Vintage pocket chronometer with detent escapement -- by Andrew Babanin

I like to collect interesting devices.

You can hardly find a modern watch with detent escapement. Nowdays there are only marine chronometers still have such a pretty nice regulator. Believe me - detent escapement - is mostly consistent than any other escapement, even traditional lever. Accuracy of this regulateur is reputable and much more closer to quartz watches.
There's a range about 2-3 seconds per day! Compare with lever range +40 / -20 seconds per day. Even COSC sertified chronometers has worse features.
It could be the best except one thing. If you shake it or hit a bit - it can halt with no damage. It was possible to wear such king of escapement in pockets but absolutely impossible in wrist watches.

Not far away the only way to measure exact time was to calculate it according to astronomical observations, so there were observatories in mountains keeping exact time. For the first time they used quite primitive timekeepers, then there were pendulum regulateurs de parquet.
For overseas cruises there used marine chronometers. For sure pendulum clocks are not fit for a boat - suffered of nausea.

So there was invented quite dodgy device to allow the movement to stay in horisontal position (I mean gimbals). Detent escapement was the best to keep accurate time for weeks.

So in this way you could hardly find a flaw of this escapement.
But still for what reason there were produced pocket chronometers?
The answer is - nobody heard about GPS systems ), so all society still relied on observatory time measurments. Pocket chronometers were in demand just to synchronize time between timekeepers (for example between observatory and town reference clock).

Here's a movement made by Lipman (LIP) in the beginning of 20s (Circa 1910-1930). It placed in a hunter gold case.
There's nothing interesting on a dial - as blank as many dials of that period.



Pic.1 Bimetallic balance wheel with helical hairspring. In most systems it has two pallet jewels (one placed in a roller cut). Here there's the only jewel and the roller has a specially shaped cut. Its walls replace the second pallet jewel (underneath)



Pic.2 Parts of detent escapement: escape wheel and spring detent

Spring detent consists a passing spring - very sensitive made of gold and locking pallet jewel.



Pic.3 Escape wheel and spring detent are mounted on the plate



Pic.4 Regulator assembled



Pic.5 After cleaning ald lubricating it works like a new one.

I will prepare a few pics of pivoted detent chronometer soon. Very interesting movement with first system of keyless works!

Andrew Babanin