Chain Elongation Inspection - Snorkel TM12 Service Manual

Elevating Assembly
C
H A I N
Refer to Figure 3-16: "Elevating Assembly," on page Section 3-20.
The lifting chains can be seperatly adjusted and should always be close to the same tension.
This tension should be checked annually and adjusted if necessar . To do this task a spring scale will
be needed with 20kg (44 lb. ) capacity.
1. Place 227kg (500 lbs.) in the platform.
2. Remove the chain inspection cover (43) and raise the platform approximately 54cm (21 in.) until the outer
inspection hole lines up with the inner inspection hole.
3. Attach the spring scale to one of the outer chains and pull until the chain makes contact with the inner
surface of the mast section. Note the scale reading.
4. Repeat step 3 on the other outer chain.
5. Compare the scale readings. The readings for each chain in the outer set should be within 20% of each
other. If not then carefully adjust the slack chain until the readings are equal. Torque up the locknuts
to 25 Nm.
6. Repeat steps 3 - 5 for the inner set of chains. The readings for each chain in the inner set should be
within 20% of each other.
C
H A I N
At five-year intervals, the
chains should be removed from
the mast and the entire length
of the chain inspected for
excessive wear and elongation.
Follow the procedure below to
disassemble the elevating
assembly. With the lift chains
removed, hang them vertically from something capable of holding 100kg (220 lbs.). Inspect the chains
thoroughly, looking for cracks in the chain links, kinks in any portion of chain, and excessive corrosion.
Complete the following elongation test:
1. Attach approximately 25kg (55 lbs.) to the lower end of each chain.
2. Measure the distance between 50 pins. This distance should be 64.5cm - 65.5cm (25 in. - 25
3. Remove the weight and measure the same on the other three chains.
If the chains have elongated beyond the indicated range, replace the lift chain sets. Before reinstalling the
lift chains, take this opportunity to thoroughly clean and lubricate the entire chain. Reassemble the elevat-
ing assembly as described below.
Page 3-22
T I
E N S I O N N S P E C T I O N &
E
L O N G A T I O N
A
DJUSTMENT
Tension Block
I
N S P E C T I O N
MEASURE DISTANCE OF 50 PITCHES
Section 3 - Service & Repair
y
Figure 3-17: Chain Elongation Inspection
ONE
PITCH
in.).
1/2