Manitowoc National Crane NBT30H-2, Service Manual

Page: 172 / 194

CRANE INSTALLATION NBT30H-2 SERVICE MANUAL
9-14
03-20-2019 Control # 613-06
5. If the frame through the rear suspension does not meet
the minimum specifications for RBM and section
modulus, it can be reinforced by adding a reinforcing
angle as shown in Figure 9-10. See Section Modulus
Table B on page 9-10 for the required size of reinforcing.
Strip all easily removable equipment from the frame
through the suspension such as spring stops, etc. Butt
the reinforcing angle up against the reinforcing forward
of the suspension and mark the areas that will require
cutting so that the angle will slide up around the spring
hangers and against the existing truck frame and
forward reinforcing. Torch out the marked areas in the
long leg of the angle deep enough so that the lip of the
angle can be slid up from the underneath the frame to
contact either existing truck frame or spring hanger
brackets (if they extend down below the existing truck
frame). If reinforcing angle is to be welded to truck
frame, cut out plug weld hole pattern as in Figure 9-8. Slide the reinforcing angle up from the bottom, butt it to
existing forward reinforcing and weld rear suspension
reinforcing to forward reinforcing. Replace as much of
the spring hanger cut out areas as possible and butt
weld these pieces in.
If reinforcing angle is to be bolted on, drill hole pattern
and install bolts according to Figure 9-9. Reinforce
spring hanger cut outs and the weld area, suspension
reinforcing to forward reinforcing by adding bars under
these areas. The bars should be of the same thickness,
width and yield strength as the reinforcing angle lip, and
should be long enough to extend at least 152 mm (6 in)
beyond either side of the weld or cut out areas. Weld
these reinforcing bars to the underside of the reinforcing
with length-wise welds. Do not weld across the flanges.
Replace any equipment that had been removed.
203 mm (8 in)
Typ
101 mm
(4 in)
51 mm (2 in)
51 mm (2 in)
FIGURE 9-9