For the new Cat 745 articulated truck, which made its global debut at ConExpo in Las Vegas, Caterpillar design engineers spent a majority of their efforts on a completely re-engineered cab that has 20% more interior volume than the previous 745C model and is twice as quiet. (The 745 is the first Caterpillar machine to feature a new numeric-only coding system, compared to the previous alphanumeric style.)
The cab design lowers sound levels by 7 dB—from 79 to 72 dB. “That's the equivalent of you guys driving your midsize sedans down the highway, that's what 72 dB is,” Scott Thomas, Application Specialist for Articulated Trucks, said at a ConExpo press briefing.
“We focused this next-generation 745 on the operator,” Thomas said. “An operator can make a huge impact on profitability just based on his comfort and his skill level.”
A new deluxe seat option is all about comfort, offering heated/cooled leather seats with a four-point belt option and more setting adjustments. Infrared glass all around the cab is exclusive to Caterpillar, according to Thomas, and reduces solar heating inside the cab.
“We already had this in the works before we came to production with C Series” about two years ago, Paul Taylor, Worldwide NPI Manager for Articulated Trucks, told Truck & Off-Highway Engineering. “Now we're coming along with the final piece of the puzzle, which is a brand-new operator station, because our operator station was about 15 years old.”
The biggest challenge was fitting the new cab on a machine that's not that much different than C Series—“We didn't want to redesign the whole machine for a new operator station but we wanted to get more space,” Taylor said.
While the cab is larger, ergonomics are improved, he noted. “Using VPD (virtual product development) and the simulation environments that we have, we've been able to develop that before we even built the cab,” Taylor said. “Our virtual reality technology allowed our engineers [in Peterlee, England] to sit on a machine in the cab for the past three years, to make sure we've got all these distances right.”
Exoskeletal design improves visibility
New mirror placement and the redesigned cab result in a truck that is 286 mm (11.3 in) shorter and 364 mm (14.3 in) narrower than the 745C it replaces. The mirrors are now cab-mounted compared to their previous placement on the fenders, which reduces vibration and improves visibility. The low-profile exhaust stack has been moved to the center and is the same height as the top of the cab. “No longer does the operator have to take off the exhaust stack [for transport] and the mirrors just fold in, so he can get from jobsite to jobsite much quicker,” Thomas said.
A convex front visibility mirror now allows the operator to see from a seated position if anyone is standing in front of the machine. Overall, the new 745 has two fewer mirrors than before. A new external “spinal” ROPS structure features bonded rear quarter glass that eliminates the structural pillar.
“Notice that we've got the two corner posts on the front, but we've eliminated them on the rear,” he said. “Why did we do that? Visibility.”
Left- and right-hand sliding windows increase ventilation and improve communication with workers and the loading vehicle.
A new “wake up” feature initiates machine displays as soon as the door is opened, instead of waiting for the key to be turned. “We've reduced that time for everything to cycle and go through its diagnostic checks. As soon as you pop the handle, it starts to warm up and wake up while the operator gets situated,” Thomas said.
The 745’s touchscreen display with revised menus enables the operator to monitor machine functions and personalize a variety of options. An emergency stop brake switch is located next to the display, in case of failure issues with both the main and secondary brake circuits.
More vents positioned above and behind the operator enables the new automatic climate control (HVAC) system to more efficiently heat and cool the cab. “We are moving 12% more air in there with more vents and a better blower fan,” he said.
A ground-level switch controls new access lights illuminating the steps and hitch area for improved safety when entering the cab. The cab door is 36% lighter than before and now offers shut assist for improved sealing against dust infiltration.
“It's a stamped door now as opposed to a prefab,” Thomas said. “The old door was literally 4 inches or more thick; this new one is maybe an inch and a quarter” and the tolerances are tighter.
Intelligent machine controls
Another Cat-exclusive technology, according to Thomas, is the new combined transmission and hoist lever inside the cab, which provides operators with single-lever control over truck speed and body hoisting functions to minimize operator effort and automate repetitive operations.
“This is big for the operators,” he said, resulting in 50% fewer inputs and improving hoisting cycle time by 20%. Operators can choose between manual or fully automatic assisted hoisting control by flipping a switch, which automatically applies the Waiting Brake, sets the transmission in neutral and hoists the body to maximum angle at high rpm.
A new push-button lever control allows the operator to set the machine speed and select transmission hold/waiting brake. Directional gear shifting protection on the new 745 articulated truck now protects the powertrain by bringing the machine safely to a stop when transitioning from forward to reverse and vice versa.
The new Cat Detect with Stability Assist system audibly and visibly warns the operator if the tractor or trailer unit has reached an angle threshold where rollover becomes a risk, both when driving and when tipping. It will stop hoisting the body if tipping. The system logs rollover events and reports via VisionLink.
Advanced Automatic Traction Control monitors underfoot conditions and proactively applies the differential locks prior to any wheel spin. Terrain-based throttle smoothing prevents the machine from surging when an operator is traveling over rough terrain and is unable to keep steady pressure on the accelerator pedal.
Cat Connect Payload technology for the new 745 truck allows customers to optimize operations and improve overall jobsite efficiency. The available Cat Production Measurement system calculates payload using sensors on the walking beams, displaying to both the machine and loading tool operator when rated payload is achieved. The system helps to maximize every payload while minimizing overloading and causing premature wear.
Load status lights on all four corners of the cab roof help to improve visibility for loading tool operator and site controllers.
Built on C Series platform
Offering a 45.2-ton (41-t) rated payload capacity, the new Cat 745 articulated truck incorporates many of the features and performance of the C Series, including Cat’s CX38B High Density Power Shift transmission and permanent six-wheel drive. The C18 ACERT engine, rated at 504 net hp (375 kW), meets U.S. EPA Tier 4 Final/EU Stage IV emissions standards.
A new economy mode can improve fuel consumption by an average of 5%, while maintaining peak torque, in applications where the truck is not required to operate at full productivity. It achieves the fuel savings via early upshifts, delayed/lugging downshift, and limiting engine speed to 1700 rpm in certain operating modes.
Automatic retarding control manages machine retarding through a combination of engine, brake, gear selection and service brake application without operator intervention. Hill Assist enables smoother stopping and starting on grades, while the Waiting Brake system, engaged by a push-button on the control lever, temporarily applies the service brake during pauses in the work cycle.
The lower portion of the front fenders is now made of a flexible rubber sheet material, in an effort to decrease maintenance and repair costs due to mud packing around the fenders.Continue reading »