Putzmeister America, Inc. Introduces Innovative Low Speed Steer Assist (LSSA) Technology
Putzmeister America, Inc. Introduces Innovative Low Speed Steer Assist (LSSA) TechnologyLSSA becomes a new standard on Putzmeister’s 63Z-Meter
STURTEVANT, WI (May 1, 2007) – A computerized system used on cranes in Europe is helping Putzmeister America, Inc. steer its truck-mounted concrete boom pump customers clear of maintenance issues while improving maneuverability and driver safety. Low Speed Steer Assist (LSSA) technology is now standard on Putzmeister’s already impressive seven-axle 63Z-Meter model. The system is the first of its kind in the concrete pumping industry.
LSSA has been in the works at Putzmeister for more than a year and includes three steering axles in the front, two drive axles, a non-drive steerable axle and a driven steerable axle. “The entire system is controlled by a computer system whereby position transducers measure how much the front axles are turning and, based upon that measurement, a signal is sent to the hydraulic proportional valves to tell the rear axles to steer at a certain amount,” comments Dave Wright, Manager – Applications & Support Engineering for Putzmeister America.
The system not only measures how much the front steering axles turn and how much the rear axles should turn, but it can also measure the speed of the unit and adjust its rear steering accordingly. The outside turning radius for the rear axles with LSSA measures 58' 6", according to Wright. LSSA allows a seven-axle model to maneuver just as well, if not better, than a smaller six-axle model.
“With LSSA,” says Wright, “the rear axles can steer up to 20 mph at the maximum steering angle. From 20 mph to 30 mph the rear steering is able to steer slightly and if speeds reach over 30 mph, the rear axles lock. When the rear axles lock, there is no movement or sensitivity in the rear steering axles.
“When the unit is traveling at high speeds on highways,” Wright continues, “it doesn’t take sharp turns; therefore there is no need for as much rear steering as there would be when the unit’s traveling at lower speeds.”
LSSA offers several key advantages to Putzmeister’s customers. According to Wright, “The previous rear steering system for this large model relied on a different mechanical method to determine the amount of rear axle steering. This caused a lot of wear to 20 different mechanical links and levers along the entire unit, resulting in additional maintenance for the customer. The LSSA computer system eliminates the levers and links completely.”
In addition to measuring the unit’s speed, LSSA also includes a switch that is located on the dash of the unit that the operator can use to manually reduce the amount of steering in the rear axles to avoid any aggressive movement. “The switch can be used if the driver feels the unit does not have enough room to maneuver around or is too close to an object, such as another vehicle, to make a turn safely,” Wright says. “This helps protect both the driver of the unit and the other vehicles in the same vicinity.”
With the development of LSSA, the standard mounting for the 63Z-Meter is now a Mack chassis. This change from the chassis originally used as standard and the elimination of levers and links required in the previous system has helped to reduce the total weight of the 63Z-Meter by a remarkable 2,200 lbs.
Putzmeister customers may find servicing their 63Z-Meter unit a little easier as well; with the 63Z-Meter model mounted on a Mack chassis, the unit can now be serviced at the same location as the rest of their fleet.
“The first 63Z-Meter unit mounted on a Mack chassis with LSSA is in the field and more units are in production,” Wright comments. “If a customer requests another chassis for the 63Z, we will certainly fulfill that request.”
LSSA is an available option on Putzmeister’s 58- and 61-Meter roll-and-fold models.
For additional details on LSSA, contact Putzmeister America at (800) 884-7210, (262) 886-3200 or visit the company’s web site at www.putzmeister.com.