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xhandy 发表于 2012-8-29 19:24 
而且他也有说得不对的地方，阿斯曼高路云的擒纵是纯正德国设计，乃德国殿堂级制表大师Moritz Grossman先生 ...
说到擒纵，钟博士给出的信息非常详细，先发个原文，容后再译：Re: how many types of escapements have really been continued today except the Swiss l"Better" is a tricky term for use with watch escapements. While the detent, spring and pivoted, produce the best results in lab settings they do not do well in rough pocket wear.
The Swiss lever, in my view, took over becuase it provides the best combination of lab and rough use results, along with ease of manufacture and adjustment. IT seems ot hold up well to minor abuswe and will run even with slightly bend pivots. Usually this robustness is good.
M Grossmann wrote a terrific book "A Theoretialc and Practical Treatise on the Lever Escapment" is available in several forms as a free download.
The English and a few Swiss consitnued ot experiiment with the Daniels over and away the most successful recent attempt to better the Swiss lever.
BTW I beleive a Swiss lever has these features
1) Straight line lay out
2) Dividied lift with club teeth on the escape wheel
3) Visible pallet jewels
4) Double roller
The staight line layout provides the best view of operation with facilitates adjustment when needed
The club tooth escape wheel is far more resitistat to wear than the English "ratchet tooth or pointed tooth. The club tooth also lends itself to oil holding goodies such as raised teeth and retention holswe as used by Breguet who use it first to my knowledge.
The visible really means that the pallets are held by their sides making them adjustable from the top on a heated surface making setting them a lot easier than on an English style. It also shows off the jewels which require removal of the lever to see them on an English watch. Its better looking at least to me.
Whether the double roller is part of a Swiss lever is debateable and if someone really knows better I will accept correction. The benefit of the double roller is that its safety action takes place on a smaller radius for less disturbance than unlocking and impulse which are at alarger radius. Less energy is lost on unlocking and more is given on impulse. The down side of the double roller is that the end of the lever is a heavier and its inertial redices escapement efficiency. For thsi reason the single roller often did better in time trials. Sibngle roller sare alos susceptible to loss of safety action leading to mislocking (Its very thin pin can bend) . US railroads insisted on double rollers once they were widely available in the probably correct belief that they did better in railroad hard use.
This is a complex history with very little authorativive information in books.
Grossman is very good on theory and readily available, but it dates from 1869 and the Swiss lever was not the emerged thing it was until the 1990's. Kemp's The English Fusee Lever Watch has a lot on the evolution but admits ignorance on the final emergence. This is a scarce book but worth looking to find.
In terms of departures from the Swiss lever, the most commong today is the Daniels Co axisl but the Freak which we discusssed and an Audemars Piguet variant have recently been put inot top grade watches. These are not going to get anything like the use that the Swiss lever so their success is not so clear. These are variants.
As to continuing production, I think the cylinder and possibly the American duplex survided the longest as alternatives and the English lever held on possibly up to World War II in very small production.
One other survivor I failed ot to include that began as a very high end and went very low was the pin pallet escapement. It is very amusing to contrast Grossmann's view on it with todays complete disdain for this variant.
One other "odd ball" was the DeLong Escapement which is very rare in Illinois and Ball watches and was later used in a much later and widely produced Timex watch. I do not know what is in modern cheap mechanical watches but the pin pallet was dominant until very recently. The overwhelming majority were robust but Grossmann has a lot of preaise for the escapement. The DeLong was a jeweled pin pallet.
I have ben careful to call tehse pin pallet becuase a few variants have pins in differnt parts of their lever but the pin pallet. sometimes also called the Roskopf has the advanatage that its parts can be build by failry simple machines. Its robustness is the attraction allowing it to work in a loosley built watch.
The problem is that they accumulated dust at critical points in the mechanism which are hard to remove. These machine made watches are held together with bent tabs and are very hard to disassemble and clean.
I suspect that a carefully built watch with high precision fits would rival a Swiss lever in various performance areas. Its bad reputation keep serious makers from trying it. That it will work in a loosely built watch does not mean it is not capable of high perofrmance. In the early days of detached levers, the table roller has a similar "image" problem but dedicated makers later took many Observatory **s with table rollers. I suspect that if true mechanical watch timing trails were re-opened some adventurous maker could win with a pin pallet.
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