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.
The "modern" electronic system I abandonned soon after because everybody has their own precise clocks with them privately. If you are interested in the clock, I can mail you pictures of it (address, because this is off the list!). Peter Kent A. Reed schrieb: > Gentle persons: > > Gene Heskett asked me if there is a website describing the > Shortt-Synchronome clock I mentioned. One could start at > http://en.wikipedia.org/wiki/Shortt-Synchronome_clock which includes a > photograph of the one at NIST, No. 32 out of perhaps twice that many > sold to others. > > The reasons I fell in love with it include: > > 1) it consists of two pendulums, one running in a commonplace industrial > clock---the Synchronome time transmitter---and one running in a > vacuum---the Shortt free pendulum---cross-coupled electrically, that was > the most accurate pendulum clock in the world. It that was surpassed as > a time keeper only when crystal oscillators were put to the task. As a > physicist, I admired this ingenious coupled oscillator system and the > two men who invented it. > > 2) the clock is a precise time keeper but it is very imprecisely made. > Most of the Synchronome parts could be hacked out of pieces of flat and > round stock using saws, files, and drill bits (so why CNC? Because I say > so, that's why!). The principal difficulty with the Shortt free pendulum > is its vacuum encasement, and more than one amateur has simply ignored > that bit and lived with the loss of precision. Anyone looking at this > clock would think "Heck, I could do that." Compare it to the Riefler > observatory clock that hangs near the Shortt-Synchronome clock at NIST. > One look behind the Riefler dial or at the Riefler patent drawings would > convince one that this is a project for the masters (see, for example, > http://www.brown.edu/Departments/Physics/Ladd/instruments/clemens.html). > > 3) Frank Hope-Jones, the inventor and manufacturer of the Synchronome > clock and first the boss and then collaborator of William Hamilton > Shortt, the inventor of the cross-coupled free pendulum, explicitly > supported amateurs desiring to make their own copies of his clocks, even > providing kits of rough parts long ago. He openly published on all > aspects of his clocks. (He was also a shameless self-promoter as you'll > see in all his publications, but what the heck, nobody's perfect.) No > trade secrets and no patent trolls to deal with. The 500 or so members > of the Yahoo Synchronome Group now have wider interests than just the > Synchronome but many members own genuine Synchronome time transmitters > or have made their own. > > 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 > > ------------------------------------------------------------------------------ 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
