MAINTENANCE OF THE M88A1 - OD1672 - LESSON 1/TASK 2
portion of the upward travel stop.
A second stub pin, shrunk into the
number 1 position arm, provides a dual stop at this position. The arm upper
spindle is a hollow cylinder machined on both surfaces.
bearings, separated by a spacer, align the lower surface of the vehicle
The inner machined surface of the upper spindle includes a
longitudinal spline which engages over the splines on one end of the torsion
bar, locking the arm to the bar.
Torsion Bar. Each pair of the twelve roadwheels and their roadwheel
arms are individually sprung with its own solid steel torsion bar. Each bar
extends across the vehicle with one end spline fitted to its respective
roadwheel arm upper spindle and the opposite end spline fitted into a
removable anchor fitting bolted on the opposite side of the hull.
weight of the vehicle, resting on the track and roadwheels, pivots the
roadwheel crank-shaped arms upward inducing an initial resisting twist in
the torsion bars. This additional twist effectively absorbs the individual
arm displacement as the vehicle moves along the ground serving to keep the
roadwheels in contact with the lower track span.
Shock Absorbers (11) (figure 4, view B, on page 13).
hydraulic shock absorbers are installed between the first, second, and sixth
roadwheel arm and the hull on each side of the vehicle.
They are bolt-
mounted to brackets welded to the roadwheel arms and vehicle hull.
shock absorbers serve to dampen the up and down motion of the roadwheels as
they move over the ground.
Volute Bump Springs.
Dual volute bump springs are bolt-mounted to
brackets welded to the hull at the number 1 and 6 roadwheel positions. They
serve to cushion the roadwheel arms when the arm is displaced upward to its
full travel. A solid bump stop, welded to the hull at the four intermediate
roadwheel positions, limits the upper travel of these arms.
Track Drive Sprocket and Hub (8) (figure 4, view A). Vehicle driving
torque from the final drive output shafts on each side of the vehicle is
transmitted to the track through a hub and two sprockets. The sprockets are
mounted on the hub by the use of cast steel and machined bolts in the final
drive output shaft flange with split tapered