2-28.
Operation
of
Crane
Front
End
Note.
Starting non-winterized units at
Attachment
ambient temperature of +20 F or lower will require
a. Perform preventive maintenance checks and
preheating of crankcase oil and coolant.
services (para 3-6); start engine (para 2-10); engage
engine clutch (fig. 2-24), then raise boom (if necessary).
2-26. Heaters
b. Lower hook block by releasing the hoist brake
a. General. Fourteen crane-shovel units, model
pedal (fig. 2-23) and allow hook block to drop slowly to
855BG2, with serial numbers 22506 through 22519,
center of load to be lifted. Swing revolving frame (para
have been winterized and equipped with three heaters,
insulation, weatherstripping, with separate controls
necessary to center hook over load.
mounted in cab to control heaters which are mounted on
c. When hook block is in desired position, apply
rear of revolving frame cab, just above counterweight
hoist brake pedal and hold.
d. After load is safely attached, allow ground crew
b. Controls. A control box for each individual
to clear load, then pull back on hoist clutch and propel
heater is mounted on a control panel in the cab (fig.
brake lever (fig. 2-23), at the same time release hoist
brake pedal.
control switch, (positions are marked ONHI, OFF, ON-
e. When load is sufficiently high to swing safely,
LO); a push-pull switch to actuate circuit breaker, (when
return hoist clutch lever to neutral position, and at same
switch is pushed in, circuit breaker is in the circuit, when
time apply hoist brake pedal to hold load in position.
pulled out, circuit breaker is out of the circuit). (This is
an overload safety factor), and an indicator light that
tells when heater is operating.
c. Operation.
Note.
Engage swing and propel clutch
(1) Before attempting to start heaters, be sure
lever (fig. 2-23) slowly so that swing motion will
fuel line valves at fuel tank are open.
start and stop smoothly.
(2) Start battery heater (fig. 2-29) by moving
g. Lower load by releasing hoist brake pedal, and
switch up to ON-HI, then open air relief valve located
control rate of load descent by varying the pressure
inside engine housing in coolant line from top of heater.
applied to hoist brake pedal.
(3) Start engine heater by moving switch up to
Note.
If it is necessary to unload at a
ON-HI.
greater or lesser radius, the boom may be raised or
(4) Check that defroster controls on manifold
lowered as required (para 2-12c) or, crane-shovel
are closed; manifold sliding door is open; and lower front
may be traveled (para 2-12d). If boom is lowered,
defroster control is closed, then start personnel heater
load must be hoisted simultaneously to prevent
by moving switch to ONHI.
load from lowering too fast and causing damage. If
Note.
In extreme low ambient temperatures,
traveled for less than 100 feet, it is not necessary to
it may be necessary to operate heaters for an hour
put idler sprockets under boom foot .
before attempting to start diesel engine.
h. When load is solidly at rest, release hoist brake
(5) After battery and engine heaters have warmed the
pedal and give ground crew slack to unfasten hitch.
equipment sufficiently, start engine (para 2-10 and
i. When load is unhitched, pull back hoist clutch
lever to raise hook block clear, and hold in position with
efficient engine operation.
hoist brake pedal.
Caution: In extreme low temperatures, be
Note.
Travel, or adjust boom if necessary, in
sure personnel heater has been operating at full cab
reverse order to change made as a result of note above.
heat for at least 20 minutes before attempting to
j. Swing revolving frame to spot for next load
defrost, and avoid breakage of glass due to sudden
extreme temperature change.
k. Repeat steps a through j cycle as necessary.
(6) Move defroster controls to open position and open
l. When through work for the day, lower bucket to
lower defroster door as required.
ground.
2-27. Trouble Light
a. Description. The trouble light is a drop cord
checks and services (para 3-6).
type, 24 Vdc, and is stowed in the cab.
2-29. Operation
of
Clamshell
Front
End
b. Operation. Remove light from stowed position
Attachment
and plug into trouble light socket on lighting panel (fig.
a. Perform preventive maintenance checks and
services (para 3-6); start engine (para 2-10), then
2-37
