JLG 534D-10 - Manual (Page 60)

Boom
3.32 534D-9, 534D-10 & 544D
5. Wrap the two extend chains around the chain rollers
on the second boom section and connect to the
clevises on the front of the first boom section. Do not
tighten the jam nuts at this time.
6. Wrap the retract chain around the chain roller on the
second boom section and connect to the rear of the
third boom section. Do not tighten the jam nuts at
this time.
3.11.7 Fourth Boom Section Installation
1. Grease the inside wear pad paths of the third boom
section and the outside wear paths of the fourth
boom section.
2. Position the fourth boom section with the extend
chain connected at the rear and laying on the fourth
boom section into the front of the third boom section.
Leave room between the sections to install the wear
pads.
3. Install the wear pads and shims at the front of the
third boom section.
4. Install the wear pads and shims at the rear of the
fourth boom section.
5. Wrap the extend chain around the chain roller on the
third boom section and connect to the clevises on
the front of the second boom section. Do not tighten
the jam nuts at this time.
6. Wrap the retract chain around the chain roller on the
third boom section and connect to the rear of the
fourth boom section. Install the retract chain bracket.
7. Position the hose carrier into the opening at the
boom head of the fourth boom section.
8. Remove each nylon tie-wrap or suitable strap as the
hose carrier is slid into place inside the fourth boom
section.
9. Secure the hose carrier at the front of the fourth
boom section and at the rear of the third boom
section.
10. Wrap the tilt/aux hoses around the hose sheaves on
the second boom section and connect to the proper
fittings at the rear of the hose carrier.
11. Install the hose guide at the rear of the second boom
section.
12. Uncap and reconnect the tilt/aux hoses to the hose
carrier at the front of the fourth boom section.
13. Adjust the complete boom to the proper dimensions.
3.12 BOOM EXTEND AND RETRACT
CHAINS - FOUR SECTION
The extend and retract chains are used to move the third
and fourth boom sections in and out, proportional with the
movement of the boom extend/retract cylinder.
• Extend Chains
The 1 in (25 mm) extend chains are located at the top
of the boom assembly. The single fourth boom
section chain attaches to the top rear of the fourth
boom section, passes over a chain roller mounted on
the third boom section and is secured to the top front
of the second boom section.
The third boom section has two 1 in (25 mm) extend
chains located at the top of the boom assembly. They
attach to the top rear of the third boom section, pass
over two rollers mounted at the front of the second
boom section and are fastened to the top front of the
first boom section.
• Retract Chains
The 3/4 in (19 mm) retract chain is fastened at the
bottom inside rear of the fourth boom section. The
chain passes over a roller mounted to the third boom
section and is fastened to the bottom front of the first
boom section.
The 1 in (25 mm) retract chain is fastened to the
bottom inside rear of the third boom section. The
chain passes over a roller mounted to the second
boom section and is fastened to the front of the first
boom section.
3.12.1 Boom Chain Inspection
Under normal operating conditions the boom chains will
need to be inspected every
250 hours of operation. The
retract chains need to be exposed and inspected every
1000 hours of operation. Environmental conditions and
dynamic impulse/shock loads can drastically affect
normal operating conditions and require more frequent
inspection intervals.
WARNING
Worn pins, stretched or cracked links or corrosive
environments can cause chain failure. A chain failure
could result in uncontrolled boom movement, loss of
load or machine instability.