(2) Reeve the main hoist line on the rear main
(6) Unreeve the boom hoist cable from the
drum, and reeve the secondary hoist line (if used) on the
gantry spreader and upper spreader sheaves.
front main drum. If a jib is used, reeve the jib line on the
(7) Lay the cable out straight on the ground.
rear main drum, and the main hoist line on the front main
(8) Roll the cable into a coil and secure it with
drum. Secure the hoist lines to the drums as shown in
wire. Label the cable for future use.
(9) Remove the guy cables by removing the
(3) A single-part line is reeved over the center
cotter pins and pins from both ends of the cables. Refer
boom point sheave, directly to a weighted hook, and is
to figure 2-9.
dead-ended at the hook. A weighted hook must be used
(10) Using a suitable lifting device, lift the upper
for single line operation, instead of a hook block.
spreader from the crane boom.
h. Removing the Crane Boom.
(4) A two-part line is reeved over the center
boom point sheave, around one hook block sheave, and
(1) Unreeve the hoist line and boom hoist line.
dead-ended at the boom point.
Support the boom on cribbing as shown in figure 2-4.
(5) A three-part line is reeved over the left
(2) Use wedges or a hydraulic jack to relieve
boom point sheave. around a hook block sheave,
the weight of the boom on the boom foot pins, and
around the right boom point sheave, and dead-ended at
remove the pins. Refer to figure 2-6.
the hook block.
(3) Disconnect the boom backstops from the
(6) A four-part line is reeved over the left
gantry A-frame and lay the backstops on the top of the
boom point sheave, around the left hook block sheave,
boom. Refer to figure 2-7.
around the right boom point sheave, around the right
(4) Drive the carrier away from the boom.
hook block sheave, and dead-ended at the boom point.
2-5. Clamshell Conversion
(7) A five-part line is reeved over the left
Note. It is the operator's responsibility to request the
boom point sheave. around the left hook block sheave,
services of organizational maintenance when converting
around the (center boom point sheave, around the right
to clamshell operation. Organizational maintenance is
hook block sheave, around the right boom point sheave.
specifically responsible for proper installation and
and dead-ended at the hook block.
removal of the clamshell and boom, and will assist
f. Unreeving the Hoist Line.
operators in proper installation of cables and other
(1) Lower the hook block to the ground.
accessory items.
Lower the boom until the boom point is approximately
five feet ,from the ground.
a. General. The truck crane may be converted to
(2) Remove the cable from the dead-end
clamshell operation by installing the. crane boom (para
socket on the boom point or hook block.
(3) Unreeve the cable from the hook block
are necessary for the equipment conversion; the crane
and boom point sheaves.
boom components (para 2-4), clamshell bucket, bucket
(4) Release the drum brake, and pull the
holding and closing lines, tagline winder, and tagline.
cable from the drum. Remove the cable wedge from the
The crane hoist cable may be used for the bucket
cable drum socket and -free the cable.
holding line, but if additional depth below ground level is
(5) Pull the cable free of the cable drum and
desired, longer holding and closing lines must be
the boom point sheave. and lay it out straight on the
installed. Refer to table 1-1.
ground.
b. Installation. Install the crane boom, backstops,
(6) Roll the cable into a coil and secure it with
and boom hoist cable as described in paragraph 2-4.
wire. Label the cable for future use.
c. Reeving.
g. Unreeving the Boom Hoist Cable.
(1) Swing the crane boom over the clamshell
(1) Swing the revolving frame so that the
bucket. Lower the boom to approximately six feet above
boom is over the rear of the carrier. Lower the boom to a
the ground beside the clamshell bucket.
horizontal position, level with the carrier.
(2) Reeve the closing line on the clamshell,
(2) Build up cribbing under the boom as
around the left boom point sheave, and to the rear hoist
shown in figure 2-4.
drum. Secure the line to the drum (fig. 2-11) and wrap
(3) Lower the boom to rest on the cribbing,
sufficient line on the drum to close the clamshell bucket.
and continue to slack off on the boom hoist cable until
(3) Reeve the holding line around the right
the upper spreader comes to rest on the boom.
boom point sheave, and to the front hoist drum. Secure
(4) Unspool the boom hoist cable from the
the line to the drum, and wrap line on the drum until the
drum. Remove the wedge from the cable drum socket,
same number of turns are on both drums. Attach. the
and free the cable.
holding line loosely to the clamshell bucket.
(5) Disconnect the cable dead-end at the
gantry and free the cable. Refer to figure 2-10.
2-7
