National Crane 600H, Service Manual

Page: 220 / 232

CRANE INSTALLATION 600H SERVICE
9-38
08-19-2022 Control # 092-13
10. Measure the overall height of the crane and truck. Post
the overall height measurement inside the truck cab to
inform the driver of the overall height.
RCL CALIBRATION
After the crane has been installed and all electrical and
hydraulic connections are completed, calibrate the RCL.
Calibrate the RCL as described in the RCL manual titled
Calibration/Service Manual.
STABILITY TEST
The chassis weight, before the crane is mounted, is intended
for use only as a guideline in determining the total weight
required for the unit to be stable with an 85% tipping factor
(i.e. when lifting capacity load, the unit is at 85% of tipping or
less).
In order to ensure the stability of the unit with an 85% tipping
factor, a live load stability test must be performed on each
completed unit. Proceed as follows:
1. Test the unit for stability on a firm level surface.
2. A Series 600H crane requires rear jacks for stability.
With the boom stowed, set the unit up level on the
outriggers and jacks.
3.
When stability testing this unit, select the load from the
capacity chart that is listed at the longest boom
extension
and approximately 30° of boom elevation.
Example: 690H
• Boom Length: 78' (23.77 m)
• Loaded Radius: 60' (18.29 m)
•
Load Rating: 2250 lb (1021 kg)
•
Stability Test Load:
1.18 x 2200 lb (998 kg) = 2596 lb (1178 kg) Includes
weights of slings and downhaul weights.
Be sure the stability test weight is accurate. A 1% increase in
stability test weight requires up to a 10% increase in
counterweight. Extend the boom to the maximum boom
length and hoist the stability load off the ground. Slowly
boom the load down so the load will swing out, until the
loaded radius is reached. As the boom is lowered, hoist the
load up to keep it about 6 in off the ground.
Do not exceed loaded radius
Slowly rotate the boom throughout the work area. As the
boom is rotated, the boom will have to be raised and/or
lowered to maintain the loaded radius because of subbase
flexure.
On front mount configuration cranes that are not equipped
with single front outriggers (SFO), tipping from jack support
to front wheel support will occur as the load or boom is
swung around the front. Do not attempt to lift rated loads
around the front of the truck unless the unit is equipped with
an SFO. This applies to front mount configuration cranes
only. Rear mount configuration cranes are not affected.
NOTE: Weights of accessories installed on the boom or
loadline (including downhaul weight) must be
deducted from the calculated load when checking
stability.
4. If slight tipping occurs, but load can be kept from coming
in contact with ground by hoisting the load up, unit is
stable. If not, counterweighting will have to be added to
get unit in a stable condition or decal must be added to
define areas of full stability and areas of reduced
capacity because of stability. If the unit is equipped with
a jib, the stability test should be repeated. Use the fully
extended jib capacity multiplied times 1.18 at the lowest
angle that the jib is rated fully extended.
5. When adding counterweight to the vehicle, it is usually
most effective when added as close to the crane as
possible. After adding counterweight, the above
procedure must be repeated to insure the added
counterweight is adequate.
DANGER
The loads used for stability tests put the crane at the
tipping point. Keep the hook load close to the ground.
Control of the boom position is critical. Do not allow the
test loads to swing out past the rated radius. If the crane
starts to overturn and the boom angle is too low the crane
will upset.
Model
Boom
Length
Loaded
Angle
Loaded
Radius
690H 78’ (23.77 m) 39.5° 60’ (18.29 m)
!
REFERENCE ONLY