Broderson IC-200-2H, Operation And Maintenance Manual

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3-24
TELESCOPE CYLINDER HOLDING VALVE:
A holding valve is directly connected to the base of the primary telescope cylinder rod. The
valve is designed to hold the boom in position should loss of power or pressure line failure oc-
cur.
The holding valve should be checked with the boom elevated to the maximum angle and the
boom extended to a 6 f oot (1.8 m) load radius. A 30, 000 pound (13600 kg) load on a 4-part
line is required for this test. Use the hoist to lift this load about 6 inches ( 15 cm) above the
ground. T he radius of the test load should be w ithin the rating on the capacity chart. Use
great care to prevent the load from hitting the crane.
Turn the engine off and pull t he TELESCOPE lever to the RETRACT position. If the boom
retracts, the valve should be adjusted.
To adjust the holding valve, loosen the lock nut on the adjusting screw and tighten screw until
unpowered movement stops. Retighten the lock nut to hold the proper adjustment.
IC-200-3 BOOM CHAIN ADJUSTMENT
Study Illustrations 1,2 and 3 t o understand the chain adjustment procedure. Proper adjust-
ment is critical at time of boom assembly or scheduled maintenance.
Initial adjustment:
Retract boom completely. The 4
th
stage extension and retraction chains
set the position of the 4
th
stage relative to the 3
rd
stage. As show n in Illustration 1,
½”
(13
mm) clearance must be held between the 4
th
stage tip and 3
rd
stage tip. To increase this dis-
tance, loosen the retraction adjustment and tighten the extension adjustment. T o decrease
this distance, loosen the extension adjustment and tighten the retraction adjustment.
Final adjustment
: Extend boom completely while horizontal, then slightly retract the boom to
let the chains relax. Measure the chain drape at the center of the rear 3
rd
stage and 2
nd
stage
windows as shown in Illustration 3. See arrows in the windows for measuring locations. Snug
the 4
th
stage extension and retraction chains until the chain tightness allows the dimensions of
approximately 1” (25 mm) and 5” (125 mm) as shown in Illustration 3. Also snug the 2
nd
and
3
rd
stage compensation chains to the dimensions of 1 1/8” (29 mm) and 3 7/8” (98 mm) as
shown. Assur e that the drape in each pair of chains is m atched so each chain car ries its
share of the load. Run boom in and out a few times and recheck all of the above dimensions.
After proper settings, retighten the adjustment lock nuts.
The numbers “3” shown in the small windows on the bottom of the 2
nd
stage and base boom
show the adjustment is about midrange. These numbers run from 1 to 6 (25 to 150 mm) in 1”
(25 mm) increments. Numbers in these windows are approximate adjustment and cannot be
used for final adjustment. Important are the dimensions stated above taken at the large side
windows.
Courtesy of Crane.Market