Glossary entry (derived from question below)
French term or phrase:
double-rond de direction (aussi sellette)
English translation:
fifth-wheel coupling (used mainly of Heavy Goods Vehicles)
Added to glossary by
Donald Pistolesi
Aug 29, 2015 22:19
8 yrs ago
1 viewer *
French term
Native in: English (Variants: US, Canadian) 
Works in: French to English, Spanish to English, Italian to English
double-rond de direction
French to English
Tech/Engineering
Mechanics / Mech Engineering
18th-century carriage steering mechanism
Not sure I put this in the best category, please let me know.
The context is: "Comme sa « grande sœur », la berline, il [un coupé de gala] est particulièrement maniable grâce au double-rond de direction situé à l’avant, et plus confortable, grâce à une suspension en soupentes en cuir"
The vehicle in question belonged to a side-branch of the Portuguese royal family in about 1750. Another technical feature mentioned in the text: "les essieux avant et arrière sont réunis par deux brancards."
The context is: "Comme sa « grande sœur », la berline, il [un coupé de gala] est particulièrement maniable grâce au double-rond de direction situé à l’avant, et plus confortable, grâce à une suspension en soupentes en cuir"
The vehicle in question belonged to a side-branch of the Portuguese royal family in about 1750. Another technical feature mentioned in the text: "les essieux avant et arrière sont réunis par deux brancards."
Proposed translations
(English)
| 4 | fifth-wheel coupling |
Jennifer Levey
|
Proposed translations
2 hrs
Jennifer Levey
Chile
Chile
Native in English
Chile
Human-scale Globalization
Native in: English (Variant: British)
Works in: Spanish to English, French to English, English to Spanish, and 2 more.
Related KudoZ points
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126
Selected
fifth-wheel coupling
The ST refers to the system which is now (in the HGV age) known as a fifth-wheel coupling.
Basically, in an 18th C. carriage, the vertical pivot around which the front axle of the carriage rotates is formed by two large circular structures in the horizontal plane, one just above the other, both rotating about a common king-pin. Between them, there is (or might be) a 'spider' carrying rollers or wheels at the extremities, so it functions like a roller thrust bearing. If there's no spider, the circular parts are in direct contact, and grease is applied to limit friction. The main advantage over a simple king-pin pivot, in historic carriages, was improved stability when negotiating curves in the road.
See https://en.wikipedia.org/wiki/Carriage (under the heading "Undergear")
"A horizontal wheel or segment of a wheel called a fifth wheel sometimes forms an extended support to prevent the carriage from tipping; it consists of two parts rotating on each other about the kingbolt above the fore axle and beneath the body. ..."
Then look at: https://en.wikipedia.org/wiki/Fifth_wheel_coupling (under the heading "Origin").
Finally, see here: https://fr.wikipedia.org/wiki/Sellette_(transport) - where we see that the modern (HGV) equivalent of a "double-rond de direction" is called a "sellette".
The 'double-rond' refers to the fact that the bearing was formed from two complete 'wheels', allowing the carriage to execute very tight turns; 'economy' versions would have bearing surfaces of less than a full circle, and would have a larger turning circle radius.
Basically, in an 18th C. carriage, the vertical pivot around which the front axle of the carriage rotates is formed by two large circular structures in the horizontal plane, one just above the other, both rotating about a common king-pin. Between them, there is (or might be) a 'spider' carrying rollers or wheels at the extremities, so it functions like a roller thrust bearing. If there's no spider, the circular parts are in direct contact, and grease is applied to limit friction. The main advantage over a simple king-pin pivot, in historic carriages, was improved stability when negotiating curves in the road.
See https://en.wikipedia.org/wiki/Carriage (under the heading "Undergear")
"A horizontal wheel or segment of a wheel called a fifth wheel sometimes forms an extended support to prevent the carriage from tipping; it consists of two parts rotating on each other about the kingbolt above the fore axle and beneath the body. ..."
Then look at: https://en.wikipedia.org/wiki/Fifth_wheel_coupling (under the heading "Origin").
Finally, see here: https://fr.wikipedia.org/wiki/Sellette_(transport) - where we see that the modern (HGV) equivalent of a "double-rond de direction" is called a "sellette".
The 'double-rond' refers to the fact that the bearing was formed from two complete 'wheels', allowing the carriage to execute very tight turns; 'economy' versions would have bearing surfaces of less than a full circle, and would have a larger turning circle radius.
3 KudoZ points awarded for this answer.
Comment: "Thanks very much for coming up with so thorough and answer and so quickly. The only drawback I can see is that the English term is used only of modern motorized heavy vehicles. But the concept appears identical."
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