99903514:TELESCOPIC CRANE:
2-16 SECTION 2: MAINTENANCE
2-14: EXCESSIVE LOAD LIMIT SYSTEM (ELLS) TEST PROCEDURE
Use this procedure to test the Excessive Load Limit System (ELLS) used on the IMT Telescoping Crane
models. Following this test procedure will ensure the system is currently operable and will not allow the
crane to be excessively overloaded.
The purpose of the ELLS is to prohibit the excessive overloading of the crane. It does this by disarming
the functions that make it possible for the operator to apply greater than allowable stress to the crane
structure and components. The functions which are involved in the ELLS may vary for each crane
model (Refer to TABLE 1 for which functions are shut down by the ELLS on each crane).
The load rating of the crane is determined by the pressure induced in the lower boom cylinder. The
ELLS senses the pressure in the base end of the lower boom cylinder with a normally closed pressure
switch located on the valve block on the top of the cylinder. When the pressure in the base end of the
cylinder exceeds the setting of the pressure switch for that particular crane, the pressure switch opens
and breaks the ground connection for the solenoids that shift the valve spool on the appropriate func-
tions. Once the ground connection is disengaged, the solenoids that shift the valve spools for the appro-
priate functions can not be activated using the remote control handle. Only those functions that will not
increase the load moment of the crane structure and components will be operable (i.e.- winch down,
extension in, lower boom up, rotation). The operator is able to use “WINCH DOWN” to set the weight
down to relieve the crane and “EXTENSION IN” to bring the load in for a shorter load radius. Either of
these two functions will decrease the load moment of the crane structure and components, thus de-
creasing the pressure in the main cylinder.
ITEMS REQUIRED TO TEST THE CRANE ELLS (SEE PHOTOS NEXT PAGE)
PRESSURE GAGE ASSEMBLY (GAGE & PIPE-JIC ADAPTER)
-5000 PSI LIQUID FILLED PRESSURE GAGE W/ ¼” PIPE THRD QTY 1
-1/4 PIPE-#6 JIC ADAPTER (ref) PARKER PART# 0203-4-6 QTY 1
16” HOSE ASSEMBLY (
3
/8”OR ¼” HOSE W/ #6 FEM. JIC FITTINGS & T-FITTING)
-TEE FITTING (ref) PARKER PART# 653T-6-6 QTY 1
-#6 FJIC FITTING (ref) PARKER PART# 10643-66 QTY 2
-3/8” SAE 100R16 HOSE (ref) PARKER PART# 431-6 QTY 16”
4” HOSE ASSEMBLY (
3
/8” OR ¼” HOSE W/ #6 FEM. JIC FITTINGS)
-#6 FJIC FITTING (ref) PARKER PART# 10643-66 QTY 2
-3/8” SAE 100R16 HOSE (ref) PARKER PART# 10643-66 QTY 4”
#6 STR-#6 MALE JIC FITTING (ref) PARKER PART# 0503-6-6 QTY 2
20030115
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