This is the prototype for my third lego clock.  It uses the same gear train as my second 
Lego clock (27.5 hours on, 5 lbs of weight, 5 foot of string and a compound pulley).  The
difference will be a chiming mechanism.  On the hour, the chime will sound the number of the
hour (for 2 o'clock, 2 chimes--you get the idea) and on the half hour a single chime will sound.

The only other version of a chiming clock I've found used a chain and tread links as a latch
plate mechanism.  The tread mechanism would jam against a fork when it was time to stop chiming.
The fork was release via a spring loaded hammer.  Problem was, as the load was applied to the 
hammer the clock slowed down.

My striking mechnism removes the spring loaded hammer and replaces it with two chains and two 
release forks driven by a cam.  The spacing on the two chains will be exacly the same, yet one
will be offset from the other by 1 chime.  This version won't slow the clock down.

Development continues.  In the end I'll havea 27.5 hour clock that chimes and runs accurately.

More info at:  www.trofemuk.org