Aratchetorrattle, more specifically, cog rattle[1] is a musical instrument of the percussion family and a warning/signaling device. It operates on the principle of the ratchet device, using a gearwheel and a stiff board mounted on a handle, which rotates freely. Variants include the gragger (Yiddish: גראַגער) used in Judaism, the rapach, and the raganella.
The player holds the handle and swings the whole mechanism around. The momentum makes the board click against the gearwheel, producing a clicking and rattling noise. A popular design consists of a thick wooden cog wheel attached to a handle and two wooden flanges that alternately hit the teeth of the cog when the handle turns. Alternatively, smaller ratchets are sometimes held still or mounted and the handle turned rapidly by the player. The mounted ratchets allow for greater control of the duration and timing of the sound. This allows the ratchet to be used like a snare drum, placing sustained rolls in precise durations of time. Dynamics are controlled by the rate at which the ratchet is rotated.[2]
In Judaism, the gragger (also groggerorgregger; from Yiddish גראַגער) is used for the holiday of Purim. The gragger is used every time Haman's name is mentioned during the reading of the Megillah.[3] Because Haman persecuted the Jews, the noise is supposed to symbolically drown out his name (although every word of the Megillah, including Haman's name, must be heard clearly; therefore, the words are often repeated after the sounding of the gragger). The gragger originated in Jewish tradition to help make noise during the reading.[4]
Up until the early 1970s, this type of rattle was commonly used by fans at soccer and rugby matches in the United Kingdom and was known as a football rattle.[5]
In the 18th and 19th centuries, a policeman's rattle was used by British[6] and Australian[7] policemen to summon assistance.[8] They were used to warn of poison gas attack in the trenches of the First World War and issued to British police and ARP wardens during the Second World War, to warn of the presence of poison gas.[9][10]
The raganella (Italian for "tree frog") is a percussion instrument common in the folk musicofCalabria in southern Italy. Technically, the raganella is a "cog rattle", producing a sound that is enough of a "croak" to have derived the folk name of the instrument from the Italian name of the common tree-frog. The raganella is about the size of a breadbox and consists of a wooden frame into which are fastened four or five stiff but flexible wooden tines fastened to one side of the frame; the other ends of the tines are struck in rapid succession by a cog-wheel that is turned by a crank handle mounted on the side of the frame.
The rapach (Ukrainian: Рапач) is a larger version of the derkach, a ratchet. Rapachs are used by churches in the Prešov region of Slovakia by ethnic Ukrainians instead of bells during Easter.
^Cross, David (2011-02-17). "On the Beat in Birmingham - Rules and regulations". BBC. Retrieved 11 March 2014. Police whistles came much later; the early Victorian constable would have carried a small wooden rattle.
^"Evolution of the Victoria Police uniform". The Australian. Retrieved 11 March 2014. Police rattle from the late 19th century. Used by early police officers in Melbourne, to call for assistance or sound warnings... Later replaced by a whistles.
![In some European churches, a ratchet known as a crotalum is used instead of bells during the Paschal Triduum, the three days before Easter Day[11]](http://en.wikipedia.org/wiki/File:Rehtacka.jpg)
