Milton CAT 777F - Manual (Page 6)

Box-Section Design. The 777F
frame uses a steel box-section design,
incorporating two forgings and
19 castings in high-stress areas with
deep penetrating and continuous
wrap-around welds to resist damage
from twisting loads without adding
extra weight.
• Steel Structures. Mild steel used
throughout the frame provides flexibility,
durability and resistance to impact
loads, even in cold climates, and allows
for easy field repairs.
• Castings. Castings have large radii
with internal reinforcing ribs to dissipate
stress in areas of high stress concentration.
Castings move welds to lower stress
areas for greater frame life.
Integral Four-Post ROPS Cab.
Resiliently mounted to the main frame
with all-new cab mounts that reduce
vibration and sound, the integral ROPS
is designed as an extension of the truck
frame. The ROPS/FOPS structure
provides “five-sided protection” for
the operator.
Suspension System. Designed to
dissipate haul-road and loading impacts
for longer frame life and a more
comfortable ride.
• Cylinders. Four independent self-
contained, oil pneumatic, variable-
rebound suspension cylinders are
designed to absorb shocks in the
most severe applications.
• Durable Design. Rugged cylinders use
a large diameter bore and low pressure
nitrogen/oil design for long life with
minimal maintenance.
– Front. Front cylinders with preset
caster and camber are mounted to the
frame and serve as steering kingpins
for a tight turning radius with excellent
maneuverability and low maintenance.
– Rear. Rear cylinders allow axle
oscillation and absorb bending and
twisting stresses caused by uneven and
rough haul roads rather than transmitting
them to the frame.
Technology Enhanced. Caterpillar
structures are tested using System
Structural Analysis (SSA) to dynamically
simulate operations in field environments
and identify potential structural
improvements in high stress areas.
With analysis of machine structures and
variables, such as haul road and payload,
structural improvements were made to
the frame to accommodate the new cab,
platform, engine and radiator.
Quality Control. A Coordinate Measuring
Machine (CMM) is used to inspect
truck frames for consistency in the
manufacturing process. Easy rebuild
ability is thereby achieved by ensuring
the frames are within tolerance, removing
the need to alter down-stream parts.
6
Structures
Rugged Cat structures are the backbone of the 777F off-highway truck’s durability.