Repeater (horology)

From Wikipedia, the free encyclopedia

A repeater is a complication in a mechanical watch or clock that audibly chimes the hours and often minutes at the press of a button. There are many types of repeater, from the simple repeater which merely strikes the number of hours, to the minute repeater which chimes the time down to the minute, using separate tones for hours, quarter hours, and minutes. They originated before widespread artificial illumination, to allow the time to be determined in the dark,^[1] and were also used by the visually impaired. Now they are mostly valued as expensive novelties by watch and clock enthusiasts. Repeaters should not be confused with striking clocks or watches, which do not strike on demand, but merely at regular intervals.

Contents 1 History 2 How they work 3 Types 3.1 Hour repeater 3.2 Quarter repeater 3.3 Half-quarter repeater 3.4 Five-minute repeater 3.5 Minute repeater 3.6 Grande sonnerie 3.7 Dumb repeater 4 Pictures 5 Bibliography 6 External links 7 Footnotes

[edit] History

The repeating clock was invented by British clergyman Edward Barlow in 1676.^[2] His innovation was the rack and snail striking mechanism, which could be made to repeat easily and became the standard mechanism used in both clock and watch repeaters ever since. Repeater clocks were easy to make; a lever merely had to be added to the striking mechanism that was an integral part of most clocks, to activate it on demand. They lost popularity after matches were invented in the first quarter of the 19th century and are no longer made.^[1]

Both Edward Barlow and Daniel Quare claimed the invention of the repeating watch, just before 1700.^[3] Both applied for a patent on it, which was decided in favor of Quare in 1687. Repeater watches were much harder to make than repeater clocks; fitting the long wire gongs and complicated striking works into a pocketwatch movement was a feat of fine watchmaking. So repeater watches were expensive luxuries and status symbols. The wire gongs used as chimes were invented by Abraham Breguet in 1789.^[1]

Repeater watches, as luxuries, survived the introduction of electric lighting and luminous watch dials in the early 1900s, and repeaters are still found in the most expensive complicated watches.

[edit] How they work

Repeater clocks often had a cord with a button on the end protruding from the side of the clock. Pulling the cord actuated the repeater mechanism. This was called a pull repeater. Repeating carriage clocks have a button on the top to activate them.

Early watch repeater mechanisms were powered by the watch mainspring and were actuated by pushing on the crown. The disadvantage of this is that using the repeater often ran down the mainspring. Later ones are activated by pushing a slide along the side of the case. This winds a separate spring to power the repeater. Releasing the slide releases the spring, and its force as it unwinds moves the repeater mechanism through its chiming sequence.

The gongs are made of long hardened steel wires that are coiled inside the watch case. Tiny hammers actuated by the repeater mechanism strike them to make the chiming sounds. Some of the complex repeaters, such as the minute repeater, need to produce three different sounds, to distinguish hours, quarter hours, and minutes in the striking sequence. Since it is difficult to fit three bulky wire gongs into a watch movement, virtually all repeaters use two gongs, made from the two ends of a single length of wire supported in the middle, and if a third sound is needed it is made by striking the two gongs rapidly in sequence, first the high tone and then the low: "bing-bong".

[edit] Types

[edit] Hour repeater

The term 'repeater', without qualifiers, usually means an hour repeater. On pressing the lever or button, the repeater strikes the number of hours that have passed since 12 o'clock on a gong. This is the only type of repeater that needs a single gong. No distinction is usually made between AM and PM, so whether the time shown is 2:00am, 2:17am, 2:59am, or 2:59pm, the repeater will give the same signal: "bong, bong".

[edit] Quarter repeater

The quarter repeater strikes the number of hours, and then the number of quarter hours since the last hour. The mechanism uses 2 chimes of different tones. The low tone usually signals the hours, and the high tone the quarter hours. As an example, if the time is 2:45, the quarter repeater sounds 2 low tones and after a short pause 3 high ones: "bong, bong, bing, bing, bing". Alternatively, some use a pair of tones to distinguish the quarter hours: "bong, bong, bing-bong, bing-bong, bing-bong"

[edit] Half-quarter repeater

The half-quarter repeater can sound the time to half a quarter hour, or 7 1/2 minutes. It strikes hours and then quarter hours, like the quarter repeater, then it uses a single tone in order to signal if more than half of the current quarter hour has passed. For example, if the time is 3:41 the mechanism will strike 3 low tones ("bong") to represent 3 hours, then 2 sequence tones ("bing-bong") to represent 2 quarter hours, then one high tone ("bing") to indicate that more than half of the third quarter hour has passed.

[edit] Five-minute repeater

The five minute repeater strikes the hours and then the number of five-minute periods since the hour. The mechanism uses a low tone for the hours and a high tone for the minutes. For example, 2:25 would be struck as: "bong, bong, bing, bing, bing, bing, bing".

[edit] Minute repeater

The minute repeater works like the quarter repeater, with the addition that, after the hours and quarter hours are sounded, the number of minutes since the last quarter hour are sounded. This requires three different sounds to distinguish hours, quarters, and minutes. Often the hours are signaled by a low tone, the quarters are signaled by a sequence of two tones ("bing-bong"), and the minutes by a high tone. For example, if the time is 2:49 then the minute repeater will sound 2 low tones representing 2 hours, 3 sequence tones representing 45 minutes, and 4 high tones representing 4 minutes: "bong, bong, bing-bong, bing-bong, bing-bong, bing, bing, bing, bing"

[edit] Grande sonnerie

A grande sonnerie is a quarter striking mechanism combined with a repeater. On each quarter hour, it sounds the hours and then the quarters on two gongs. In addition it can strike the hours at the push of a button.^[4]

[edit] Dumb repeater

Used by the hearing impaired and to tell the time quietly in meetings and concerts, 'dumb' repeater watches did not chime audibly, but instead produced vibrations. Instead of a gong, the hammer struck the hours on a solid metal block attached to the case, producing a dull 'thud' that could be felt in the hand. ^{[5] [6]}

[edit] Pictures

Minute Repeater Ébauche, dial side.

Minute Repeater Ebauche, back side

Minute repeater gong, about 2 in. diameter

Gong support point, showing hollowing to lower tone.

[edit] Bibliography

• Emanuel Seibel and Orville R. Hagans Ed. (1945) Complicated Watches, The Roberts Publishing Co., Denver Colorado.
• C. T. Etchells (1917) Repairing Repeating Watches, Hazlitt & Walker, Chicago. . 26 pages, 11 drawings.
• M. John Huguenin (1897) Etablissage et Repassage des Montres à Répétition, Journal Suisse d'Horlogerie. 48 pages. No drawing.
• François Lecoultre, Les Montres Compliquées, A. Simonin, Neuchâtel, Switzerland.
• J. H. Francis Wadsworth (1965) A History of Repeating Watches, Antiguarian Horology. Ca.

[edit] External links

• Perez, Carlos (January 31, 2001). Hammer and Gong. Carlos' Journal. TimeZone.com. Retrieved on April 22, 2008. Explanation of terminology of repeaters, Sonneries, and clockwatches, as used today.
• (fr) How work a Minute-Repeater Watches
• Minute-Repeater Watches in detail
• example of minute repeater http://www.youtube.com/watch?v=H3L37lU1muM

[edit] Footnotes