Repeater mechanism
A repetition hammer mechanism (from Latin repetere : 'repeat') also called call hammer mechanism or pull hammer mechanism is a mechanical bell mechanism (synonym hammer mechanism ) integrated into a clockwork , which can acoustically reproduce the current time and the elapsed hour, quarter hour, eighth hour , 5 minutes or Minute strikes on the bell or gong .
description
The triggering of the signal can be repeated at will by using the principle of the rack bar mechanism with relay. The repetition devices can also be connected to self- striking mechanisms that are regularly triggered by the clockwork. The calculator controls the number of hammer blows on the gongs or bells. In the past, instead of the arithmetic unit, there were also lock washer striking mechanisms , which could strike incorrectly if the hands were adjusted. Due to the much simpler mechanism of a lock disc striking mechanism, repeating is not possible; every time the striking mechanism is triggered in between, it "counts" on and strikes the next value (e.g. if it is triggered at 4:50 pm, it already strikes 5:00 pm, if it is triggered again, 5:30 pm, etc.).
Clocks with a quarter-hour repeater or minute repeater have at least two gongs. Repeater clocks with more than three gongs or bells for the hour, quarter hour and minute are called glockenspiel (French: carillon or cathédrale ). With a large striking mechanism (French: Grande Sonnerie ), the bell rings both automatically and when the release lever is operated.
Since the striking mechanism can be operated any number of times, the necessary energy is supplied to the watch by pressing a button. The key travel and workload is therefore significantly greater than z. B. the stop system .
history
The oldest known repeater striking mechanisms date from 1676 by the London watchmakers Edward Barlow (1636–1716) and Daniel Quare (1648–1724). Typically the trigger lever of the rack bar mechanism is extended over the edge of the plate of the clockwork, so that this extension can be pulled down, which leads directly to a lifting of the other end of the trigger lever and thus triggers the repetition blow. For wristwatches with repeater there is usually a slider on the left side of the watch case. The minute repeater wristwatches, which are particularly complex to manufacture, were first presented in 1914.
The repeater mechanism was created at a time when there were no luminous hands and you couldn't simply turn on the light quickly if you wanted to know the time during the night. Due to this historical function, it is still possible today to attach a cord to the release lever of the repeater hammer mechanism. Is the other end of the cord then z. B. tied to the bed post, you can hear the time using the repetition stroke without having to get out of bed.
Individual evidence
- ↑ Lukas Stolberg: Lexicon of the pocket watch ; Carinthia Verlag; Klagenfurt 1995; ISBN 3-85378-423-2 ; P. 186.
- ↑ Fritz von Osterhausen: Callweys lexicon ; Munich 1999; ISBN 3-7667-1353-1 ; P. 271.
- ^ Helmut Kahlert , Richard Mühe , Gisbert L. Brunner , Christian Pfeiffer-Belli: wrist watches: 100 years of development history. Callwey, Munich 1983; 5th edition, ibid 1996, ISBN 3-7667-1241-1 , p. 505.
- ^ GA Berner: Illustrated specialist encyclopedia of watchmaking , accessed on January 16, 2012.
- ^ Gisbert L. Brunner : wristwatches with repeater striking mechanism. In: Old clocks. No. 2, 1986, pp. 65-79, and No. 3, 1986, pp. 50-58.
- ↑ Helmut Kahlert u. a .: Wristwatches: 100 years of development history. 1996, p. 505.
