What Are Spider Lifts or Compact Crawl Booms? How Do You Pick One?
Life would be much simpler if tasks were always performed at ground level, but they’re not. A whole lot of what we do is above the ground, which is where MEWPs (mobile elevating work platforms) in general and spider lifts in particular come in. We turned to Craig Edwards, vice president of strategic accounts at JLG Industries, for insight into these machines.
Within JLG’s extensive catalog of various types of lifts are seven models of compact crawler boom lifts, aka spider lifts. The smallest model is the X430AJ with a 43-ft, 6-in. platform height and 21-ft, 7-in. horizontal outreach. The largest is the X1000AJ with a 106-ft platform height and 54-ft, 2-in. horizontal outreach. JLG’s first straight-boom model (all others are articulated boom) is the X660SJ. While the characteristics spider lifts share with other MEWPs are well-defined, their working environments are not. Indoor and outdoor. Confined spaces and open areas. Finished and natural underfoot conditions. Surfaces virtually immune to damage and surfaces subject to disruption and marking. So, spider lifts are machines with specific features and design elements that must be versatile enough for use in a wide range of diverse applications.
Spider Lift’s Unique Undercarriage
As is common with tracked undercarriage drives, the drive systems on these machines provide excellent traction and maneuverability. Outside on rocky terrain or inside on finished floors, the tracks provide nimble and sure-footed movement. JLG spider lifts can even climb stairs. Counter-rotating tracks provide zero-radius turning. The tracks of the X1000AJ have a maximum ground pressure of 11.3 psi, which minimizes surface disruption, and the non-marking material ensures that finished floors remain unmarred.
While most undercarriage equipment relies on its tracks for stability while in use, tracks on spider lifts are used only when the machine is in motion, as when positioning the lift. Once in place, stability is wholly dependent on the outriggers. As a result, the undercarriage can be made much narrower. The five smallest machines will fit through a standard 36-in. gate or door opening (although just barely with the X660SJ and its 35-in. width). The X770AJ and X1000AJ with overall widths of 39 and 47 in., respectively, require double doors for entry into interior spaces. Travel speeds are 0.7 to 0.87 mph. Gradeability is 28 percent with the articulating models and 40 percent with the straight-boom X660SJ.
Spider Lift Power Options
Depending on the model, JLG offers Honda gasoline or Kubota diesel engines. Lithium-ion battery electric power is also available with 36, 48, 72 and 76 volts and 100 amp-hour batteries (150 Ah in the X1000AJ). JLG offers Bi-Energy technology option on the X660SJ as well as the X770AJ and X1000AJ. The Bi-Energy package equips these models with two full-power drive systems, lithium-ion battery electric and diesel. These two systems operate independently to allow one machine to work both indoors and out.
Performance Features for Spider Lifts
“Go Home” and “Back to Work” functions provide ease in returning the spider lift to the stowed position or to a recorded work position. Software optimizes the path to the stowed or work position based on machine stability. Envelope tracking allows the operator to boom up/down while also telescoping in/out with a single control function so that the platform travels a path perpendicular to the ground. This greatly simplifies placement next to walls and other infrastructure. An interactive display and intuitive controls in the platform make all operations easier.
SkyGuard operator protection is standard on all JLG models for enhanced operator safety. When detached, the platform can be moved easily thanks to caster wheels on all models. Forklift pockets for loading and unloading are standard on all models. Optional air, water and power lines can be run to the platform. One-touch automated outrigger leveling simplifies setup and ensures maximum stability. And because the outriggers, not the undercarriage, provide stability, there is no need for heavy counterweights. The machines themselves are comparatively lightweight, from 4,392 lbs for the X430AJ to 16,790 lbs for the X1000AJ. This improves transportability and enables use on not just slab-on-grade ground floors but in weight-sensitive areas where heavier equipment could not be used, such as upper levels in buildings. The outriggers’ ability to distribute weight across a large area also helps in this regard.
All models have 500-lb unrestricted platforms for up to two workers plus tools and materials as long as the total load does not exceed the maximum weight rating. All models use fully synthetic, biodegradable hydraulic fluid.
Common Spider Lift Applications
Spider lifts with the lithium-ion power options provide inherently quiet and zero emissions operation, making them ideal for indoor applications such as fit-out construction projects and maintenance work. Core indoor applications for compact crawler boom lifts are fairly well-established, such as use in atriums, gymnasiums, arenas, auditoriums, airports, hotels, convention centers, schools and universities, as well as city, state, federal and military facilities. Use in warehouses and data centers is increasing. Primary outdoor applications for spider lifts include window washing, painting, hanging decor, performing maintenance tasks and installing utilities that require crews to bring tools and materials to hard-to-access spaces. Utility installs include plumbing, HVAC systems and electrical.
Projects in congested urban and city centers have also increased demand for these machines. Crews increasingly need the agility of compact crawler boom lifts to complete work in these tight, hard-to-access areas. Steel erection professionals use these highly maneuverable boom lifts for work between steel joists and X-beams. These are typically only a few feet apart, presenting small, challenging spaces for equipment operators. Compact crawler boom lifts allow ironworkers to navigate tight spaces on the ground and at height. Vegetation management, such as tree trimming and arborist tasks, is becoming a more popular use for these machines.
To Rent or Buy a Spider Lift?
The decision to rent or buy is the same as with other equipment. It depends on such factors as utilization rate and whether a new piece of equipment opens up new business opportunities. Rental options are the same as for other machines, too. Many rental yards offer spider lifts, and lift dealers usually have rental services including rent-to-own or lease-purchase agreements. All of these options vary by market. Your best source of information may well be other contractors.
Richard Ries is a freelance writer for Compact Equipment.
MEWP: What Does It Stand For?
Mobile elevating work platform, or MEWP, does a nice job of capturing what these machine are and what they do. While there are several styles of MEWPs, they have four traits in common. They must exhibit all four traits and must be mobile, elevating, designed for work and have a platform. By clearly defining what a MEWP is, the acronym clearly defines what it is not and thereby excludes other apparatuses such as telehandlers, forklifts, cranes, scaffolding, rope access and bosun’s chairs, ladders and catwalks. And while we’re discussing nomenclature, MEWP OEMs continue to use the term “outriggers” while other segments of the construction industry, notably compact equipment and backhoe loaders, have moved to “stabilizers.” Different name; same function.
