What started as a scale-model prototype shown at Bauma 2016 to explore the viability of a lift with a “smart” suspension has become reality for JLG Industries. At ConExpo-Con/Agg 2020, the manufacturer introduced and provided demos of its new 670SJ self-leveling boom lift, showcasing its ability to automatically self-level – with the boom elevated – on surfaces up to 10 degrees in any direction.
“There were challenges along the way,” Nate Hoover, director of product management for boom lifts, told SAE’s Truck & Off-Highway Engineering in Las Vegas. “The full-size concept machine we introduced for ConExpo 2017 had a fixed axle, basically, that pivoted, it was a solid axle all the way across. We learned that having independent control arms was an important feature to be able to adjust to the ground, not just one side to the other but independent in all four [corners].”
Extensive research, testing and field trials followed since that last ConExpo. Rental companies and end-user contractors visited JLG’s proving grounds in McConnellsburg, Penn., to provide feedback on the machine’s functionality and ease-of-use. “The cylinders and mechanics are one thing,” said Hoover. “It’s another thing to be able to have an algorithm, software and everything else that goes into making that functionality real. That was one of the biggest hurdles that we had.” The smart suspension on the 670SJ results in 1 ft (0.3 m) increased platform height, marking the introduction of a new size class for booms, according to JLG.
The 670SJ boom lift, with a 67-ft (20.4-m) platform height, boasts a 550-lb (250-kg) unrestricted and 750-lb (340-kg) restricted capacity. It offers 45% gradeability, a 57-ft 1-in. horizontal reach, and elevates to full height or back to ground level from full height in just 101 seconds. It automatically levels on grades up to 10° when in self-leveling mode, while two additional modes include a standard mode for driving with the boom down at faster speeds, and shipping mode, which allows the suspension to be lowered during transport.
JLG engineers realized that the industry had designed current lifts for the near-ideal conditions of firm, flat surfaces with a grade of 5 degrees or less. With current ANSI (American National Standards Institute) standards, after 5°, traditional boom lifts are cut off in terms of functionality. “If they are uneven, they cannot ascend,” Hoover said, adding that the new 670SJ boom lift is also able to drive at height while maintaining active leveling.
“As an alternative, we’ve seen people simply taking boards and shoving them under a tire just to be able to get it level for a period of time,” Hoover said. “We’ve also seen them having to use excavating equipment in order to create a level location in uneven terrain. Another pain point they shared was having to use a very-high-value, larger boom lift in order to do the job. They would take this large machine, whether it was an 800-series or even an ultra-boom, place it at a distance from the building and reach over all the terrain.”
Besides offering safety and productivity benefits, JLG also discovered that the self-leveling suspension helped reduce operator fatigue because the platform was continuously level and tools and materials on the platform do not shift as they normally would. This new technology will be phased into production across a wide range of models, the company said, and will evolve to meet international compliance standards in the future. “Our hope is that this becomes a ‘Why didn’t we have this before?’ type of moment for the industry,” said Hoover. “Now that it’s here, let’s make it universally applicable.”
The 670SJ will be available for shipment to North America-based customers in fall 2020. A limited number of pre-orders for the 670SJ were being taken at ConExpo. “We believe the 670SJ self-leveling boom is a step change for the industry; a technology that will transform the way people work at height,” said Milan Klimes, senior chief engineer for JLG.Continue reading »