TANGLEY CALLIOPE RESTORATION PROJECT (part 12)
by Dr. Bill Black
FINISHING THE AIR MOTOR
Having disassembled the air motor and cleaned the individual parts, the
next step is to recover the pneumatics. These are recovered the same way
as the stack pneumatics except we will use motor cloth which is a bit
heavier than the material used for the stack pneumatics.
In PHOTO A we see the pneumatics recovered, painted and joined together
by means of the nipples in the center of each pneumatic and metal strips.
The top surface of the blocks where the sliders move back and forth have
been block sanded to insure a flat surface for these sliders.
In PHOTO B the air motor has been completely reassembled. The holes in
the ends of the wooden rods have been rebushed, slid onto the crankshaft
and the other ends attached to the pneumatics . The outermost pneumatics
each have a bracket mounted on the top to support each end of the
crankshaft and serve as a central bearing. The right side of the
crankshaft has a sprocket which will have a ladder chain connecting to
the sprocket on the roll frame. The slider valves have been mounted on
the pneumatics. Each side of the slider has a wire bracket to hold it in
place as they move back and forth.
PHOTO C shows the air motor from another view.
PHOTO D shows a closer view of the slider valves. Note the connection
between the valve and the wooden arm connected to the crankshaft. This
consists of wire rods which are threaded and screwed into a wooden dowel.
This arrangement provides a means to either lengthen or shorten this link
between the wooden arm and the slider by screwing the wire rod in or out.
This adjustment allows the timing of the sliders to be adjusted to allow
a smooth sequence of the pneumatics opening and closing and provide a
constant rpm of the crankshaft. Note the wooden block with the two
nipples on it. The nipple on the lower side is the inlet for the
regulated vacuum to the air motor coming from the vacuum control
discussed in part 10. The nipple on the top is the inlet for the vacuum
supply to increase the speed of the air motor for the rewind function of
the roll frame.
PHOTO E shows a closeup view of the inside of the top nipple. Inside this nipple is a check valve. This internal valve serves to seal off this
nipple when the lower nipple has vacuum applied to it and the upper
nipple does not. In this mode, the vacuum is directed to the air motor
from the vacuum control box and prevents leakage through the top nipple.
This nipple is connected to the unit which controls the rewind vacuum
supply and the stack cutout. When the higher level of vacuum for rewind
is applied to the top nipple, the check valve opens and causes the air
motor to operate at a higher speed for the rewind function.
