JLG 4017RS Service Manual - Manual (Page 44)

Boom
3-4 3614RS, 4017RS
3.2 BOOM SYSTEM - 3614RS
3.2.1 Boom System Operation
The 3614RS three section boom consists of the first, second
and third assemblies with first and second section extend
chains, and a single first and second section retract chain.
As the extend/retract cylinder, which is anchored at the top
rear of the first boom section, and the top front of the second
boom section begins to extend, it pushes the second boom
section out of the first boom section.
The boom sections are connected by extend and retract
chains. These chains are routed around rollers on the front
and the rear of the second boom section. As the extend/
retract cylinder is forced out hydraulically, the third boom
section is pulled out by the extend chains.
As hydraulic pressure is applied to the retract port on the
extend/retract cylinder, the retract chain pulls the third boom
section back into the second boom section as the extend/
retract cylinder pulls the second boom section into the first
boom section.
This mechanical linkage formed by the chains and
supporting hardware, extends and retracts the third boom
section into the second boom section at the same rate.
The boom section lifts and lowers via action of the lift
cylinder.
3.3 BOOM ASSEMBLY MAINTENANCE -
3614RS
These instructions must be completed in sequence. The
second and third boom sections are removed from the first
boom section. The third boom section is removed from the
second boom section or the complete boom assembly can
be removed from the machine.
Before beginning, conduct a visual inspection of the
machine and work area, and review the task about to be
undertaken. Read, understand and follow these
instructions.The boom assembly consists of the first, second
and third section booms and supporting hardware.
Note: Before removing the boom or boom section, the carriage
or any other attachment must be removed from the quick
coupler.
Before beginning, conduct a visual inspection of the
machine and work area, and review the task about to be
undertaken. Read, understand and follow these instructions.
During service of the boom, perform the following:
1. Check wear pads. (Refer to Section 3.16.1, “Wear Pad
Inspection.”)
2. Check chain rollers.
3. Apply grease at all lubrication points (grease fittings).
(Refer to Section 2.7, “Lubrication Schedule.”)
4. Check for proper operation by operating all boom
functions through their full ranges of motion several
times.
Depending on your particular circumstance, the following
procedures explain the removal/installation of individual
boom sections or removal/installation of the complete
boom.
WARNING
NEVER weld or drill the boom unless approved in writing
by JLG. The structural integrity of the boom will be
impaired if subjected to any repair involving welding or
drilling.