Modern European weight drive mechanism repair hints

European mechanism (WEIGHT DRIVE)
The american floor clock with automatic chime change changes every hour on
the hour, be sure the hammer lift cam moves before the chime trips. At ¼ after it
starts a different melody.
24,25
These mechanisms are designed with close tolerances as far as power reserve
is concerned , and they are very sensitive to wear and excess friction of any kind.
The hammer support shaft on these mechanisms is critical. Too much oil inside the
sleeves on the hammer bases will , in a short period of time , thicken up and cause the
hammers to bind up and this in turn will cause the chime to stall. The amount of power
supplied by the weights designed for this mechanism is enough , but only enough
to run the device. This is true particularly in the chime gear train. Pay close attention
to the amount of throw the hammers have (that is; the height they are lifted to before
they strike the gong rods.) If you are having trouble with the chime stalling ; and
you have checked EVERYTHING ,and I mean everything , except the hammer
throw ; then try reducing the throw slightly , evenly across all the hammers ,
keeping in mind that if the throw is reduced too much , the volume will be reduced
too much.
Be sure to check the pulleys .If they are gummed up or worn , they will
drastically reduce the amount of power available to run the gear trains to which they 
certain nothing moves when you do (except the set screw , of course!) . Be absolutely
certain that the hour tube still has endshake after this cam is secured. Now move
your attention to the back plate. There is a cam friction fit on the back of the
centerpost that needs to push the hammer lift assembly out (via the swivel lever
on the back plate) far enough to clear the indexing pin so the hammer lift assembly
is in position to lift the hammers that will sound the quarter hour chime after the trip
lever releases. On the hour this cam must just be starting to lift the swivel lever in
order for the hammer lift assembly to be in the correct position when the quarter
hour chime starts. This mechanism can take as long a 1 and a quarter hours to self
corrare attached. When one of these mechanisms is in for service , it is absolutely
necessary to disassemble and clean the pulleys. If a pulley is worn enough so that
the edge of the pulley rubs against the inside of the holder , the pulley must either
be re-bushed or replaced.
Many of the newer versions of this mechanism have winding stops on
the winding arbors. This system usually consists of two round toothed gears on
the outside of the front plate at the winding arbor area of all three gear trains.
PICTURE. There is a very simple way to deal with these little puzzles. Wind
the mechanism fully before you disassemble it ,then measure the length of cable
left over after removing the pulleys. Make careful note of the exact position of both
cogs at each of the three locations BEFORE THEY ARE REMOVED. Be sure to
put the cogs back on the same arbor that they are removed from in the same
quadrant. PICTURE. After the mechanism is reassembled and adjusted and lubricated
install the cables and wind them up so exactly the same length is left over that you
had when the cable end was measured before the mechanism was disassembled. If
the winding stop gears were marked correctly , they will now be able to be re-installed
so that the winding will stop in the same place as it was before the mechanism
was serviced.In the newer kieningers the chime will bind if there is even a slightest
burr on the shutoff cam.

This entry was posted in Clock repair, specific clock repair techniques. Bookmark the permalink.