Broderson RT-400-A, Operation And Maintenance Manual

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SHEAVE BLOCK AND DOWNHAUL WEIGHT
The capacity chart shows the approved hoist rope arrangements. The downhaul weight and
sheave blocks supplied by Broderson are specially designed to operate the BMC Anti-Two-
Block system. Other blocks or downhauls may bypass this system and create a dangerous
condition. All retaining pins that pass through the sheave plates must be locked in place with
cotters to hold the hoist rope (also called the load line) on the sheaves. Notice the load limit
for each hoist rope arrangement.
For single part reeving the load line must pass through the center of the downhaul, through
the wedge socket, and the dead end clamped in the block , as shown in the figure below.
When resting the downhaul or sheave block on the ground for changing it, use the following
procedure to prevent fouling the load line on the hoist. Raise the boom about 5 feet (1.5m)
and lower the hoist until the hook nearly touches the ground. Then lay the hook on the
ground by lowering the boom, not the hoist.
To stow the sheave block, pull the sheave block, lift the block into the storage compartment
by the hook. See the figure above.