Primus and understanding energy transference
  • I have finished cutting and assembling Primus (my first clock). This will be a very basic and obvious fact for those of you who have built clocks before, but I cannot see the answer. My clock appears to be running as it should when the pendulum is swung by hand. I know that the weight attached to the winding barrel acts as the energy source to keep this going. However, I cannot understand how this energy is transferred across the gears to maintain this. I have not glued the cog onto the drive arbor (is this correct?) My belief is, if it is glued, the clock would not wind (unless the winding barrel is unscrewed from the arbor when the clock is wound) and there would be no point to the click wheel ratchet mechanism. I have looked at various websites on pendulum clock mechanisms but the penny is not dropping for me.
  • The weight pulls the barrel around, which pushes on the ratchels/clicks rotating the gearing - without the esacapement, the clock would 'run' as fast as friction would allow. The pendulum and escapement regulate this so the clock runs at the required speed. The weights and rotation of the gears will also cause the escapement to provide an impulse force at some point on the pendulum to keep it swinging. The trick of clock designers is to do this with minimal amount of interference to the period of the pendulum and minimal losses due to friction.
  • Oh, also take a look at the wikipedia article on anchor escapements (of which the deadbeat is a variety) - it's not at all bad.
  • @wembley: Nice reading, thanks!!

    @Wfloyd: I know this video is a bit far away from our clocks, but changing the main spring for our weights, and the balance wheel and hairspring for our pendula, you will see all the steps explained by wembley and the wiki page:

  • Wfloyd
    You are of course right, the drive cog must turn independently of the winding barrel, otherwise you could not wind your clock, so leave your drive cog free turning on the arbor.
    For a better understanding of what your clock actually does take a look below.

    If you are having problems with friction please look here.

  • It's working! Just lots and lots of fine tuning now.

    Thank you for your comments and suggestions.