood, metal, felt and leather, which are connected to one another in a movable or fixed manner.
history
The forerunners of instruments with piano action include the harpsichord , in which the strings are torn with the help of quills, and the clavichord , in which the strings are struck ("touched") by tangents . For the development of the mechanics of the piano, in which the strings are struck by hammers, the model of the chopping board was also important, the strings of which a player strikes with mallets in hand.
When around 1700 a dulcimer virtuoso named Pantaleon Hebenstreit (1668–1750) toured Europe and gave acclaimed concerts, various instrument makers set about mechanizing the playing of the dulcimer with a keyboard .
One of these men was the Florentine Bartolomeo Cristofori , who made the first examples of a jack mechanism around 1698. Independently of this, the French J. Marius (1716) and the Nordhäuser Christoph Gottlieb Schröter (1717) also invented a keyboard instrument whose strings were not plucked, but struck by hammers. Gottfried Silbermann (1683–1753) in Strasbourg and Johann Andreas Stein in Augsburg , who is considered the spiritual father of bouncing mechanics, were particularly important for the further development of the hammer piano .
Further markings in the development of piano mechanics were the construction of a double action mechanism by Nannette Streicher and Theodor Stöcker and the invention of a repetition mechanism ("double échappement") by Sébastien Érard in 1823.
Innovations in 1870/71 were the first use of metal frames and tubes with wooden inlays as well as the invention of the pilot screw by Theodor Steinweg in March 1875 , with which the previous bound mechanism ( button and lifting link connected by means of a coupling link) was dissolved. This made it much easier to separate the keyboard and the mechanical structure for maintenance and repair purposes.
From approx. 1880 onwards, piano mechanics became more and more standard and purchased goods in the course of the rise of German piano makers (against French and British competition) and removed from the processes of a piano factory. Today, piano mechanics are largely bought-in parts from specialist suppliers who are active in southern Germany on the one hand, and there are specialist piano mechanics suppliers in the USA in the Boston area , in Hamamatsu in Japan and in the Guangdong region in China on the other .
In the 1900s, the great era of the "German" or "Vienna" bounce mechanics went to a close, one of the last defenders of the Viennese action was until about 1910 the Viennese piano maker Bösendorfer , which for about ten years either "double English" and " Wiener “mechanics built in. Other special versions such as the Blüthner patent mechanism also disappeared from the market. The double repetition mechanism according to Erard has established itself as the standard for grand pianos, and the bottom-damping mechanism for pianos. Table pianos, with their usually simple push mechanism, no longer played a role in Western Europe around 1850 and in the USA from around 1890.
One of the most recent innovations in the history of piano mechanics is a patent from the Bamberg piano maker Josef Meingast, who presented a rolling hammer roll in 2002.
A piano action is mentally divided today:
- Keyboard or keyboard,
- Repetition mechanism above,
- Hammers with felt pads,
- Damping mechanics.
Types of mechanisms for grand pianos and how they work
Almost as many names have emerged for the multitude of different types of mechanisms that have been developed over the last two and a half centuries. Mechanism types were not only baptized according to their mode of operation or their inventor, but also according to their origin or where they were most widely distributed, which can lead to some confusion. It is also necessary to distinguish between machine heads for vertically-strung pianinos and machine heads for horizontally-strung grand or table pianos.
Tangent mechanics
An early form of mechanics in the transition from the clavichord and harpsichord to the fortepiano was the tangent mechanics. With her, a hammer is not yet thrown against the string, but a wooden bar called "Tangente".
Pressing the button (A) lifts its rear end with the pilot (B). The pilot pushes the driver (C) up, which in turn hurls the tangent (D) in a rake against the string (E). At the same time the damper (F) rises so that the string can vibrate freely.
When the button (A) is released, the damper (F) also lowers and the string (E) stops vibrating. In addition, driver (C) and tangent (D) lower and are ready for the next stop.
