On 11/18/2011 2:52 AM, Peter Blodow wrote: > Kent, > I have a mechanical clock that was used to control and synchronize about > 100 slave clocks in our company. It is built very simple, but uses two > important principles: the pendulum is made if invar steel and the > driving chain is endless, the weight being wound up electrically every > minute by the same amount that it has been sinking during that minute. > The minute slave impulse was used for this. Thus, the weight of the > chain is to be neglected. For decades, all the employees came to work as > the clock ruled. Being a physicist, too, I could not let such a device > just go down the drain. When it was replaced by an electronic radio > controlled system, I salvaged it - literally - out of the junk > container, gave it a goldish outer appearance and placed it on the wall > behind the desk chair in my director's office. When I retired, I took it > home, and it will be placed right next to the other wall clocks I am > keeping for sentimentality. > ny Peter:
That's the same master-slave purpose Hope-Jones designed his Synchronome time transmitter to serve. They were used throughout factories, schools, railway systems, first in England and then elsewhere. It also employs an invar pendulum rod and a bit of dissimilar-metals magic at the pendulum bob to achieve reasonable temperature compensation and yet another method to achieve "perpetual" running time involving a precise impulsive force applied every 30 seconds, a so-called gravity escapement. There's a nice Shockwave animation on a Swiss website of the entire Shortt-Synchronome system (http://homepage.bluewin.ch/electric-clocks/Shortt.htm). The driving force for the Synchronome gravity escapement is delivered by the L-shaped arm on the right---Gene, this animation is for you too. They had their competitors in many countries, for example, IBM in the US, Siemens in Germany. Some years ago I bid on eBay for a Siemens master clock stated to have been retired from the Physics Department at TU Berlin but others wanted it even more than I did. Obviously a lot of us don't like to see these things "go down the drain"! That I'm wearing a perfectly adequate $10 watch doesn't come into it. I have a similar affection for vintage analytical balances---lovely combinations of metal, wood, and glass---which mostly went straight into dumpsters when electronic balances were introduced. The few that are left and still in decent condition go for outrageous prices, in part I suspect because they are so attractive to the eye. In my advancing age, I have become quite fond of vintage measurement technology and have a meager collection of standard resistors, weight sets, analytical balances, a WWII-vintage Jo-block set, and the like. As you might imagine, my wife is not nearly so fond as I am of these things cluttering our house :-) And now back to EMC2. Regards, Kent ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
