The Cat PL72, PL83, and PL87 pipelayers feature an integrated, all-Cat power train with differential steering and an electronically controlled hydraulic system that places total control of lifting functions into one single joystick.
Independent, variable-speed winches for the boom and hook provide precise control, and the enhanced counterweight system ensures a low center of gravity. A new ROPS provides added safety for both open and enclosed operator’s stations. Also, the purpose-built pipelayer cab is now pressurized and incorporates new operator-comfort and convenience features.
The three units are designed to meet the demands of the pipeline industry for increased lift capacity, enhanced slope capability, ease of operation, performance, and transportability, the company says. Rated lift capacity (at tipping point) for the PL72 is 90,000 pounds; 170,000 pounds for the PL83; and 216,000 pounds for the PL87. A non-suspended, elevated-sprocket undercarriage provides ample track-on-ground for added stability, and the new models’ mainframes and main cases are built to resist operating stress.
The PL72’s Cat C9.3 ACERT engine has a maximum power rating of 257 horsepower; the Cat C15 ACERT engine in the PL83 and PL87 has a maximum power rating of 363 horsepower; all engines meet Tier 4-Final emissions standards. All three models feature Cat’s torque divider and electronically controlled 3F/3R power-shift transmission.
The compact-profile winch assemblies for the pipelayers feature oil-disc brakes to provide smooth operation and positive retention of boom and hook positions; the modular, pin-on design of the winches allows fast service in the field. Counterweight segments are contoured to provide optimum lifting performance and are extended hydraulically for efficient load balance and clearance, Cat says. An electronic kick-out switch for the PL83 and PL87 ensures that counterweights are retracted to the correct position.
The boom features high-tensile-strength-steel construction and a narrow design designed to enchance visibility to the work area. Replaceable boom-mount bearings are designed for long life. The new PL83 and PL87 now use two booms in common, 24-foot and 28-foot configurations. The PL72 also features two booms, 20-foot and 24-foot.
The short-profile block set enhances visibility to the work area and extends the working range of the boom. Heavy-lifting components include hook and boom blocks with sleeve bearings, forged hook with latch, ductile iron sheaves, and heavy-duty frame structures pinned together. Added operator-comfort features include a quieter cab, adjustable armrests, and heated/ventilated seat options. A dash-mounted LCD display provides on-board diagnostic information for the operator, allows operators to create individual profiles and operational settings, and provides access to multiple switch-controlled functions.
The available enclosed cab is designed by Caterpillar specifically for pipeline applications, allowing truck transport with the ROPS in place. The cab is fully sealed and supplied with filtered, pressurized air for the interior environment. Expansive glass surfaces allow visibility around the machine and into the trench, and a large skylight with sliding shade provides a clear view to the boom and block.
A low-effort joystick and a single-lever steering tiller place complete machine control at the operator’s fingertips, including hook and boom, counterweight position, throttle, transmission, and steering. A planetary differential turns the machine by speeding one track and slowing the other to maintain full power to both tracks for added maneuverability in congested areas and for enhanced slope capability, according to Cat.