Single action
An early push mechanism that can be found in English square pianos is called "single action", which means something like "simple release". In her case, flat hammer bars with semicircular leather-covered hammer heads are attached by a leather tongue hinge in an independent hammer chair. A pusher made of brass wire with a leather-covered wooden dummy serves as a trigger. When the button (A) is pressed, the pusher (B) hurls the hammer bar (C) against the string (D). At the same time, the rear end of the key lifts the damper (E) off the string so that it can vibrate freely.
Double action
In 1776 Georg Fröschle first built a square piano push mechanism with a driver in London. Ten years later, John Geib patented this type of mechanism as "Double Action", and until 1800 only instruments from Longman & Broderip were allowed to be equipped with it. Compared to the "Single Action" it has an additional driver. The technical advantage consists in a more nuanced attack and a more familiar game. When the button (A) is pressed, the trigger (B) hits the driver (C). This in turn hurls the hammer (D) up against the string (E). At the same time, a mechanism at the end of the key lifts the damper (F) off the string so that it can vibrate freely.
Bounce mechanism
Piano mechanisms based on the prel principle were given the name "German Mechanics" or "Wiener Mechanik" at an early stage, as they were mainly built by German and Austrian piano makers. By pressing the front end (on the right in the illustration) of the button (A), the rear end (on the left in the illustration) with the capsule (B) and the hammer (C) located in it lifts. The rear (left) end of the hammer, called the "beak" (D), bounces against the bar (E) so that the front end with the hammer head (F) snaps against the string (G). At the same time the damper (B) leaves the string so that it can vibrate freely. After the stop, the beak slips past the bar so that the hammer head can fall back onto the hammer rest pad (I).
Bounce tongue mechanism with single release
Since fine adjustment of the release is problematic with a rigid bump bar common to all hammers, the bump bar was soon replaced by individual movable bump tongues. These bounce tongues are attached to a leather hinge and are held over the end of the hammer handle by a spring. Due to the adjustable tension of the spring, the moment and the energy of the release can now be changed.
By pressing the front end (on the right in the illustration) of the button (A), its rear end (on the left in the illustration) with the capsule (B) on it, in which the hammer (C) is suspended on one axis, is raised. Its rear end, called the "beak" (D), gets caught in the heel of a spring-mounted bouncing tongue (E) (also called "trigger"), so that the front end lifts and hurls the hammer head (F) up against the string. At the same time, the damper dummy (G) is moved upwards and lifts the damper (H) above it from the string. After the stop, the hammer head falls back into the catcher (I). When the key goes down, the beak leather slides back along the buffer tongue into its starting position.
Overlap mechanics
The overturning mechanism represents a special case in the history of the piano, which was initially tried out by the Viennese piano makers Andreas Streicher and Nannette Streicher , and later by the London piano maker Robert Wornum and the Berlin piano maker Theodor Stöcker . With her, the hammers hit the horizontal strings from above. The advantage is that the strings are struck by the hammers in the direction of the bridge and the soundboard and not away from them, so that there is a higher efficiency between the effort and the sound result. On the other hand, it is disadvantageous that the hammers cannot fall back into their rest position due to gravity, but have to be brought back using a spring mechanism. In addition, an overturning mechanism requires a more complicated arrangement of the tuning pegs , so that the tuning process is made more difficult.
The pressure on the front end (on the right in the illustration) of the button (A) is transmitted through the bridge (B) to the pusher (C), which pushes the hammer butt (D) downwards so that the hammer head (E) against it the string (F) bounces. At the same time, a small rod at the back of the key pushes the damper (G) off the string so that it can vibrate freely. After the stop, the spring (H) brings the hammer back up. When the button is released, the spring (I) pushes it back up to its starting position.
Jack mechanics
Due to the spread of jack mechanics by English piano makers, mechanics types based on the jack principle were also given the name "English mechanics". Further modifications were also called "Half English Mechanics" and "Fully English Mechanics", although these were developed by German and Austrian piano makers, such as the "Blüthner Patent Mechanics". "Half-English mechanics" existed until around 1900.
When you press the front end (on the right in the illustration) of the button (A), its rear end (on the left in the illustration) with the jack (B) on it lifts. This strikes against the butt of a hammer (C) of a hammer suspended by an axis in the hammer chair (D) and thus hurls the hammer head (E) up against the string. After the stop, the hammer falls back into the catcher (F).
