Figure 6-56.Lashing for shears.
position when the shears have been raised, but will be
out of the way during erection.
b. If the shears are to be used on heavy lifts,
another tackle is rigged in the base guy near its
anchorage. The two guys should be secured to the top
of the shears with clove hitches to legs opposite their
anchorages above the lashing.
c. Several men (depending on the size of the
shears) should lift the top end of the shear legs and
walk them up by hand until the tackle on the rear guy
line can take affect. After this, the shear legs can be
raised into final position by hauling in on the tackle.
Secure the front guy line to its anchorage before raising
the shear legs and keep a slight tension on this line to
control movement. (See fig. 6-57.)
d. The legs should be kept from spreading by
connecting them with rope chain, or bards. It can be
necessary, under some conditions, to anchor each leg of
the shears during erection to keep the legs from sliding
in the wrong direction.
3. Operating. The rear guy is a very important part
of the shears rigging, as it is under a considerable strain
when hoisting. The front guy has very little strain on it
and is used mainly to aid in adjusting the drift and to
steady the top of the shears when hoisting or placing the
load. It maybe necessary to rig a tackle in the rear guy
for handling heavy loads. In operation, the drift
(inclination of the shears) desired is set by adjustment
of the rear guy, but this should not be done while a load
is on the shears. For handling light loads, the fall line of
the tackle of the shears can be led straight out of the
upper block. When heavy loads are handled, you should
lash a snatch block (fig. 6-58) near the base of one of
the shear legs to act as a leading block,
should be run through the leading block
power-operated winch for heavy loads.
The fall line
to a hand- or