TM 55-1680-320-23 & P
1-13. Boom Position Support Assembly.
a. The boom position support assembly (Figure 1-5) consists of upper and lower support assemblies, a height adjuster
assembly, four limit switches, boom position motor, gear drive assembly, a mechanical stop assembly, reaction arm, and
the rotary actuator.
b. The boom position rotary actuator swivels the boom head assembly, positioning the cable hook for proper operation,
The actuators maximum operating load is 6500 in.lbs. (734.5 N.m), with a 205 degree operational range. Limit switches
prevent operation when maximum operating load is exceeded.
c. Rotation is powered by the boom position motor and gear drive assembly. The mechanical stop assembly regulates
to prevent rotation beyond the 205 degree range. Hoist positioning can be adjusted through actuation of the height adjuster
or reaction arm assemblies.
Figure 1-5. Boom Position Support Assembly