National Crane 600H, Service Manual

Page: 196 / 232

CRANE INSTALLATION 600H SERVICE
9-14
08-19-2022 Control # 092-13
REQUIREMENTS FOR OPTIONAL SINGLE
FRONT OUTRIGGER (SFO)
The truck frame must have adequate strength from under the
crane frame through the front suspension to the bumper
assembly for single front outrigger (SFO) installation. A truck
frame yield strength of 110,000 psi (758 MPa) is required.
The following diagram shows the required section modulus
at various stations along the front end of the truck frame for a
standard behind-the-cab mount with torsion box.
In order to safely mount an SFO in place of the normal front
bumper, a minimum bolt pattern as shown is required. The
bracket must be capable of supporting 0.50 in (12.7 mm)
DIA. Grade 8 bolts to their nominal breaking strength. Torque
the mounting bolts supplied with the SFO to 110 ft-lb (149
N·m).
Do not use spacers between the bumper bracket and the
SFO bumper assembly.
If the bumper bracket and front of the truck frame do not
meet these specifications, an extended frame truck must be
used. Contact factory for details. Details for mounting a jack
on an extended frame truck are included in that installation
instruction. However, the Section Modulus requirements
outlined below do apply.
Front
Axle
L
C
2.0 in
3
(33 cm
3
)
Front of
T-Box
7.5 in
3
(123 cm
3
)
11.0 in
3
(180 cm
3
)
15.9 in
3
(261 cm
3
)
Section Modulus per Truck
Frame Rail (Frame Rail Yield
Stress = 110,000 psi (785 MPa)
4.50 in (11.4 cm) Min
Bumper
REFERENCE ONLY