PUMP driveshafts should be located as close as possible to the underside of a tank trailer to minimize exposure to drivers and other operating personnel, according to Duane Plumski, R&D engineer for Polar Tank Trailer LLC.
In a presentation entitled “Drive Shaft Protection,” Plumski said factors affecting driveshaft clearances include suspensions, air tanks, valves, hoses, brackets, and the shaft guard. Plumski spoke during the National Tank Truck Carriers 2010 Cargo Tank Maintenance Seminar.
“Do not ‘hide’ drive shafts,” he said. “Hidden and unguarded drive shafts can create a hazardous situation to personnel unfamiliar with the equipment. The trailer slide shaft should include protection, and shaft-to-pump couplers should be designed with a removable guard.”
He said tank operators should post a decal on the trailer to warn personnel of the potential dangers involved, and that decal should be maintained throughout the life of the vehicle.
Driveshaft guards should be designed and installed to shield from snow and ice, for maintainability (disassembly and lubrication), and with as few parts as possible.
He said tank trailers often require different types of pumps, compressors, or blowers to aid in loading or unloading lading. In terms of components that require couplings to be driven, no protection is required on internal systems, but external ones with exposed couplings and exposed rotating shafts can snag loose-fitting clothing like coveralls.
“These systems typically operate at high RPMs, so be aware of danger,” he said. “It's important to clearly indicate the presence of these systems to protect operators, mechanics, and untrained or unauthorized personnel, or anyone near the operation of rotating components.”
Plumski said alternatives to driveshafts include hydraulic systems, directly-coupled electric motors, or gas- or diesel-powered motors and pulleys (which still could require guarding).
He referred to TTMA RP No. 80-09, Drive Shaft Protection on Trailers, which was adopted on May 1, 2009. It serves as a guide for installing power takeoff (PTO) shaft guards on tank trailers. The practice only describes areas of the PTO assembly that should be protected and does not recommend specific guard design.
“It acknowledges the need for guidance on a topic that could pose danger to trailer operators and establishes consistency so the components are recognizable on all trailers,” he said.
For more information: Guarding for Agricultural Equipment, ASAE 493; Safety for Industrial Wheeled Equipment, SAE J98; and Operating Requirements for Tractors and Power Take-Off Driven Implements, SAE J721.