Repetition mechanism ("double échappement")
The repetition mechanism by Sébastien Érard from 1821 is a further developed jack mechanism that enables notes to be repeated (= repeatedly struck). It represents the current status in the development of piano mechanics.
Pressing the front end of the button (A) lifts the rear end with the pilot (B) on it. The pilot pushes the whisker unit (C) upwards so that the jack (D), which is movably mounted in it, hits the hammer shaft roller (E) and hurls the hammer head (F) upwards. Before it touches the string, however, the trigger arm (G) hits the trigger doll (H) so that the jack (D) is moved out of its position under the hammer shaft roller (E). Before that, the repeater arm (J) was detached from the hammer roll by the buckling screw attached to the hammer cap in newer mechanisms - hence the term "repeater mechanism with double release". This interrupts the direct power transmission between the key and the hammer, so that the hammer head overcomes the rest of the way to the string simply through the impulse transmitted to it, while the key reaches its lower resting point. After the impact, the hammer head rebounds and is stopped in the catcher (I) halfway up. The repeater arm (J) is pressed down and the tension on the repeater spring (K) is increased. As soon as the catcher releases the hammer head, the repeating shank lifts the hammer handle (L) so far that the jack (D) can return to its attack position under the hammer handle roller (E). This means that the lever system is ready for a new stop before the button (A) has completely returned to its upper rest position.
Mechanism types for pianinos and their modes of operation
With the pianino, the upward movement of the rocker switch must be converted into a forward movement of the hammer. This makes the contact with the hammer a little more indirect. This is usually done by engaging a jack under the so-called "hammer nut", the swivel joint for the hammer. The movement of the hammer is "decoupled" at this nut, the jack is released and deflected backwards before the movement of the hammer reaches the strings. As with the grand piano, the pianino must also be prevented from pressing the strings tight with a hammer and finger force - the hammer's stop point can only be reached with the swing in free flight. The technical term for this is "release".
With pianos, the set of strings of a note, the “choir”, is struck quite high up. As with the grand piano, for almost all cases of ideal tone generation, the hammer stop point should be provided at approximately one seventh to ninth of the free-swinging string length. With very tall concert pianos (over approx. 135 length), rod-shaped extensions of the key actuation, so-called abstracts, are required for this purpose.
In contrast, there were small pianos (so-called "spinets" in English) in the 1950s to 1970s that were built so low that the hammers could not strike the keys and the key lever would therefore be transferred downwards. These tiny pianos have a disadvantage in terms of sound, and because of the offset operation they are much more difficult and time-consuming to maintain, repair and also to tune.
Lower damper
The damping of a pianino or high piano is usually located below the hammers on the same side of the string system, in the area of the stronger amplitudes of the antinodes.
Upper damper
However, some older pianinos (up to around 1910) have a so-called upper damper mechanism; the damper dolls sit over the hammers. In English one also finds the term “birdcage action”, “bird cage” mechanism, because of the damper actuating wires built in front of the hammer mechanism. On the one hand, this type of damping is less effective than with a piano under-mute, because it only dampens the vibrations in the edge area of the antinodes, and on the other hand, the damper dummy can thwart an optimal hammer contact point with short treble strings - with corresponding disadvantages for sound quality, and furthermore, can tuning and especially the regulation of the mechanics can be made more difficult. However, one cannot say that upper mute pianos are generally completely unsuitable, as is often claimed. A well-regulated upper mute piano is the ideal instrument for early jazz and especially for ragtime because of its clear reverberation.
Web links
swell
- Julius Blüthner, Heinrich Gretschel: Textbook of Pianofortebau . Weimar 1872. Reprint Edition Bochinsky.
- Andreas E. Beurmann: Sounding treasures. Keyboard instruments from the Beurmann collection. Museum of Arts and Crafts Hamburg . Drägerdruck, Lübeck 2000.
Individual evidence
- ^ David Crombie: Piano. Evolution, design and performance . London 1995, ISBN 1-871547-99-7 , p. 34.
- ↑ Function of the mechanics. Louis Renner GmbH , accessed on July 24, 2020 .