give way first, thus protecting the rest of the mechanism against damage. A
hand crank is connected to this main gearing to provide a means of
advancing the mechanism by hard in cases of making adjustments or repairs.
The vertical drive shaft runs in ball bearings and is supported on
the lower main drive bevel gear. Three bevel metal to metal gear sets
transmit power from this vertical shaft to the horizontal drive shafts
driving the fast drums. All other gearing working off the vertical shaft is
of the worm gear type.
The horizontal drive shafts are supported in ball bearings and drive
the fast drums through 12 sets of worm drives on each shaft with an
additional worm drive on the middle shaft to drive the indicator drum.
The carry cams for the intermediate and slow drums of each shaft are