Flaps (English key, clef French, Italian chiave ) serve (rarely also in some early brass instruments ) for wood wind instruments to achieve tone holes, which are not accessible because of the size or type of the instrument to the normal hand position or to close with the fingertip are too large.
The first simple woodwind instruments were flutes, where the tone holes for the fingers were easily accessible. In the recorder, this system is visible to this day. With the development of instruments and music in general you looking for ways to increase the range and be able to execute all chromatic notes of the scale. The more complex the requirements are, the more difficult it is to produce these sounds through handle combinations with the existing holes and the woodwind makers began to drill more holes that helped with the over-blowing, generated more semitones or the intonation improved, was by - regardless of the ergonomics hand - the tone holes were drilled at the acoustically correct locations of the pipe. These holes were provided with flaps, a mechanism that virtually increases the player's finger ( and enlarged). By flaps ( combinations ) and the fingering could ( fingering) to facilitate and so additional flaps were attached to certain trills, double-stopping or even for the legato.
Flaps are detectable since the first third of the 16th century, with the closed flaps seem to have emerged only in the 17th century. The application of flaps on brass instruments at the beginning of the 19th century could not prevail over the benefits of approximately simultaneously invented valves.
A flap consists in part of the cushion ( cushion), which is attached to a round metal disc, the tone hole covers. With various mechanical structures made of metal bars it connects to the finger flap that can open or close the hole by pressing.
On the detail picture of a bassoon are right below two tone holes with lids, of which the visible leads right to the door in the middle of the image. This is the cover for the big Fis. It is, like the other three flaps actuated left of the right thumb of the player, the round button in the middle (the big E) is the actual valve cover with the pad itself: this tone hole is the modern bassoon too large to the thumb alone be covered can. ( At the baroque bassoon is at this point a smaller hole without flap )
- After the match function: Binding flap: is used to facilitate " tenuto " bonds of certain sounds (English slur, French ligature, Italian LEGATURA ).
- Double handle flap: (only saxophone) allows double handles, ie two flaps with a finger operated (English double -plate key, French double clef; Italian raddoppia, chiave di Comodita ).
- Trill key: used to facilitate certain trills (English trill / shake key, French clef du / pour Trille, Italian chiave del trillo ).
- Octave key (also Überblas or abrasive flap ) is used for relief of overblowing; is mounted on the bottom of the tube (german speaker key, clef d' octave French, Italian portavoce ). with clarinets: Duodezklappe (also register flap ) flap for overblowing ( clarinets overblow into the twelfth, not in the octave ); circa 1690 invented by Joh Christoph Denner. Bass clarinet had two Duodezklappen (double flap ), which is present day reduced by mechanical solutions to a.
- Open flap: holds in its normal position by spring pressure a hole open ( engl. open key, clef ouverte French, Italian chiave aperta ).
- Flip closed: includes in its normal position by spring pressure a hole ( engl. closed key, clef fermée French, Italian chiave chiusa ).
- Tilting flap: Simple flap, in which a lever via a bearing on the cushion reduces the hole. It is reset by " leaf springs ".
- Rotation flap: the movement of the lever is transmitted by a leading along the tube shaft to the door. It is reset by "pin feathers " (English key on rod; French à clef tringle; Italian cannetta con perno, Profilato contropunte ).
- Plateau flap: a non-perforated flap.
- Ring flap: an annular actuating lever which is located over an open finger hole and when grasping the flap moves over another tone hole or a hole closes, which is too large to be closed by a finger can. 1808 invented by Fr Nolan. 1839 by Hyacinthe Klosé become popular in connection with the Boehm system. (English key ring, glasses, French anneau mobile; Italian chiave ad anello ).
- Spoon flap: mechanism for closing even larger ( " sunk " ) holes. Invented in 1813 by Iwan Müller.
- Thumb flap: operated by the thumb flap for overblowing (English thumb -key, clef du pouce French, Italian chiave del pollice ).
- Glasses flap: the combination of a ring flap with a flap plateau, by Adolf Sax invented.
- Water key: with brass instruments flap, for flowing out of the condensate ( the player breath) from the instrument ( engl. water key, French clef d'eau, Italian chiave dell'acqua / di scala ).
- The flap assembly (English - key arrangement, French disposition of the clefs, Italian disposizione delle chiavi ).
- Flaps hole: is either " easy" or " sunk" (with clarinet ); has a margin or "flat". (English key hole, French trou de clef, Italian foro della chiave ).
- Key pads: the padded cap for the tone hole; initially felt, later made of soft leather (usually goat leather). (English key cushion / pad, French tampon de clef, Italian tampone cuscinetto ).
- Flaps spoon: spoon -shaped part of the mechanism on which the pad seating (English key cap, French plateau / plaque de clef, Italian Piattello della chiave ).
- Valve stem: the flaps spoon and stalk connecting part (german shank, pipe; French rouleau; Italian coda della chiave ).
- Valve stem: The part of the flap mechanism on which rests the fingers ( engl. key lever; French levier / languette de clef; Italian leva della chiave, tasto ).
- Hermann Halbig: The History of the flap on flutes and reed instruments until the beginning of the 18th century, in: Archives of Musicology VI. Born 1924, pp. 1-52. Internet Archive